Journal of Composites Science

20 pages, 24517 KiB

Open AccessArticle

Investigations of Thin-Walled Glass Fiber Reinforced Plastic Laminates with Sealing Function for Electric Motors

by Jan David Hübsch, Nils Meyer, Daniela Feldten, Christian Mittelstedt and Philipp Berendes

J. Compos. Sci. 2025, 9(4), 175; https://doi.org/10.3390/jcs9040175 (registering DOI) - 3 Apr 2025

This article presents, in detail, design considerations for a thin-walled glass fiber reinforced plastic (GFRP) liner on a fluid-cooled stator lamination of an electric motor. In addition to structural requirements due to the cooling fluid pressure, the GFRP liner needs to guarantee impermeability. [...] Read more.

This article presents, in detail, design considerations for a thin-walled glass fiber reinforced plastic (GFRP) liner on a fluid-cooled stator lamination of an electric motor. In addition to structural requirements due to the cooling fluid pressure, the GFRP liner needs to guarantee impermeability. Analytical considerations deriving from different coefficients of thermal expansion (CTEs) determine the two-layered laminate design. Empirical investigations show two innovative, simple, and, therefore, efficient test setups for the leakage of liquid media through a GFRP liner. The weeping investigations employ two different GFRP systems with four different configurations of interfiber failure (IFF) and, therefore, crack densities. The weeping investigations show that at least one ply in the laminate needs to be flawless regarding IFF cracks in order to guarantee the sealing function. Alternatively, a third sealing layer can be used. Full article

(This article belongs to the Section Composites Applications)

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18 pages, 6813 KiB

Open AccessArticle

Effects of Matrix Properties on the Interfacial Shear Strength Between Carbon Fiber and Various Thermoplastic Polymers, and Their Influence on the Mechanical Properties of Composites

by Kazuto Tanaka and Ryota Sakakibara

J. Compos. Sci. 2025, 9(4), 174; https://doi.org/10.3390/jcs9040174 - 2 Apr 2025

Viewed by 42

Abstract

Although fiber–matrix interfacial strengths, which affect the mechanical properties of fiber-reinforced plastics (FRPs), are considered to be determined by complex factors, few studies have systematically evaluated the relationship between the matrix properties and the fiber–matrix interfacial shear strength. In this study, the properties [...] Read more.

Although fiber–matrix interfacial strengths, which affect the mechanical properties of fiber-reinforced plastics (FRPs), are considered to be determined by complex factors, few studies have systematically evaluated the relationship between the matrix properties and the fiber–matrix interfacial shear strength. In this study, the properties of various thermoplastics were measured, and the matrix tightening stress that constricts the fiber was simulated using finite element method (FEM) analysis. The relationships between the fiber–matrix interfacial shear strength and the matrix properties were clarified. The mechanical properties of carbon fiber reinforced thermoplastic (CFRTP) laminates were also evaluated, and the relationships between the fiber–matrix interfacial shear strength and the mechanical properties of CFRTP laminates were examined. The fiber–matrix interfacial shear strength showed a positive correlation with the matrix tightening stress tightening the fiber in the radial direction, as well as with matrix density, tensile strength, modulus, and melting temperature, while a negative correlation was found with the coefficient of linear expansion of the matrix. A higher fiber–matrix interfacial shear strength can be achieved by using a matrix with higher density, even without direct evaluation of the fiber–matrix interfacial strength, as the fiber–matrix interfacial shear strength showed a strong positive correlation with matrix density. Furthermore, the mechanical properties of CFRTP laminates were enhanced when matrices with higher fiber–matrix interfacial shear strength were used. Full article

(This article belongs to the Special Issue Carbon Fiber Composites, 4th Edition)

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17 pages, 14026 KiB

Open AccessArticle

Analysis of the Deformation Mechanisms of Fabrics Based on rCF Staple Fiber Yarns for Thermoset Composite Applications

by Tobias Georg Lang, Mir Mohammad Badrul Hasan, Anwar Abdkader, Chokri Cherif and Thomas Gereke

J. Compos. Sci. 2025, 9(4), 173; https://doi.org/10.3390/jcs9040173 - 2 Apr 2025

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Abstract

The draping of textile semi-finished products for complex geometries is still prone to errors, e.g., wrinkles, gaps, and fiber undulations, leading to reduced mechanical properties of the composite. Reinforcing textiles made from carbon fiber (CF) rovings (i.e., endless continuous fibers) can be draped [...] Read more.

The draping of textile semi-finished products for complex geometries is still prone to errors, e.g., wrinkles, gaps, and fiber undulations, leading to reduced mechanical properties of the composite. Reinforcing textiles made from carbon fiber (CF) rovings (i.e., endless continuous fibers) can be draped mainly based on their ability to deform under in-plane shearing. However, CF rovings are hardly stretchable in the fiber direction. These limited degrees of freedom make the production of complex shell-shaped geometries from standard CF-roving fabrics challenging. Contrary to continuous rovings, this paper investigates the processing of spun yarns made of recycled carbon fibers (rCFs), which are discontinuous staple fibers with defined lengths. rCFs are obtained from end-of-life composites or production waste, making them a sustainable alternative to virgin carbon fibers in the high-performance components of, e.g., automobiles, boats, or sporting goods. These staple fiber-spun yarns are considerably more stretchable, which is due to the ability of the individual fibers to slide against each other when deformed, resulting in improved formability of fabrics made from rCF yarns, enabling the draping of much more complex structures. This study aims to develop and characterize woven fabrics based on previous studies of rCF yarns for thermoset composites. In order to investigate staple fiber-spun yarns, a previous micro-scale modeling approach is extended. The formability of fabrics made from those rCF yarns is investigated through experimental forming tests and meso-scale simulations. Full article

(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2025)

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15 pages, 4473 KiB

Open AccessArticle

Composite Films Based on Poly(3-hexylthiophene):Perylene Diimide Derivative:Copper Sulfide Nanoparticles Deposited by Matrix Assisted Pulsed Laser Evaporation on Flexible Substrates for Photovoltaic Applications

by Marcela Socol, Nicoleta Preda, Andreea Costas, Gabriela Petre, Andrei Stochioiu, Gianina Popescu-Pelin, Sorina Iftimie, Ana Maria Catargiu, Gabriel Socol and Anca Stanculescu

J. Compos. Sci. 2025, 9(4), 172; https://doi.org/10.3390/jcs9040172 - 1 Apr 2025

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Abstract

Today, flexible and lightweight electronics are regarded as a viable alternative to conventional rigid and heavy devices in various application fields. In the optoelectronic area, organic semiconductors offer advantages such as high absorption coefficients, low processing temperatures, mechanical flexibility and compatibility with plastic [...] Read more.

Today, flexible and lightweight electronics are regarded as a viable alternative to conventional rigid and heavy devices in various application fields. In the optoelectronic area, organic semiconductors offer advantages such as high absorption coefficients, low processing temperatures, mechanical flexibility and compatibility with plastic substrates, while inorganic nanostructures provide good electronic properties and high thermal stability. Thus, composite films with enhanced properties can be achieved by inserting inorganic nanostructures within organic layers. In this research work, CuS nanoparticles were prepared by wet chemical precipitation and then added to an organic mixture containing poly(3-hexylthiophene) (P3HT) and N,N-bis-(1-dodecyl)perylene-3,4,9,10 tetracarboxylic diimide (AMC14), a chemically synthesized semiconductor, for fabricating hybrid composite films by matrix assisted pulsed laser evaporation (MAPLE) on indium tin oxide/poly(ethylene terephthalate) (ITO/PET) flexible substrates. A comparative assessment of the morphological, compositional, optical and electrical properties of the composite (P3HT:AMC14:CuS) and organic (P3HT:AMC14) layers was performed to evaluate their applicability in the photovoltaic cells. The transmission and emission spectra of the composite films are dominated by the optical features of AMC14, a perylene diimide derivative compound used as acceptor. In the case of devices based on MAPLE deposited composite layer fabricated on ITO/PET substrates, the electrical measurements carried under illumination revealed an improvement in the open circuit voltage parameter emphasizing their potential applications in the flexible device area. Full article

(This article belongs to the Section Polymer Composites)

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16 pages, 8016 KiB

Open AccessArticle

Structural Insights: In Situ Synthesis of Titanium Carbide by Magnesiothermic Method Using Carbon Nanotubes and Turbostratic Carbon as Carbon Sources

by María Luisa Camacho-Ríos, Guillermo Herrera-Pérez, Luis Carlos Rodriguez-Pacheco, Mariana Lizbeth Luján-Aguilar, Antonio Ramírez-de la Cruz, Nathaly Withney Aguilar-Cisneros, Marco Antonio Ruiz Esparza-Rodriguez, Daniel Lardizabal-Gutierrez, Raúl Pérez-Bustamante and José Antonio Betancourt-Cantera

J. Compos. Sci. 2025, 9(4), 171; https://doi.org/10.3390/jcs9040171 - 31 Mar 2025

Viewed by 72

Abstract

The current work presents the influence of the magnesiothermic synthesis method on titanium carbide (TiC). In this method, powdered titanium precursors and two carbon sources—turbostratic carbon and carbon nanotubes—were employed in proportions of 10 wt.% and 20 wt.%. The refinement of the X-ray [...] Read more.

The current work presents the influence of the magnesiothermic synthesis method on titanium carbide (TiC). In this method, powdered titanium precursors and two carbon sources—turbostratic carbon and carbon nanotubes—were employed in proportions of 10 wt.% and 20 wt.%. The refinement of the X-ray diffraction (XRD) patterns using the Rietveld method for TiC suggests suggested coexistence of two phases, cubic with Fm-3m space group and hexagonal with P3₁21 space group. In particular, for the sample with 20 wt.% of carbon sources, the XRD refinement revealed that the cubic phase accounted for 94% of the composition, in contrast to a secondary hexagonal phase, Ti₆C_3.75, which comprised 6%. The influence of carbon on the morphology (particle size and shape) and crystallite size was monitored through bright-field transmission electron microscopy (BF-TEM) imaging and XRD. In samples containing 20 wt.% carbon, a homogeneous morphology in both size (around 11 microns) and shape was observed, along with a reduction in crystallite size (from 22.7 to 17.8 nm). Raman band analysis further revealed vibrational modes indicating that carbon induced disorder in the TiC structure. The magnesiothermic synthesis method developed in this work offers a low-cost approach of interest in the aerospace and automotive industries. Additionally, the study provides significant insights for particles used as additives or reinforcing agents to enhance the mechanical properties of metal matrix composites (MMCs). Full article

(This article belongs to the Section Carbon Composites)

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14 pages, 4439 KiB

Open AccessArticle

Dual Influence of Li Concentration and Nanoparticle Size in LiCoO₂ on the Conductivity and Storage Capacity of Lithium Batteries

by Obaidallah A. Algethami

J. Compos. Sci. 2025, 9(4), 170; https://doi.org/10.3390/jcs9040170 - 31 Mar 2025

Viewed by 40

Abstract

Li_xCo_1−xO₂ nanocomposites with molar concentrations x (0.1, 0.3, 0.5, 0.7, 0.9) were prepared using the sol–gel method. The optical and electrical properties were determined using UV-Vis spectrometer. The results obtained indicate that the absorption coefficient increases upon increase [...] Read more.

Li_xCo_1−xO₂ nanocomposites with molar concentrations x (0.1, 0.3, 0.5, 0.7, 0.9) were prepared using the sol–gel method. The optical and electrical properties were determined using UV-Vis spectrometer. The results obtained indicate that the absorption coefficient increases upon increase of nanoparticle size, while the energy gap decreases when nanoparticle size increases. The storage capacity reaches its maximum value near resonance at minimum nanoparticle size. This is attributed to the fact that the optical properties, electrical conductivity, and actual electrical permittivity reach their maximum values near the resonance region and increase as the nanoparticle size decreases. The operating voltages at which the storage capacity attains maximum value in the range from 2.3 to 3.5 volts. These operating voltages can be adjusted to achieve the required range by controlling the Li concentrations and the crystallite size of Li_xCo_1−xO₂ NPs which directly affect the energy gap and, in turn, influence the operating voltage. The operating voltage can thus be increased by increasing the energy gap, which requires decreasing the nano size and the Li concentration. Full article

(This article belongs to the Section Nanocomposites)

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43 pages, 7222 KiB

Open AccessFeature PaperReview

Materials and Energy-Centric Life Cycle Assessment for Drones: A Review

by Ajitanshu Vedrtnam, Harsha Negi and Kishor Kalauni

J. Compos. Sci. 2025, 9(4), 169; https://doi.org/10.3390/jcs9040169 - 30 Mar 2025

Viewed by 83

Abstract

The rapid expansion of drone applications across industries such as defense, healthcare, construction, agriculture, and surveillance has intensified the need for advanced materials that enhance performance while minimizing environmental impact. This review provides a comprehensive analysis of materials used in drone construction, categorizing [...] Read more.

The rapid expansion of drone applications across industries such as defense, healthcare, construction, agriculture, and surveillance has intensified the need for advanced materials that enhance performance while minimizing environmental impact. This review provides a comprehensive analysis of materials used in drone construction, categorizing them based on their application in key components such as frames, propellers, wings, and structural supports. An energy-centric life cycle assessment (LCA) examines the environmental footprint of drone materials, emphasizing energy use, emissions, and recyclability. The review highlights the trade-offs between mechanical performance and environmental impact, identifying materials that optimize structural efficiency while reducing environmental impact. Additionally, emerging sustainable alternatives such as bio-based composites and recycled carbon fibers are explored as potential solutions for next-generation UAV design. By addressing existing research gaps, this study aims to guide the development of environmentally responsible drone manufacturing technologies. The findings offer valuable insights into optimizing drone materials for enhanced environmental efficiency, supporting the transition toward more energy-efficient and eco-friendly UAVs. Full article

(This article belongs to the Section Composites Applications)

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25 pages, 2459 KiB

Open AccessArticle

Implementation of Composite Materials for an Industrial Vehicle Component: A Design Approach

by Ivan Tomasi, Stefano Grandi and Luigi Solazzi

J. Compos. Sci. 2025, 9(4), 168; https://doi.org/10.3390/jcs9040168 - 29 Mar 2025

Viewed by 66

Abstract

The aim of this research is to define a design approach for implementing composite materials in a component of an industrial vehicle, having weight reduction as the primary goal. Through the schematisation of the problem and analytical analysis, the definition of a new [...] Read more.

The aim of this research is to define a design approach for implementing composite materials in a component of an industrial vehicle, having weight reduction as the primary goal. Through the schematisation of the problem and analytical analysis, the definition of a new geometry, a material and production process, and numerical simulations and experimental studies to test the new solution, an optimization process of the chosen geometry is proposed. After the definition of the process, an applicative example is presented, analysing a front underrun protection device in two different solutions: one made of glass-fibre-reinforced polymer and the other of carbon-fibre-reinforced polymer. An economic comparison has also been conducted between the new configurations and the traditional steel version, showing a weight reduction of approximately 55% for the carbon-fibre-reinforced polymer solution and around 18% for the glass-fibre-reinforced polymer solution. These weight reductions are achievable through a reinvestment that can be amortized in less than five years, thanks to fuel consumption savings. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Modeling and Simulation of Composite Materials)

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Graphical abstract

23 pages, 3897 KiB

Open AccessArticle

Enhancing Polylactic Acid/Carbon Fiber-Reinforced Biomedical Composites (PLA/CFRCs) with Multi-Walled Carbon Nanotube (MWCNT) Fillers: A Comparative Study on Reinforcing Techniques

by Juan Antonio Paz-González, Yadira Gochi-Ponce, Carlos Velasco-Santos, Enrique Alcudia-Zacarias, Arturo Zizumbo-López, Balter Trujillo-Navarrete, Oscar Adrián Morales-Contreras and Luis Jesús Villarreal-Gómez

J. Compos. Sci. 2025, 9(4), 167; https://doi.org/10.3390/jcs9040167 - 29 Mar 2025

Viewed by 109

Abstract

The limited mechanical properties of composite materials, including stiffness, strength, and biocompatibility, restrict their effectiveness in biomedical applications. This research enhanced the mechanical properties and biocompatibility of polylactic acid and carbon fiber-reinforced composites (PLA/CFRCs) by incorporating multi-walled carbon nanotube (MWCNT) fillers. The methodology [...] Read more.

The limited mechanical properties of composite materials, including stiffness, strength, and biocompatibility, restrict their effectiveness in biomedical applications. This research enhanced the mechanical properties and biocompatibility of polylactic acid and carbon fiber-reinforced composites (PLA/CFRCs) by incorporating multi-walled carbon nanotube (MWCNT) fillers. The methodology involved synthesizing MWCNTs and integrating them into PLA/CFRC laminates using fusion-blending, dispersion, and interlaminar spray-coating. Raman spectroscopy confirmed the presence of MWCNTs, with characteristic D and G band peaks and an I_D/I_G of 1.44 ± 0.089. SEM revealed MWCNTs in the PLA/CFRC matrix and allowed size determination, with an outer diameter range of 125–150 nm and a length of 14,407 ± 2869 nm. FTIR identified interactions between the matrix and the MWCNTs, evidenced by band shifts. TGA/DSC analysis showed thermal stability above 338 °C for all composites. The tensile tests revealed that all composites had values greater than 19 GPa for the elastic modulus and 232 MPa for the ultimate strength. Cytotoxicity assays confirmed biocompatibility, and all samples maintained a cell growth rate greater than 80%. This study highlighted the potential of nanotechnology to optimize the mechanical behavior of polymer-based composites, expanding their applicability in biomedical fields. Full article

(This article belongs to the Special Issue Advances in Carbon Bionanocomposites: Recent Innovations and Applications)

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16 pages, 12954 KiB

Open AccessArticle

A Study on the Charging–Discharging Mechanism of All Solid-State Aluminum–Carbon Composite Secondary Batteries

by Jia-Ying Lin, Bo-Ding Wu and Fei-Yi Hung

J. Compos. Sci. 2025, 9(4), 166; https://doi.org/10.3390/jcs9040166 - 29 Mar 2025

Viewed by 137

Abstract

Aluminum solid-state batteries are emerging as one of the most promising energy storage systems, offering advantages such as low cost and high safety. This study adopts a safe and cost-effective approach by alloying and doping the all-solid-state aluminum-ion battery to enhance its electrochemical [...] Read more.

Aluminum solid-state batteries are emerging as one of the most promising energy storage systems, offering advantages such as low cost and high safety. This study adopts a safe and cost-effective approach by alloying and doping the all-solid-state aluminum-ion battery to enhance its electrochemical performance. This research further explores the electrochemical impacts of these modifications on the performance of solid-state aluminum batteries. In this experiment, aluminum-based anodes were deposited onto nickel foil using the thermal evaporation (TE) method. At the same time, the graphite film (GF) cathode material was enriched with sodium (GFN) through a solution-based process. The system was combined with magnesium silicate solid electrolytes to investigate the all-solid-state aluminum-carbon battery′s structural characteristics and charge–discharge mechanisms. The experimental results demonstrate that the aluminum-coated electrode alloying effects and the graphite film modification significantly improve battery performance. The system achieved a maximum specific capacity of approximately 700 mAh g⁻¹, with a cycle life exceeding 100 cycles. Furthermore, the microstructural characteristics and phase structure of the aluminum evaporation film were confirmed. Analysis of ion transport pathways during the charge–discharge cycles of the all-solid-state aluminum-carbon battery revealed that both aluminum and magnesium ions play critical roles in the electrode processes. Full article

(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2025)

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9 pages, 439 KiB

Open AccessArticle

Effect of Adhesive System on Bond Strength of Polyetheretherketone (PEEK) and Polyetherketoneketone (PEKK)

by Thais Marques Simek Vega Gonçalves, Isabela Reginaldo, Kusai Baroudi, Zuíla Maria Lobato Wanghon, Pedro Santos Diamantino, Mariana Gadelho Gimenez, Analucia Gebler Phillippi, Guilherme de Siqueira Ferreira Anzaloni Saavedra, Fernando Cabral and João Paulo Mendes Tribst

J. Compos. Sci. 2025, 9(4), 165; https://doi.org/10.3390/jcs9040165 - 29 Mar 2025

Viewed by 125

Abstract

It is uncertain whether the interchangeable use of two adhesive systems would yield comparable shear bond strength (SBS) for both Polyetheretherketone (PEEK) and Polyetherketoneketone (PEKK); investigating this was the main objective of this study. Milled PEEK (Bredent, Senden, Germany) and PEKK (Pekkton Ivory, [...] Read more.

It is uncertain whether the interchangeable use of two adhesive systems would yield comparable shear bond strength (SBS) for both Polyetheretherketone (PEEK) and Polyetherketoneketone (PEKK); investigating this was the main objective of this study. Milled PEEK (Bredent, Senden, Germany) and PEKK (Pekkton Ivory, AnaxDent, Stuttgart, Germany) blocks were prepared with standardized roughness (0.20 μm) and randomly assigned into two groups (n = 72): with and without aluminum oxide air abrasion (AquaCare Twin, Medivance Instruments, London, UK). Two adhesive systems (Visio.link, Bredent, Senden, Germany, or PEKKBond, AnaxDent, Stuttgart, Germany) were randomly applied (n = 36). Flowable gingival composite (AnaxGum Gingiva, AnaxDent, Stuttgart, Germany) was bonded, and the samples were stored in water (37 °C, 24 h). SBS was measured (MPa) and data were analyzed using three-way ANOVA, followed by Tukey’s test (α = 0.05). All main effects and interactions were significant (p < 0.05), except for polymer (p = 0.163) and the triple interaction (p = 0.601). In the PEEK group, Visiolink showed higher SBS (p < 0.001), regardless of prior air abrasion. For the PEKK group, PEKKBond significantly increased SBS values (p < 0.001) for both pre-treatment groups. Previous air abrasion only significantly increased the SBS of controls without adhesive. This study highlights the importance of material-specific adhesive selection, rather than interchangeable use, for optimal results. The bond strength of PEEK and PEKK is influenced by the adhesive system applied. Moreover, PEKK consistently demonstrated higher SBS values in comparison to PEEK, even without the need for pre-treatment or adhesive conditioning. This characteristic renders PEKK a preferred choice for the fabrication of adhesive restorations. Full article

(This article belongs to the Special Issue Recent Progress in Hybrid Composites)

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18 pages, 8893 KiB

Open AccessArticle

Optimization of Innovative Hybrid Polylactic Acid+ and Glass Fiber Composites: Mechanical, Physical, and Thermal Evaluation of Woven Glass Fiber Reinforcement in Fused Filament Fabrication 3D Printing

by Ardi Jati Nugroho Putro, Galang Bagaskara, Ibnu Adnan Prasetya, Jamasri, Ardi Wiranata, Yi-Chieh Wu and Muhammad Akhsin Muflikhun

J. Compos. Sci. 2025, 9(4), 164; https://doi.org/10.3390/jcs9040164 - 29 Mar 2025

Viewed by 188

Abstract

The growing demand for complex structures, energy absorption, and mechanically strong materials has led to the exploration of innovative composites. This study focuses on the manufacture, characterization, and evaluation of PLA+ reinforced with woven glass fiber. Using Fused Filament Fabrication (FFF) 3D Printer [...] Read more.

The growing demand for complex structures, energy absorption, and mechanically strong materials has led to the exploration of innovative composites. This study focuses on the manufacture, characterization, and evaluation of PLA+ reinforced with woven glass fiber. Using Fused Filament Fabrication (FFF) 3D Printer technology, the effects of adding woven glass fiber were examined through a tensile test with Digital Image Correlation (DIC)-induced, flexural, Charpy impact resistance, Shore D hardness, Differential Scanning Calorimetry (DSC) thermal tester, and SEM morphological tests. Results showed that adding four layers of glass fiber significantly improved mechanical properties: tensile strength increased by 85% to 95.44 MPa, flexural strength by 13% to 91.51 MPa, and impact resistance by 450% to 15.12 kJ/m². However, a reduction in hardness and thermal resistance was noted due to chemical interactions. These findings suggest potential applications of PLA+ composites in high-strength products for vehicle bumpers in the automotive industry and shin pads in the sports industry. Full article

(This article belongs to the Special Issue Recent Progress in Hybrid Composites)

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16 pages, 6626 KiB

Open AccessArticle

Effect of Monomer Composition on the Core–Shell Structure and Expansion Performance of Thermally Expandable Microspheres

by Deli Yang, Yanxiang Wang, Yanqiu Feng, Haotian Jiang, Yongbo Wang, Shichao Dai, Bohan Ding, Yue Sun and Jinghe Guo

J. Compos. Sci. 2025, 9(4), 163; https://doi.org/10.3390/jcs9040163 - 28 Mar 2025

Viewed by 171

Abstract

This study investigated the effect of different monomer compositions of acrylonitrile (AN) and methyl methacrylate (MMA) on the synthesis and expansion performance of thermally expandable microspheres (TEMs). TEMs with different monomer ratios, specifically AN to MMA ratios of 100:0, 90:10, 80:20, and 70:30, [...] Read more.

This study investigated the effect of different monomer compositions of acrylonitrile (AN) and methyl methacrylate (MMA) on the synthesis and expansion performance of thermally expandable microspheres (TEMs). TEMs with different monomer ratios, specifically AN to MMA ratios of 100:0, 90:10, 80:20, and 70:30, were synthesized via free radical suspension polymerization. The inner morphology, crystallinity, blowing agent encapsulation efficiency, and expansion ratio of the microspheres were analyzed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and other characterization techniques. The results showed that as the MMA content and reaction time increased, the internal structure of the microsphere shell became more uniform, and its thickness increased. Notably, the P(AN:MMA)(90:10) microspheres exhibited the lowest expansion temperature and the highest expansion ratio. This study provides a theoretical basis for the further optimization of TEM synthesis processes. Full article

(This article belongs to the Special Issue Recent Progress in Hybrid Composites)

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36 pages, 9977 KiB

Open AccessArticle

Auxetic Composite Sandwich for Vibration Damping Through Axisymmetric Deformation

by Chun Seng Yong, Sridhar Idapalapati, Chee Wang Lim and Kheng Lim Goh

J. Compos. Sci. 2025, 9(4), 162; https://doi.org/10.3390/jcs9040162 - 27 Mar 2025

Viewed by 85

Abstract

External undesirable vibrations from the environment can affect the performance of vibration-sensitive equipment. Passive isolators are simpler, lighter, and cheaper, and constrained layer damping is a low-cost yet effective method of vibration dampening. Traditional methods of improving constrained layer damping include increasing the [...] Read more.

External undesirable vibrations from the environment can affect the performance of vibration-sensitive equipment. Passive isolators are simpler, lighter, and cheaper, and constrained layer damping is a low-cost yet effective method of vibration dampening. Traditional methods of improving constrained layer damping include increasing the number of layers or directly connecting one end of the constraining layers to the base structure. The drawback of these methods is the requirement to increase the overall thickness. Also, like most passive isolators, it has a limitation on stability, which is usually solved by external mechanical limiters. The novel concept of an auxetic composite sandwich addresses both issues of having an external limiter by using the constraining layer for load bearing and enhancing damping performance without increasing the overall thickness, achieved through an auxetic interlayer and deforming axis-symmetrically. The rotating triangle auxetic interlayer is selected based on biomimicry of animals that endure impact and pressure, such as cranial sutures, beaks, ammonoid and turtle shells. Finite element analysis shows significantly higher damping ratio at the beginning of free vibration, and experiment results show an eightfold increase in damping ratio (from 0.04 to 0.29). Additionally, settling time to 0.25 g is reduced from 70.7 ms to 60.9 ms as acceleration is increased from 0.5 g to 4 g. Power spectrum density shows better attenuation, three to four times better than the plain model. The successful demonstration of the concept motivates further study to understand the performance of auxetic patterns in enhancing constrained layer damping. Full article

(This article belongs to the Section Composites Applications)

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14 pages, 16060 KiB

Open AccessArticle

Manufacturing and Characterisation of a Tungsten Fibre-Reinforced Polymer Composite

by Daniel Dickes, Stephan Maidl, Johann Riesch, Rudolf Neu and Klaus Drechsler

J. Compos. Sci. 2025, 9(4), 161; https://doi.org/10.3390/jcs9040161 - 27 Mar 2025

Viewed by 149

Abstract

Using metal fibres in fibre-reinforced polymers is a way to tailor not only the mechanical properties but also material properties like, e.g., electrical and thermal conductivity or toughness. While recent works focus on ductile steel fibres, this work demonstrates the manufacturability of tungsten [...] Read more.

Using metal fibres in fibre-reinforced polymers is a way to tailor not only the mechanical properties but also material properties like, e.g., electrical and thermal conductivity or toughness. While recent works focus on ductile steel fibres, this work demonstrates the manufacturability of tungsten fibre-reinforced polymers. The Vacuum Assisted Process works well to quasi-unidirectionally reinforce an epoxy matrix with tungsten fibres of 150 µm diameter, achieving a fibre volume content of 23 ± 1% (±standard deviation). Tensile tests of 10 mm-wide tungsten fibre-reinforced polymer specimens yield a Young’s modulus of 89 ± 5 GPa, an ultimate tensile strength of 615 ± 33 MPa, and a failure strain of 1.9 ± 0.2%. The fractured specimens are further investigated, revealing that 66% of the tungsten fibres fail in a dominantly ductile manner with a strongly localised region of plastic deformation. This is a unique feature of tungsten fibres with the potential to enhance the fracture toughness of fibre-reinforced polymers. Full article

(This article belongs to the Section Polymer Composites)

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15 pages, 5208 KiB

Open AccessArticle

Numerical Study on the Influence of Saltwater Seepage in High-Pressure Salt-Gypsum Layers on Wellbore Integrity

by Bin Li, Nanxiang Liu, Mingchi Zhu and Xuyue Chen

J. Compos. Sci. 2025, 9(4), 160; https://doi.org/10.3390/jcs9040160 - 27 Mar 2025

Viewed by 122

Abstract

The salt layer serves as an excellent caprock for oil and gas resources, with its underlying strata often containing abundant hydrocarbon reserves. However, the strong creep characteristics of the salt layer frequently lead to damage issues. Therefore, research on the wellbore integrity of [...] Read more.

The salt layer serves as an excellent caprock for oil and gas resources, with its underlying strata often containing abundant hydrocarbon reserves. However, the strong creep characteristics of the salt layer frequently lead to damage issues. Therefore, research on the wellbore integrity of salt layers holds significant practical value. This study focuses on the wellbore integrity of high-pressure salt layers. Based on the Heard time-hardening creep model, a numerical simulation model of composite salt-layered wellbores incorporating a saline water seepage field was established. This study analyzed the mechanical influence of factors such as well inclination angle, azimuth angle, brine density, and liquid column density on the wellbore. The results indicate that high formation pressure, salt creep, and saline water seepage in high-pressure salt layers are the main causes of wellbore stress and deformation. These conditions pose a high risk of damage to the casing and cement sheath. When designing directional well trajectories within high-pressure salt layers, the inclination angle should be controlled between 45° and 60°, and the azimuth angle should be kept below 30°. Full article

(This article belongs to the Section Composites Applications)

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19 pages, 4201 KiB

Open AccessArticle

Effects of Key Parameters on Thermal Conductivity of Carbon Nanotube–Epoxy Composites by Molecular Dynamics Simulations

by Lida Najmi and Zhong Hu

J. Compos. Sci. 2025, 9(4), 159; https://doi.org/10.3390/jcs9040159 - 26 Mar 2025

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Abstract

The application of carbon nanotube (CNT)-reinforced epoxy matrix composites (CRECs) has attracted extensive attention in various industrial sectors due to the significant improvement of material properties imparted by CNTs. The thermal behavior of these nanocomposites is governed by complex heat transfer mechanisms operating [...] Read more.

The application of carbon nanotube (CNT)-reinforced epoxy matrix composites (CRECs) has attracted extensive attention in various industrial sectors due to the significant improvement of material properties imparted by CNTs. The thermal behavior of these nanocomposites is governed by complex heat transfer mechanisms operating at different scales, resulting in a complex relationship between the effective thermal response and the microstructural characteristics of the composite. In order to fundamentally understand the thermal behavior of the CRECs on the nanoscale, in this study, molecular dynamics (MD) simulation methods were used to investigate the thermal conductivity of CRECs, focusing on the effects of key parameters such as the length and volume fraction of CNTs, the degree of cross-linking within the epoxy matrix, and the temperature on the overall thermal properties. First, the thermal behavior of the epoxy matrix was simulated and analyzed. This approach allowed the isolation of the intrinsic thermal response of the epoxy resin as a benchmark for evaluating the enhancement introduced by CNT reinforcement. By systematically varying those key parameters, the study comprehensively evaluates how nanoscale interactions and structural modifications affect the overall thermal conductivity of CRECs, providing valuable insights for optimizing their design for advanced thermal management applications. The simulation results were validated by comparing them with experimental data from literature and analytical predictions. The results show that for the configurations examined, the thermal conductivity of CRECs increases with increasing CNT length and volume fraction, epoxy cross-linking degree, and the system temperature. From a broader perspective, the approach presented here has the potential to be applied to study a wide range of materials and their properties. Full article

(This article belongs to the Special Issue Theoretical and Computational Investigation on Composite Materials)

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15 pages, 2715 KiB

Open AccessArticle

Exploration of Alkaline Degumming Printing Techniques for Silk Gauze Fabric: Alkaline Boiling, Alkaline Steaming, and Alkaline Gel

by Huihui Wu, Jiali Zhou and Yufeng Li

J. Compos. Sci. 2025, 9(4), 158; https://doi.org/10.3390/jcs9040158 - 26 Mar 2025

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Abstract

As an important branch of ancient Chinese silk dyeing and printing technology, alkali degumming printing utilizes alkali agents to degum raw silk, creating differences in fiber water absorption, dye uptake, and optical characteristics between degummed and non-degummed areas to achieve localized pattern formation.Based [...] Read more.

As an important branch of ancient Chinese silk dyeing and printing technology, alkali degumming printing utilizes alkali agents to degum raw silk, creating differences in fiber water absorption, dye uptake, and optical characteristics between degummed and non-degummed areas to achieve localized pattern formation.Based on the differences in degumming processes of Silk Gauze using alkaline boiling, alkaline steaming, and alkaline gel, this study compares the effects of these three alkaline degumming techniques under different conditions of alkaline agent dosage, hot press temperature, and hot press duration. The degumming efficiency, fiber surface morphology, and infrared spectra of the degummed Silk Gauze were analyzed and compared. Through the analysis of the degumming mechanisms, it was found that the alkaline gel, within a localized micro-system, meets the conditions of alkali, water, and heat required for precise degumming of Silk Gauze. Combining the dual effects of alkaline boiling and alkaline steaming, the alkaline gel can achieve rapid degumming at a hot press temperature of 80 °C within 50 s, without significantly affecting the surface morphology or the primary structure of the Silk Gauze. The implementation of alkaline gel for precise degumming of Silk Gauze holds significant importance for expanding the application of traditional alkaline printing techniques in modern silk degumming and printing processes. Full article

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12 pages, 9168 KiB

Open AccessArticle

A Study on the Uniaxial Compressive Constitutive Characteristics of Phosphogypsum-Based Irregular-Shaped Bricks (PG-ISBs) for Underground Filling Retaining Walls

by Jixiang Jiang, Guihong Xu, Zhenhua Zhao, Hejun Li, Mingwei He, Wenqi Wu and Ziwei Chen

J. Compos. Sci. 2025, 9(4), 157; https://doi.org/10.3390/jcs9040157 - 25 Mar 2025

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Abstract

This study investigated the mechanical properties of a cementitious material used to prepare irregular-shaped brick masonry structures (PG-ISBs) from industrial solid wastes, including phosphogypsum, calcium powder, cementitious agents, and construction brick debris. The hydration products, microstructure, and elemental composition of the system were [...] Read more.

This study investigated the mechanical properties of a cementitious material used to prepare irregular-shaped brick masonry structures (PG-ISBs) from industrial solid wastes, including phosphogypsum, calcium powder, cementitious agents, and construction brick debris. The hydration products, microstructure, and elemental composition of the system were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Based on the experimental stress–strain relationship curves, a constitutive model for the cementitious material was established. The results show that the compressive strength of the PG-ISB cementitious material meets the requirements for filling retaining walls. SEM observations reveal a significant number of micro-pores within the PG-ISB cementitious material, which are important factors affecting its strength. An empirical constitutive model for the uniaxial compression of the specimen was established based on the experimental stress–strain full curves, and the fitting curves showed good agreement with the experimental data. Full article

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17 pages, 8542 KiB

Open AccessArticle

Plasmonic Rutile TiO₂/Ag Nanocomposites Tailored via Nonthermal-Plasma-Assisted Synthesis: Enhanced Spectroscopic and Optical Properties with Tuned Electrical Behavior

by Essam M. Abdel-Fattah and Ali A. Azab

J. Compos. Sci. 2025, 9(4), 156; https://doi.org/10.3390/jcs9040156 - 25 Mar 2025

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Abstract

In this study, silver nanoparticles (Ag NPs) were synthesized on the surface of rutile-phase titanium dioxide (R-TiO₂) using a plasma-assisted technique. Comprehensive analyses were conducted to investigate the structural, morphological, optical, and electrical properties of the synthesized nanocomposites. Transmission electron microscopy [...] Read more.

In this study, silver nanoparticles (Ag NPs) were synthesized on the surface of rutile-phase titanium dioxide (R-TiO₂) using a plasma-assisted technique. Comprehensive analyses were conducted to investigate the structural, morphological, optical, and electrical properties of the synthesized nanocomposites. Transmission electron microscopy (TEM) images revealed the uniform decoration of Ag NPs (average size: 29.8 nm) on the R-TiO₂ surface. X-ray diffraction (XRD) confirmed the polycrystalline nature of the samples, with decreased diffraction peak intensity indicating reduced crystallinity due to Ag decoration. The Williamson–Hall analysis showed increased crystallite size and reduced tensile strain, suggesting grain growth and stress relief. Raman spectroscopy revealed quenching and broadening of R-TiO₂ vibrational modes, likely due to increased oxygen vacancies. X-ray photoelectron spectroscopy (XPS) confirmed successful plasma-assisted deposition and the coexistence of Ag⁰ and Ag⁺ states, enhancing surface reactivity. UV-Vis spectroscopy demonstrated enhanced light absorption across the spectral range, attributed to localized surface plasmon resonance (LSPR), and a reduced optical bandgap. Dielectric properties, including dielectric constants, loss factor, and AC conductivity, were evaluated across frequencies (4–8 MHz) and temperatures (20–240 °C). The AC conductivity results indicated correlated barrier hopping (CBH) and overlapping large polaron tunneling (OLPT) as the primary conduction mechanisms. Composition-dependent dielectric behavior was interpreted through the Coulomb blockade effect. These findings suggest the potential of plasma assisted Ag NP-decorated R-TiO₂ nanostructures for photocatalysis, sensor and specific electro electrochemical systems applications. Full article

(This article belongs to the Section Nanocomposites)

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16 pages, 4629 KiB

Open AccessArticle

Evaluation of Mechanical, Thermal, and Tribological Properties of 3D-Printed Nylon (PA6) Hybrid Composites Reinforced with MWCNTs and Carbon Fibers

by Palaiam Siddikali and P. S. Rama Sreekanth

J. Compos. Sci. 2025, 9(4), 155; https://doi.org/10.3390/jcs9040155 - 24 Mar 2025

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Abstract

Three-dimensionally-printed carbonfiber-reinforced composites are increasingly replacing thermosetting polymers and metals due to their lightweight structure and enhanced mechanical performance. This investigation examines the mechanical, thermal and tribological characteristics of 3D-printed nylon (PA6) composites reinforced with 0.5 wt.% multi-walled carbon nanotubes (MWCNTs), 15 wt.% [...] Read more.

Three-dimensionally-printed carbonfiber-reinforced composites are increasingly replacing thermosetting polymers and metals due to their lightweight structure and enhanced mechanical performance. This investigation examines the mechanical, thermal and tribological characteristics of 3D-printed nylon (PA6) composites reinforced with 0.5 wt.% multi-walled carbon nanotubes (MWCNTs), 15 wt.% short carbon fibers (CF), and a hybrid combination of both, consisting of 0.5 wt.% MWCNTs and 15 wt.% CF. This study focuses on evaluating the individual and synergistic effects of these reinforcements on the performance of nylon-based composites. A series of characterizations, including mechanical, thermal, tribological, morphological and FTIR analyses, are conducted. The tensile and flexural strengths of the hybrid composite are improved by 35% and 42%, respectively, compared to pure nylon. The findings emphasize the substantial influence of hybrid reinforcement on enhancing mechanical, thermal, and tribological properties, providing useful information on the possible utilization of these composites in engineering applications requiring high-performance materials. Full article

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27 pages, 3332 KiB

Open AccessArticle

Reliability-Based Calibration of Strength-Reduction Factors for Flexural Design of FRP-RC Beams Under Various Load Combinations

by Nahid Attarchian, Reza Aghamohammadi and Kourosh Nasrollahzadeh

J. Compos. Sci. 2025, 9(4), 154; https://doi.org/10.3390/jcs9040154 - 23 Mar 2025

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Abstract

The aim of this paper is to conduct reliability analysis of flexural strength design provisions of FRP-reinforced concrete (FRP-RC) beams in accordance with CSA S806. In particular, different load combinations, including dead, live, wind and snow, are investigated. Through this, the various sources [...] Read more.

The aim of this paper is to conduct reliability analysis of flexural strength design provisions of FRP-reinforced concrete (FRP-RC) beams in accordance with CSA S806. In particular, different load combinations, including dead, live, wind and snow, are investigated. Through this, the various sources of uncertainty related to the material strength and geometrical properties are taken into account when examining the reliability of the flexural strength provisions of CSA. The uncertainty inherent in the flexural strength model is assessed using a large experimental database of 303 FRP-RC beams assembled from the literature. The first-order reliability method (FORM) is employed for reliability analysis. The results indicated that the reliability index, β, of the current code is not consistent for different failure modes, yielding overly conservative values for the FRP rupture mode (β = 4.895) compared to the concrete crushing mode of failure (β = 3.726). Based on the reliability-based calibration of the existing design equations, modifications to the current provisions are proposed to achieve a variety of target reliability indexes of 3.5, 3.8, and 4 for the failure modes of concrete crushing and FRP rupture, separately, and for a common range of load ratios in the different load combinations. The results presented enable designers to choose proper strength-reduction factors to reach the desired level of safety for each failure mode in the flexural design of FRP-RC beams. Full article

(This article belongs to the Special Issue Advanced Composite Materials and Design for Structural Safety and Sustainability)

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22 pages, 8792 KiB

Open AccessArticle

A Numerical Tool for Assessing Random Vibration-Based Fatigue Damage Diagnosability in Thermoplastic Coupons

by Niki Tsivouraki, Spilios Fassois and Konstantinos Tserpes

J. Compos. Sci. 2025, 9(4), 153; https://doi.org/10.3390/jcs9040153 - 23 Mar 2025

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Abstract

A numerical tool is developed to simulate the random vibration-response-only-based fatigue delamination diagnosability in thermoplastic coupons. That is the ability to both detect damage and identify its current severity, aiming to establish a virtual framework for optimizing diagnosability methods. The numerical tool employs [...] Read more.

A numerical tool is developed to simulate the random vibration-response-only-based fatigue delamination diagnosability in thermoplastic coupons. That is the ability to both detect damage and identify its current severity, aiming to establish a virtual framework for optimizing diagnosability methods. The numerical tool employs the FE method. It comprises two modules: a fatigue delamination module and a random vibration module. The first module implements a fatigue crack growth model based on the cohesive zone modeling method to predict delamination accumulation, while the second module uses an experimentally verified FE model of the delaminated coupon to predict its random vibration response. Delamination accumulation is evident in the ‘predicted’ FE-based power spectral densities. The model’s capability to diagnose delamination is demonstrated using seven different damage metrics based on simulated random vibration responses, enabling damage detection and severity assessment (increasing trend guides to distinguishing each fatigue state from its counterparts). Comparisons with their experimentally obtained counterparts are also used in the assessment. The procedure clearly suggests that the proposed numerical tool may be reliably used for virtually assessing the efficacy of random vibration-based fatigue damage diagnosability for any given structure and also to aid the user in selecting the method’s parameters for virtual diagnosability optimization. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Modeling and Simulation of Composite Materials)

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28 pages, 7166 KiB

Open AccessArticle

Enhanced Stability and Adsorption of Cross-Linked Magnetite Hydrogel Beads via Silica Impregnation

by Nur Maisarah Mohamad Sarbani, Endar Hidayat, Kanako Naito, Mitsuru Aoyagi and Hiroyuki Harada

J. Compos. Sci. 2025, 9(4), 152; https://doi.org/10.3390/jcs9040152 - 23 Mar 2025

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Abstract

Hydrogel-based adsorbents have gained increasing recognition in recent years due to their promising potential for pollutant removal. However, conventional hydrogels often suffer from low mechanical strength over prolonged use. Therefore, this study explores the incorporation of silica extracted from bamboo culm (Dendrocalamus [...] Read more.

Hydrogel-based adsorbents have gained increasing recognition in recent years due to their promising potential for pollutant removal. However, conventional hydrogels often suffer from low mechanical strength over prolonged use. Therefore, this study explores the incorporation of silica extracted from bamboo culm (Dendrocalamus asper) to enhance the mechanical stability of hydrogel beads composed from carboxymethyl cellulose (CMC), chitosan (CS), and magnetite ferrofluid (Fe₃O₄), through cross-linking. We hypothesize that silica enhances the mechanical properties of magnetite hydrogel beads without compromising their adsorption capacity. The extracted silica was confirmed with FTIR and EDS analysis. The synthesized CMC-CS-Fe₃O₄-Si hydrogel beads were characterized using FTIR and SEM. Its stability was assessed through dry weight loss measurements, while its adsorption efficiency was evaluated using batch adsorption experiments. The silica-incorporated hydrogel exhibited enhanced mechanical and thermal stability under various pH and temperature conditions, without negatively affecting its adsorption performance, achieving maximum adsorption capacities of 53.00 mg/g for Cr (VI) and 85.06 mg/g for Cu (II). Desorption and regeneration studies confirmed the reusability of the hydrogel for more than four cycles. Overall, the interaction between the hydrogel and silica resulted in excellent adsorption performance, improved mechanical properties, and long-term reusability, making this a promising hydrogel adsorbent for wastewater remediation. Full article

(This article belongs to the Section Composites Applications)

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15 pages, 6722 KiB

Open AccessArticle

Numerical Simulation of the Thermal Effect of Firebrand Deposition on External Composite Walls

by Mohamed Zitouni, Antonio Renato Albuquerque Bicelli, Mário Rui Tiago Arruda and Fernando Branco

J. Compos. Sci. 2025, 9(4), 151; https://doi.org/10.3390/jcs9040151 - 22 Mar 2025

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Abstract

This paper presents research concerning simulating the thermal firebrand effect due to its accumulation in exterior construction wall elements by developing a 3D finite element model (FEM) via ABAQUS (2022) software to analyze the exterior walls commonly applied to the exterior of dwellings [...] Read more.

This paper presents research concerning simulating the thermal firebrand effect due to its accumulation in exterior construction wall elements by developing a 3D finite element model (FEM) via ABAQUS (2022) software to analyze the exterior walls commonly applied to the exterior of dwellings in southern Europe and South America. A non-linear thermal transient analysis is undertaken, in which the results are directly compared with a previous experimental campaign, in which firebrands are deposited on localized surfaces of construction wall specimens, and the temperature is measured in the several layers of the construction elements. The walls are composite elements, made of different layer combinations of masonry brick and wood, varying the type of thermal insulation in the internal core from cork to classical rigid rockwool and polystyrene foam (XPS). It can be summarized from the results that the FEM effectively simulates the thermal response of brick, normal wood (NW), and cross-laminated timber (CLT) walls when insulated with materials like cork or rockwool coated with mortar against firebrand accumulation. However, the lack of accounting for uncontrolled combustion leads to inconsistent results. Additionally, for walls using XPS as the insulation material, the model requires further refinement to accurately simulate the melting phenomenon and its thermal impact. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Modeling and Simulation of Composite Materials)

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18 pages, 14810 KiB

Open AccessArticle

Electromagnetic Shielding Effectiveness of Carbon Nanotubes Hydrogel Nanocomposites in the Frequency Range from 1.7 to 6.0 GHz

by Moaz M. Altarawneh

J. Compos. Sci. 2025, 9(4), 150; https://doi.org/10.3390/jcs9040150 - 22 Mar 2025

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Abstract

Carbon nanotube-based nanocomposites are being increasingly utilized in materials for electromagnetic shielding purposes due to their exceptional electrical and mechanical properties. The current study optimizes a simple procedure to prepare multi-wall carbon nanotubes (MWCNTs)-based hydrogel nanocomposites out of water, gelatin, and glycerol. The [...] Read more.

Carbon nanotube-based nanocomposites are being increasingly utilized in materials for electromagnetic shielding purposes due to their exceptional electrical and mechanical properties. The current study optimizes a simple procedure to prepare multi-wall carbon nanotubes (MWCNTs)-based hydrogel nanocomposites out of water, gelatin, and glycerol. The content ratio of each component in the hydrogel composite is carefully selected to optimize the dielectric properties over the electromagnetic (EM) wave frequency of 0.5 to 20 GHz. The hydrogel nanocomposites were prepared with MWCNT concentrations ranging from 0.1 to 0.9 wt%. The dispersion of MWCNTs in the nanocomposites was investigated and confirmed using a scanning electron microscope (SEM). The dielectric parameters, including the real dielectric constant

ε^{'}

, imaginary dielectric constant

ε^{″}

, and tangent loss tan

δ

along with the DC and AC electrical conductivity (

σ_{D C}

,

σ_{A C}

) were investigated. The study shows a significant enhancement in the dielectric parameters of the prepared nanocomposites as the MWCNT concentration is increased. The shielding effectiveness (SE) of the hydrogel nanocomposites against electromagnetic waves in the frequency range from 1.7 to 6.0 GHz is investigated and found to be enhanced as the concentration of MWCNTs and frequency have increased. The shielding effectiveness of the prepared hydrogel nanocomposites ranges from 10 dB to 26 dB, equivalent to shielding of 90% and more than 99% of incident radiation, respectively. Full article

(This article belongs to the Special Issue Recent Progress in Hybrid Composites)

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19 pages, 13388 KiB

Open AccessArticle

Spirally Confined Reinforcing Bar for Flexural Behavior of Glass Fiber-Reinforced Concrete Beam

by Nuria S. Mohammed, Ashraf A. M. Fadiel, Ahmad Baharuddin Abdul Rahman, Esam Abu Baker Ali, Taher Abu-Lebdeh, Antreas Kantaros and Florian Ion Tiberiu Petrescu

J. Compos. Sci. 2025, 9(4), 149; https://doi.org/10.3390/jcs9040149 - 22 Mar 2025

Cited by 1 | Viewed by 198

Abstract

This paper presents experimental results on the influence of the spiral anchor system on the flexural behavior of concrete beams reinforced with glass fiber-reinforced plastic (GFRP) bars. The experimental program consisted of eight beams with the spiral anchor system and two control fiber-reinforced [...] Read more.

This paper presents experimental results on the influence of the spiral anchor system on the flexural behavior of concrete beams reinforced with glass fiber-reinforced plastic (GFRP) bars. The experimental program consisted of eight beams with the spiral anchor system and two control fiber-reinforced concrete beams without any spiral anchor system. All specimens were tested under bending load. Rough and smooth surface textures of GFRP bars were considered. The test parameters were the diameter of spiral anchor and the condition of the GFRP reinforcement bars as either bonded or unbonded to the surrounding grout. The experimental results indicate that beams reinforced with a rough GFRP bar with an anchor system under flexural load had higher ultimate flexural strength, first crack strength, and stiffness as compared to the beams without an end anchor system. The success of the anchor system is attributed to the confining effect of the steel spiral in anchoring the reinforcement ends. This confining effect enhances the anchorage capacity of the anchor system and subsequently improves the overall flexural performance of the reinforced concrete beams. Full article

(This article belongs to the Special Issue Sustainable Composite Construction Materials, Volume II)

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10 pages, 3157 KiB

Open AccessArticle

Preliminary Study on Syngas Production from a CO₂ and CH₄ Mixture via Non-Thermal Dielectric Barrier Discharge Plasma Incorporated with Metal–Organic Frameworks

by Naveen Sunder, Yeong Yin Fong and Serene L. S. Mun

J. Compos. Sci. 2025, 9(4), 148; https://doi.org/10.3390/jcs9040148 - 21 Mar 2025

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Abstract

Dry reforming has gained widespread attention among CO₂ utilization approaches, as it is able to convert both CO₂ and CH₄ into syngas, thus mitigating global warming. Moreover, dielectric barrier discharge (DBD) non-thermal catalytic plasma reactors are potential technologies for CO [...] Read more.

Dry reforming has gained widespread attention among CO₂ utilization approaches, as it is able to convert both CO₂ and CH₄ into syngas, thus mitigating global warming. Moreover, dielectric barrier discharge (DBD) non-thermal catalytic plasma reactors are potential technologies for CO₂ and CH₄ conversion, due to their low energy consumption and ease of operation. Catalysts also play an important role in ensuring optimal performance. For instance, metal–organic frameworks (MOFs) such as ZIF-8, NH₂-UiO-66(Zr), and NH₂-MIL-53(Al) are rarely reported in the literature for plasma technologies in dry reforming, despite their strong attributes such as high surface area and charge characteristics. In this work, these MOF catalysts were synthesized and characterized to evaluate their internal morphology, crystallinity, and surface area. Characterization studies showed that ZIF-8, NH₂-UiO-66(Zr), and NH₂-MIL-53(Al) generally showed similar properties to those results reported in the literature. Additionally, based on DBD catalytic plasma testing, NH₂-UiO-66(Zr) with an input power of 30 W recorded the highest H₂ and CO yields of 3.20% and 2.34%, respectively, at a CO₂:CH₄ molar ratio of 7:3. These values could be referred to for future studies on the improvement of MOF catalysts performance in dry reforming under the plasma processes prior to upscaling. Full article

(This article belongs to the Section Composites Applications)

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27 pages, 6567 KiB

Open AccessArticle

Comparison Study on Flat and Curved Glass-Fiber-Reinforced Polymer Panels Subjected to High-Velocity Impacts with Spherical and Conical Projectiles: An Experimental and Numerical Study

by Chinnarasu Arivoli and Kashi Ramajeyathilagam

J. Compos. Sci. 2025, 9(4), 147; https://doi.org/10.3390/jcs9040147 - 21 Mar 2025

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Abstract

This research investigates the performance of glass-fiber-reinforced polymer (GFRP) composite panels under high-velocity impacts, with a focus on panels of varying radii of curvature (ROC): flat, 203 mm ROC, and 112 mm ROC. Both spherical and conical projectiles were used in the impact [...] Read more.

This research investigates the performance of glass-fiber-reinforced polymer (GFRP) composite panels under high-velocity impacts, with a focus on panels of varying radii of curvature (ROC): flat, 203 mm ROC, and 112 mm ROC. Both spherical and conical projectiles were used in the impact tests conducted using experimental and numerical approaches using an LS-DYNA solver. The results show that, as the curvature increases, the energy absorption increases for both types of projectiles. The 112 mm ROC panel demonstrated the highest ballistic limit velocity and energy absorption, outperforming both the flat and 203 mm ROC panels. Specifically, it exhibited a 22% higher ballistic limit velocity for spherical projectiles and a 17% increase for conical projectiles compared to the flat panel. The 112 mm ROC panel also absorbed the most energy, with a maximum of 36.3 J at 91 m/s for spherical impacts, resulting in extensive damage, including delamination, fiber pullout, and matrix debonding. The findings highlight the enhanced impact resistance of GFRP composite panels with higher curvature, particularly under spherical impacts. Full article

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31 pages, 15532 KiB

Open AccessArticle

Effect of Phosphogypsum Origin and Calcination Temperature on Characteristics of Supersulfated Cements

by Nataliya Alfimova, Ksenia Levickaya, Ivan Nikulin, Mikhail Elistratkin, Natalia Kozhukhova and Nikita Anosov

J. Compos. Sci. 2025, 9(4), 146; https://doi.org/10.3390/jcs9040146 - 21 Mar 2025

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Abstract

Supersulfated cements (SSCs) are one of the promising binders characterized by low CO₂ emissions. A significant advantage of SSC is the possibility of using phosphoanhydrite binders as a sulfate component, obtained by the calcination of phosphogypsum—a waste product of acid and fertilizer [...] Read more.

Supersulfated cements (SSCs) are one of the promising binders characterized by low CO₂ emissions. A significant advantage of SSC is the possibility of using phosphoanhydrite binders as a sulfate component, obtained by the calcination of phosphogypsum—a waste product of acid and fertilizer production. The utilization of phosphogypsum is a global problem. Differences in the properties of phosphogypsums from various industrial enterprises are determined by the difference in phosphate rock and the technological mode of production. This gives reason to believe that phosphoanhydrite binders (FABs) will also have differences in properties, which in turn will influence the process of structural formation of SSC. In the article, the effect of FAB produced at calcination temperatures of 600, 800, and 1000 °C using phosphogypsum of two different industrial enterprises was studied. It is established that the morphology and pH value of FAB particles, and the ratio of components in the binder have the greatest influence on the physical and mechanical characteristics of the SSC. The use of FAB with a high pH value (≈12) allows for obtaining free-of-cement SSC, with compressive strengths of up to 50 MPa at the age of 90 days. Full article

(This article belongs to the Special Issue From Waste to Advance Composite Materials, 2nd Edition)

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J. Compos. Sci., Volume 9, Issue 4 (April 2025) – 32 articles

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