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Polymers
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Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications
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Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Processing and Engineering".

Deadline for manuscript submissions: closed (5 October 2022) | Viewed by 72330

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editors

Dr. Giorgio Luciano

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Guest Editor
National Research Council of Italy—Institute of Chemical Sciences and Technologies “Giulio Natta” CNR SCITEC, Via De Marini 6, 16149 Genova, Italy
Interests: polymer calorimetric characterization; spettroscopy; design of experiments
Special Issues, Collections and Topics in MDPI journals
Dr. Paola Stagnaro

E-Mail Website
Guest Editor
Consiglio Nazionale delle Ricerche, Istituto di Scienze e Tecnologie Chimiche "Giulio Natta", CNR-SCITEC, Genova, Italy
Interests: polymer chemistry; multicomponent polymer materials; polymer processing; polymer characterization; structure–propreties relationship.
Dr. Maurizio Vignolo

E-Mail Website1 Website2
Guest Editor
Consiglio Nazionale delle Ricerche, Istituto di Scienze e Tecnologie Chimiche "Giulio Natta", CNR-SCITEC, 16149 Genova, Italy
Interests: composite material processing; material characterization
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The subject of composite materials is truly a multi and interdisciplinary one. People who work in fields such as materials science, processing, polymer chemistry, inorganic chemistry, chemical engineering, solid mechanics and fracture mechanics, nanotechnologies, etc., are important contributors to the field of composite materials. Furthermore, polymer-based composites are often a valid alternative to traditional materials, because they combine mechanical resistance to lightness, flexibility to optical properties, formability to low cost processing. Due to their peculiar properties and versatility polymer-based composites, they have found applications in many industrial fields: construction, automotive, aerospace, biomedicine, marine, just to name a few. The performance of a polymeric composite material mainly depends on the nature of the components, the degree of interaction between its components and the processing technology.

The purpose of this Special Issue is to highlight the latest original results in the development of advanced composite materials based on synthetic/natural polymers and synthetic/natural (nano)fillers/fibers, with improved properties required by the foreseen different applications. As a consequence, the present Special Issue represents the right channel to publish on cutting-edge applications related to advanced polymeric composite materials. All kinds of polymer matrices, either commodity and engineering polymers or newly developed ones, such as bio-based and/or biodegradable polymers, from thermosets and thermoplastics to vitrimers, can be considered. The submission of manuscripts is welcome, but not limited to, those covering the following hot fields of applications:

  • Energy storage and harvesting;
  • Biomedicals;
  • Sensors and actuators;
  • Coatings;
  • Textiles;
  • Optoelectronics and photonics;
  • Flexible and stretchable electronics;
  • Membranes;
  • Industrial (automotive, aerospace, naval);
  • 3D printing.

Dr. Giorgio Luciano
Dr. Paola Stagnaro
Dr. Maurizio Vignolo
Guest Editors

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. Polymers is an international peer-reviewed open access semimonthly 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 2700 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.

Keywords

  • processing technologies
  • modelling, simulation and material optimization
  • synthetic and/or natural polymers
  • modification and/or activation of polymers
  • surface modifcation
  • filllers and nanofillers
  • (natural) fibers
  • nanoparticles
  • biocomposites
  • bio-based hybrid materials
  • renewable materials
  • green chemistry
  • composites and nanocomposites
  • polymer composites
  • biocomposites
  • composite recycling
  • phase compatibilization
  • properties of composites
  • characterization
  • applications

Published Papers (26 papers)

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13 pages, 2636 KiB  
Article
Study of Microwave-Active Composite Materials to Improve the Polyethylene Rotomolding Process
by Giorgio Luciano, Maurizio Vignolo, Elisabetta Brunengo, Roberto Utzeri and Paola Stagnaro
Polymers 2023, 15(5), 1061; https://doi.org/10.3390/polym15051061 - 21 Feb 2023
Cited by 2 | Viewed by 1498
Abstract
The present paper reports on the formulation and characterization of composite coating materials susceptible to microwave (MW) heating to investigate their application in making the rotomolding process (RM) more energy efficient. SiC, Fe2SiO4, Fe2O3, TiO [...] Read more.
The present paper reports on the formulation and characterization of composite coating materials susceptible to microwave (MW) heating to investigate their application in making the rotomolding process (RM) more energy efficient. SiC, Fe2SiO4, Fe2O3, TiO2 and BaTiO3 and a methyl phenyl silicone resin (MPS) were employed for their formulations. Experimental results showed that the coatings with a ratio of 2:1 w/w of inorganic/MPS are the most MW-susceptible materials. To test the coatings in working mimicking conditions, they were applied to molds, and polyethylene samples were manufactured by MW-assisted laboratory uni-axial RM and then characterized by calorimetry, infrared spectroscopy and tensile tests. The results obtained suggest that the coatings developed can be successfully applied to convert molds employed for classical RM process to MW-assisted RM processes. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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18 pages, 12418 KiB  
Article
Rheological Properties of Non-Adhesive Embolizing Compounds—The Key to Fine-Tuning Embolization Process-Modeling in Endovascular Surgery
by Iuliia Kuianova, Alexander Chupakhin, Alexey Besov, Anton Gorbatykh, Dmitry Kislitsin, Kirill Orlov and Daniil Parshin
Polymers 2023, 15(4), 1060; https://doi.org/10.3390/polym15041060 - 20 Feb 2023
Cited by 2 | Viewed by 1663
Abstract
The study of polymers’ rheological properties is of paramount importance both for the problems of their industrial production as well as for their practical application. Two polymers used for embolization of arteriovenous malformations (AVMs) are studied in this work: Onyx-18® and Squid-12 [...] Read more.
The study of polymers’ rheological properties is of paramount importance both for the problems of their industrial production as well as for their practical application. Two polymers used for embolization of arteriovenous malformations (AVMs) are studied in this work: Onyx-18® and Squid-12®. Viscosity curve tests and computational fluid dynamics (CFD) were used to uncover viscosity law as a function of shear rate as well as behavior of the polymers in catheter or pathological tissue models. The property of thermal activation of viscosity was demonstrated, namely, the law of dependence of viscosity on temperature in the range from 20 °C to 37 °C was established. A zone of viscosity nonmonotonicity was identified, and a physical interpretation of the dependence of the embolic polymers’ viscosity on the shear rate was given on the basis of Cisco’s model. The obtained empirical constants will be useful for researchers based on the CFD of AVMs. A description of the process of temperature activation of the embolic polymers’ viscosity is important for understanding the mechanics of the embolization process by practicing surgeons as well as for producing new prospective embolic agents. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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19 pages, 4427 KiB  
Article
Squeezing Mechanical Analysis and Model Establishment of the Viscoelastic Rubber-Strip-Feeding Process of the Cold-Feed Rubber Extruder
by Yanchang Liu, Yiren Pan, Xuehua Hu and Fang Yu
Polymers 2022, 14(17), 3602; https://doi.org/10.3390/polym14173602 - 31 Aug 2022
Cited by 1 | Viewed by 2112
Abstract
In the process of rubber extrusion, the feed structure directly affects the extrusion quality, extrusion uniformity, screw lateral force, and feed power consumption. Until now, the feed structure was mainly based on empirical designs, and there was no theoretical model for the optimal [...] Read more.
In the process of rubber extrusion, the feed structure directly affects the extrusion quality, extrusion uniformity, screw lateral force, and feed power consumption. Until now, the feed structure was mainly based on empirical designs, and there was no theoretical model for the optimal design of a feed structure. This paper focused on the squeezing mechanical analysis and model establishment of the feeding process in which viscoelastic rubber strips are passed through feed-wedge clearance in cold-feed extruders. The screw flight rotation squeezing process was simplified into a disc rotation squeezing process; the instantaneous squeezing velocity h˙(t) in the disc rotation squeezing model was derived according to feed wedge clearance geometry and the disc rotating speed. By transforming rotation squeezing into differential slab squeezing, mathematical expressions of the velocity distribution, pressure distribution, total squeezing force, and power consumption in the feeding process were derived in a rectangular coordinate system under isothermal and quasi-steady assumptions and certain boundary conditions by using balance equations and a Newtonian viscous constitutive relation. Theoretical calculations and experimental values showed the same trend. Through comparison, it was found that the power consumption (P3) caused by sliding friction is about 200–900 W according to theoretical calculations, while the experimental test results show it to be about 300–700 W. Additionally, the difference between theoretical pressure value and the experimental pressure value can be controlled within 5–15%. This could reflect the main factors that affect the feeding process, so could be used for analyses of actual feeding problems, and to contribute to rough quantitative descriptions of the feeding process, finite element simulation, and the optimization of the feeding structure. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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26 pages, 6947 KiB  
Article
Research on the Mechanical Properties and Stretch Forming Simulation of Triaxial Geogrid with Different Pre-Punched Hole Diameters
by Xinbo Ren, Xinhai Zhao, Chao Zheng, Libin Song, Ji Liu and Zhiyuan Si
Polymers 2022, 14(13), 2594; https://doi.org/10.3390/polym14132594 - 27 Jun 2022
Cited by 2 | Viewed by 1579
Abstract
In this paper, the tensile behavior of industrial polypropylene triaxial geogrid with different pre-punched hole diameters was studied by experiment and numerical analysis. The industrial polypropylene sheets with different diameters of circular holes were stretched at elevated temperature and then the tensile properties [...] Read more.
In this paper, the tensile behavior of industrial polypropylene triaxial geogrid with different pre-punched hole diameters was studied by experiment and numerical analysis. The industrial polypropylene sheets with different diameters of circular holes were stretched at elevated temperature and then the tensile properties of triaxial geogrids at room temperature were evaluated. It was found that the pre-punched hole diameter of triaxial geogrid had a very close relationship with the mechanical properties. With the increase of the pre-punched hole diameter, the tensile strength of triaxial geogrid shows a trend of first increasing and then decreasing. Combined with numerical simulation, the optimal pre-punched hole diameter can be accurately obtained, and the distribution law of the width, thickness, stress, and strain of triaxial geogrid can be obtained. Under the condition of a stretching ratio of 3 and node spacing of 3 mm, it was found that the mechanical properties of industrial polypropylene triaxial geogrid was the best when the pre-punched hole diameter was 2.6 mm. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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20 pages, 4350 KiB  
Article
A Design of Experiments (DoE) Approach to Optimize Cryogel Manufacturing for Tissue Engineering Applications
by Duarte Nuno Carvalho, Cristiana Gonçalves, Joaquim Miguel Oliveira, David S. Williams, Andrew Mearns-Spragg, Rui L. Reis and Tiago H. Silva
Polymers 2022, 14(10), 2026; https://doi.org/10.3390/polym14102026 - 16 May 2022
Cited by 4 | Viewed by 2471
Abstract
Marine origin polymers represent a sustainable and natural alternative to mammal counterparts regarding the biomedical application due to their similarities with proteins and polysaccharides present in extracellular matrix (ECM) in humans and can reduce the risks associated with zoonosis and overcoming social- and [...] Read more.
Marine origin polymers represent a sustainable and natural alternative to mammal counterparts regarding the biomedical application due to their similarities with proteins and polysaccharides present in extracellular matrix (ECM) in humans and can reduce the risks associated with zoonosis and overcoming social- and religious-related constraints. In particular, collagen-based biomaterials have been widely explored in tissue engineering scaffolding applications, where cryogels are of particular interest as low temperature avoids protein denaturation. However, little is known about the influence of the parameters regarding their behavior, i.e., how they can influence each other toward improving their physical and chemical properties. Factorial design of experiments (DoE) and response surface methodology (RSM) emerge as tools to overcome these difficulties, which are statistical tools to find the most influential parameter and optimize processes. In this work, we hypothesized that a design of experiments (DoE) model would be able to support the optimization of the collagen-chitosan-fucoidan cryogel manufacturing. Therefore, the parameters temperature (A), collagen concentration (B), and fucoidan concentration (C) were carefully considered to be applied to the Box–Behnken design (three factors and three levels). Data obtained on rheological oscillatory measurements, as well as on the evaluation of antioxidant concentration and adenosine triphosphate (ATP) concentration, showed that fucoidan concentration could significantly influence collagen-chitosan-fucoidan cryogel formation, creating a stable internal polymeric network promoted by ionic crosslinking bonds. Additionally, the effect of temperature significantly contributed to rheological oscillatory properties. Overall, the condition that allowed us to have better results, from an optimization point of view according to the DoE, were the gels produced at −80 °C and composed of 5% of collagen, 3% of chitosan, and 10% fucoidan. Therefore, the proposed DoE model was considered suitable for predicting the best parameter combinations needed to develop these cryogels. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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14 pages, 3673 KiB  
Article
Effect of Organoclay Addition on Rheological, Thermal, and Mechanical Properties of Nitrile Rubber/Phenolic Resin Blend
by Sara Shafiee, Leila Bazli, Mohammad Karrabi, Mir Hamid Reza Ghoreishy and Milad Bazli
Polymers 2022, 14(7), 1463; https://doi.org/10.3390/polym14071463 - 03 Apr 2022
Cited by 1 | Viewed by 1953
Abstract
In this study, the effects of NBR polarity and organoclay addition on the curing, rheological, mechanical, and thermal properties of an NBR/phenolic resin blend were investigated. The samples were prepared using a two-roll mill. The results showed that rheological and tensile properties improved [...] Read more.
In this study, the effects of NBR polarity and organoclay addition on the curing, rheological, mechanical, and thermal properties of an NBR/phenolic resin blend were investigated. The samples were prepared using a two-roll mill. The results showed that rheological and tensile properties improved due to the good distribution of nanoparticles, as well as the good compatibility of nitrile butadiene rubber with phenolic resin. The addition of 1.5 phr of nanoparticles to blends containing 33% and 45% acrylonitrile increased the curing torque difference by approximately 12% and 28%, respectively. In addition, the scorch time and curing time decreased in nanocomposites. Adding nanoparticles also increased the viscosity. The addition of phenolic resins and nanoparticles has a similar trend in modulus changes, and both of these factors increase the stiffness and, consequently, the elastic and viscous modulus of the specimens. Adding 1.5 phr of organoclay increased the tensile strength of the blends by around 8% and 13% in the samples with low and high content of acrylonitrile, respectively. Increasing the temperature of the tensile test led to a reduction in the tensile properties of the samples. Tensile strength, elongation at break, modulus, and hardness of the samples increased with increasing organoclay content. In addition, with increasing nanoparticle concentration, the samples underwent lower deterioration in tensile strength and Young’s modulus at different temperatures compared to the blends. In the samples containing 1.5 phr of organoclay, the thermal decomposition temperatures were enhanced by around 24 and 27 °C for low and high acrylonitrile content. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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27 pages, 11097 KiB  
Article
A Low-Cost Filament Winding Technology for University Laboratories and Startups
by Artem Andrianov, Erika Kamada Tomita, Carlos Alberto Gurgel Veras and Bruno Telles
Polymers 2022, 14(5), 1066; https://doi.org/10.3390/polym14051066 - 07 Mar 2022
Cited by 11 | Viewed by 5107
Abstract
This paper systematically explains the methodology and results of empirical work on the development of a low-cost filament winding technology for manufacturing axisymmetric polymer composite structures with a high length-to-diameter ratio, such as tubes, motor casings, and pressure vessels. The principal objective was [...] Read more.
This paper systematically explains the methodology and results of empirical work on the development of a low-cost filament winding technology for manufacturing axisymmetric polymer composite structures with a high length-to-diameter ratio, such as tubes, motor casings, and pressure vessels. The principal objective was to examine the experiences and most optimal practices in the development of computer-controlled equipment and auxiliary tooling for the wet filament-winding process. To preclude expensive commercial software for the automated control of a winding machine, analytical equations were derived for the winding trajectory of a four-axis filament-winding machine. The feasibility of the proposed equations was successfully validated by laying the fiber along the geodesic path marked on the surface of a cylindrical mandrel with hemispherical ends. Moreover, the carbon/epoxy cylindrical casings with hemispherical ends and port openings of the same diameter were wound to determine the thickness distribution in the hemispherical dome. The fiber volume ratio in the wound composite parts was evaluated using an optical technique. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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21 pages, 5721 KiB  
Article
Failure-Mode Shift of Metal/Composite L-Joint with Grooved Structure under Compressive Load
by Zhenhang Kang, Zhu Liu, Yongpeng Lei and Jifeng Zhang
Polymers 2022, 14(5), 1051; https://doi.org/10.3390/polym14051051 - 06 Mar 2022
Cited by 1 | Viewed by 1721
Abstract
Bond length and bond interface morphology have a great influence on the performance of metal/composite hybrid joints. In this paper, a metal/composite L-joint with groove structure was designed, and seven groups with different bonding lengths were fabricated using the VARI (Vacuum Assisted Resin [...] Read more.
Bond length and bond interface morphology have a great influence on the performance of metal/composite hybrid joints. In this paper, a metal/composite L-joint with groove structure was designed, and seven groups with different bonding lengths were fabricated using the VARI (Vacuum Assisted Resin Infusion) process to study the effect of different bonding lengths on the performance of the joint. In the simulation analysis of the metal/composite L-joint, the stiffness equivalence method was adopted, and the groove structure was equivalent to a 0-thickness element layer. The applicability of the simulation method was verified by comparing the ultimate load, displacement and failure mode of the test and simulation. Furthermore, the simulation method was used to simulate more compression experiments of metal/composite L-joints with different bonding lengths, and prediction diagrams of failure displacement and failure mode were produced. According to the prediction map, when the bonding length is 100.00 mm, the metal/composite L-joint has better compressive properties. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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17 pages, 6761 KiB  
Article
Effect Mechanism and Simulation of Voids on Hygrothermal Performances of Composites
by Zhu Liu, Yongpeng Lei, Xiangyang Zhang, Zhenhang Kang and Jifeng Zhang
Polymers 2022, 14(5), 901; https://doi.org/10.3390/polym14050901 - 24 Feb 2022
Cited by 13 | Viewed by 1925
Abstract
Voids are comment defects generated during the manufacturing process and highly sensitive to moisture in the hygrothermal environment, which has deleterious effects on the mechanical performances. However, the combined impact of void content and water-absorbed content on mechanical properties is not clear. Based [...] Read more.
Voids are comment defects generated during the manufacturing process and highly sensitive to moisture in the hygrothermal environment, which has deleterious effects on the mechanical performances. However, the combined impact of void content and water-absorbed content on mechanical properties is not clear. Based on the random sequential adsorption algorithm, a microscale unit cell with random distribution of fibers, interfaces and voids was established. The quantitative effects of voids content on strength and modulus under the loading of transverse tension, compression and shear were investigated by introducing a degradation factor dependent on water content into the constitutive model, and the different failure mechanisms before and after hygrothermal aging were revealed. Conclusively, before hygrothermal aging, voids induce the decrease in mechanical properties due to stress concentration, and every 1% increase in the void content results in a 6.4% decrease in transverse tensile strength. However, matrix degradation due to the absorbed water content after hygrothermal aging is the dominant factor, and the corresponding rate is 3.86%. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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14 pages, 2807 KiB  
Article
Numerical Simulation of Impregnation Process of Reactive Injection Pultrusion for Glass Fiber/PA6 Composites
by Xueliang Ding, Quanguo He, Qun Yang, Suwei Wang and Ke Chen
Polymers 2022, 14(4), 666; https://doi.org/10.3390/polym14040666 - 10 Feb 2022
Cited by 8 | Viewed by 2397
Abstract
Pultrusion of thermoplastic composites has been the hotspot of manufacturing high-performance thermoplastic composites in recent years. The optimization of process parameters in the pultrusion usually needed repeated attempts, which wasted lots of manpower and material resources. A numerical simulation method can accelerate the [...] Read more.
Pultrusion of thermoplastic composites has been the hotspot of manufacturing high-performance thermoplastic composites in recent years. The optimization of process parameters in the pultrusion usually needed repeated attempts, which wasted lots of manpower and material resources. A numerical simulation method can accelerate the optimization of process parameters. In this work, the impregnation process of reactive injection pultrusion for glass fiber reinforced nylon 6 (GF/PA6) composites was modeled and numerically simulated by a finite element/controlled volume (Fe/CV) method. Based on Darcy’s law, the impregnation process can be regarded as the two-phase flow (liquid resin and air) in porous media (undirectional glass fibers). The distribution of resin flow during the impregnation was explored. The effects of pulling rate and injection pressure on the impregnation time and resin reflux distance were analyzed, and the appropriate range of relevant process parameters was determined. The results showed that increasing the pulling rate can significantly control the reflux distance of resin in the impregnation mold and shorten the impregnation time, but too high a pulling rate would increase the impregnation time. Increasing the injection pressure can greatly shorten the resin impregnation time, but it would significantly increase the resin reflux distance. This work can effectively guide the subsequent optimization of process parameters of reactive injection pultrusion for GF/PA6 composites. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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11 pages, 90081 KiB  
Article
An Enamel Based Biopolymer Prosthesis for Dental Treatment with the Proper Bond Strength and Hardness and Biosafety
by Morakot Piemjai and Patcharee Santiwarapan
Polymers 2022, 14(3), 538; https://doi.org/10.3390/polym14030538 - 28 Jan 2022
Cited by 2 | Viewed by 2136
Abstract
Although dental prosthesis materials such as metal alloys, ceramics, and cured resin composite have long been utilized to restore teeth, their bond strength and hardness values are not well matched to human enamel. Prosthesis detachment and opposing enamel wear are major concerns in [...] Read more.
Although dental prosthesis materials such as metal alloys, ceramics, and cured resin composite have long been utilized to restore teeth, their bond strength and hardness values are not well matched to human enamel. Prosthesis detachment and opposing enamel wear are major concerns in restorative dentistry. An experimental biopolymer, hybridized enamel, was synthesized and utilized as a dental prosthesis to compare hardness and tensile bond strength (TBS) with those of commercial materials. Vickers hardness (VHN) with a 100 g loading for 15 s at eight indentations on each specimen (n = 20) was measured. TBSs between prostheses and two types of resin luting agents (n = 10), Super-Bond C&B and All-Bond2 + Duo-Link, were tested. Fractured surfaces and the luting resin-prosthesis interface were examined under a stereomicroscope or a scanning electron microscope (SEM). Statistically significant differences in the TBS and hardness were revealed (p < 0.05). The experimental biopolymer provided a hardness value comparable with human enamel and the highest TBS for both luting agent types. The SEM micrograph demonstrated a honeycomb-like pattern interface between the experimental biopolymer and luting resin. These results suggest that this experimental biopolymer may be a better restorative material to protect from natural enamel loss from tooth reduction or attrition and prevent prosthesis detachment during mastication. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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21 pages, 4651 KiB  
Article
Multi-Criteria Decision Approach to Design a Vacuum Infusion Process Layout Providing the Polymeric Composite Part Quality
by Sergey Shevtsov, Igor Zhilyaev, Shun-Hsyung Chang, Jiing-Kae Wu and Natalia Snezhina
Polymers 2022, 14(2), 313; https://doi.org/10.3390/polym14020313 - 13 Jan 2022
Cited by 11 | Viewed by 1843
Abstract
The increasingly widespread use of vacuum assisted technologies in the manufacture of polymer-composite structures does not always provide the required product quality and repeatability. Deterioration of quality most often appears itself in the form of incomplete filling of the preform with resin as [...] Read more.
The increasingly widespread use of vacuum assisted technologies in the manufacture of polymer-composite structures does not always provide the required product quality and repeatability. Deterioration of quality most often appears itself in the form of incomplete filling of the preform with resin as a result of the inner and outer dry spot formation, as well as due to premature gelation of the resin and blockage of the vacuum port. As experience shows, these undesirable phenomena are significantly dependent on the location of the resin and vacuum ports. This article presents a method for making a decision on the rational design of a process layout. It is based on early forecasting of its objectives in terms of quality and reliability when simulating its finite element model, on the correlation analysis of the preliminary and final quality assessments, as well as on the study of the cross-correlation of a group of early calculated sub-criteria. The effectiveness of the proposed method is demonstrated by the example of vacuum infusion of a 3D thin-walled structure of complex geometry. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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12 pages, 1766 KiB  
Article
A Flexible Sandwich Structure Carbon Fiber Cloth with Resin Coating Composite Improves Electromagnetic Wave Absorption Performance at Low Frequency
by Yuanjun Liu, Qianqian Lu, Jing Wang and Xiaoming Zhao
Polymers 2022, 14(2), 233; https://doi.org/10.3390/polym14020233 - 07 Jan 2022
Cited by 15 | Viewed by 2688
Abstract
In order to improve the electromagnetic wave absorbing performance of carbon fiber cloth at low frequency and reduce the secondary pollution caused by the shielding mechanism, a flexible sandwich composite was designed by a physical mixing coating process. This was composed of a [...] Read more.
In order to improve the electromagnetic wave absorbing performance of carbon fiber cloth at low frequency and reduce the secondary pollution caused by the shielding mechanism, a flexible sandwich composite was designed by a physical mixing coating process. This was composed of a graphene layer that absorbed waves, a carbon fiber cloth layer that reflected waves, and a graphite layer that absorbed transmitted waves. The influence of the content of graphene was studied by a control variable method on the electromatic and mechanical properties. The structures of defect polarization relaxation and dipole polarization relaxation of graphene, the interfacial polarization and electron polarization of graphite, the conductive network formed in the carbon fiber cloth, and the interfacial polarization of each part, combined together to improve the impedance matching and wave multiple reflections of the material. The study found that the sample with 40% graphene had the most outstanding absorbing performance. The minimum reflection loss value was −18.62 dB, while the frequency was 2.15 GHz and the minimum reflection loss value compared to the sample with no graphene increased 76%. The composites can be mainly applied in the field of flexible electromagnetic protection, such as the preparation of stealth tent, protective covers of electronic boxes, helmet materials for high-speed train drivers, etc. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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12 pages, 6510 KiB  
Article
PLA Biocomposites: Evaluation of Resistance to Mold
by Piotr Borysiuk, Krzysztof Krajewski, Alicja Auriga, Radosław Auriga, Izabela Betlej, Katarzyna Rybak, Małgorzata Nowacka and Piotr Boruszewski
Polymers 2022, 14(1), 157; https://doi.org/10.3390/polym14010157 - 31 Dec 2021
Cited by 7 | Viewed by 2208
Abstract
Due to the content of lignocellulosic particles, wood plastic composites (WPC) composites can be attacked by both domestic and mold fungi. Household fungi reduce the mechanical properties of composites, while mold fungi reduce the aesthetics of products by changing their color and surface [...] Read more.
Due to the content of lignocellulosic particles, wood plastic composites (WPC) composites can be attacked by both domestic and mold fungi. Household fungi reduce the mechanical properties of composites, while mold fungi reduce the aesthetics of products by changing their color and surface decomposition of the wood substance. As part of this study, the impact of lignocellulosic fillers in the form of sawdust and bark in poly (lactic acid) (PLA)-based biocomposites on their susceptibility to mold growth was determined. The evaluation of the samples fouled with mold fungi was performed by computer analysis of the image. For comparison, tests were carried out on analogous high-density polyethylene (HDPE) composites. Three levels of composites’ filling were used with two degrees of comminution of lignocellulosic fillers and the addition of bonding aids to selected variants. The composites were produced in two stages employing extrusion and flat pressing. The research revealed that PLA composites were characterized by a higher fouling rate by Aspergillus niger Tiegh fungi compared to HDPE composites. In the case of HDPE composites. The type of filler (bark, sawdust) affected this process much more in the case of HDPE composites than for PLA composites. In addition, the use of filler with smaller particles enhanced the fouling process. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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13 pages, 8590 KiB  
Article
Effect of Low Nanodiamond Concentrations and Polymerization Techniques on Physical Properties and Antifungal Activities of Denture Base Resin
by Shaimaa M. Fouda, Mohammed M. Gad, Passent Ellakany, Maram A. Al Ghamdi, Soban Q. Khan, Sultan Akhtar, Doaa M. Al Eraky and Fahad A. Al-Harbi
Polymers 2021, 13(24), 4331; https://doi.org/10.3390/polym13244331 - 10 Dec 2021
Cited by 5 | Viewed by 1978
Abstract
Background: Denture base resin has some drawbacks. This study investigated the impact of nanodiamonds (ND) and autoclave polymerization on the surface characteristics, translucency, and Candida albicans adherence in polymethyl methacrylate (PMMA) denture base resin after thermocycling. Methods: Heat-polymerized PMMA discs (15 × 2 [...] Read more.
Background: Denture base resin has some drawbacks. This study investigated the impact of nanodiamonds (ND) and autoclave polymerization on the surface characteristics, translucency, and Candida albicans adherence in polymethyl methacrylate (PMMA) denture base resin after thermocycling. Methods: Heat-polymerized PMMA discs (15 × 2 mm) with a total sample size n = 160 were studied. Specimens were categorized into two main groups (N = 80): conventional water-bath-polymerized PMMA (CP/PMMA) and autoclave-polymerized PMMA (AP/PMMA). Each group was subdivided according to the ND concentration into four groups (n = 20): unmodified PMMA as a control, and 0.1%, 0.25%, and 0.5% ND–PMMA. Scanning electron microscopy (SEM) was used to inspect the morphology of the ND and the ND–PMMA mixtures before heat polymerization. The specimens were exposed to thermal cycling (5000 cycles at 5 and 55 °C), then surface roughness was measured with a non-contact optical interferometric profilometer, contact angle with an automated goniometer, and translucency using a spectrophotometer. Colony-forming units (CFU) were used to determine the adherence of Candida albicans cells to the specimens. ANOVA and Tukey post hoc tests for pairwise comparison were utilized for the statistical analysis (α = 0.05). Results: Surface roughness was significantly reduced with ND addition to CP/PMMA (p ˂ 0.001), while the reduction was not statistically significant in AP/PMMA (p = 0.831). The addition of ND significantly reduced the contact angle, translucency, and Candida albicans count of CP/PMMA and AP/PMMA (p ˂ 0.001). The incorporation of ND in conjunction with autoclave polymerization of PMMA showed significant reduction in all tested properties (surface roughness, contact angle and Candida albicans adherence) except translucency (p = 0.726). Conclusions: ND addition to PMMA and autoclave polymerization improved the surface properties with respect to antifungal activities, while the translucency was adversely affected. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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15 pages, 9340 KiB  
Article
Assessment of Extremely Cold Subarctic Climate Environment Destruction of the Basalt Fiber Reinforced Epoxy (BFRE) Rebar Using Its Moisture Uptake Kinetics
by Anatoly K. Kychkin, Anna A. Gavrilieva, Alina A. Vasilieva, Aisen A. Kychkin, Mikhail P. Lebedev and Anastasia V. Sivtseva
Polymers 2021, 13(24), 4325; https://doi.org/10.3390/polym13244325 - 10 Dec 2021
Cited by 1 | Viewed by 1838
Abstract
A quite simple method is proposed for the assessment of extremely cold subarctic climate environment destruction of the basalt fiber reinforced epoxy (BFRE) rebar. The method involves the comparison of experimentally obtained long-term moisture uptake kinetic curves of unexposed and exposed BFRP rebars. [...] Read more.
A quite simple method is proposed for the assessment of extremely cold subarctic climate environment destruction of the basalt fiber reinforced epoxy (BFRE) rebar. The method involves the comparison of experimentally obtained long-term moisture uptake kinetic curves of unexposed and exposed BFRP rebars. A moisture uptake test was carried out at the temperature of 60 °C and relative humidity of 98 ± 2% for 306 days. The plasticization can be neglected because of low-level moisture saturation (<0.41% wt.); the swelling and structural relaxation of the polymer network can be neglected due to the high fiber content of BFRP rebar; moisture diffusion into the basalt fibers can be neglected since it is a much lesser amount than in the epoxy binder. These assumptions made it possible to build a three-stage diffusion model. It is observed that an increase in the density of defects with an increase in the diameter of the BFRP rebar is the result of the technology of manufacturing a periodic profile. The diffusion coefficient of the BFRP rebar with a 6, 10, or 18 mm diameter increased at an average of 82.7%, 56.7%, and 30%, respectively, after exposure to the climate of Yakutsk during 28 months, whereas it was known that the strength indicators had been increased. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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14 pages, 64414 KiB  
Article
Evaluation of the Sensitivity of Various Reinforcement Patterns for Structural Carbon Fibers to Open Holes during Tensile Tests
by Elena Strungar, Dmitrii Lobanov and Valery Wildemann
Polymers 2021, 13(24), 4287; https://doi.org/10.3390/polym13244287 - 07 Dec 2021
Cited by 10 | Viewed by 2172
Abstract
This paper is devoted to the experimental study of polymeric composite specimens, with various types of reinforcement, in order to evaluate the breaking strength of specimens with open holes when undergoing uniaxial compression and tensile tests. Four types of interlaced 3D woven preforms [...] Read more.
This paper is devoted to the experimental study of polymeric composite specimens, with various types of reinforcement, in order to evaluate the breaking strength of specimens with open holes when undergoing uniaxial compression and tensile tests. Four types of interlaced 3D woven preforms were considered (orthogonal, orthogonal combined, with pairwise inter-layer reinforcement, and with pairwise inter-layer reinforcement and a longitudinal layer), with a layered preform used for comparison. Tensile tests of solid specimens without a hole, under ASTM D 3039, and of specimens with an open hole, under ASTM D 5766, were carried out using the Instron 5989 universal electromechanical testing system. Movements and strains on the specimen surface were recorded using a Vic-3D contactless optical video system and the digital images correlation method (DIC). For all the series of carbon fiber tension specimens, strain and stress diagrams, mechanical characteristics, and statistical processing for 10 specimens were obtained. The paper evaluated deformation fields for certain points in time; the obtained fields showed an irregular distribution of deformation and dependency on types of reinforcing fibers. A coefficient of strength variation is introduced, which is defined as a ratio of the ultimate stress limits obtained on solid samples with and without open holes. Within the framework of ASTM D 5766, when calculating the ultimate stress, the hole is not taken into account, and the paper shows that for certain structures a hole cannot be excluded. The hole size must not be neglected when calculating the ultimate stress. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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14 pages, 2020 KiB  
Article
Antibacterial and UV Protection Properties of Modified Cotton Fabric Using a Curcumin/TiO2 Nanocomposite for Medical Textile Applications
by M. M. Abd El-Hady, A. Farouk, S. El-Sayed Saeed and S. Zaghloul
Polymers 2021, 13(22), 4027; https://doi.org/10.3390/polym13224027 - 21 Nov 2021
Cited by 24 | Viewed by 3135
Abstract
Medical textiles are one of the most rapidly growing parts of the technical textiles sector in the textile industry. This work aims to investigate the medical applications of a curcumin/TiO2 nanocomposite fabricated on the surface of cotton fabric. The cotton fabric was [...] Read more.
Medical textiles are one of the most rapidly growing parts of the technical textiles sector in the textile industry. This work aims to investigate the medical applications of a curcumin/TiO2 nanocomposite fabricated on the surface of cotton fabric. The cotton fabric was pretreated with three crosslinking agents, namely citric acid, 3-Chloro-2-hydroxypropyl trimethyl ammonium chloride (Quat 188) and 3-glycidyloxypropyltrimethoxysilane (GPTMS), by applying the nanocomposite to the modified cotton fabric using the pad-dry-cure method. The chemistry and morphology of the modified fabrics were examined by Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. In addition, the chemical mechanism for the nanocomposite-modified fabric was reported. UV protection (UPF) and antibacterial properties against Gram-positive S. aureus and Gram-negative E. coli bacterial strains were investigated. The durability of the fabrics to 20 washing cycles was also examined. Results demonstrated that the nanocomposite-modified cotton fabric exhibited superior antibacterial activity against Gram-negative bacteria than Gram-positive bacteria and excellent UV protection properties. Moreover, a good durability was obtained, which was possibly due to the effect of the crosslinker used. Among the three pre-modifications of the cotton fabric, Quat 188 modified fabric revealed the highest antibacterial activity compared with citric acid or GPTMS modified fabrics. This outcome suggested that the curcumin/TiO2 nanocomposite Quat 188-modified cotton fabric could be used as a biomedical textile due to its antibacterial properties. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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16 pages, 5189 KiB  
Article
Effect of Fibre Surface Treatment and Nanofiller Addition on the Mechanical Properties of Flax/PLA Fibre Reinforced Epoxy Hybrid Nanocomposite
by Adnan Amjad, M. Shukur Zainol Abidin, Hassan Alshahrani and Aslina Anjang Ab Rahman
Polymers 2021, 13(21), 3842; https://doi.org/10.3390/polym13213842 - 06 Nov 2021
Cited by 17 | Viewed by 2595
Abstract
Natural fibre-based materials are gaining popularity in the composites industry, particularly for automotive structural and semi-structural applications, considering the growing interest and awareness towards sustainable product design. Surface treatment and nanofiller addition have become one of the most important aspects of improving natural [...] Read more.
Natural fibre-based materials are gaining popularity in the composites industry, particularly for automotive structural and semi-structural applications, considering the growing interest and awareness towards sustainable product design. Surface treatment and nanofiller addition have become one of the most important aspects of improving natural fibre reinforced polymer composite performance. The novelty of this work is to examine the combined effect of fibre surface treatment with Alumina (Al2O3) and Magnesia (MgO) nanofillers on the mechanical (tensile, flexural, and impact) behaviour of biotex flax/PLA fibre reinforced epoxy hybrid nanocomposites. Al2O3 and MgO with a particle size of 50 nm were added in various weight proportions to the epoxy and flax/PLA fibre, and the composite laminates were formed using the vacuum bagging technique. The surface treatment of one set of fibres with a 5% NaOH solution was investigated for its effect on mechanical performance. The results indicate that the surface-treated reinforcement showed superior tensile, flexural, and impact properties compared to the untreated reinforcement. The addition of 3 wt. % nanofiller resulted in the best mechanical properties. SEM morphological images demonstrate various defects, including interfacial behaviour, fibre breakage, fibre pullout, voids, cracks, and agglomeration. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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17 pages, 2976 KiB  
Article
3D Printed Hollow Off-Axis Profiles Based on Carbon Fiber-Reinforced Polymers: Mechanical Testing and Finite Element Method Analysis
by Martina Kalova, Sona Rusnakova, David Krzikalla, Jakub Mesicek, Radek Tomasek, Adela Podeprelova, Jiri Rosicky and Marek Pagac
Polymers 2021, 13(17), 2949; https://doi.org/10.3390/polym13172949 - 31 Aug 2021
Cited by 14 | Viewed by 3122
Abstract
The aim of the paper is to design, manufacture, and test an off-axis composite profile of circular cross-section. Composite profile based on continuous carbon fibers reinforcing the onyx matrix, i.e., a matrix that consists of nylon and micro carbon fibers, was produced by [...] Read more.
The aim of the paper is to design, manufacture, and test an off-axis composite profile of circular cross-section. Composite profile based on continuous carbon fibers reinforcing the onyx matrix, i.e., a matrix that consists of nylon and micro carbon fibers, was produced by fused deposition modeling (FDM) method. A buckling test of the six printed composite specimens was performed on a tensile test machine. The values of the experiment were compared with the values of the computational simulation using the Finite Element Method (FEM) analysis. The mean value of the experimentally determined critical force at which the composite profile failed was 3102 N, while the value of the critical force by FEM analysis was calculated to be 2879 N. Thus, reliability of the simulation to determine the critical force differed from the experimental procedure by only 7%. FEM analysis revealed that the primary failure of 3D printed composite parts was not due to loss of stability, but due to material failure. With great accuracy, the results of the comparison show that it is possible to predict the mechanical properties of 3D printed composite laminates on the basis of a theoretical model. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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14 pages, 39797 KiB  
Article
Influence of Curing Time on the Microbiological Behavior of Bulk-Fill Nanohybrid Resin Composites
by Andrei C. Ionescu, Allegra Comba, Eugenio Brambilla, Nicoleta Ilie, Lorenzo Breschi, Milena Cadenaro and Nicola Scotti
Polymers 2021, 13(17), 2948; https://doi.org/10.3390/polym13172948 - 31 Aug 2021
Cited by 5 | Viewed by 1748
Abstract
This in vitro study aimed to evaluate the influence of curing time on surface characteristics and microbiological behavior of three bulk-fill resin-based composites (RBCs). Materials were light-cured for either 10 s or 80 s, then finished using a standard clinical procedure. They were [...] Read more.
This in vitro study aimed to evaluate the influence of curing time on surface characteristics and microbiological behavior of three bulk-fill resin-based composites (RBCs). Materials were light-cured for either 10 s or 80 s, then finished using a standard clinical procedure. They were characterized by surface morphology (SEM), surface elemental composition (EDS), surface roughness (SR), and surface free energy (SFE). Microbiological behavior was assessed as S. mutans adherence (2 h) and biofilm formation (24 h) using a continuous-flow bioreactor. Statistical analysis included a two-way ANOVA and Tukey’s test (p < 0.05). Materials differed substantially as filler shape, dimension, elemental composition and resin matrix composition. Significant differences between materials were found for SR, SFE, and microbiological behavior. Such differences were less pronounced or disappeared after prolonged photocuring. The latter yielded significantly lower adherence and biofilm formation on all tested materials, similar to conventional RBCs. Improved photoinitiators and UDMA-based resin matrix composition may explain these results. No correlation between surface characteristics and microbiological behavior can explain the similar microbiological behavior of bulk-fill materials after prolonged photocuring. This different performance of bulk-fill materials compared with conventional RBCs, where surface characteristics, especially surface chemistry, influence microbiological behavior, may have important implications for secondary caries occurrence and restoration longevity. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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15 pages, 3473 KiB  
Article
Polyaniline: Doping and Functionalization with Single Walled Carbon Nanotubes for Photovoltaic and Photocatalytic Application
by Mariem Saoudi, Boubaker Zaidi, Abdullah A. Alotaibi, M.G. Althobaiti, Eid M. Alosime and Ridha Ajjel
Polymers 2021, 13(16), 2595; https://doi.org/10.3390/polym13162595 - 05 Aug 2021
Cited by 9 | Viewed by 2282
Abstract
Polyaniline (PANI) was chemically doped and functionalized with single walled carbon nanotubes (SWCNTs). Various characterization methods were employed to study the structure and optical properties of PANI/SWCNTs nanocomposite, such as Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), optical [...] Read more.
Polyaniline (PANI) was chemically doped and functionalized with single walled carbon nanotubes (SWCNTs). Various characterization methods were employed to study the structure and optical properties of PANI/SWCNTs nanocomposite, such as Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), optical absorption, and stationary photoluminescence. Additionally, a theoretical study using density functional theory calculations was also carried out. It has been demonstrated that the doping process may reduce the band gap without affecting the molecular structure, leading to a better compatibility with the solar spectrum. Moreover, the functionalization process with SWCNTs was able to significantly improve the properties of the resulting nanocomposite. The final interpenetrating network of PANI/SWCNTs exhibited an optical gap of nearly 2.28 eV, from which localized states induced by the charge transfer were created at nearly 1.70 eV. In addition, the resulting donor–acceptor network leads to a separation of electron holes pairs rather than their recombination, which can be used as an active layer in photovoltaic applications and a photocatalyst for advanced oxidation processes. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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15 pages, 15134 KiB  
Article
EVA Films Loaded with Layered Double Hydroxide (LDH) Modified with Methacrylic Anion: Effect of the Nanohybrid Filler on the Photodegradation Phenomena
by Giuliana Gorrasi, Gianluca Viscusi, Giusy Curcuruto, Maria Cantarella, Alessandro Di Mauro, Paola Bernardo, Gabriele Clarizia, Andrea A. Scamporrino and Sabrina Carroccio
Polymers 2021, 13(15), 2525; https://doi.org/10.3390/polym13152525 - 30 Jul 2021
Viewed by 2029
Abstract
The photo-oxidative studies of ethylene vinyl acetate copolymer (EVA) matrix, filled with Layered Double Hydroxide (LDH) modified with methacrylic anion (MA), were herein reported, together with gas permeation tests. The formulation of nano-hybrid LDHs was characterized using X-ray diffractometry (XRD) and thermogravimetric analysis [...] Read more.
The photo-oxidative studies of ethylene vinyl acetate copolymer (EVA) matrix, filled with Layered Double Hydroxide (LDH) modified with methacrylic anion (MA), were herein reported, together with gas permeation tests. The formulation of nano-hybrid LDHs was characterized using X-ray diffractometry (XRD) and thermogravimetric analysis (TGA), demonstrating the partial intercalation of the 30% of MA anion between the LDH’s galleries. The as-modified filler was introduced into an EVA matrix by mechanical milling, producing free-standing films subjected to accelerated aging. Fourier transform infrared spectroscopy (FT-IR) results suggested that the nanohybrid presence determined a stabilizing effect up to 45 days of UV irradiation, especially if compared to the EVA/LDH references for all formulated EVA hybrid nanocomposites. Conversely, the presence of nanohybrid in the matrix did not significantly change the thermal stability of EVA samples. The dispersion of modified MA-LDH in the EVA matrix produces defect-free samples in the whole range of investigated loadings. The samples show a slight decrease in gas permeability, coupled with a substantial stabilization of the original CO2/O2 selectivity, which also proves the integrity of the films after 30 days of UV irradiation. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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15 pages, 3878 KiB  
Article
Effects of Particle Size on the Dielectric, Mechanical, and Thermal Properties of Recycled Borosilicate Glass-Filled PTFE Microwave Substrates
by Ibrahim Abubakar Alhaji, Zulkifly Abbas, Mohd Hafiz Mohd Zaid and Ahmad Mamoun Khamis
Polymers 2021, 13(15), 2449; https://doi.org/10.3390/polym13152449 - 26 Jul 2021
Cited by 5 | Viewed by 2860
Abstract
Low dielectric loss and low-cost recycled borosilicate (BRS) glass-reinforced polytetrafluoroethylene (PTFE) composites were fabricated for microwave substrate applications. The composites were prepared through a dry powder processing technique by dispersing different micron sizes (25 µm, 45 µm, 63 µm, 90 µm, and 106 [...] Read more.
Low dielectric loss and low-cost recycled borosilicate (BRS) glass-reinforced polytetrafluoroethylene (PTFE) composites were fabricated for microwave substrate applications. The composites were prepared through a dry powder processing technique by dispersing different micron sizes (25 µm, 45 µm, 63 µm, 90 µm, and 106 µm) of the recycled BRS filler in the PTFE matrix. The effect of the filler sizes on the composites’ thermal, mechanical, and dielectric properties was studied. The dielectric properties of the composites were characterised in the frequency range of 1–12 GHz using an open-ended coaxial probe (OCP) connected to a vector network analyser (VNA). XRD patterns confirmed the phase formation of PTFE and recycled BRS glass. The scanning electron microscope also showed good filler dispersion at larger filler particle sizes. In addition, the composites’ coefficient of thermal expansion and tensile strength decreased from 12.93 MPa and 64.86 ppm/°C to 7.12 MPa and 55.77 ppm/°C when the filler size is reduced from 106 μm to 25 μm. However, moisture absorption and density of the composites increased from 0.01% and 2.17 g/cm3 to 0.04% and 2.21 g/cm3. The decrement in filler size from 106 μm to 25 μm also increased the mean dielectric constant and loss tangent of the composites from 2.07 and 0.0010 to 2.18 and 0.0011, respectively, while it reduced the mean signal transmission speed from 2.088 × 108 m/s to 2.031 × 108 m/s. The presented results showed that PTFE/recycled BRS composite exhibited comparable characteristics with commercial high-frequency laminates. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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Review

Jump to: Research

28 pages, 8289 KiB  
Review
In Situ Thermoset Cure Sensing: A Review of Correlation Methods
by Molly Hall, Xuesen Zeng, Tristan Shelley and Peter Schubel
Polymers 2022, 14(15), 2978; https://doi.org/10.3390/polym14152978 - 22 Jul 2022
Cited by 4 | Viewed by 1971
Abstract
Thermoset polymer composites have increased in use across multiple industries, with recent applications consisting of high-complexity and large-scale parts. As applications expand, the emphasis on accurate process-monitoring techniques has increased, with a variety of in situ cure-monitoring sensors being investigated by various research [...] Read more.
Thermoset polymer composites have increased in use across multiple industries, with recent applications consisting of high-complexity and large-scale parts. As applications expand, the emphasis on accurate process-monitoring techniques has increased, with a variety of in situ cure-monitoring sensors being investigated by various research teams. To date, a wide range of data analysis techniques have been used to correlate data collected from thermocouple, dielectric, ultrasonic, and fibre-optic sensors to information on the material cure state. The methods used in existing publications have not been explicitly differentiated between, nor have they been directly compared. This paper provides a critical review of the different data collection and cure state correlation methods for these sensor types. The review includes details of the relevant sensor configurations and governing equations, material combinations, data verification techniques, identified potential research gaps, and areas of improvement. A wide range of both qualitative and quantitative analysis methods are discussed for each sensing technology. Critical analysis is provided on the capability and limitations of these methods to directly identify cure state information for the materials under investigation. This paper aims to provide the reader with sufficient background on available analysis techniques to assist in selecting the most appropriate method for the application. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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32 pages, 21799 KiB  
Review
Comprehensive Review of the Properties and Modifications of Carbon Fiber-Reinforced Thermoplastic Composites
by Basheer A. Alshammari, Mohammed S. Alsuhybani, Alaa M. Almushaikeh, Bander M. Alotaibi, Asma M. Alenad, Naif B. Alqahtani and Abdullah G. Alharbi
Polymers 2021, 13(15), 2474; https://doi.org/10.3390/polym13152474 - 27 Jul 2021
Cited by 68 | Viewed by 10979
Abstract
Carbon fiber-reinforced polymers are considered a promising composite for many industrial applications including in the automation, renewable energy, and aerospace industries. They exhibit exceptional properties such as a high strength-to-weight ratio and high wear resistance and stiffness, which give them an advantage over [...] Read more.
Carbon fiber-reinforced polymers are considered a promising composite for many industrial applications including in the automation, renewable energy, and aerospace industries. They exhibit exceptional properties such as a high strength-to-weight ratio and high wear resistance and stiffness, which give them an advantage over other conventional materials such as metals. Various polymers can be used as matrices such as thermosetting, thermoplastic, and elastomers polymers. This comprehensive review focuses on carbon fiber-reinforced thermoplastic polymers due to the advantages of thermoplastic compared to thermosetting and elastomer polymers. These advantages include recyclability, ease of processability, flexibility, and shorter production time. The related properties such as strength, modulus, thermal conductivity, and stability, as well as electrical conductivity, are discussed in depth. Additionally, the modification techniques of the surface of carbon fiber, including the chemical and physical methods, are thoroughly explored. Overall, this review represents and summarizes the future prospective and research developments carried out on carbon fiber-reinforced thermoplastic polymers. Full article
(This article belongs to the Special Issue Advanced Polymer Composite Materials: Processing, Modeling, Properties and Applications)
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