Research

Jump to: Review

15 pages, 5220 KiB

Open AccessArticle

Three-Dimensional Printing Process for Musical Instruments: Sound Reflection Properties of Polymeric Materials for Enhanced Acoustical Performance

by Tomáš Zvoníček, Martin Vašina, Vladimír Pata and Petr Smolka

Polymers 2023, 15(9), 2025; https://doi.org/10.3390/polym15092025 - 24 Apr 2023

Cited by 5 | Viewed by 2207

Abstract

Acoustical properties of various materials were analyzed in order to determine their potential for the utilization in the three-dimensional printing process of stringed musical instruments. Polylactic acid (PLA), polyethylene terephthalate with glycol modification (PET-G), and acrylonitrile styrene acrylate (ASA) filaments were studied in [...] Read more.

Acoustical properties of various materials were analyzed in order to determine their potential for the utilization in the three-dimensional printing process of stringed musical instruments. Polylactic acid (PLA), polyethylene terephthalate with glycol modification (PET-G), and acrylonitrile styrene acrylate (ASA) filaments were studied in terms of sound reflection using the transfer function method. In addition, the surface geometry parameters (Sa, Sq, Sz, and Sdr) were measured, and their relation to the acoustic performance of three-dimensional-printed samples was investigated. It was found that a higher layer height, and thus a faster printing process, does not necessarily mean poor acoustical properties. The proposed methodology also proved to be a relatively easy and rapid way to test the acoustic performance of various materials and the effect of three-dimensional printing parameters to test such a combination at the very beginning of the production process. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Graphical abstract

17 pages, 8261 KiB

Open AccessArticle

Geant4 Simulation of the Effect of Different Composites on Polyimide Photon and Neutron Shielding Properties

by Hanan Akhdar and Rawan Alotaibi

Polymers 2023, 15(8), 1973; https://doi.org/10.3390/polym15081973 - 21 Apr 2023

Cited by 3 | Viewed by 1343

Abstract

Polymers are widely used materials that have many medical and industrial applications. Some polymers have even been introduced as radiation-shielding materials; therefore, many studies are focusing on new polymers and their interactions with photons and neutrons. Research has recently focused on the theoretical [...] Read more.

Polymers are widely used materials that have many medical and industrial applications. Some polymers have even been introduced as radiation-shielding materials; therefore, many studies are focusing on new polymers and their interactions with photons and neutrons. Research has recently focused on the theoretical estimation of the shielding effectiveness of Polyimide doped with different composites. It is well known that theoretical studies on the shielding properties of different materials through modeling and simulation have many benefits, as they help scientists to choose the right shielding material for a specific application, and they are also much more cost-effective and take much less time compared to experimental studies. In this study, Polyimide (C₃₅H₂₈N₂O₇) was investigated. It is a high-performance polymer, well known for its outstanding chemical and thermal stability, as well as for its high mechanical resistance. Because of its exceptional properties, it is used in high-end applications. The performance of Polyimide and Polyimide doped with different weight fractions of composites (5, 10, 15, 20 and 25 wt.%) as a shielding material against photons and neutrons were investigated using a Monte Carlo-based simulation toolkit Geant4 within a wide range of energies of both photons and neutrons from 10 to 2000 KeVs. Polyimide can be considered a good neutron shielding material, and its photon shielding abilities could be further enhanced when adding different high atomic number composites to it. The results showed that Au and Ag gave the best results in terms of the photon shielding properties, while ZnO and TiO₂ had the least negative effect on the neutron shielding properties. The results also indicate that Geant4 is a very reliable tool when it comes to evaluating the shielding properties against photons and neutrons of any material. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

18 pages, 30455 KiB

Open AccessArticle

Fabrication of 3D Printed Ceramic Part Using Photo-Polymerization Process

by Da-Sol Lim, Jin-Kyo Chung, Ji-Sun Yun and Min-Soo Park

Polymers 2023, 15(7), 1601; https://doi.org/10.3390/polym15071601 - 23 Mar 2023

Cited by 4 | Viewed by 1786

Abstract

Ceramics are high-strength and high-temperature resistant materials that are used in various functional parts. However, due to the high strength and brittleness properties, there are many difficulties in the fabrication of complex shapes. Therefore, there are many studies related to the fabrication of [...] Read more.

Ceramics are high-strength and high-temperature resistant materials that are used in various functional parts. However, due to the high strength and brittleness properties, there are many difficulties in the fabrication of complex shapes. Therefore, there are many studies related to the fabrication of ceramic parts using 3D printing technology optimized for complex shapes. Among them, studies using photo-polymerization (PP) 3D printing technology with excellent dimensional accuracy and surface quality have received the most widespread attention. To secure the physical properties of sintered ceramic, the content and distribution of materials are important. This study suggests a novel 3D printing process based on a high-viscosity composite resin that maximizes the content of zirconia ceramics. For reliable printing, the developed 3D printers that can adjust the process environment were used. To minimize warpage and delamination, the divided micro square pattern images were irradiated in two separate intervals of 1.6 s each while maintaining the internal chamber temperature at 40 °C. This contributed to improved stability and density of the sintered structures. Ultimately, the ceramic parts with a Vickers hardness of 12.2 GPa and a relative density of over 95% were able to be fabricated based on a high-viscosity resin with 25,000 cps. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

17 pages, 2625 KiB

Open AccessArticle

Antimicrobial and Antiviral Properties of Triclosan-Containing Polymer Composite: Aging Effects of pH, UV, and Sunlight Exposure

by Zhandos Tauanov, Olzhas Zakiruly, Zhuldyz Baimenova, Alzhan Baimenov, Nuraly S. Akimbekov and Dmitriy Berillo

Polymers 2023, 15(5), 1236; https://doi.org/10.3390/polym15051236 - 28 Feb 2023

Cited by 4 | Viewed by 1600

Abstract

The present study deals with the synthesis and characterization of a polymer composite based on an unsaturated ester loaded with 5 wt.% triclosan, produced by co-mixing on an automated hardware system. The polymer composite’s non-porous structure and chemical composition make it an ideal [...] Read more.

The present study deals with the synthesis and characterization of a polymer composite based on an unsaturated ester loaded with 5 wt.% triclosan, produced by co-mixing on an automated hardware system. The polymer composite’s non-porous structure and chemical composition make it an ideal material for surface disinfection and antimicrobial protection. According to the findings, the polymer composite effectively inhibited (100%) the growth of Staphylococcus aureus 6538-P under exposure to physicochemical factors, including pH, UV, and sunlight, over a 2-month period. In addition, the polymer composite demonstrated potent antiviral activity against human influenza virus strain A and the avian coronavirus infectious bronchitis virus (IBV), with infectious activities of 99.99% and 90%, respectively. Thus, the resulting triclosan-loaded polymer composite is revealed to have a high potential as a surface-coating non-porous material with antimicrobial properties. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

14 pages, 27558 KiB

Open AccessArticle

A Shape Memory Alloy-Based Soft Actuator Mimicking an Elephant’s Trunk

by Minchae Kang, Ye-Ji Han and Min-Woo Han

Polymers 2023, 15(5), 1126; https://doi.org/10.3390/polym15051126 - 23 Feb 2023

Cited by 10 | Viewed by 3694

Abstract

Soft actuators that execute diverse motions have recently been proposed to improve the usability of soft robots. Nature-inspired actuators, in particular, are emerging as a means of accomplishing efficient motions based on the flexibility of natural creatures. In this research, we present an [...] Read more.

Soft actuators that execute diverse motions have recently been proposed to improve the usability of soft robots. Nature-inspired actuators, in particular, are emerging as a means of accomplishing efficient motions based on the flexibility of natural creatures. In this research, we present an actuator capable of executing multi-degree-of-freedom motions that mimics the movement of an elephant’s trunk. Shape memory alloys (SMAs) that actively react to external stimuli were integrated into actuators constructed of soft polymers to imitate the flexible body and muscles of an elephant’s trunk. The amount of electrical current provided to each SMA was adjusted for each channel to achieve the curving motion of the elephant’s trunk, and the deformation characteristics were observed by varying the quantity of current supplied to each SMA. It was feasible to stably lift and lower a cup filled with water by using the operation of wrapping and lifting objects, as well as effectively performing the lifting task of surrounding household items of varying weights and forms. The designed actuator is a soft gripper that incorporates a flexible polymer and an SMA to imitate the flexible and efficient gripping action of an elephant trunk, and its fundamental technology is expected to be used as a safety-enhancing gripper that requires environmental adaptation. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

24 pages, 4461 KiB

Open AccessArticle

Structural Insights into LDPE/UHMWPE Blends Processed by γ-Irradiation

by Traian Zaharescu, Nicoleta Nicula, Maria Râpă, Mihai Iordoc, Violeta Tsakiris and Virgil Emanuel Marinescu

Polymers 2023, 15(3), 696; https://doi.org/10.3390/polym15030696 - 30 Jan 2023

Cited by 2 | Viewed by 1295

Abstract

Ultra-high-molecular-weight polyethylene (UHMWPE) matrices containing low-density polyethylene (LDPE), hydroxyapatite (HAp) as filler, and rosemary extract (RM) as stabilizer were investigated for their qualification for long-term applications. The significant contributions of the blend components were analyzed, and variations in mechanical properties, oxidation strength, thermal [...] Read more.

Ultra-high-molecular-weight polyethylene (UHMWPE) matrices containing low-density polyethylene (LDPE), hydroxyapatite (HAp) as filler, and rosemary extract (RM) as stabilizer were investigated for their qualification for long-term applications. The significant contributions of the blend components were analyzed, and variations in mechanical properties, oxidation strength, thermal behavior, crystallinity, and wettability were discussed. SEM images of microstructural peculiarities completed the introspective survey. The stability improvement due to the presence of both additives was an increase in the total degradation period of 67% in comparison with an unmodified HDPE/UHMWPE blend when the materials were subjected to a 50 kGy γ-dose. There was growth in activation energies from 121 kJ mol⁻¹ to 139 kJ mol⁻¹ when HAp and rosemary extract delayed oxidation. The exposure of samples to the action of γ-rays was found to be a proper procedure for accomplishing accelerated oxidative degradation. The presence of rosemary extract and HAp powder significantly increased the thermal and oxidation resistances. The calculation of material lifetimes at various temperatures provided meaningful information on the wearability and integrity of the inspected composites. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Graphical abstract

10 pages, 2754 KiB

Open AccessArticle

Molecular Simulations of Low-Shrinkage Dental Resins Containing Methacryl-Based Polyhedral Oligomeric Silsesquioxane (POSS)

by Chandra Mouli R. Madhuranthakam, Sudharsan Pandiyan and Ali Elkamel

Polymers 2023, 15(2), 432; https://doi.org/10.3390/polym15020432 - 13 Jan 2023

Cited by 1 | Viewed by 1787

Abstract

Nanocomposites of methacrylate-based polyhedral oligomeric silsesquioxane (POSS) are used as resins in dentistry to fill dental cavities. In this article, molecular dynamics simulations (MDS) are used to study and understand the interactions of monofunctional and multifunctional methacrylate groups on hybrid resins containing POSS [...] Read more.

Nanocomposites of methacrylate-based polyhedral oligomeric silsesquioxane (POSS) are used as resins in dentistry to fill dental cavities. In this article, molecular dynamics simulations (MDS) are used to study and understand the interactions of monofunctional and multifunctional methacrylate groups on hybrid resins containing POSS additives for dental applications. These interactions are further related to the structural properties of the nanocomposites, which in turn affect their macro-properties that are important, especially when used for specific uses such as dental resins. For monofunctional methacrylate, nanocomposite of methacryl isobutyl POSS (MIPOSS) and for multifunctional methacrylate, methacryl POSS (MAPOSS) are used in this study. Molecular dynamic simulations (MDS) are performed on both MIPOSS and MAPOSS systems by varying the amount of POSS. On a weight percent basis, 1%, 3%, 5%, and 10% POSS are added to the resin. Density calculations, stress–strain, and powder diffraction simulations are used to evaluate the macro-properties of these nanocomposites and compare them with the experimental findings reported in the literature. The observations from the simulation results when compared to the experimental results show that MDS can be efficiently used to design, analyze, and simulate new nanocomposites of POSS. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

17 pages, 5163 KiB

Open AccessArticle

Designing Bioinspired Composite Structures via Genetic Algorithm and Conditional Variational Autoencoder

by Yi-Hung Chiu, Ya-Hsuan Liao and Jia-Yang Juang

Polymers 2023, 15(2), 281; https://doi.org/10.3390/polym15020281 - 05 Jan 2023

Cited by 3 | Viewed by 2575

Abstract

Designing composite materials with tailored stiffness and toughness is challenging due to the massive number of possible material and geometry combinations. Although various studies have applied machine learning techniques and optimization methods to tackle this problem, we still lack a complete understanding of [...] Read more.

Designing composite materials with tailored stiffness and toughness is challenging due to the massive number of possible material and geometry combinations. Although various studies have applied machine learning techniques and optimization methods to tackle this problem, we still lack a complete understanding of the material effects at different positions and a systematic experimental procedure to validate the results. Here we study a two-dimensional (2D) binary composite system with an edge crack and grid-like structure using a Genetic Algorithm (GA) and Conditional Variational Autoencoder (CVAE), which can design a composite with desired stiffness and toughness. The fitness of each design is evaluated using the negative mean square error of their predicted stiffness and toughness and the target values. We use finite element simulations to generate a machine-learning dataset and perform tensile tests on 3D-printed specimens to validate our results. We show that adding soft material behind the crack tip, instead of ahead of the tip, tremendously increases the overall toughness of the composite. We also show that while GA generates composite designs with slightly better accuracy (both methods perform well, with errors below 20%), CVAE takes considerably less time (~1/7500) to generate designs. Our findings may provide insights into the effect of adding soft material at different locations of a composite system and may also provide guidelines for conducting experiments and Explainable Artificial Intelligence (XAI) to validate the results. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Graphical abstract

14 pages, 2559 KiB

Open AccessArticle

Magnetic Hydrogel Composite for Wastewater Treatment

by Bidita Salahuddin, Shazed Aziz, Shuai Gao, Md. Shahriar A. Hossain, Motasim Billah, Zhonghua Zhu and Nasim Amiralian

Polymers 2022, 14(23), 5074; https://doi.org/10.3390/polym14235074 - 22 Nov 2022

Cited by 4 | Viewed by 2121

Abstract

Nanocomposite hydrogels are highly porous colloidal structures with a high adsorption capacity, making them promising materials for wastewater treatment. In particular, magnetic nanoparticle (MNP) incorporated hydrogels are an excellent adsorbent for aquatic pollutants. An added advantage is that, with the application of an [...] Read more.

Nanocomposite hydrogels are highly porous colloidal structures with a high adsorption capacity, making them promising materials for wastewater treatment. In particular, magnetic nanoparticle (MNP) incorporated hydrogels are an excellent adsorbent for aquatic pollutants. An added advantage is that, with the application of an external magnetic field, magnetic hydrogels can be collected back from the wastewater system. However, magnetic hydrogels are quite brittle and structurally unstable under compact conditions such as in fixed-bed adsorption columns. To address this issue, this study demonstrates a unique hydrogel composite bead structure, providing a good adsorption capacity and superior compressive stress tolerance due to the presence of hollow cores within the beads. The gel beads contain alginate polymer as the matrix and MNP-decorated cellulose nanofibres (CNF) as the reinforcing agent. The MNPs within the gel provide active adsorption functionality, while CNF provide a good stress transfer phenomenon when the beads are under compressive stress. Their adsorption performance is evaluated in a red mud solution for pollutant adsorption. Composite gel beads have shown high performance in adsorbing metal (aluminium, potassium, selenium, sodium, and vanadium) and non-metal (sulphur) contaminations. This novel hybrid hydrogel could be a promising alternative to the conventionally used toxic adsorbent, providing environmentally friendly operational benefits. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

13 pages, 8334 KiB

Open AccessArticle

A Metal Coordination-Based Supramolecular Elastomer with Shape Memory-Assisted Self-Healing Effect

by Fang Xie, Zhongxin Ping, Wanting Xu, Fenghua Zhang, Yuzhen Dong, Lianjie Li, Chengsen Zhang and Xiaobo Gong

Polymers 2022, 14(22), 4879; https://doi.org/10.3390/polym14224879 - 12 Nov 2022

Cited by 2 | Viewed by 1465

Abstract

Rubber materials are widely used in aerospace, automotive, smart devices and artificial skin. It is significant to address the aging susceptibility of conventional vulcanized rubber and to impart it rapid self-healing performance for destructive crack damage. Herein, a novel supramolecular rubber elastomer is [...] Read more.

Rubber materials are widely used in aerospace, automotive, smart devices and artificial skin. It is significant to address the aging susceptibility of conventional vulcanized rubber and to impart it rapid self-healing performance for destructive crack damage. Herein, a novel supramolecular rubber elastomer is prepared by introducing metal coordination between carboxyl-terminated polybutadiene and polystyrene-vinylpyridine copolymer. Based on the metal coordination interaction, the elastomer exhibits shape memory and self-healing properties. Moreover, a rapid closure-repair process of destructive cracks is achieved by presetting temporary shapes. This shape memory-assisted self-repair model is shown to be an effective means for rapid repair of severe cracks. An approach to enhance the mechanical and self-healing properties of elastomer was demonstrated by adding appropriate amounts of oxidized carbon nano-onions (O-CNO) into the system. The tensile strength of the elastomer with an O-CNOs content of 0.5 wt% was restored to 83 ± 10% of the original sample after being repaired at 85 °C for 6 h. This study confirms that metal coordination interaction is an effective method for designing shape memory self-healing rubber elastomer. The shape memory-assisted self-healing effect provides a reference for the rapid self-repairing of severe cracks. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

16 pages, 11626 KiB

Open AccessArticle

Morphology Analysis of Friction Surfaces of Composites Based on PTFE and Layered Silicates

by Iuliia Kapitonova, Nadezhda Lazareva, Praskovia Tarasova, Aitalina Okhlopkova, Samuel Laukkanen and Vasiliy Mukhin

Polymers 2022, 14(21), 4658; https://doi.org/10.3390/polym14214658 - 01 Nov 2022

Cited by 8 | Viewed by 1539

Abstract

In the present study, the tribological behavior of polytetrafluoroethylene (PTFE) composites filled with natural layered silicates (LS) was investigated. The change in the morphology of the friction surface of composites depending on the content and chemical composition of layered silicates has been shown. [...] Read more.

In the present study, the tribological behavior of polytetrafluoroethylene (PTFE) composites filled with natural layered silicates (LS) was investigated. The change in the morphology of the friction surface of composites depending on the content and chemical composition of layered silicates has been shown. The friction surface of PTFE composites with layered silicates was investigated by scanning electron microscopy (SEM). The formation on the friction surface of a special layer with a structure different from the bulk of the polymer, which is formed from particles of fillers and wear products, has been established. The thickness of this layer is independent of the content of layered silicates in the polymer. It was indicated that wear debris of PTFE composites was assembled during friction and uniformly cover the friction surface layer by layer, thereby forming a protective layer. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

16 pages, 3437 KiB

Open AccessArticle

Flexible Composites with Variable Conductivity and Memory of Deformation Obtained by Polymerization of Polyaniline in PVA Hydrogel

by Andrei Honciuc, Ana-Maria Solonaru and Mirela Teodorescu

Polymers 2022, 14(21), 4638; https://doi.org/10.3390/polym14214638 - 31 Oct 2022

Cited by 4 | Viewed by 1898

Abstract

Flexible materials that provide an electric, magnetic, or optic response upon deformation or tactile pressure could be important for the development of smart monitors, intelligent textiles, or in the development of robotic skins. In this work we demonstrate the capabilities of a flexible [...] Read more.

Flexible materials that provide an electric, magnetic, or optic response upon deformation or tactile pressure could be important for the development of smart monitors, intelligent textiles, or in the development of robotic skins. In this work we demonstrate the capabilities of a flexible and electrically conductive polymer material that produces an electrical response with any deformation, namely the electrical resistance of the material changes proportionally with the deformation pressure. Furthermore, the material exhibits a memory effect. When compressed beyond the elastic regime, it retains the memory of the plastic deformation by increasing its resistance. The material was obtained by in situ polymerization of semiconducting polyaniline (PANi) in a polyvinyl alcohol/glycerol (PVA/Gly) hydrogel matrix at −17 °C. Upon drying of the hydrogel, an elastomer composite is obtained, with rubber-like characteristics. When compressed/decompressed, the electrical resistance of the material exhibits an unusually long equilibration/relaxation time, proportional with the load applied. These phenomena indicate a complex relaxation and reconfiguration process of the PANi/PVA elastomer matrix, with the shape change of the material due to mechanical stress. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Graphical abstract

14 pages, 3337 KiB

Open AccessArticle

Effect of Microwave Irradiation at Different Stages of Manufacturing Unsaturated Polyester Nanocomposite

by Andrey Shcherbakov, Anton Mostovoy, Amirbek Bekeshev, Igor Burmistrov, Sergey Arzamastsev and Marina Lopukhova

Polymers 2022, 14(21), 4594; https://doi.org/10.3390/polym14214594 - 29 Oct 2022

Cited by 11 | Viewed by 1512

Abstract

The possibility of using microwave radiation at various stages of obtaining an unsaturated polyester composite modified with carbon nanotubes was studied. The optimal content of MWCNTs in the system was experimentally selected, having the best effect on the strength of the composite. The [...] Read more.

The possibility of using microwave radiation at various stages of obtaining an unsaturated polyester composite modified with carbon nanotubes was studied. The optimal content of MWCNTs in the system was experimentally selected, having the best effect on the strength of the composite. The effect of the microwave field on the properties of a polyester composite during the microwave treatment of an oligomer, a polymerized composite, and MWCNTs before their addition into the oligomer was studied. The processes of the structure formation, the structure of the composite, the effect of the microwave radiation on MWCNTs, and the thermal stability of the resulting composites were considered. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

14 pages, 3656 KiB

Open AccessArticle

Low Dielectric Properties and Transmission Loss of Polyimide/Organically Modified Hollow Silica Nanofiber Composites

by Shu-Yang Lin, Yu-Min Ye, Erh-Ching Chen and Tzong-Ming Wu

Polymers 2022, 14(20), 4462; https://doi.org/10.3390/polym14204462 - 21 Oct 2022

Cited by 5 | Viewed by 2321

Abstract

In this study, a series of low dielectric constant and transmission loss of polyimide (PI)/organically modified hollow silica nanofiber (m-HSNF) nanocomposites were synthesized via two-step polymerization. Two different PIs were fabricated using two types of diamine monomers with or without fluorine-containing groups and [...] Read more.

In this study, a series of low dielectric constant and transmission loss of polyimide (PI)/organically modified hollow silica nanofiber (m-HSNF) nanocomposites were synthesized via two-step polymerization. Two different PIs were fabricated using two types of diamine monomers with or without fluorine-containing groups and biphenylene structure of dianhydride. The chemical structure and morphology of the fabricated composites were characterized using Nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) and field-emission scanning electron microscopy (FESEM). The two-step polymerization process successfully manufactured and converted from polyamic acid to polyimide after thermal imidization was proved by the NMR and FTIR results. The FESEM and their related energy-dispersive X-ray spectroscopy (EDS) images of nanocomposites indicate that the m-HSNF is extremely dispersed into the polyimide matrix. The high-frequency dielectric constants of the nanocomposite materials decrease as the presence of fluorine-containing groups in diamine monomers and the loadings of the m-HSNF increase. These findings are probably attributed to the presence of the steric hindrance effect brought by trifluoromethyl groups, and the m-HSNF can disrupt the chain packing and increase the free volume, thus reducing the dielectric properties of polyimides. The transmission loss and its related uncertainty of fabricated composite materials contain excellent performance, suggesting that the fabricated materials could be used as substrate materials for 5G printed circuit board. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

15 pages, 6763 KiB

Open AccessArticle

Electrothermally Self-Healing Delamination Cracks in Carbon/Epoxy Composites Using Sandwich and Tough Carbon Nanotube/Copolymer Interleaves

by Qin Ouyang, Ling Liu and Zhanjun Wu

Polymers 2022, 14(20), 4313; https://doi.org/10.3390/polym14204313 - 14 Oct 2022

Cited by 4 | Viewed by 1381

Abstract

Herein, two sandwich and porous interleaves composed of carbon nanotube (CNT) and poly(ethylene-co-methacrylic acid) (EMAA) are proposed, which can simultaneously toughen and self-heal the interlaminar interface of a carbon fiber-reinforced plastic (CFRP) by in situ electrical heating of the CNTs. The critical strain [...] Read more.

Herein, two sandwich and porous interleaves composed of carbon nanotube (CNT) and poly(ethylene-co-methacrylic acid) (EMAA) are proposed, which can simultaneously toughen and self-heal the interlaminar interface of a carbon fiber-reinforced plastic (CFRP) by in situ electrical heating of the CNTs. The critical strain energy release rate modes I (G_IC) and II (G_IIC) are measured to evaluate the toughening and self-healing efficiencies of the interleaves. The results show that compared to the baseline CFRP, the CNT-EMAA-CNT interleaf could increase the G_IC by 24.0% and the G_IIC by 15.2%, respectively, and their respective self-healing efficiencies could reach 109.7–123.5% and 90.6–91.2%; meanwhile, the EMAA-CNT-EMAA interleaf can improve the G_IC and G_IIC by 66.9% and 16.7%, respectively, and the corresponding self-healing efficiencies of the G_IC and G_IIC are 122.7–125.9% and 93.1–94.7%. Thus, both the interleaves show good toughening and self-healing efficiencies on the interlaminar fracture toughness. Specifically, the EMAA-CNT-EMAA interleaf possesses better multi-functionality, i.e., moderate toughening ability but notable self-healing efficiency via electrical heating, which is better than the traditional neat EMAA interleaf and oven-based heating healing method. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

20 pages, 9201 KiB

Open AccessArticle

Solvent-Free Production by Extrusion of Bio-Based Poly(glycerol-co-diacids) Sheets for the Development of Biocompatible and Electroconductive Elastomer Composites

by Shengzhi Ji, Mathilde Stricher, Frédéric Nadaud, Erwann Guenin, Christophe Egles and Frédéric Delbecq

Polymers 2022, 14(18), 3829; https://doi.org/10.3390/polym14183829 - 13 Sep 2022

Viewed by 1581

Abstract

Faced with growing global demand for new potent, bio-based, biocompatible elastomers, the present study reports the solvent-free production of 13 pure and derived poly(glycerol-co-diacid) composite sheets exclusively using itaconic acid, sebacic acid, and 2,5-furandicarboxylic acid (FDCA) with glycerol. Herein, modified melt polycondensation and [...] Read more.

Faced with growing global demand for new potent, bio-based, biocompatible elastomers, the present study reports the solvent-free production of 13 pure and derived poly(glycerol-co-diacid) composite sheets exclusively using itaconic acid, sebacic acid, and 2,5-furandicarboxylic acid (FDCA) with glycerol. Herein, modified melt polycondensation and Co(II)-catalyzed polytransesterification were employed to produce all exploitable prepolymers, enabling the easy and rapid manufacturing of elastomer sheets by extrusion. Most of our samples were loaded with 4 wt% of various additives such as natural polysaccharides, synthetic polymers, and/or 25 wt% sodium chloride as porogen agents. The removal of unreacted monomers and acidic short oligomers was carried out by means of washing with NaHCO₃ aqueous solution, and pH monitoring was conducted until efficient sheet surface neutralization. For each sheet, their surface morphologies were observed by Field-emission microscopy, and DSC was used to confirm their amorphous nature and the impact of the introduction of every additive. The chemical constitution of the materials was monitored by FTIR. Then, cytotoxicity tests were performed for six of our most promising candidates. Finally, we achieved the production of two different types of extrusion-made PGS elastomers loaded with 10 wt% PANI particulates and 4 wt% microcrystalline cellulose for adding potential electroconductivity and stability to the material, respectively. In a preliminary experiment, we showed the effectiveness of these materials as performant, time-dependent electric pH sensors when immersed in a persistent HCl atmosphere. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

20 pages, 6608 KiB

Open AccessArticle

Silicon Carbide Nanoparticles as a Mechanical Boosting Agent in Material Extrusion 3D-Printed Polycarbonate

by Markos Petousis, Nectarios Vidakis, Nikolaos Mountakis, Sotirios Grammatikos, Vassilis Papadakis, Constantine N. David, Amalia Moutsopoulou and Subrata C. Das

Polymers 2022, 14(17), 3492; https://doi.org/10.3390/polym14173492 - 26 Aug 2022

Cited by 15 | Viewed by 2355

Abstract

In this work, the effect of silicon carbide (carborundum, SiC), as a boosting agent of the mechanical response of the polycarbonate (PC) polymer, was investigated. The work aimed to fabricate nanocomposites with an improved mechanical performance and to further expand the utilization of [...] Read more.

In this work, the effect of silicon carbide (carborundum, SiC), as a boosting agent of the mechanical response of the polycarbonate (PC) polymer, was investigated. The work aimed to fabricate nanocomposites with an improved mechanical performance and to further expand the utilization of 3D printing in fields requiring an enhanced material response. The nanocomposites were produced by a thermomechanical process in various SiC concentrations in order to evaluate the filler loading in the mechanical enhancement. The samples were 3D printed with the material extrusion (MEX) method. Their mechanical performance was characterized, following international standards, by using dynamic mechanical analysis (DMA) and tensile, flexural, and Charpy’s impact tests. The microhardness of the samples was also measured. The morphological characteristics were examined, and Raman spectra revealed their structure. It was found that SiC can improve the mechanical performance of the PC thermoplastic. A 19.5% increase in the tensile strength was found for the 2 wt.% loading nanocomposite, while the 3 wt.% nanocomposite showed a 16% increase in the flexural strength and a 35.9% higher impact strength when compared to the unfilled PC. No processability issues were faced for the filler loadings that have been studied here. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Graphical abstract

11 pages, 2728 KiB

Open AccessArticle

Scalable Fabrication of Thermally Conductive Layered Nacre-like Self-Assembled 3D BN-Based PVA Aerogel Framework Nanocomposites

by Mohammad Owais, Aleksei Shiverskii, Artem Sulimov, Dmitriy Ostrizhiniy, Yuri Popov, Biltu Mahato and Sergey G. Abaimov

Polymers 2022, 14(16), 3316; https://doi.org/10.3390/polym14163316 - 15 Aug 2022

Cited by 7 | Viewed by 3259

Abstract

In this study, three-dimensional (3D) polyvinyl alcohol (PVA)/aligned boron nitride (BN) aerogel framework nanocomposites with high performance were fabricated by a facile strategy. The boron nitride powder was initially hydrolyzed and dispersed with a chemically crosslinked plasticizer, diethyl glycol (DEG), in the PVA [...] Read more.

In this study, three-dimensional (3D) polyvinyl alcohol (PVA)/aligned boron nitride (BN) aerogel framework nanocomposites with high performance were fabricated by a facile strategy. The boron nitride powder was initially hydrolyzed and dispersed with a chemically crosslinked plasticizer, diethyl glycol (DEG), in the PVA polymer system. The boron nitride and DEG/PVA suspensions were then mixed well with different stoichiometric ratios to attain BN/PVA nanocomposites. Scanning electron microscopy revealed that BN platelets were well dispersed and successfully aligned/oriented in one direction in the PVA matrix by using a vacuum-assisted filtration technique. The formed BN/PVA aerogel cake composite showed excellent in-plane and out-of-plane thermal conductivities of 0.76 W/mK and 0.61 W/mK with a ratio of BN/PVA of (2:1) in comparison with 0.15 W/mK for the pure PVA matrix. These high thermal conductivities of BN aerogel could be attributed to the unidirectional orientation of boron nitride nanoplatelets with the post-two days vacuum drying of the specimens at elevated temperatures. This aerogel composite is unique of its kind and displayed such high thermal conductivity of the BN/PVA framework without impregnation by any external polymer. Moreover, the composites also presented good wettability results with water and displayed high electrical resistivity of ~10¹⁴ Ω cm. These nanocomposites thus, with such exceptional characteristics, have a wide range of potential uses in packaging and electronics for thermal management applications. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

14 pages, 41450 KiB

Open AccessArticle

Shape Memory Behaviour of PMMA-Coated NiTi Alloy under Thermal Cycle

by Sneha Samal, Olga Kosjakova, David Vokoun and Ivo Stachiv

Polymers 2022, 14(14), 2932; https://doi.org/10.3390/polym14142932 - 20 Jul 2022

Cited by 7 | Viewed by 1881

Abstract

Both poly(methyl methacrylate) (PMMA) and NiTi possess shape memory and biocompatibility behavior. The macroscale properties of PMMA–NiTi composites depend immensely on the quality of the interaction between two components. NiTi shape memory alloy (SMA) and superelastic (SE) sheets were spin coated on one [...] Read more.

Both poly(methyl methacrylate) (PMMA) and NiTi possess shape memory and biocompatibility behavior. The macroscale properties of PMMA–NiTi composites depend immensely on the quality of the interaction between two components. NiTi shape memory alloy (SMA) and superelastic (SE) sheets were spin coated on one side with PMMA. The composite was prepared by the spin coating method with an alloy-to-polymer-thickness ratio of 1:3. The bending stiffness and radius of curvature were calculated by using numerical and experimental methods during thermal cycles. The experimental radius curvatures in actuation have good agreement with the model. The change in shape results from the difference in coefficients of thermal expansion between PMMA and NiTi. Actuation temperatures were between 0 and 100 °C for the SMA–PMMA composite with a change in curvature from 10 to 120 mm with fixed Young’s modulus of PMMA at 3 GPa, and a change in Young’s modulus of NiTi from 30 to 70 GPa. PMMA–NiTi composites are useful as actuators and sensor elements. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

11 pages, 2965 KiB

Open AccessArticle

Performance for Fly Ash Reinforced HDPE Composites over the Ageing of Material Components

by Mohammed N. Alghamdi

Polymers 2022, 14(14), 2913; https://doi.org/10.3390/polym14142913 - 18 Jul 2022

Cited by 6 | Viewed by 1875

Abstract

The by-product abundances of fly ash allow them to be used as the reinforcing filler for high-volume and high-performance thermoplastic composites. However, the durability of the composites remains questioned as polymer degradation during environmental weathering creates brittle materials, leading to surface cracks, which [...] Read more.

The by-product abundances of fly ash allow them to be used as the reinforcing filler for high-volume and high-performance thermoplastic composites. However, the durability of the composites remains questioned as polymer degradation during environmental weathering creates brittle materials, leading to surface cracks, which potentially release hazardous fly ash particles into the environment. This paper reports the effect of environmental ageing (UV and moisture exposure) on the morphological and mechanical properties of fly ash mixed high-density polyethylene (FA/HDPE) composites with three dissimilar weight fractions (5, 10 and 15 wt%) of filler and compared the results with similarly aged neat HDPE samples. The consequence of environmental ageing on the elevated mechanical properties of composites is investigated. Fifteen wt% fly ash reinforced composite appears to have better morphological and mechanical properties after 20 weeks of ageing, with only ~5 and ~9% reduction in Young’s modulus and tensile strength, respectively. The driving factors controlling the ageing effects are broadly discussed and recommendations are made for research advancements. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

Review

Jump to: Research

18 pages, 3490 KiB

Open AccessReview

Artificial Intelligence-Empowered 3D and 4D Printing Technologies toward Smarter Biomedical Materials and Approaches

by Raffaele Pugliese and Stefano Regondi

Polymers 2022, 14(14), 2794; https://doi.org/10.3390/polym14142794 - 08 Jul 2022

Cited by 30 | Viewed by 4823

Abstract

In the last decades, 3D printing has played a crucial role as an innovative technology for tissue and organ fabrication, patient-specific orthoses, drug delivery, and surgical planning. However, biomedical materials used for 3D printing are usually static and unable to dynamically respond or [...] Read more.

In the last decades, 3D printing has played a crucial role as an innovative technology for tissue and organ fabrication, patient-specific orthoses, drug delivery, and surgical planning. However, biomedical materials used for 3D printing are usually static and unable to dynamically respond or transform within the internal environment of the body. These materials are fabricated ex situ, which involves first printing on a planar substrate and then deploying it to the target surface, thus resulting in a possible mismatch between the printed part and the target surfaces. The emergence of 4D printing addresses some of these drawbacks, opening an attractive path for the biomedical sector. By preprogramming smart materials, 4D printing is able to manufacture structures that dynamically respond to external stimuli. Despite these potentials, 4D printed dynamic materials are still in their infancy of development. The rise of artificial intelligence (AI) could push these technologies forward enlarging their applicability, boosting the design space of smart materials by selecting promising ones with desired architectures, properties, and functions, reducing the time to manufacturing, and allowing the in situ printing directly on target surfaces achieving high-fidelity of human body micro-structures. In this review, an overview of 4D printing as a fascinating tool for designing advanced smart materials is provided. Then will be discussed the recent progress in AI-empowered 3D and 4D printing with open-loop and closed-loop methods, in particular regarding shape-morphing 4D-responsive materials, printing on moving targets, and surgical robots for in situ printing. Lastly, an outlook on 5D printing is given as an advanced future technique, in which AI will assume the role of the fifth dimension to empower the effectiveness of 3D and 4D printing for developing intelligent systems in the biomedical sector and beyond. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Figure 1

36 pages, 7893 KiB

Open AccessReview

Functional Ultra-High Molecular Weight Polyethylene Composites for Ligament Reconstructions and Their Targeted Applications in the Restoration of the Anterior Cruciate Ligament

by Sonia B. Wahed, Colin R. Dunstan, Philip C. Boughton, Andrew J. Ruys, Shaikh N. Faisal, Tania B. Wahed, Bidita Salahuddin, Xinying Cheng, Yang Zhou, Chun H. Wang, Mohammad S. Islam and Shazed Aziz

Polymers 2022, 14(11), 2189; https://doi.org/10.3390/polym14112189 - 28 May 2022

Cited by 5 | Viewed by 2931

Abstract

The selection of biomaterials as biomedical implants is a significant challenge. Ultra-high molecular weight polyethylene (UHMWPE) and composites of such kind have been extensively used in medical implants, notably in the bearings of the hip, knee, and other joint prostheses, owing to its [...] Read more.

The selection of biomaterials as biomedical implants is a significant challenge. Ultra-high molecular weight polyethylene (UHMWPE) and composites of such kind have been extensively used in medical implants, notably in the bearings of the hip, knee, and other joint prostheses, owing to its biocompatibility and high wear resistance. For the Anterior Cruciate Ligament (ACL) graft, synthetic UHMWPE is an ideal candidate due to its biocompatibility and extremely high tensile strength. However, significant problems are observed in UHMWPE based implants, such as wear debris and oxidative degradation. To resolve the issue of wear and to enhance the life of UHMWPE as an implant, in recent years, this field has witnessed numerous innovative methodologies such as biofunctionalization or high temperature melting of UHMWPE to enhance its toughness and strength. The surface functionalization/modification/treatment of UHMWPE is very challenging as it requires optimizing many variables, such as surface tension and wettability, active functional groups on the surface, irradiation, and protein immobilization to successfully improve the mechanical properties of UHMWPE and reduce or eliminate the wear or osteolysis of the UHMWPE implant. Despite these difficulties, several surface roughening, functionalization, and irradiation processing technologies have been developed and applied in the recent past. The basic research and direct industrial applications of such material improvement technology are very significant, as evidenced by the significant number of published papers and patents. However, the available literature on research methodology and techniques related to material property enhancement and protection from wear of UHMWPE is disseminated, and there is a lack of a comprehensive source for the research community to access information on the subject matter. Here we provide an overview of recent developments and core challenges in the surface modification/functionalization/irradiation of UHMWPE and apply these findings to the case study of UHMWPE for ACL repair. Full article

(This article belongs to the Special Issue Smart and Functional Polymer Composites)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Smart and Functional Polymer Composites

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (22 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI