Feature Papers in Journal of Composites Science in 2022

A special issue of Journal of Composites Science (ISSN 2504-477X).

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 163854

Special Issue Editor


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Guest Editor
Department of Innovation Engineering, University of Salento, 73100 Lecce, Italy
Interests: theory of shells, plates, arches, and beams; generalized differential quadrature; FEM; SFEM; WFEM; IGA; SFIGA; WFIGA; advanced composite materials; functionally graded materials; nanomaterials and nanotechnology
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Special Issue Information

Dear Colleagues,

As Editor-in-Chief of the Journal of Composites Science, I am pleased to announce this Special Issue, entitled “Feature Papers in Journal of Composites Science in 2022”. This Special Issue will be a collection of articles from Editorial Board Members, Guest Editors, and Leading Researchers discussing new knowledge or new cutting-edge developments in the science of composites in 2022. Potential topics include but are not limited to the following items:

  • Fiber-reinforced composites;
  • Novel composites;
  • Nanocomposites;
  • Biomedical composites;
  • Energy composites;
  • Modeling, nondestructive evaluation;
  • Processing and manufacturing, properties and performance;
  • Repair, testing, nanotechnology;
  • Physics, chemistry, and mechanics characterization of composites.

Dr. Francesco Tornabene
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Journal of Composites Science is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (62 papers)

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17 pages, 2335 KiB  
Article
Static and Dynamic Analysis of Linear Piezoelectric Structures Using Higher Order Shear Deformation Theories
by Konstantinos I. Ntaflos, Konstantinos G. Beltsios and Evangelos P. Hadjigeorgiou
J. Compos. Sci. 2023, 7(2), 87; https://doi.org/10.3390/jcs7020087 - 17 Feb 2023
Cited by 1 | Viewed by 1514
Abstract
This paper explores the effects of shear deformation on piezoelectric materials and structures that often serve as substrate layers of multilayer composite sensors and actuators. Based on higher-order shear elastic deformation and electric potential distribution theories, a general mathematical model is derived. Governing [...] Read more.
This paper explores the effects of shear deformation on piezoelectric materials and structures that often serve as substrate layers of multilayer composite sensors and actuators. Based on higher-order shear elastic deformation and electric potential distribution theories, a general mathematical model is derived. Governing equations and the associated boundary conditions for a piezoelectric beam are developed using a generalized Hamilton’s principle. The static and dynamic behavior of the piezoelectric structure is investigated. A bending problem in static analysis and a free vibration problem in dynamic analysis are solved. The obtained results are in very good agreement with the results of the exact two dimensional solution available in the literature. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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11 pages, 478 KiB  
Article
Evaluation of Some Composite Paint Coatings’ Appearance Quality Using Fractal Dimension
by Valentina Loganina, Roman Fediuk, Valery Lesovik, Mugahed Amran, Diyar N. Qader, Olga Litvinets, Viktoria Okhotkina, Raizal S. M. Rashid, Maksim Lomov and Irina Moskovaya
J. Compos. Sci. 2023, 7(1), 9; https://doi.org/10.3390/jcs7010009 - 3 Jan 2023
Cited by 3 | Viewed by 1373
Abstract
Composite materials are characterized by multiple layers, which leads to a complexity in the design in order to ensure the effective operation of the constituent elements. This article provides information on the use of fractal dimension in assessing the quality of the appearance [...] Read more.
Composite materials are characterized by multiple layers, which leads to a complexity in the design in order to ensure the effective operation of the constituent elements. This article provides information on the use of fractal dimension in assessing the quality of the appearance of paint coatings. The scientific originality of the article lies in the establishment of a correlation between the surface roughness of coatings, the quality grade of their appearance and fractal dimension. As a result, a model of the length of the coating surface profile, with the fractal dimension D, was proposed. The practical significance lies in the proposal to evaluate the quality of the surface of paint and varnish coatings in terms of fractal dimension. An increase in the surface roughness of the coating, a decrease in the appearance quality grade and an increase in the fractal dimension have been observed. Numerical values of the index of the fractal dimension of the coating surface profile, which depended on the porosity of the substrate, have been obtained. The influence of the filling of the paint composition on the quality of the appearance of the coatings has been estimated. It has been revealed that there was an increase in the surface tension of the paint composition, a decrease in the quality of the appearance of the resulting coating and an increase in the roughness and fractal dimension of the coating surface. The influence of the method of applying the paint composition and the preparation of the base surface on the quality of the appearance of the coatings are considered. The results obtained can be applied in various types of production to improve the quality of paint coatings. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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15 pages, 5558 KiB  
Article
Thermomechanical and Pre-Ignition Properties of Multicomponent Poly(Vnylidene Fluoride)/Aluminum Oxide/Single-Walled Carbon Nanotube Hybrid Nanocomposites
by Ruchinda Gooneratne and Jude O. Iroh
J. Compos. Sci. 2022, 6(12), 380; https://doi.org/10.3390/jcs6120380 - 12 Dec 2022
Cited by 2 | Viewed by 1316
Abstract
Poly(vinylidene fluoride), PVDF is a piezoelectric semi-crystalline fluoroplastic that is widely used in the electronics and semiconductor industry for packaging, sensors, and actuators. PVDF nanocomposites containing single-walled carbon nanotubes, SWCNTs and fumed alumina, Al2O3 were prepared in dimethylformamide, and their [...] Read more.
Poly(vinylidene fluoride), PVDF is a piezoelectric semi-crystalline fluoroplastic that is widely used in the electronics and semiconductor industry for packaging, sensors, and actuators. PVDF nanocomposites containing single-walled carbon nanotubes, SWCNTs and fumed alumina, Al2O3 were prepared in dimethylformamide, and their thermal and dynamic mechanical properties were determined by using thermogravimetric analysis, TGA, differential scanning calorimetry, DSC and dynamic mechanical analysis, DMA. It was observed from differential scanning calorimetry that the matrix’s degree of crystallinity and enthalpy of melting was reduced in the presence of the nanofillers to about 7.1%, compared to the neat PVDF whose degree of crystallinity was determined to be about 51.3%. The melting temperature, Tm obtained by DSC measurements was also reduced from 171.6 °C to 162.7 °C at high SWCNT loadings. The onset degradation temperature was also lowered in the presence of the nanofillers, especially alumina particulates. Dynamic mechanical analysis of the composites showed a significant improvement in the storage modulus of about 18 GPa in the presence of SWCNT. The glass transition temperature, Tg was significantly increased from −42.6 °C to −33.2 °C due to reinforcement with SWCNT. The reinforcement of PVDF with SWCNT and alumina resulted in greater char retention at 600 °C. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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18 pages, 4124 KiB  
Article
Numerical Model for a Geometrically Nonlinear Analysis of Beams with Composite Cross-Sections
by Damjan Banić, Goran Turkalj, Sandra Kvaternik Simonetti and Domagoj Lanc
J. Compos. Sci. 2022, 6(12), 377; https://doi.org/10.3390/jcs6120377 - 7 Dec 2022
Viewed by 1566
Abstract
This paper presents a beam model for a geometrically nonlinear stability analysis of the composite beam-type structures. Each wall of the cross-section can be modeled with a different material. The nonlinear incremental procedure is based on an updated Lagrangian formulation where in each [...] Read more.
This paper presents a beam model for a geometrically nonlinear stability analysis of the composite beam-type structures. Each wall of the cross-section can be modeled with a different material. The nonlinear incremental procedure is based on an updated Lagrangian formulation where in each increment, the equilibrium equations are derived from the virtual work principle. The beam model accounts for the restrained warping and large rotation effects by including the nonlinear displacement field of the composite cross-section. First-order shear deformation theories for torsion and bending are included in the model through Timoshenko’s bending theory and a modified Vlasov’s torsion theory. The shear deformation coupling effects are included in the model using the six shear correction factors. The accuracy and reliability of the proposed numerical model are verified through a comparison of the shear-rigid and shear-deformable beam models in buckling problems. The obtained results indicated the importance of including the shear deformation effects at shorter beams and columns in which the difference that occurs is more than 10 percent. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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7 pages, 376 KiB  
Article
Comparison of Coronal Discoloration Induced by White MTA and CEM Cement
by Mamak Adel, Sareh Aflaki, Mohammad Jafar Eghbal, Alireza Darvish, Amanda Mandana Golshiri, Nima Moradi Majd, Rodolfo Reda, Maryam Tofangchiha, Alessio Zanza and Luca Testarelli
J. Compos. Sci. 2022, 6(12), 371; https://doi.org/10.3390/jcs6120371 - 5 Dec 2022
Viewed by 1419
Abstract
Coronal discoloration of endodontically treated teeth is a challenge in clinical dentistry. This study aimed to compare coronal discoloration induced by White Mineral Trioxide Aggregate and Calcium-enriched mixture cement. Fifty single-rooted, unrestored premolar teeth extracted for orthodontic reasons were selected. After access cavity [...] Read more.
Coronal discoloration of endodontically treated teeth is a challenge in clinical dentistry. This study aimed to compare coronal discoloration induced by White Mineral Trioxide Aggregate and Calcium-enriched mixture cement. Fifty single-rooted, unrestored premolar teeth extracted for orthodontic reasons were selected. After access cavity preparation, all the root canals were instrumented with MTWO rotary files up to #40.6%. The specimens were randomly assigned to two experimental groups, White Mineral Trioxide Aggregate and Calcium-enriched mixture cement groups (n = 20), and two control groups (n = 5). In the White Mineral Trioxide Aggregate and Calcium-enriched mixture cement groups, the material was condensed via the access cavity 3 mm below the cementoenamel junction to a thickness of 3 mm. Tooth color was assessed using computer analysis of digital images. Tooth color measurements were recorded at eight time intervals: before material placement (but after tooth preparation), at 24 h, 48 h, one week, two weeks, four weeks, eight weeks, and sixteen weeks after material placement. Data were analyzed using t-test, ANOVA, repeated measure ANOVA, and Tukey HSD tests. The significance level was set at 5% for all the tests. Cervical discoloration of teeth in both experimental groups significantly increased over time (p < 0.05). However, samples in the White Mineral Trioxide Aggregate group showed more discoloration in cervical regions than Calcium-enriched mixture cement specimens after two, four, eight, and sixteen weeks (p < 0.05). Applying both White Mineral Trioxide Aggregate and Calcium-enriched mixture cement induced coronal discoloration; however, White Mineral Trioxide Aggregate samples exhibited greater cervical discoloration than Calcium-enriched mixture cement specimens after two, four, eight, and sixteen weeks. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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13 pages, 6802 KiB  
Article
Improving the Anchorage in Textile Reinforced Cement Composites by 3D Spacer Connections: Experimental Study of Flexural and Cracking Behaviors
by Michael El Kadi, Danny Van Hemelrijck and Tine Tysmans
J. Compos. Sci. 2022, 6(12), 357; https://doi.org/10.3390/jcs6120357 - 23 Nov 2022
Cited by 2 | Viewed by 1292
Abstract
Textile-reinforced cement (TRC) composites can lead to significant material (and dimensional) savings compared to steel-reinforced concrete, particularly when applied in thin-walled structures such as façade panels, shells, etc. In conditions where the geometrical restrictions do not allow for sufficient anchorage, however, the exploitation [...] Read more.
Textile-reinforced cement (TRC) composites can lead to significant material (and dimensional) savings compared to steel-reinforced concrete, particularly when applied in thin-walled structures such as façade panels, shells, etc. In conditions where the geometrical restrictions do not allow for sufficient anchorage, however, the exploitation of this reinforcement may be suboptimal and the TRC’s mechanical properties may decrease. As shown in the literature, the use of 3D textile reinforcement can lead to an improved anchorage in the reinforcement points and superior post-cracking behavior in terms of bending. The question remains as to whether similar improvements can be achieved using 3D spacer connections, inserted post-manufacturing of the textiles. Therefore, this research experimentally investigated the effect of discretely inserted spacer connections on the flexural properties and cracking behavior of TRCs. Six different TRC beam configurations—varying in the placement of the spacer connections over the span—were investigated. Moreover, a comparison was made with two additional configurations: one equivalent 2D TRC system (using the same in-plane textiles but without through-thickness connections) and one 3D TRC system using knitted 3D textiles (with spacer yarns uniformly distributed). The four-point bending tests were monitored via digital image correlation (DIC) to visualize the full-field cracking pattern. The experimental results showed that the spacer connections could strongly improve the post-cracking bending stiffness and the modulus of rupture (MOR) when placed close to the free end of the sample and could also lead to reduced crack widths when placed around the midspan. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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15 pages, 3967 KiB  
Article
Aminated Graphene Nanomesh: Theoretical and Experimental Insights into Process of Decorating, Topology and Electron Properties
by Olga E. Glukhova, Maxim K. Rabchinskii, Svyatoslav D. Saveliev, Demid A. Kirilenko and Pavel V. Barkov
J. Compos. Sci. 2022, 6(11), 335; https://doi.org/10.3390/jcs6110335 - 4 Nov 2022
Cited by 4 | Viewed by 1504
Abstract
The physicochemical nature of the amino group NH2’s landing on the basal plane of the graphene and on the edge atoms of the graphene nanomesh was revealed. The mechanism of covalent binding between the NH2 groups and the carbon atoms [...] Read more.
The physicochemical nature of the amino group NH2’s landing on the basal plane of the graphene and on the edge atoms of the graphene nanomesh was revealed. The mechanism of covalent binding between the NH2 groups and the carbon atoms of the graphene and the GNM was discovered in silico by the SCC DFTB method. The maximum amount ratio of the amino groups to carbon atoms equaled 4.8% for GNM and 4.6% for the basal plane. The established values of the concentration and the trend of change in the work function of electrons are experimentally confirmed. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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15 pages, 2940 KiB  
Article
Defects Detection and Identification in Adhesively Bonded Joints between CFRP Laminate and Reinforced Concrete Beam Using Acousto-Ultrasonic Technique
by Cheikh A. T. Sarr, Sylvain Chataigner, Laurent Gaillet and Nathalie Godin
J. Compos. Sci. 2022, 6(11), 334; https://doi.org/10.3390/jcs6110334 - 3 Nov 2022
Viewed by 1360
Abstract
Adhesively bonded composite reinforcements have been increasingly used in civil engineering since the 1980s. They depend on the effective transfer of forces throughout the adhesive joint that may be affected by defects or damages. It is therefore necessary to provide methods to detect [...] Read more.
Adhesively bonded composite reinforcements have been increasingly used in civil engineering since the 1980s. They depend on the effective transfer of forces throughout the adhesive joint that may be affected by defects or damages. It is therefore necessary to provide methods to detect and/or identify these defects present in the bonded joints without affecting their future use. This should be carried out through nondestructive methods (NDT) and should be able to discriminate the different types of defects that may be encountered. The acousto-ultrasonic technique shows good potential to answer to this challenge, as illustrated in recent studies led on small-scale model samples. In this paper, we assess the robustness of this methodology on larger scale samples using reinforced concrete beams (RC beam), that is a mandatory step prior to on-site applications. A mono-parametric analysis allows the detection of all types of defects using a simple criterion set. For the identification, it was necessary to conduct a data-driven strategy by means of a Principal Component Analysis (PCA) and a random forest (RF) method used from extracted parameters. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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12 pages, 2180 KiB  
Article
Controlling Surface Wettability and Plasmonic Resonance of Au/ZnO Heterostructured Films
by Sheng-Chiang Chen and Da-Hua Wei
J. Compos. Sci. 2022, 6(11), 328; https://doi.org/10.3390/jcs6110328 - 2 Nov 2022
Cited by 1 | Viewed by 1574
Abstract
This work investigated the (0002) textured ZnO films without and with the addition of an Au continuous top layer and its effects on their surface wettability and plasmonic resonance characteristics. The ZnO films were directly fabricated onto glass substrates at the synthesized temperature [...] Read more.
This work investigated the (0002) textured ZnO films without and with the addition of an Au continuous top layer and its effects on their surface wettability and plasmonic resonance characteristics. The ZnO films were directly fabricated onto glass substrates at the synthesized temperature of 300 °C via a plasma-enhanced chemical vapor deposition (PECVD) system, and the as-synthesized ZnO film exhibited an average optical transmittance value of 85%. The ultraviolet (UV) light irradiation can be applied to enhance the hydrophilicity, changing it from a hydrophobic status to hydrophilic status due to the existing and adjustable characteristics of the photocatalytic activity. On the other hand, the surface wetting/contact angle (CA) value of the ZnO film with a controllable surface wettability switched from 94° (hydrophobicity) to 44° (hydrophilicity), after it was exposed to UV light irradiation for 5 min, and stably reversed back to hydrophobicity (92°) via a post-annealed treatment using rapid thermal annealing (RTA) at 350 °C for 5 min in air. A fast, simple, and reversible method for switching between hydrophilic and hydrophobic status is claimed in this present work. The improved surface plasmonic resonance is owning to the coupled electron and photon oscillations that can be obtained and produced at the interface between the flat Au layer and ZnO (metal/metallic oxide) heterostructured films for future applications of various wide-bandgap compound semiconductors. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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21 pages, 6283 KiB  
Article
A Data Driven Modelling Approach for the Strain Rate Dependent 3D Shear Deformation and Failure of Thermoplastic Fibre Reinforced Composites: Experimental Characterisation and Deriving Modelling Parameters
by Johannes Gerritzen, Andreas Hornig, Benjamin Gröger and Maik Gude
J. Compos. Sci. 2022, 6(10), 318; https://doi.org/10.3390/jcs6100318 - 17 Oct 2022
Cited by 2 | Viewed by 1495
Abstract
The 3D shear deformation and failure behaviour of a glass fibre reinforced polypropylene in a shear strain rate range of γ˙=2.2×104 to 3.4 1s is investigated. An Iosipescu testing setup on a [...] Read more.
The 3D shear deformation and failure behaviour of a glass fibre reinforced polypropylene in a shear strain rate range of γ˙=2.2×104 to 3.4 1s is investigated. An Iosipescu testing setup on a servo-hydraulic high speed testing unit is used to experimentally characterise the in-plane and out-of-plane behaviour utilising three specimen configurations (12-, 13- and 31-direction). The experimental procedure as well as the testing results are presented and discussed. The measured shear stress–shear strain relations indicate a highly nonlinear behaviour and a distinct rate dependency. Two methods are investigated to derive according material characteristics: a classical engineering approach based on moduli and strengths and a data driven approach based on the curve progression. In all cases a Johnson–Cook based formulation is used to describe rate dependency. The analysis methodologies as well as the derived model parameters are described and discussed in detail. It is shown that a phenomenologically enhanced regression can be used to obtain material characteristics for a generalising constitutive model based on the data driven approach. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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10 pages, 5212 KiB  
Article
Simplified Modelling of Failure in High Strength Bolts under Combined Tension and Bending
by Francesco Plaitano, Aurel Stratan and Elide Nastri
J. Compos. Sci. 2022, 6(10), 302; https://doi.org/10.3390/jcs6100302 - 11 Oct 2022
Cited by 3 | Viewed by 3369
Abstract
Bolted connections are widely adopted in steel structures and their behaviour affects to a large extent the global response of the system. High-strength bolts of type HV are commonly employed. Under pure tension, these bolt assemblies usually fail by thread stripping. However, it [...] Read more.
Bolted connections are widely adopted in steel structures and their behaviour affects to a large extent the global response of the system. High-strength bolts of type HV are commonly employed. Under pure tension, these bolt assemblies usually fail by thread stripping. However, it was observed experimentally that, under combined tension and bending, the failure mode changes to fracture of the shank. The former loading condition commonly occurs in the case of thick extended end plate connections and the latter in the case of flush end plates. In order to analyse the behaviour of the structure, the finite element method (FEM) is usually employed. While there is a wealth of information on FEM modelling of bolts for standard loading conditions (e.g., tension), the authors are unaware of a model able to replicate both tension-only and combined tension and bending conditions. In this paper, a simplified approach to be used in the framework of FEM is proposed to model the behaviour of high-strength HV bolts which can replicate the failure mechanism of bolts under tension only and combined tension and bending. The bolt assembly is modelled with continuum elements, supplemented by a non-linear spring connecting the nut to the bolt shank. The spring captures the stiffness, resistance, and ductility of the bolt-to-nut threaded connection, reproducing the experimentally observed failure mode in the case of pure tension conditions. A simplified damage model is applied to the continuum finite elements used to model the bolt, which replicates shank failure under combined tension and bending as a result of large local stresses and strains occurring under these conditions. The proposed model captures with good accuracy the actual behaviour of high-strength HV bolts under tension only as well as under combined tension and bending. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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19 pages, 5093 KiB  
Article
Influence of Hybrid Basalt Fibres’ Length on Fresh and Mechanical Properties of Self-Compacted Ambient-Cured Geopolymer Concrete
by Mohamed Heweidak, Bidur Kafle and Riyadh Al-Ameri
J. Compos. Sci. 2022, 6(10), 292; https://doi.org/10.3390/jcs6100292 - 4 Oct 2022
Cited by 7 | Viewed by 1504
Abstract
Recently, short basalt fibres (BFs) have been gaining considerable attention in the building materials industry because of their excellent mechanical properties and lower production cost than their counterparts. Reinforcing geopolymer composites with small volumes of fibres has been proven an efficient technique to [...] Read more.
Recently, short basalt fibres (BFs) have been gaining considerable attention in the building materials industry because of their excellent mechanical properties and lower production cost than their counterparts. Reinforcing geopolymer composites with small volumes of fibres has been proven an efficient technique to enhance concrete’s mechanical properties and durability. However, to date, no study has investigated the effect of basalt fibers’ various lengths and volume content on self-compacted geopolymer concrete’s fresh and mechanical properties (SCGC). SCGC is prepared by mixing fly ash, slag, and micro fly ash as the binder with a solid alkali-activator compound named anhydrous sodium metasilicate (Na₂SiO₃). In the present study, a hybrid length of long and short basalt fibres with different weight contents were investigated to reap the benefits of multi-scale characteristics of a single fibre type. A total of 10 mixtures were developed incorporating a single length and a hybrid mix of long (30) mm and short (12) mm basalt fibres, with a weight of 1%, 1.5% and 2% of the total binder content, respectively. The fresh and mechanical properties of SCGC incorporating a hybrid mix of long and short basalt fibres were compared to plain SCGC and SCGC containing a single fibres length. The results indicate that the hybridization of long and short fibres in SCGC mixture yields better mechanical properties than single-length BF-reinforced SCGC. A hybrid fibre coefficient equation will be validated against the mechanical properties results obtained from the current experimental investigation on SCGC to assess its applicability for different concrete mixes. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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12 pages, 2272 KiB  
Article
Preparation of Nanochitin from Crickets and Comparison with That from Crab Shells
by Kana Kishida, Toshifumi Mizuta, Hironori Izawa and Shinsuke Ifuku
J. Compos. Sci. 2022, 6(10), 280; https://doi.org/10.3390/jcs6100280 - 23 Sep 2022
Cited by 1 | Viewed by 1817
Abstract
Crickets are gaining worldwide attention as a nutrient source with a low environmental impact. We considered crickets as a new source of chitin raw material. Chitin isolated from crickets was successfully converted to nanochitin by pulverization. First, chitin was obtained from cricket powder [...] Read more.
Crickets are gaining worldwide attention as a nutrient source with a low environmental impact. We considered crickets as a new source of chitin raw material. Chitin isolated from crickets was successfully converted to nanochitin by pulverization. First, chitin was obtained from cricket powder in a 2.6% yield through a series of chemical treatments. Chitin identification was confirmed by FT-IR and 13C NMR. The chitin had an α-type crystal structure and a deacetylation degree of 12%. Next, it was pulverized in a disk mill to obtain nanochitin. Cricket nanochitin was of a whisker shape, with an average fiber width of 10.1 nm. It was larger than that of crab shells, while the hydrodynamic diameter and crystal size were smaller. Such differences in shape affected the physical properties of the dispersion. The transmittance was higher than that of crab nanochitin due to the size effect, and the viscosity was smaller. Moreover, the dry non-woven cricket nanochitin sheets were more densely packed, and their modulus and breaking strength were greater. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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47 pages, 5931 KiB  
Article
Industry 4.0 Implementation Framework for the Composite Manufacturing Industry
by Miroslav Stojkovic and Javaid Butt
J. Compos. Sci. 2022, 6(9), 258; https://doi.org/10.3390/jcs6090258 - 6 Sep 2022
Cited by 3 | Viewed by 6632
Abstract
This paper aims to propose an Industry 4.0 implementation model relevant to the composite manufacturing industry and offer it to academia and manufacturing practice in order to aid successful change and adoption. The research scope is defined at an intersection of challenges within [...] Read more.
This paper aims to propose an Industry 4.0 implementation model relevant to the composite manufacturing industry and offer it to academia and manufacturing practice in order to aid successful change and adoption. The research scope is defined at an intersection of challenges within the composites industry, as well as Industry 4.0. A critical review of relevant papers was used to establish key trends and gaps in professional practice. Exposed challenges and opportunities were then synthesized to propose a conceptual framework for implementing Industry 4.0. Findings suggest that the predicted growth of the composites sector depends on the paradigm shift in manufacturing. Industry 4.0, including automation, and horizontally and vertically integrated business models are seen as enablers. However, the value proposition or organizational resistance in establishing such integration is not sufficiently addressed or understood by the industry. Achieving a successful design for manufacturing (DFM), or, more generally, design for excellence (DFX), is identified as the target performance objectives and key business process enablers used to introduce Industry 4.0 technology. The identified key gap in professional practice indicate the lack of a model used for structuring and implementing Industry 4.0 technology into composite businesses. The existence of an identified gap, evidenced by the lack of literature and available knowledge, reinforces the need for further research. To enable further research, and to facilitate the introduction of Industry 4.0 in composite manufacturing firms, a conceptual implementation framework based on the systems engineering V model is proposed. The paper concludes with topics for further investigation. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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14 pages, 4051 KiB  
Article
Anhydrous Proton Conductivity in HAp-Collagen Composite
by Tomoki Furuseki and Yasumitsu Matsuo
J. Compos. Sci. 2022, 6(8), 236; https://doi.org/10.3390/jcs6080236 - 10 Aug 2022
Cited by 2 | Viewed by 1777
Abstract
It is well known that a proton conductor is needed as an electrolyte of hydrogen fuel cells, which are attracting attention as an environmentally friendly next-generation device. In particular, anhydrous proton-conducting electrolytes are highly desired because of their advantages, such as high catalytic [...] Read more.
It is well known that a proton conductor is needed as an electrolyte of hydrogen fuel cells, which are attracting attention as an environmentally friendly next-generation device. In particular, anhydrous proton-conducting electrolytes are highly desired because of their advantages, such as high catalytic efficiency and the ability to operate at high temperatures, which will lead to the further development of fuel cells. In this study, we have investigated the proton-conducting properties of the hydroxyapatite (HAp)-collagen composite without external humidification conditions. It was found that, by injecting HAp into collagen, the electrical conductivity becomes higher than that of the HAp or the collagen. Moreover, the motional narrowing of the proton NMR line is observed above 130 °C. These results indicate that the electrical conductivity observed in the HAp-collagen composite is caused by mobile protons. Furthermore, we measured the proton conduction of HAp-collagen composite films with different HAp contents and investigated the necessity of the appearance of proton conductivity in HAp-collagen composites. HAp content (n = 0–0.38) is the number of HAp per collagen peptide representing Gly-Pro-Hyp. These results indicate that injection of HAp into collagen decreases the activation energy of proton conduction which becomes almost constant above a HAp content n of 0.3. It is deduced that the proton-conduction pathway in the HAp-collagen composite is fully formed above n = 0.3. Furthermore, these results indicate that the value of the activation energy of proton conductivity was lowered, accompanied by the formation of the HAp-collagen composite, and saturated at n > 0.3. From these results, the HAp-collagen composite forms the proton-conduction pathway n > 0.3 and becomes the proton conductor with no external humidification in the condition of n > 0.3 above 130 °C. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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16 pages, 1919 KiB  
Article
Electrically Conductive Biocomposites Based on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Wood-Derived Carbon Fillers
by Christoph Unterweger, Matija Ranzinger, Jiri Duchoslav, Francesco Piana, Igor Pasti, Franz Zeppetzauer, Stefan Breitenbach, David Stifter and Christian Fürst
J. Compos. Sci. 2022, 6(8), 228; https://doi.org/10.3390/jcs6080228 - 4 Aug 2022
Cited by 2 | Viewed by 1552
Abstract
In this paper, biobased carbons were used as fillers in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The mechanical and electrical properties of these 100% biocomposites were analyzed. First, biocarbons were prepared from wood dust and cellulose fibers using carbonization temperatures ranging 900–2300 °C. XRD revealed significant improvements [...] Read more.
In this paper, biobased carbons were used as fillers in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The mechanical and electrical properties of these 100% biocomposites were analyzed. First, biocarbons were prepared from wood dust and cellulose fibers using carbonization temperatures ranging 900–2300 °C. XRD revealed significant improvements of the graphitic structure with increasing temperatures for both precursors, with slightly higher ordering in wood-dust-based carbons. An increase of the carbon content with continuous removal of other elements was observed with increasing temperature. The carbonized cellulose fiber showed an accumulation of Na and O on the fiber surface at a carbonization temperature of 1500 °C. Significant degradation of PHBV was observed when mixed with this specific filler, which can, most probably, be attributed to this exceptional surface chemistry. With any other fillers, the preparation of injection-molded PHBV composites was possible without any difficulties. Small improvements in the mechanical performance were observed, with carbonized fibers being slightly superior to the wood dust analogues. Improvements at higher filler content were observed. These effects were even more pronounced in the electrical conductivity. In the range of 15–20 vol.% carbonized fibers, the percolation threshold could be reached, resulting in an electrical conductivity of 0.7 S/cm. For comparison, polypropylene composites were prepared using cellulose fibers carbonized at 2000 °C. Due to longer fibers retained in the composites, percolation could be reached in the range of 5–10 vol.%. The electrical conductivity was even higher compared to that of composites using commercial carbon fibers, showing a great potential for carbonized cellulose fibers in electrical applications. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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15 pages, 4457 KiB  
Article
Characterization of Caseinate–Carboxymethyl Chitosan-Based Edible Films Formulated with and without Transglutaminase Enzyme
by Amal Mohamed and Hosahalli S. Ramaswamy
J. Compos. Sci. 2022, 6(7), 216; https://doi.org/10.3390/jcs6070216 - 21 Jul 2022
Cited by 7 | Viewed by 1765
Abstract
Edible composite packaging has the advantage of complementary functional properties over its individual bio-components. However, film composites made from caseinate (CA) and carboxymethyl chitosan (CMCH) have not yet been well explored. In this study, four types of CA-CMCH composite films were prepared and [...] Read more.
Edible composite packaging has the advantage of complementary functional properties over its individual bio-components. However, film composites made from caseinate (CA) and carboxymethyl chitosan (CMCH) have not yet been well explored. In this study, four types of CA-CMCH composite films were prepared and evaluated with and without transglutaminase (TGase) supplement. Aqueous CA (8%, w/v) and CMCH solutions (2%, w/v) were mixed in different volume ratios of CA: CMCH as 100:0, 75:25, 50:50, 75:25, and 25:75. Those to be supplemented with TGase were incorporated at 10 U/g of caseinate protein level. Results revealed that CMCH incorporation to CA facilitated a smooth and uniform surface microstructure on films and markedly improved the transparency, water barrier properties, mechanical properties, and solubility of the composite film. Furthermore, addition of TGase resulted in an improvement in the water vapor permeability. TGase successfully enforced the formation of CA-CMCH composites with some enhanced functional properties. The resulting composite film offers potential for applications as an alternative edible film or in the preparation of edible packaging films. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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10 pages, 1307 KiB  
Article
Exploring the High Frequencies AC Conductivity Response in Disordered Materials by Using the Damped Harmonic Oscillator
by Christos Tsonos
J. Compos. Sci. 2022, 6(7), 200; https://doi.org/10.3390/jcs6070200 - 8 Jul 2022
Viewed by 1861
Abstract
The AC conductivity response of disordered materials follows a universal power law of the form σ(ω)ωn at the low frequency regime, with the power exponent values in the range 0 < n < 1. At the [...] Read more.
The AC conductivity response of disordered materials follows a universal power law of the form σ(ω)ωn at the low frequency regime, with the power exponent values in the range 0 < n < 1. At the high frequency regime, in many experimental data of different disordered materials, superlinear values of the power exponent n were observed. The observed superlinear values of the power exponent are usually within 1<n<2, but in some cases values n>2 were detected. The present work is based on the definitions of electromagnetic theory as well as the Havriliak–Negami equation and the damped harmonic oscillator equation, which are widely used for the description of dielectric relaxation mechanisms and vibration modes in the THz frequency region, respectively. This work focuses mainly on investigating the parameters that affect the power exponent and the range of possible n values. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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16 pages, 34983 KiB  
Article
A Quantitative Investigation of Dislocation Density in an Al Matrix Composite Produced by a Combination of Micro-/Macro-Rolling
by Behzad Sadeghi, Ali Shabani, Ali Heidarinejad, Aleksandra Laska, Marek Szkodo and Pasquale Cavaliere
J. Compos. Sci. 2022, 6(7), 199; https://doi.org/10.3390/jcs6070199 - 7 Jul 2022
Cited by 8 | Viewed by 1933
Abstract
An aluminum matrix composite with dispersed carbon nanotubes (CNTs) was produced via flake powder metallurgy using a micro-rolling process and vacuum hot pressing (VHP), followed by conventional rolling using a macro-rolling process. The microstructure and mechanical properties of the produced composites were studied. [...] Read more.
An aluminum matrix composite with dispersed carbon nanotubes (CNTs) was produced via flake powder metallurgy using a micro-rolling process and vacuum hot pressing (VHP), followed by conventional rolling using a macro-rolling process. The microstructure and mechanical properties of the produced composites were studied. In addition, a new quantitative model was introduced to study the dislocation density based on the microstructural parameters. The results revealed that the distribution characteristics of the CNTs in the Al matrix and the Al-CNT interfaces were the two main governing parameters of dislocation density. Moreover, the dependence of dislocation density on the geometry of the grains and crystallographic texture was shown in this model. The microstructural evolution revealed that a lamellar grain structure had been achieved, with a high capacity for the storage of dislocation. A uniform distribution of CNTs with high bonding quality was also seen in the final microstructure. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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16 pages, 3551 KiB  
Article
Titanium Dioxide/Polysiloxane Composites: Preparation, Characterization and Study of Their Color Stability Using Thermochromic Pigments
by Evangelia Papachristou, Dimitrios Korres, Diomi Mamma, Dimitris Kekos, Petroula A. Tarantili and Gregory Polyzois
J. Compos. Sci. 2022, 6(7), 195; https://doi.org/10.3390/jcs6070195 - 2 Jul 2022
Cited by 2 | Viewed by 1890
Abstract
In order to improve thermomechanical, antibacterial and temperature-controlled color-response performance of polydimethylsiloxane (PDMS) in maxillofacial prostheses, the incorporation of titania (TiO2) nanoparticles and thermochromic pigments (TCP) into PDMS was examined. The thermal transitions of TiO2/PDMS nanocomposites, investigated by differential [...] Read more.
In order to improve thermomechanical, antibacterial and temperature-controlled color-response performance of polydimethylsiloxane (PDMS) in maxillofacial prostheses, the incorporation of titania (TiO2) nanoparticles and thermochromic pigments (TCP) into PDMS was examined. The thermal transitions of TiO2/PDMS nanocomposites, investigated by differential scanning calorimetry (DSC), remain almost unaffected, while an increase of the crystallinity of PDMS was recorded in specimens with higher titania concentrations. The incorporation of titania improves the thermal stability, as it was revealed by thermogravimetric analysis (TGA), as well as the tensile properties of the reinforced elastomer. Nanocomposites with 10 wt% titania presented antibacterial activity against Escherichia Coli, leading to 72% reduction of the bacterial colony after 3 h of exposure. Specimens colored with red TCP (0.2 and 0.6 wt%) showed significant color change at a lower temperature (−20 °C) in comparison with that at an ambient temperature, especially at lower TCP concentration (0.2 wt%). Accelerating aging experiments, consisting of repeated cycles of combined exposure to UV-radiation and damp heating, of PDMS colored with TCP showed poor color stability of the specimens, from the first hours of exposure. The addition of titania to polysiloxane specimens works as an opacifier providing a positive effect on the color stability of the examined thermochromic pigment. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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18 pages, 8218 KiB  
Article
Adhesion and Proliferation of Mesenchymal Stem Cells on Plasma-Coated Biodegradable Nanofibers
by Anton M. Manakhov, Anastasiya O. Solovieva, Elizaveta S. Permyakova, Natalya A. Sitnikova, Lyubov S. Klyushova, Philipp V. Kiryukhantsev-Korneev, Anton S. Konopatsky and Dmitry V. Shtansky
J. Compos. Sci. 2022, 6(7), 193; https://doi.org/10.3390/jcs6070193 - 1 Jul 2022
Cited by 4 | Viewed by 1672
Abstract
Various biomedical applications of biodegradable nanofibers are a hot topic, as evidenced by the ever-increasing number of publications in this field. However, as-prepared nanofibers suffer from poor cell adhesion, so their surface is often modified. In this work, active polymeric surface layers with [...] Read more.
Various biomedical applications of biodegradable nanofibers are a hot topic, as evidenced by the ever-increasing number of publications in this field. However, as-prepared nanofibers suffer from poor cell adhesion, so their surface is often modified. In this work, active polymeric surface layers with different densities of COOH groups from 5.1 to 14.4% were successfully prepared by Ar/CO2/C2H4 plasma polymerization. It has been shown that adhesion and proliferation of mesenchymal stem cells (MSCs) seeded onto plasma-modified PCL nanofibers are controlled by the CO2:C2H4 ratio. At a high CO2:C2H4 ratio, a well-defined network of actin microfilaments is observed in the MSCs. Nanofibers produced at a low CO2:C2H4 ratio showed poor cell adhesion and very poor survival. There were significantly fewer cells on the surface, they had a small spreading area, a poorly developed network of actin filaments, and there were almost no stress fibrils. The maximum percentage of proliferating cells was recorded at a CO2:C2H4 ratio of 35:15 compared with gaseous environments of 25:20 and 20:25 (24.1 ± 1.5; 8.4 ± 0.9, and 4.1 ± 0.4%, respectively). Interestingly, no differences were observed between the number of cells on the untreated surface and the plasma-polymerized surface at CO2:C2H4 = 20:25 (4.9 ± 0.6 and 4.1 ± 0.4, respectively). Thus, Ar/CO2/C2H4 plasma polymerization can be an excellent tool for regulating the viability of MSCs by simply adjusting the CO2:C2H4 ratio. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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17 pages, 4522 KiB  
Article
Influence of Sensor Position and Low-Frequency Modal Shape on the Sensitivity of Vibro-Acoustic Modulation for Impact Damage Detection in Composite Materials
by Gabriela Loi, Francesco Aymerich and Maria Cristina Porcu
J. Compos. Sci. 2022, 6(7), 190; https://doi.org/10.3390/jcs6070190 - 30 Jun 2022
Cited by 2 | Viewed by 1689
Abstract
Very sensitive structural health monitoring methods are needed to detect barely visible impact damage in composite materials. Based on extracting non-linear modulated components from the frequency response of the damaged system, vibro-acoustic modulation (VAM) has shown to be effective in identifying the presence [...] Read more.
Very sensitive structural health monitoring methods are needed to detect barely visible impact damage in composite materials. Based on extracting non-linear modulated components from the frequency response of the damaged system, vibro-acoustic modulation (VAM) has shown to be effective in identifying the presence of damage at its early stage. A decisive role in the success of this technique is played by the choice of the high-frequency probe and the low-frequency pump sinusoidal signals that simultaneously excites the system. This study explores how the position of the sensing transducer, with respect to the modal shape of the pump excitation, may influence the sensitivity of the VAM technique for impact damage detection in composite laminates. This aspect has been scarcely investigated in previous research works, as other studies have focused more on the role of the probe frequency. Here, VAM tests were performed on a composite beam by using a frequency-swept pump vibration simultaneously with a high frequency probe excitation. The results of the experimental tests indicate that the VAM technique is capable of clearly revealing the presence of impact damage only when the sensor is placed on appropriate locations, which are directly related to the shape of the deformation activated by the applied excitation. These results suggest the adoption of low frequency excitations that activate multiple modal shapes to improve the effectiveness and reliability of VAM approaches. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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31 pages, 5860 KiB  
Article
Analysis of RC Beams under Combined Torsion and Shear Using Optimization Techniques Evaluation of NBR 6118 and AASHTO LRFD Standards
by William Obel, Bernardo Horowitz and Luís F. A. Bernardo
J. Compos. Sci. 2022, 6(6), 175; https://doi.org/10.3390/jcs6060175 - 15 Jun 2022
Viewed by 1965
Abstract
In this article, a novel calculation procedure using optimization techniques is proposed to compute the torsion–shear interaction curves for reinforced concrete (RC) beams. The calculation procedure is applied to NBR 6118 and AASHTO LRFD standards in order to evaluate their reliability. For this, [...] Read more.
In this article, a novel calculation procedure using optimization techniques is proposed to compute the torsion–shear interaction curves for reinforced concrete (RC) beams. The calculation procedure is applied to NBR 6118 and AASHTO LRFD standards in order to evaluate their reliability. For this, some experimental results found in the literature and related to RC beams tested under combined torsion and shear, as well as results from the combined-action softened truss Model (CA-STM), are used for comparison. From the obtained results, AASHTO LRFD provisions are found to –be satisfactorily accurate. The NBR 6118 provisions are found to be consistent with the experimental results when the angle of the concrete struts is assumed to be variable or equal to the lower bound value of 30°, according to model II of the standard. For an angle assumed equal to 45°, according to model I of the NBR 6118 standard, the predicted strengths are found to be excessively conservative. The results demonstrate that formulating the analysis of RC beams under combined torsion and shear as an optimization problem, as proposed in this article, constitutes an alternative and efficient option. In addition, the generality of the proposed calculation procedure allows it to be applied to any design standard to compute the torsion–shear interaction curves for RC beams. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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14 pages, 4438 KiB  
Article
Dependence of the Dynamic Mechanical Properties and Structure of Polyurethane-Clay Nanocomposites on the Weight Fraction of Clay
by Shirley Peng and Jude O. Iroh
J. Compos. Sci. 2022, 6(6), 173; https://doi.org/10.3390/jcs6060173 - 14 Jun 2022
Cited by 9 | Viewed by 1715
Abstract
The effect of clay and chemical cross-linking on the dynamic mechanical properties of polyurethane reinforced with different concentrations of organically modified montmorillonite clay is investigated in this study. The polyurethane matrix is constituted of polytetrahydrofuran soft segment and 4,4′-methylenebis(phenyl isocyanate) hard segment. Glycerin [...] Read more.
The effect of clay and chemical cross-linking on the dynamic mechanical properties of polyurethane reinforced with different concentrations of organically modified montmorillonite clay is investigated in this study. The polyurethane matrix is constituted of polytetrahydrofuran soft segment and 4,4′-methylenebis(phenyl isocyanate) hard segment. Glycerin was used as the chemical crosslinking agent, while Cloisite 30B clay was the reinforcing filler. The nanocomposites containing up to 1 wt.% clay showed a uniform dispersion of clay; however, the nanocomposites containing higher concentrations of clay showed the presence of heterogeneities. Dynamic mechanical spectroscopy, DMS revealed that the nanocomposites containing between 2 and 10 wt.% clay had two glass transition temperatures, Tg,1 and Tg,2. The higher-temperature glass transition temperature, Tg,2 increased with increasing clay concentration, while the low-temperature glass transition temperature, Tg,1 decreased with increasing clay concentration. The nanocomposites containing low clay concentrations up to 1 wt.% showed only one glass transition temperature with a narrow glass transition region. The crosslink density for the nanocomposites increased with increasing wt.% clay. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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25 pages, 4353 KiB  
Article
Investigation of Specimen Size Effects on P-Quantile Diagrams and Normal Distributions of Critical Flaw Strengths in Fiber Tows
by Jacques Lamon and Mohamed R’Mili
J. Compos. Sci. 2022, 6(6), 171; https://doi.org/10.3390/jcs6060171 - 13 Jun 2022
Cited by 2 | Viewed by 1407
Abstract
The present paper proposes a model of the specimen size effect on the critical flaw strength distribution in fiber tows for composite reinforcement. The model is based on the basic assumption of brittle fracture that the failure probability at a given strength increases [...] Read more.
The present paper proposes a model of the specimen size effect on the critical flaw strength distribution in fiber tows for composite reinforcement. The model is based on the basic assumption of brittle fracture that the failure probability at a given strength increases with specimen size in the p-quantile vs. strength relation and on the normal distribution. Empirical results derived from force–strain curves determined on tows made of 1000 and 500 Nicalon SiC filaments and with various gauge lengths show some discrepancy with predictions using the model. The empirical p-quantile diagrams and cumulative distributions of critical flaw strengths exhibited excellent reproducibility at longer gauge lengths, which suggests the absence of a size effect above a critical tow size. The reproducibility of flaw strength distributions at gauge lengths above 60 mm and the higher strengths obtained at lower gauge lengths despite structural effects were related to the features of the critical flaw distribution in tows of parallel fibers. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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11 pages, 1577 KiB  
Article
A Practical Procedure for Predicting the Remaining Fatigue Life at an Arbitrary Stress Ratio
by Ho Sung Kim
J. Compos. Sci. 2022, 6(6), 170; https://doi.org/10.3390/jcs6060170 - 11 Jun 2022
Viewed by 1570
Abstract
A practical procedure for predicting the remaining fatigue life at an arbitrary stress ratio is developed and verified. The procedure was based on the validated damage function, in conjunction with the Kim and Zhang S-N curve model. The damage function was used for [...] Read more.
A practical procedure for predicting the remaining fatigue life at an arbitrary stress ratio is developed and verified. The procedure was based on the validated damage function, in conjunction with the Kim and Zhang S-N curve model. The damage function was used for finding various iso-damage points dependent on three independent variables (i.e., stress level, number of fatigue cycles, and stress ratio). The verification was conducted using Alclad 24S-T aluminium alloy, available in the literature for fatigue loading varied under three different loading schemes. The first scheme was for two different stress ratios, the second was for three different stress ratios, and the last was for a single stress ratio as a special case. The prediction accuracies were found to be in an error range of −0.1 to 5.6%, −0.5 to −0.6, and 1.5 to 1.7% for the 1st, 2nd, and 3rd schemes, respectively. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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13 pages, 3131 KiB  
Article
Proton Generation Using Chitin–Chitinase and Collagen–Collagenase Composites
by Hitoki Semizo, Ryusei Yabu and Yasumitsu Matsuo
J. Compos. Sci. 2022, 6(6), 166; https://doi.org/10.3390/jcs6060166 - 7 Jun 2022
Cited by 1 | Viewed by 1709
Abstract
Hydrogen energy is focused on as next-generation energy without environmental load. Therefore, hydrogen production without using fossil fuels is a key factor in the progress of hydrogen energy. In the present work, it was found that chitin–chitinase and collagen–collagenase composites can generate protons [...] Read more.
Hydrogen energy is focused on as next-generation energy without environmental load. Therefore, hydrogen production without using fossil fuels is a key factor in the progress of hydrogen energy. In the present work, it was found that chitin–chitinase and collagen–collagenase composites can generate protons by the hydrolysis of the enzyme. The concentration of the generated proton in the chitin–chitinase and collagen–collagenase composites are 1.68 × 1017 cm−3 and 1.02 × 1017 cm−3, respectively. Accompanying these results, proton diffusion constants in the chitin and collagen membranes are also estimated to be 8.59 × 10−8 cm2/s and 8.69 × 10−8 cm2/s, respectively. Furthermore, we have fabricated the bio-fuel cell using these composites as hydrogen fuel and demonstrated that these composites become a fuel of the fuel cell. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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16 pages, 4424 KiB  
Article
Formation of FePt–MgO Nanocomposite Films at Reduced Temperature
by Da-Hua Wei, Sheng-Chiang Chen, Cheng-Jie Yang, Rong-Tan Huang, Chung-Li Dong and Yeong-Der Yao
J. Compos. Sci. 2022, 6(6), 158; https://doi.org/10.3390/jcs6060158 - 26 May 2022
Cited by 3 | Viewed by 1956
Abstract
The MgO nanolayer effect on the microstructure and magnetic characterizations added into Fe/Pt stacked films directly deposited onto MgO (001) single-crystal substrates at the reduced temperature of 380 °C using electron-beam technology was investigated in this present work. The nanograin isolation and exchange [...] Read more.
The MgO nanolayer effect on the microstructure and magnetic characterizations added into Fe/Pt stacked films directly deposited onto MgO (001) single-crystal substrates at the reduced temperature of 380 °C using electron-beam technology was investigated in this present work. The nanograin isolation and exchange decoupling for the FePt–MgO system is attributed to the magnetic FePt isolated grains that originate from MgO atoms with a spreading behavior mostly along grain boundaries owing to its weaker surface energy than that of a single Fe or Pt element. The grain and domain size decreased when the MgO nanolayer was applied due to the interpenetration of MgO and created a strain-energy variation at the MgO/FePt interface. Measuring angular-dependent coercivity indicates a general trend of a domain-wall motion, and changes to the rotation of the reverse-domain model occurred as the MgO nanolayers were added into FePt films. The intergrain interaction is confirmed by the Kelly–Henkel plot, which shows that there is strong intergrain exchange coupling (positive δM type) between neighboring grains in the continuous Fe/Pt stacked films without MgO nanolayers. In addition, a negative δM type occurred when the Fe/Pt stacked films were added into MgO nanolayers, showing that the MgO nanolayer can be applied to adjust the force of intergrain exchange coupling between the adjacent FePt nanograins, and the addition of MgO nanolayers change into magnetic decoupling; thus, there was a formed dipole interaction in our claimed FePt–MgO composite structure of stacked ultrathin films at a reduced temperature of 380 °C. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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11 pages, 2500 KiB  
Article
Measurement of the Heat Transfer Properties of Carbon Fabrics via Infrared Thermal Mapping
by Phillip Kearney, Constantina Lekakou and Stephen Belcher
J. Compos. Sci. 2022, 6(6), 155; https://doi.org/10.3390/jcs6060155 - 25 May 2022
Cited by 1 | Viewed by 1858
Abstract
The aim of this paper is to determine the heat transfer properties of biaxial carbon fabrics of different architectures, including non-crimp stitch bonded fabrics, plain, twill and satin woven fabrics. The specific heat capacity was determined via DSC (differential scanning calorimetry). A novel [...] Read more.
The aim of this paper is to determine the heat transfer properties of biaxial carbon fabrics of different architectures, including non-crimp stitch bonded fabrics, plain, twill and satin woven fabrics. The specific heat capacity was determined via DSC (differential scanning calorimetry). A novel method of numerical analysis of temperature maps from a video using a high-resolution thermal camera is investigated for the measurement of the in-plane and transverse thermal diffusivity and conductivity. The determined thermal conductivity parallel to the fibers of a non-crimp stitch bonded fabric agrees well with the theoretical value calculated employing the rule of mixtures. The presence of voids due to the yarn crossover regions in woven fabrics leads to a reduced value of transverse thermal conductivity, especially in the single ply measurements of this study. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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12 pages, 3397 KiB  
Article
In Vitro Electrochemical Corrosion Assessment of Magnesium Nanocomposites Reinforced with Samarium(III) Oxide and Silicon Dioxide Nanoparticles
by Moataz Abdalla, Austin Sims, Sherif Mehanny, Meysam Haghshenas, Manoj Gupta and Hamdy Ibrahim
J. Compos. Sci. 2022, 6(6), 154; https://doi.org/10.3390/jcs6060154 - 25 May 2022
Cited by 9 | Viewed by 1936
Abstract
Recent research on biodegradable magnesium-based implants has been focusing on increasing their mechanical strength and controlling their corrosion rate. One promising approach to significantly improve the mechanical properties of magnesium is the addition of nanoparticles to the magnesium matrix. However, there is limited [...] Read more.
Recent research on biodegradable magnesium-based implants has been focusing on increasing their mechanical strength and controlling their corrosion rate. One promising approach to significantly improve the mechanical properties of magnesium is the addition of nanoparticles to the magnesium matrix. However, there is limited research on the corrosion behavior of these new magnesium nanocomposites. In this study, the electrochemical corrosion characteristics of this new class of biomaterials are investigated. Two magnesium nanocomposites reinforced with nanoparticles (0.5, 1.0, and 1.5 Vol%) of samarium oxide (Sm2O3), and silicon dioxide (SiO2), were fabricated and tested. Corrosion behavior was assessed in comparison with high-purity magnesium samples as the control group. The addition of the nanoparticles to the magnesium matrix strengthened the materials, which was represented in an increase in the microhardness. However, the fabricated nanocomposite samples exhibited a slightly reduced corrosion resistance compared to the high-purity magnesium control due to the differences in the purity level and fabrication methods. Both nanocomposites showed the highest corrosion resistance, represented in the slowest corrosion rates, at the 1.0 Vol% content. Hence, the developed nanocomposites are still promising candidates as biodegradable materials for bone-fixation application owing to their superior mechanical properties and acceptable corrosion characteristics. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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10 pages, 1878 KiB  
Article
Axisymmetric Contact Problems for Composite Pressure Vessels
by Aleksander Muc
J. Compos. Sci. 2022, 6(5), 143; https://doi.org/10.3390/jcs6050143 - 14 May 2022
Cited by 2 | Viewed by 2285
Abstract
The present analysis is conducted for the evaluation of contact pressures of axisymmetric shells made of laminated composites or functionally graded materials. This class of problems is usually called the Signorini–Fichera problem (unilateral constraints) and can be solved as the lower-bound problem. The [...] Read more.
The present analysis is conducted for the evaluation of contact pressures of axisymmetric shells made of laminated composites or functionally graded materials. This class of problems is usually called the Signorini–Fichera problem (unilateral constraints) and can be solved as the lower-bound problem. The numerical solution of this problem is proposed both for symmetric and unsymmetric shell configurations. The first-ply-failure of such structures is considered. It is demonstrated that the failure occurs at the end of the contact area corresponding to the appearance of stress concentration of radial concentrated forces. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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13 pages, 2481 KiB  
Article
Obtaining the Dimensions and Orientation of 2D Rectangular Flakes from Sectioning Experiments in Flake Composites
by Thanasis D. Papathanasiou, Andreas Tsiantis and Yanwei Wang
J. Compos. Sci. 2022, 6(5), 142; https://doi.org/10.3390/jcs6050142 - 13 May 2022
Viewed by 1900
Abstract
Recently, we developed and reported the statistical validity of two methods for determining the planar aspect ratios of two-dimensional (2D) rectangular flakes in composites from the statistics of intersection lengths: one method is based on the maximum intersection length, and the other on [...] Read more.
Recently, we developed and reported the statistical validity of two methods for determining the planar aspect ratios of two-dimensional (2D) rectangular flakes in composites from the statistics of intersection lengths: one method is based on the maximum intersection length, and the other on the average intersection length. In this work, we show that these methods are valid and robust not only for flakes having isotropic, random in-plane orientations, but for the more general situations of planar orientations ranging from unidirectional (misalignment angle ϵ=0), to partially aligned (0<ϵ<π/2), to flakes of isotropic, random-in-plane orientations (ϵ=π/2). We prove, by Monte Carlo simulations and by numerical sectioning experiments, the validity of the proposed methods for characterizing the extent of the partial alignment (the misalignment angle ϵ) of 2D rectangular flakes in composites, based again on the statistics of the intersection lengths; this information can be obtained from cross-sections of composite samples used in optical or electron microscopy or using tomographic imaging techniques. The performance of these techniques was tested using blind experiments in numerically sectioned composites which contained up to 106 individual flakes, and was found to be very good for a wide range of flake aspect ratios. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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15 pages, 4901 KiB  
Article
Investigating the Effects of Ironing Parameters on the Dimensional Accuracy, Surface Roughness, and Hardness of FFF-Printed Thermoplastics
by Javaid Butt, Raghunath Bhaskar and Vahaj Mohaghegh
J. Compos. Sci. 2022, 6(5), 121; https://doi.org/10.3390/jcs6050121 - 22 Apr 2022
Cited by 12 | Viewed by 3001
Abstract
Ironing is a useful feature for parts made by fused filament fabrication (FFF), as it can smooth out surfaces using heat and extruding a small amount of material. Like any other processing parameter for FFF, ironing also requires optimisation to ensure a smooth [...] Read more.
Ironing is a useful feature for parts made by fused filament fabrication (FFF), as it can smooth out surfaces using heat and extruding a small amount of material. Like any other processing parameter for FFF, ironing also requires optimisation to ensure a smooth surface can be achieved with limited adverse effects on the other features of the printed part. Even with such a beneficial use case, ironing is still considered experimental and, therefore, this study aims to investigate its effects on dimensional accuracy, surface roughness, and the hardness of two commonly used amorphous thermoplastics, i.e., ABS (acrylonitrile butadiene styrene) and ASA (acrylonitrile styrene acrylate). An extensive comparative analysis has been provided where parts have been manufactured using a low-cost, desktop-based 3D printer, with the two materials at three different ironing line spacings (0.1 mm, 0.2 mm, 0.3 mm), three different ironing flows (10%, 20%, 30%), and three different ironing speeds (50 mm/s, 100 mm/s, 150 mm/s). The study focuses on evaluating the effects of these different ironing parameters and determining the optimal combination for bespoke product requirements. The results showed that ASA was more adversely affected by the changes in ironing parameters compared to ABS. However, the different ironing parameters were proven to improve the smoothness as well as hardness of the parts, compared to the un-ironed samples of ABS and ASA. This work provides a good comparison between two popular amorphous materials and offers ways to leverage ironing parameters to achieve dimensional accuracy, optimal surface finish, and better hardness values. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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11 pages, 2868 KiB  
Communication
Biogenic Preparation, Characterization, and Biomedical Applications of Chitosan Functionalized Iron Oxide Nanocomposite
by Devaraj Bharathi, Ranjithkumar Rajamani, Belay Zeleke Sibuh, Soumya Pandit, Sharad Agrawal, Neeraj Mishra, Mohit Sahni, Vijay Kumar Thakur and Piyush Kumar Gupta
J. Compos. Sci. 2022, 6(5), 120; https://doi.org/10.3390/jcs6050120 - 22 Apr 2022
Cited by 6 | Viewed by 2415
Abstract
Chitosan (CS) functionalization over nanomaterials has gained more attention in the biomedical field due to their biocompatibility, biodegradability, and enhanced properties. In the present study, CS functionalized iron (II) oxide nanocomposite (CS/FeO NC) was prepared using Sida acuta leaf extract by a facile [...] Read more.
Chitosan (CS) functionalization over nanomaterials has gained more attention in the biomedical field due to their biocompatibility, biodegradability, and enhanced properties. In the present study, CS functionalized iron (II) oxide nanocomposite (CS/FeO NC) was prepared using Sida acuta leaf extract by a facile and eco-friendly green chemistry route. Phyto-compounds of S. acuta leaf were used as a reductant to prepare CS/FeO NC. The existence of CS and FeO crystalline peaks in CS/FeO NC was confirmed by XRD. FE-SEM analysis revealed that the prepared CS/FeO NC were spherical with a 10–100 nm average size. FTIR analyzed the existence of CS and metal-oxygen bands in the prepared NC. The CS/FeO NC showed the potential bactericidal activity against E. coli, B. subtilis, and S. aureus pathogens. Further, CS/FeO NC also exhibited the dose-dependent anti-proliferative property against human lung cancer cells (A549). Thus, the obtained outcomes revealed that the prepared CS/FeO NC could be a promising candidate in the biomedical sector to inhibit the growth of bacterial pathogens and lung cancer cells. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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15 pages, 5799 KiB  
Article
Mechanical Characterization and Finite Element Analysis of Hierarchical Sandwich Structures with PLA 3D-Printed Core and Composite Maize Starch Biodegradable Skins
by Maria Zoumaki, Michel T. Mansour, Konstantinos Tsongas, Dimitrios Tzetzis and Gabriel Mansour
J. Compos. Sci. 2022, 6(4), 118; https://doi.org/10.3390/jcs6040118 - 15 Apr 2022
Cited by 18 | Viewed by 2870
Abstract
The objective of this research is the fabrication of biodegradable starch-based sandwich materials. The investigated sandwich structures consist of maize starch-based films as skins and biodegradable 3D-printed polylactic filaments (PLA) as the core. To investigate the tensile properties of the skins, conventional and [...] Read more.
The objective of this research is the fabrication of biodegradable starch-based sandwich materials. The investigated sandwich structures consist of maize starch-based films as skins and biodegradable 3D-printed polylactic filaments (PLA) as the core. To investigate the tensile properties of the skins, conventional and nanocomposite films were prepared by a solution mixing procedure with maize starch and glycerol as the plasticizer, and they were reinforced with sodium montmorillonite clay, cellulose fibers and fiberglass fabric, with different combinations. Test results indicated a significant improvement in the mechanical and morphological properties of composite films prepared with sodium montmorillonite clay in addition with cellulose fibers and fiberglass fabric, with 20 wt% of glycerol. The morphology of the skins was also examined by scanning electron microscopy (SEM). Three orders of hierarchical honeycombs were designed for the 3D-printed core. To investigate how the skin material and the design of the core affect the mechanical properties of the starch-based sandwich, specimens were tested under a three-point bending regime. The test results have shown that the flexural strength of the biodegradable sandwich structure increased with the use of a second order hierarchy core and starch-based skins improved the strength and stiffness of the neat PLA-based honeycomb core. The bending behavior of the hierarchical honeycombs was also assessed with finite element analysis (FEA) in combination with experimental findings. Flexural properties demonstrated that the use of starch-based films and a PLA honeycomb core is a suitable solution for biodegradable sandwich structures. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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14 pages, 2371 KiB  
Article
Patent Blue V Dye Adsorption by Fresh and Calcined Zn/Al LDH: Effect of Process Parameters and Experimental Design Optimization
by Aicha Machrouhi, Nawal Taoufik, Alaâeddine Elhalil, Hanane Tounsadi, Zakia Rais and Noureddine Barka
J. Compos. Sci. 2022, 6(4), 115; https://doi.org/10.3390/jcs6040115 - 11 Apr 2022
Cited by 14 | Viewed by 2223
Abstract
This work focuses on the adsorptive removal of patent blue V (PBV) dye from aqueous solution by Zn/Al layered double hydroxide in fresh (LDH) and calcined (CLDH) forms. The material was synthesized via coprecipitation and samples were characterized by XRD, FTIR and TGA-DTA. [...] Read more.
This work focuses on the adsorptive removal of patent blue V (PBV) dye from aqueous solution by Zn/Al layered double hydroxide in fresh (LDH) and calcined (CLDH) forms. The material was synthesized via coprecipitation and samples were characterized by XRD, FTIR and TGA-DTA. Dye retention was evaluated under different experimental conditions of contact time, pH, adsorbent dosage, temperature and initial dye concentration. Experimental results show that highest adsorption capacity occurred at acidic medium. Kinetics data were properly fitted with the pseudo-second-order model. Equilibrium data were best correlated to Langmuir model with maximum monolayer adsorption capacities of 185.40 and 344.37 mg/g, respectively, for LDH and CLDH. The process was endothermic and spontaneous in nature. Based on the preliminary study, full factorial experimental design (24) was used for the optimization of the effect of solution pH, adsorbent dose, initial dye concentration and the calcination. Thus, the optimal conditions to reach high equilibrium adsorption capacity were achieved at pH of 5, adsorbent dosage of 0.1 g/L, and initial dye concentration of 15 mg/L by CLDH. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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10 pages, 4363 KiB  
Article
Synthesis of TiB2/TiC/Al2O3 and ZrB2/ZrC/Al2O3 Composites by Low-Exotherm Thermitic Combustion with PTFE Activation
by Chun-Liang Yeh and Kuan-Ting Liu
J. Compos. Sci. 2022, 6(4), 111; https://doi.org/10.3390/jcs6040111 - 7 Apr 2022
Cited by 3 | Viewed by 1890
Abstract
TiB2–TiC–Al2O3 and ZrB2–ZrC–Al2O3 composites were produced via PTFE (polytetrafluoroethene)-activated combustion synthesis involving low-exotherm thermites. The reactant stoichiometries were 3TiO2 + 4Al + 0.5B4C + (1 − x)C + xCPTFE [...] Read more.
TiB2–TiC–Al2O3 and ZrB2–ZrC–Al2O3 composites were produced via PTFE (polytetrafluoroethene)-activated combustion synthesis involving low-exotherm thermites. The reactant stoichiometries were 3TiO2 + 4Al + 0.5B4C + (1 − x)C + xCPTFE and 3ZrO2 + 4Al + 0.5B4C + (1 − y)C + yCPTFE. PTFE played a dual role in promoting the reaction and carburizing reduced Ti and Zr. The threshold amount of PTFE for the TiO2/Al-based reaction was 2 wt% (i.e., x = 0.15) and for the ZrO2/Al-based reaction was 3 wt% (i.e., y = 0.25). The increase in PTFE increased the combustion front velocity and reaction temperature. The TiO2/Al-based reaction was more exothermic than the ZrO2/Al-based reaction and exhibited a faster combustion front and a lower activation energy. The TiB2–TiC–Al2O3 composite was produced with the minimum amount of PTFE at x = 0.15. The formation of ZrB2–ZrC–Al2O3 composites required more PTFE at y = 0.5 to improve the reduction of ZrO2. Both triplex composites displayed mixed microstructures consisting of short-rod borides, fine spherical carbides, and Al2O3 agglomerates. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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7 pages, 1609 KiB  
Article
Ion Beam Effect on the Structural and Optical Properties of AlN:Er
by Asmat Ullah, Muhammad Usman, Ahmer Hussain Shah, Altaf Hussain Shar and Muhammad Maqbool
J. Compos. Sci. 2022, 6(4), 110; https://doi.org/10.3390/jcs6040110 - 7 Apr 2022
Viewed by 1965
Abstract
Erbium (Er)-doped Aluminum Nitride (AlN) thin films were deposited and fabricated on Si (100) and Si (111) substrates in a Nitrogen atmosphere using the plasma magnetron sputtering technique. The deposited and fabricated thin films were thermally annealed at 900 °C in Argon (Ar) [...] Read more.
Erbium (Er)-doped Aluminum Nitride (AlN) thin films were deposited and fabricated on Si (100) and Si (111) substrates in a Nitrogen atmosphere using the plasma magnetron sputtering technique. The deposited and fabricated thin films were thermally annealed at 900 °C in Argon (Ar) atmosphere. The samples were irradiated with protons at a dose of 1 × 1014 ions/cm2 which carried an incident energy of 335 keV, using a tandem pelletron accelerator. Rutherford backscattering spectroscopy (RBS) and X-ray diffraction (XRD) were used for the stoichiometric and structural analysis of the films, while Fourier transforms infrared spectroscopy (FTIR) was performed to track the changes in the optical characteristics of thin films before and after the ions’ irradiation and implantation. The irradiation has affected the optical and structural properties of the films, which could be exploited to use the AlN:Er films for various optoelectronic and solid-state device applications. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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11 pages, 6487 KiB  
Article
Poly(ethyl methacrylate) Composite Coatings Containing Halogen-Free Inorganic Additives with Flame-Retardant Properties
by Xinqian Liu, Stephen Veldhuis, Ritch Mathews and Igor Zhitomirsky
J. Compos. Sci. 2022, 6(4), 104; https://doi.org/10.3390/jcs6040104 - 28 Mar 2022
Cited by 1 | Viewed by 2070
Abstract
This investigation is motivated by the need for the development of polymer coatings containing inorganic flame-retardant materials (FRMs) and the replacement of toxic halogenated FRMs. A green strategy is reported for the fabrication of poly(ethyl methacrylate) (PEMA)-FRM composite coatings using a dip-coating method. [...] Read more.
This investigation is motivated by the need for the development of polymer coatings containing inorganic flame-retardant materials (FRMs) and the replacement of toxic halogenated FRMs. A green strategy is reported for the fabrication of poly(ethyl methacrylate) (PEMA)-FRM composite coatings using a dip-coating method. The use of water-isopropanol co-solvent allows the replacement of regular toxic solvents for PEMA. The abilities to form concentrated solutions of high-molecular-mass PEMA and to disperse FRM particles in such solutions are the main factors in the fabrication of coatings using a dip-coating technique. Huntite, halloysite, and hydrotalcite are used as advanced FRMs for the fabrication of PEMA-FRM coatings. FTIR, XRD, SEM, and TGA data are used for the analysis of the microstructure and composition of PEMA-FRM coatings. PEMA and PEMA-FRM coatings provide corrosion protection of stainless steel. The ability to form laminates with different layers using a dip-coating method facilitates the fabrication of composite coatings with enhanced properties. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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13 pages, 6273 KiB  
Article
Effects of Wetting and Drying Cycles on Microstructure Change and Mechanical Properties of Coconut Fibre-Reinforced Mortar
by Huyen Bui, Daniel Levacher, Mohamed Boutouil and Nassim Sebaibi
J. Compos. Sci. 2022, 6(4), 102; https://doi.org/10.3390/jcs6040102 - 25 Mar 2022
Cited by 5 | Viewed by 2343
Abstract
Natural fibre-reinforced cementitious composites are commonly used as outer construction materials. They usually suffer weather as a result of being expose to various types of climates. In this study, a series of experimental tests were carried out to investigate the deterioration mechanism and [...] Read more.
Natural fibre-reinforced cementitious composites are commonly used as outer construction materials. They usually suffer weather as a result of being expose to various types of climates. In this study, a series of experimental tests were carried out to investigate the deterioration mechanism and mechanical properties of mortars incorporating coconut fibres due to repeated wetting and drying. The results indicated that although the compressive strength was found to increase after the first cycle, both compressive and flexural strengths underwent a significant decrease in the fifth cycle. In addition, at high temperatures, mortar matrixes retain their stable structure, according to the results of TGA analysis. When wetting and drying curing was applied, there was a significant degradation of fibres in the mortar. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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11 pages, 1273 KiB  
Article
Mechanical Properties of Dragline Silk Fiber Using a Bottom-Up Approach
by Sandeep P. Patil, Ambarish Kulkarni and Bernd Markert
J. Compos. Sci. 2022, 6(3), 95; https://doi.org/10.3390/jcs6030095 - 17 Mar 2022
Cited by 3 | Viewed by 2969
Abstract
We propose a molecular-based three-dimensional (3D) continuum model of dragline silk of Araneus diadematus, which takes into account the plasticity of the β-sheet crystals, the rate-dependent behavior of the amorphous matrix, and the viscous interface friction between them. For the proposed [...] Read more.
We propose a molecular-based three-dimensional (3D) continuum model of dragline silk of Araneus diadematus, which takes into account the plasticity of the β-sheet crystals, the rate-dependent behavior of the amorphous matrix, and the viscous interface friction between them. For the proposed model, we computed the tensile properties, the effects of velocity on the mechanical properties, and hysteresis values, which are in good agreement with available experimental data. The silk fiber model’s yield point, breaking strength, post-yield stiffness, and toughness increased with increasing pulling velocity, while extensibility and the diameter of the silk fiber decreased. Our bottom-up approach has shed light on silk fiber mechanics, which can be used as an essential tool to design artificial composite materials. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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16 pages, 15498 KiB  
Article
A Numerical and Experimental Investigation into the Impact Response of Sandwich Composites under Different Boundary Conditions
by Dianshi Feng, Gabriela Loi and Francesco Aymerich
J. Compos. Sci. 2022, 6(3), 88; https://doi.org/10.3390/jcs6030088 - 11 Mar 2022
Cited by 3 | Viewed by 2386
Abstract
The paper reports the results of an experimental and numerical investigation into the effect of the support conditions on the low velocity impact behaviour of sandwich composite panels. Significant differences are observed experimentally between the structural and damage responses to impact of small-span [...] Read more.
The paper reports the results of an experimental and numerical investigation into the effect of the support conditions on the low velocity impact behaviour of sandwich composite panels. Significant differences are observed experimentally between the structural and damage responses to impact of small-span and large-span sandwich panels. In particular, impact events on large-span panels generate lower peak forces, larger displacements and smaller damage sizes in comparison to small-span panels subjected to the same impact energy. The experimental results are employed to validate the capability of a finite element (FE) tool to simulate the impact behaviour of the sandwich panels for the different boundary conditions. The comparison of FE and experimental results shows that the model provides a good prediction of the structural response as well as of the extent and mechanisms of impact damage for both small-span and large-span lengths, thus demonstrating the potential of the FE tool for verification and design of sandwich components in real engineering applications. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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19 pages, 3830 KiB  
Article
Optimising Crystallisation during Rapid Prototyping of Fe3O4-PA6 Polymer Nanocomposite Component
by Ranjeetkumar Gupta, James Njuguna and Ketan Pancholi
J. Compos. Sci. 2022, 6(3), 83; https://doi.org/10.3390/jcs6030083 - 7 Mar 2022
Cited by 1 | Viewed by 1970
Abstract
Polymer components capable of self-healing can rapidly be manufactured by injecting the monomer (ε-caprolactam), activator and catalyst mixed with a small amount of magnetic nanoparticles into a steel mould. The anionic polymerisation of the monomer produces a polymer component capturing magnetic nanoparticles in [...] Read more.
Polymer components capable of self-healing can rapidly be manufactured by injecting the monomer (ε-caprolactam), activator and catalyst mixed with a small amount of magnetic nanoparticles into a steel mould. The anionic polymerisation of the monomer produces a polymer component capturing magnetic nanoparticles in a dispersed state. Any microcracks developed in this nanocomposite component can be healed by exposing it to an external alternating magnetic field. Due to the magnetocaloric effect, the nanoparticles locally melt the polymer in response to the magnetic field and fill the cracks, but the nanoparticles require establishing a network within the matrix of the polymer through effective dispersion for functional and uniform melting. The dispersed nanoparticles, however, affect the degree of crystallinity of the polymer depending on the radius of gyration of the polymer chain and the diameter of the magnetic nanoparticle agglomerates. The variation in the degree of crystallinity and crystallite size induced by nanoparticles can affect the melting temperature as well as its mechanical strength after testing for applications, such as stimuli-based self-healing. In the case of in situ synthesis of the polyamide-6 (PA6) magnetic nanocomposite (PMC), there is an opportunity to alter the degree of crystallinity and crystallite size by optimising the catalyst and activator concentration in the monomer. This optimisation method offers an opportunity to tune the crystallinity and, thus, the properties of PMC, which otherwise can be affected by the addition of nanoparticles. To study the effect of the concentration of the catalyst and activator on thermal properties, the degree of crystallinity and the crystallite size of the component (PMC), the ratio of activator and catalyst is varied during the anionic polymerisation of ε-caprolactam, but the concentration of Fe3O4 nanoparticles is kept constant at 1 wt%. Differential Scanning Calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), XRD (X-ray diffraction) and Thermogravimetric analysis (TGA) were used to find the required concentration of the activator and catalyst for optimum properties. It was observed that the sample with 30% N-acetyl caprolactam (NACL) (with 50% EtMgBr) among all of the samples was most suitable to Rapid Prototype the PMC dog-bone sample with the desired degree of crystallinity and required formability. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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14 pages, 8053 KiB  
Article
Effect of Basalt Fibres on Thermal and Mechanical Properties of Recycled Multi-Material Packaging
by Claudia Sergi, Jacopo Tirillò, Teodoro Valente and Fabrizio Sarasini
J. Compos. Sci. 2022, 6(3), 72; https://doi.org/10.3390/jcs6030072 - 24 Feb 2022
Cited by 5 | Viewed by 2328
Abstract
The low-density polyethylene (LDPE)/aluminium mix obtained after the recovery of cellulose from multilayer aseptic packaging used in the food and beverage industry is generally destined for energy recovery. In this work we propose it as a matrix for value-added composite materials. A commercially [...] Read more.
The low-density polyethylene (LDPE)/aluminium mix obtained after the recovery of cellulose from multilayer aseptic packaging used in the food and beverage industry is generally destined for energy recovery. In this work we propose it as a matrix for value-added composite materials. A commercially available material (EcoAllene) obtained from multilayer packaging recycling was reinforced with short natural basalt fibres up to 30 wt.% by twin screw extrusion, aiming at improving the mechanical profile of such material and widening its applications. Thermal characterizations by thermogravimetric analysis and differential scanning calorimetry showed that the material is indeed a complex mixture of LDPE, HDPE, PP, and aluminium. Basalt fibres did not modify the melting and crystallization profile as well as the global degradation behaviour. Composites were then subjected to tensile, bending, Charpy impact tests and the fracture surfaces were investigated by scanning electron microscopy. Results highlighted a beneficial effect of basalt fibres to stiffness and strength in both loading conditions, with improvements by 107% and 162% for tensile and bending strength, respectively, which were linked also to a 45% enhancement of impact strength. This increased mechanical performance is promising for their use in automotive interiors and outdoor decking applications. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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7 pages, 4199 KiB  
Article
Damage Evolution Analysis on Compression-Loaded Multidirectional Carbon Fiber Laminates Using Ex-Situ CT Scans
by Jonas J. A. D’haen, Michael May, Christian Boegle and Stefan Hiermaier
J. Compos. Sci. 2022, 6(2), 63; https://doi.org/10.3390/jcs6020063 - 19 Feb 2022
Cited by 2 | Viewed by 1926
Abstract
Damage evolution inside compression-loaded laminates is a crucial aspect when designing crash structures. In this study, ex situ CT scanning is used to identify damage evolution in multidirectional composite laminates. Multiple CT scans throughout the stress–strain envelope are used to quantify the internal [...] Read more.
Damage evolution inside compression-loaded laminates is a crucial aspect when designing crash structures. In this study, ex situ CT scanning is used to identify damage evolution in multidirectional composite laminates. Multiple CT scans throughout the stress–strain envelope are used to quantify the internal damage and failure propagation of a [45, −45, 90]s carbon fiber laminate. Initially, observed damage occurs in form of delamination between the −45° and 90° layers. Afterward, shear failure propagates from the central layers throughout the entire laminate. Shear failure in the middle two layers expands after continued loading up to double shear failure. The same distinct failure sequence is observed in multiple specimens, and the small deviation supports consistency. Furthermore, the stress–strain envelope of the successive load cycles matches closely with reference measurements. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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20 pages, 4246 KiB  
Article
Simplified Approach for the Seismic Assessment of Existing X Shaped CBFs: Examples and Numerical Applications
by Rosario Montuori, Elide Nastri, Vincenzo Piluso and Paolo Todisco
J. Compos. Sci. 2022, 6(2), 62; https://doi.org/10.3390/jcs6020062 - 18 Feb 2022
Cited by 5 | Viewed by 1888
Abstract
The capacity of a structure can be assessed using inelastic analyses, requiring sophisticated numerical procedures such as pushover and incremental dynamic analyses. A simplified method for the evaluation of the seismic performance of steel Concentrically Braced Frames (CBFs) to be used in everyday [...] Read more.
The capacity of a structure can be assessed using inelastic analyses, requiring sophisticated numerical procedures such as pushover and incremental dynamic analyses. A simplified method for the evaluation of the seismic performance of steel Concentrically Braced Frames (CBFs) to be used in everyday practice and the immediate aftermath of an earthquake has been recently proposed. This method evaluates the capacity of an existing building employing an analytical trilinear model without resorting to any non-linear analysis. The proposed methodology has been set up through a large parametric analysis, carried out on 420 frames designed according to three different approaches: the first one is the Theory of Plastic Mechanism Control (TPMC), ensuring the design of structures showing global collapse mechanisms (GCBFs), the second one is based on the Eurocode 8 design requirements (SCBFs), and the third is a non-seismic design, based on a non-seismic design (OCBFs). In this paper, some examples of the application of this simplified methodology are proposed with references to structures that are supposed to exhibit global, partial, and soft storey mechanisms. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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20 pages, 4157 KiB  
Article
A DMA-Based Approach to Quality Evaluation of Digitally Manufactured Continuous Fiber-Reinforced Composites from Thermoplastic Commingled Tow
by Patrick A. Rodriguez and Donald W. Radford
J. Compos. Sci. 2022, 6(2), 61; https://doi.org/10.3390/jcs6020061 - 18 Feb 2022
Cited by 4 | Viewed by 2259
Abstract
Direct digital manufacturing of continuous fiber-reinforced thermoplastics exhibits the potential to relieve many of the constraints placed on the current design and manufacture of composite structures. At present, the additive manufacturing of continuous fiber-reinforced thermoplastics is demonstrated to varying extents; however, a comprehensive [...] Read more.
Direct digital manufacturing of continuous fiber-reinforced thermoplastics exhibits the potential to relieve many of the constraints placed on the current design and manufacture of composite structures. At present, the additive manufacturing of continuous fiber-reinforced thermoplastics is demonstrated to varying extents; however, a comprehensive investigation of manufacturing defects and the quality of additively manufactured high fiber volume fraction continuous fiber-reinforced thermoplastic composites is limited. Considering the preliminary nature of the additive manufacturing of continuous fiber-reinforced thermoplastics, composites processed in this manner are typically subject to various manufacturing defects, including excessive void content in the thermoplastic matrix. Generally, quality evaluation of processed composites in the literature is limited to test methods that are largely influenced by the properties of the continuous fiber reinforcement, and as such, defects in the thermoplastic matrix are usually less impactful on the results and are often overlooked. Hardware to facilitate the direct digital manufacturing of continuous fiber-reinforced thermoplastic matrix composites was developed, and specimens were successfully processed with intentionally varied void content. The quality of the additively manufactured specimens was then evaluated in terms of the measured maximum storage modulus, maximum loss modulus, damping factor and the glass transition temperature by means of dynamic mechanical analysis (DMA). DMA allows for thermomechanical (i.e., highly matrix sensitive) evaluation of the composite specimens, specifically in terms of the measured elastic storage modulus, viscous loss modulus, damping factor and the glass transition temperature. Within the tested range of void contents from roughly 4–10%, evaluation by DMA resulted in a distinct reduction in the maximum measured storage modulus, maximum loss modulus and glass transition temperature with increasing void content, while the damping factor increased. Thus, the results of this work, which focused on the effect of void content on DMA measured properties, have demonstrated that DMA exhibits multi-faceted sensitivity to the presence of voids in the additively manufactured continuous fiber-reinforced thermoplastic specimens. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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20 pages, 2284 KiB  
Article
Maltodextrin Moderated Microwave Osmotic Dehydration of Mango Cubes with Finish Air-Drying: Optimum Considerations
by Bhakti Shinde and Hosahalli S. Ramaswamy
J. Compos. Sci. 2022, 6(2), 56; https://doi.org/10.3390/jcs6020056 - 14 Feb 2022
Cited by 2 | Viewed by 2045
Abstract
The microwave osmotic dehydration of mango cubes under the continuous flow of maltodextrin moderated sucrose solution spray (MWODS) was evaluated based on the quality of the finish air-dried product. Experiments were designed according to a central composite rotatable design to evaluate the effect [...] Read more.
The microwave osmotic dehydration of mango cubes under the continuous flow of maltodextrin moderated sucrose solution spray (MWODS) was evaluated based on the quality of the finish air-dried product. Experiments were designed according to a central composite rotatable design to evaluate the effect of maltodextrin moderated sucrose solution [sucrose + maltodextrin (10DE) at a proportion of 85:15] on the finish air-dried product. The process variables were temperature (30 to 70 °C), solute concentration (30 to 70%), contact time (10 to 50 min) and flow rate (0.8 to 3.8 L/min). The optimum processing conditions were determined based on several processes and product-related quality parameters such as moisture loss (ML), solids gain (SG), weight gain, ML/SG, color, texture, rehydration capacity (RHC), bulk density and drying time. The MWODS contact time was the largest significant contributor with respect to most of the parameters, followed by temperature. The optimum values found were an osmotic treatment temperature of 51.7 °C, a solute concentration of 58.5%, a contact time of 30.6 min and a solution flow rate of 1.8 L/min. Finally, these optimized processing conditions were used to compare three different solute mixtures [sucrose only, sucrose + dextrose and sucrose + maltodextrin (10DE) at a ratio of 85:15%] to understand the effect of various solutes on the quality of the finished dried product. Based on the color and textural parameters, along with the RHC, of the finished product, the sucrose + maltodextrin mixture was shown to result in the most desirable quality and the air-dried product without MWODS pretreatment (control) resulted in the least desirable. Overall, the results suggest that the sucrose + maltodextrin combination offered an advantage in terms of quality for the MWODS air-drying of mango cubes. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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13 pages, 1862 KiB  
Article
Waste Glass-Derived Tobermorite Carriers for Ag+ and Zn2+ Ions
by Habib Rahman, Qiu Li and Nichola J. Coleman
J. Compos. Sci. 2022, 6(2), 52; https://doi.org/10.3390/jcs6020052 - 9 Feb 2022
Cited by 1 | Viewed by 2356
Abstract
In this study, the layer-lattice calcium silicate hydrate mineral, tobermorite, was synthesized from waste green or amber container glass and separately ion-exchanged with Ag+ or Zn2+ ions under batch conditions. Hydrothermal treatment of stoichiometrically adjusted mixtures of waste glass and calcium [...] Read more.
In this study, the layer-lattice calcium silicate hydrate mineral, tobermorite, was synthesized from waste green or amber container glass and separately ion-exchanged with Ag+ or Zn2+ ions under batch conditions. Hydrothermal treatment of stoichiometrically adjusted mixtures of waste glass and calcium oxide in 4 M NaOH(aq) at 125 °C yielded tobermorite products of ~75% crystallinity with mean silicate chain lengths of 17 units after one week. Maximum uptake of Zn2+ ions, ~0.55 mmol g−1, occurred after 72 h, and maximum uptake of Ag+ ions, ~0.59 mmol g−1, was established within 6 h. No significant differences in structure or ion-exchange behavior were observed between the tobermorites derived from either green or amber glass. Composite membranes of the biopolymer, chitosan, incorporating the original or ion-exchanged tobermorite phases were prepared by solvent casting, and their antimicrobial activities against S. aureus and E. coli were evaluated using the Kirby–Bauer assay. S. aureus and E. coli formed biofilms on pure chitosan and chitosan surfaces blended with the original tobermorites, whereas the composites containing Zn2+-substituted tobermorites defended against bacterial colonization. Distinct, clear zones were observed around the composites containing Ag+-substituted tobermorites which arose from the migration of the labile Ag+ ions from the lattices. This research has indicated that waste glass-derived tobermorites are functional carriers for antimicrobial ions with potential applications as fillers in polymeric composites to defend against the proliferation and transmission of pathogenic bacteria. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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Review

Jump to: Research

28 pages, 7151 KiB  
Review
State-Of-The-Art of Sandwich Composite Structures: Manufacturing—to—High Performance Applications
by Ayesha Kausar, Ishaq Ahmad, Sobia A. Rakha, M. H. Eisa and Abdoulaye Diallo
J. Compos. Sci. 2023, 7(3), 102; https://doi.org/10.3390/jcs7030102 - 7 Mar 2023
Cited by 9 | Viewed by 10016
Abstract
This cutting-edge review highlights the fundamentals, design, and manufacturing strategies used for sandwich composites. Sandwich composite structures have the advantages of light weight, high strength, impact resistance, stability, and other superior features for advanced applications. In this regard, different core materials have been [...] Read more.
This cutting-edge review highlights the fundamentals, design, and manufacturing strategies used for sandwich composites. Sandwich composite structures have the advantages of light weight, high strength, impact resistance, stability, and other superior features for advanced applications. In this regard, different core materials have been used in the sandwich composite structures, such as cellular polymer foam, metallic foam, honeycomb, balsa, tubular, and other core geometries. Among these, honeycomb sandwich composite materials have been effectively applied in space engineering, marine engineering, and construction applications. The foremost manufacturing techniques used for sandwiched composite structures include hand lay-up, press method, prepreg method, vacuum bagging/autoclave, vacuum assisted resin infusion, resin transfer molding, compression molding, pultrusion, three-dimensional (3D) printing, four-dimensional (4D) printing, etc. In advanced composite manufacturing, autoclave processes have been the method of choice for the aerospace industry due to less delamination between plies and easy control of thickness dimensions. Moreover, machining processes used for sandwich composites are discussed in this article. In addition to aerospace, the high-performance significance of sandwiched composite structures is covered mainly in relation to automobile engineering and energy absorption applications. The structure-, fabrication-, and application-related challenges and probable future research directions are also discussed in this article. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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21 pages, 2346 KiB  
Review
Mechanical, Thermal, and Acoustic Properties of Hemp and Biocomposite Materials: A Review
by Raj Kumar Dahal, Bishnu Acharya and Animesh Dutta
J. Compos. Sci. 2022, 6(12), 373; https://doi.org/10.3390/jcs6120373 - 6 Dec 2022
Cited by 18 | Viewed by 3372
Abstract
Bio-based products are paving a promising path towards a greener future and helping win the fight against climate change and global warming mainly caused by fossil fuel consumption. This paper aims at highlighting the acoustic, thermal, and mechanical properties of hemp-based biocomposite materials. [...] Read more.
Bio-based products are paving a promising path towards a greener future and helping win the fight against climate change and global warming mainly caused by fossil fuel consumption. This paper aims at highlighting the acoustic, thermal, and mechanical properties of hemp-based biocomposite materials. Change in sound absorption as a result of hemp fibers and hemp particle reinforcement are discussed in this paper. The thermal properties characterized by the thermal conductivity of the composites are also presented, followed by the mechanical properties and the current issues in biocomposite materials mainly containing hemp as a constituent element. Lastly, the effects of biofillers and biofibers on the various properties of the hemp-composite materials are discussed. This paper highlights the development of and issues in the field of hemp-based composite materials. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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32 pages, 3152 KiB  
Review
Seismic Composite Metamaterial: A Review
by Al-Shami Qahtan, Jiankun Huang, Mugahed Amran, Diyar N. Qader, Roman Fediuk and Al-Dhabir Wael
J. Compos. Sci. 2022, 6(11), 348; https://doi.org/10.3390/jcs6110348 - 12 Nov 2022
Cited by 5 | Viewed by 2494
Abstract
The modern construction revolution throughout the past two decades has brought the need for ground vibration mitigation, and this has been one of the major study areas. These studies were mainly focused on the effect of forestation on vibration reduction as the available [...] Read more.
The modern construction revolution throughout the past two decades has brought the need for ground vibration mitigation, and this has been one of the major study areas. These studies were mainly focused on the effect of forestation on vibration reduction as the available natural metamaterial. Physical methods such as the finite element method and the boundary conditions of 2D and 3D applications in ground vibration reduction have been developed. Many researchers, scientists, and organizations in this field have emphasized the importance of these methods theoretically and numerically. This paper presents the historical context of resonant metamaterials (MMs), the current progress of periodic 2D and 3D structures, and the possible future outcomes from the seismic metamaterials (SMs), and it relates them with their elastic counterparts to the natural metamaterial (NMs). The idea of bandgaps (FBGs) in the frequency range of interest is reviewed and discussed in some detail. Moreover, the attenuation associated with ground vibrations, noise, seismology, and the like is explained by managing the peculiar mechanisms of ground vibrations. However, a comprehensive computational review focuses on shielding MMs for ground vibration mitigation in urban areas. This phenomenon led to unique features for various techniques to control the bandgap width for various construction applications. Ecological solutions involve the creation of an economic, environmentally based seismic shield for both the Bragg scattering and the local resonance bandgaps. Reportedly, additive studies based on numerical simulation and experiments have improved the functionality of the 2D and 3D periodic structures. It was found that the mechanical properties differ (i.e., stiffness, Poisson’s ratio, and bulk density) and that the geometrical parameters (i.e., lattice, model dimensions, distance from vibration sources, and number of periodic structures) exhibited strong effects on the width and location of the derived FBGs. The geometrical properties of the used unit cell have a strong effect on the attenuation mechanism. Although deep analysis was created in much of the previous research, it was revealed, based on that research, that the attenuation mechanism is still unclear. However, this review article presents a detailed exposition of the recent research progress of the seismic metamaterials, including 2D, 3D, and the main mechanisms of the theoretical backgrounds of energy attenuation. It also summarizes the effects of the factors on the width and location of the bandgaps at a low frequency. In addition, the natural metamaterials and the study of the urban environment are surveyed. The major findings of this review involve the effectiveness of NMs for different functionalities in ground vibration attenuation, which leads to diverse purposes and applications and proposes a roadmap for developing natural materials for clean and quiet environments. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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22 pages, 1572 KiB  
Review
Recent Developments and Current Challenges of Heparin-Grafted Hemodialysis Membranes
by Amira Abdelrasoul, Denis Kalugin and Ahmed Shoker
J. Compos. Sci. 2022, 6(9), 244; https://doi.org/10.3390/jcs6090244 - 23 Aug 2022
Cited by 6 | Viewed by 2513
Abstract
Hemodialysis (HD) is a life-sustaining extracorporeal blood purifying treatment for end-stage renal disease (ESRD) patients. However, this membrane-based therapy is associated with acute side effects, life-threatening chronic conditions, and unacceptably high morbidity and mortality rates. Numerous surface coatings have been developed to improve [...] Read more.
Hemodialysis (HD) is a life-sustaining extracorporeal blood purifying treatment for end-stage renal disease (ESRD) patients. However, this membrane-based therapy is associated with acute side effects, life-threatening chronic conditions, and unacceptably high morbidity and mortality rates. Numerous surface coatings have been developed to improve the blood compatibility of biomaterials. Heparin is a widely used anticoagulant substance that increases the clotting time and increases the membrane hemocompatibility in terms of platelet adhesion and protein adsorption and anti-clotting activity. However, using heparin is challenging due to its severe or life-threatening side effects such as heparin-induced thrombocytopenia (HIT), in addition to heparin induced thrombocytopenia and thrombosis (HITT). In addition, heparin is strongly electronegative and exhibits a binding affinity for the positive active sites of human serum proteins, which is an additional challenge. Consequently, covalently immobilized heparin would create a more charged surface to induce more blood–membrane interactions, and consequently more adsorbed human serum proteins and biochemical pathway activations, which can negatively affect dialysis patients. Therefore, the current critical review has thoroughly focused on different heparin HD membrane systems, the challenges of heparin-coated dialysis membranes, and the factors affecting its hemocompatibility, in addition to the methods that can be used to enhance its hemocompatibility. Furthermore, this review summarizes the advantages and disadvantages of heparin-grafted methods. Furthermore, the influence of the heparin-immobilization method on the hemocompatibility and performance of the HD membrane was comprehensively analyzed. Finally, we conclude with the future perspectives for the strategies toward the heparinization and heparin-like/mimicking modification of membrane surfaces. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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22 pages, 5816 KiB  
Review
A Review on Analysis of Reinforced Recycled Rubber Composites
by Gamze Cakir Kabakçi, Ozgur Aslan and Emin Bayraktar
J. Compos. Sci. 2022, 6(8), 225; https://doi.org/10.3390/jcs6080225 - 4 Aug 2022
Cited by 2 | Viewed by 2703
Abstract
Rubber recycling attracts considerable attention by a variety of industries around the world due to shrinking resources, increasing cost of raw materials, growing awareness of sustainable development, and environmental issues. Recycled rubber is commonly used in aeronautic, automotive, and transportation industries. In this [...] Read more.
Rubber recycling attracts considerable attention by a variety of industries around the world due to shrinking resources, increasing cost of raw materials, growing awareness of sustainable development, and environmental issues. Recycled rubber is commonly used in aeronautic, automotive, and transportation industries. In this study, recycled rubber composites designed with different reinforcements in the literature are scrutinized by means of toughening mechanisms, mechanical and physical properties, as well as microstructural and fracture surface analysis. Microscale reinforcements (glass bubbles, alumina fiber, etc.) and nanoscale reinforcements (nanosilica, graphene nanoplatelets, etc.) utilized as reinforcements in rubber composites are thoroughly reviewed. The general mechanical properties reported by previous studies, such as tensile, compressive, and flexural strength, are investigated with the main goal of optimizing the amount of reinforcement used. The majority of the studies on recycled rubber composites show that recycled rubber reinforced with microscale particles leads to the development of physical and mechanical properties of the structures and also provides low-cost and lightweight composites for several application areas. Moreover, recycled rubber containing composites can be suitable for applications where high toughness and high resistance to impact are desirable. The present review aims to demonstrate research on reinforced recycled rubber composites in the literature and prospective outcomes. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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12 pages, 1001 KiB  
Review
Color Stability Determination of CAD/CAM Milled and 3D Printed Acrylic Resins for Denture Bases: A Narrative Review
by Mariya Dimitrova, Massimo Corsalini, Rada Kazakova, Angelina Vlahova, Giuseppe Barile, Fabio Dell’Olio, Zlatina Tomova, Stoyan Kazakov and Saverio Capodiferro
J. Compos. Sci. 2022, 6(7), 201; https://doi.org/10.3390/jcs6070201 - 8 Jul 2022
Cited by 16 | Viewed by 3546
Abstract
The aim of this paper is to review the available literature on the different methods for color stability determination of CAD/CAM milled and 3D printed resins for denture bases. The methodology included applying a search strategy, defining inclusion and exclusion criteria and selecting [...] Read more.
The aim of this paper is to review the available literature on the different methods for color stability determination of CAD/CAM milled and 3D printed resins for denture bases. The methodology included applying a search strategy, defining inclusion and exclusion criteria and selecting studies to summarize the results. Searches of PubMed, Scopus, and Embase databases were performed independently by three reviewers to gather the literature published between 1998 and 2022. A total of 186 titles were obtained from the electronic database, and the application of exclusion criteria resulted in the identification of 66 articles pertaining to the different methods for color stability determination of CAD/CAM acrylic resins for denture bases. Color change in dental materials is clinically very important for the dental operator, as it determines the clinical serviceability of the material. Discoloration of the denture bases can be evaluated with various instruments and methods. Dental resins may undergo color changes over time due to intrinsic and/or extrinsic factors. The extrinsic factors are considered the more frequent causes of color changes. According to a number of studies, CAD/CAM fabricated acrylics have achieved better color stability than the conventional PMMA (polymethyl methacrylate) resins. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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17 pages, 10104 KiB  
Review
Materials Development Using High-Energy Ball Milling: A Review Dedicated to the Memory of M.A. Korchagin
by Dina V. Dudina and Boris B. Bokhonov
J. Compos. Sci. 2022, 6(7), 188; https://doi.org/10.3390/jcs6070188 - 25 Jun 2022
Cited by 13 | Viewed by 3241
Abstract
High-energy ball milling (HEBM) of powders is a complex process involving mixing, morphology changes, generation and evolution of defects of the crystalline lattice, and formation of new phases. This review is dedicated to the memory of our colleague, Prof. Michail A. Korchagin (1946–2021), [...] Read more.
High-energy ball milling (HEBM) of powders is a complex process involving mixing, morphology changes, generation and evolution of defects of the crystalline lattice, and formation of new phases. This review is dedicated to the memory of our colleague, Prof. Michail A. Korchagin (1946–2021), and aims to highlight his works on the synthesis of materials by self-propagating high-temperature synthesis (SHS) and thermal explosion (TE) in HEBM mixtures as important contributions to the development of powder technology. We review results obtained by our group, including those obtained in collaboration with other researchers. We show the applicability of the HEBM mixtures for the synthesis of powder products and the fabrication of bulk materials and coatings. HEBM influences the parameters of synthesis as well as the structure, phase composition, phase distribution (in composites), and grain size of the products. The microstructural features of the products of synthesis conducted using the HEBM precursors are dramatically different from those of the products formed from non-milled mixtures. HEBM powders are also suitable as feedstock materials for depositing coatings by thermal spraying. The emerging applications of HEBM powders and future research directions in this area are discussed. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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