Journal of Composites Science

20 pages, 2771 KiB

Open AccessArticle

Obtaining Composite Zinc Phosphate Cement with the Addition of Phosphoric Slag

by Aidana Abdullin, Nurgali Zhanikulov, Bakhitzhan Taimasov, Ekaterina Potapova, Yana Alfereva, Dmitry Ksenofontov and Bibol Zhakipbayev

J. Compos. Sci. 2025, 9(5), 200; https://doi.org/10.3390/jcs9050200 - 22 Apr 2025

Abstract

The feasibility of producing high-quality zinc phosphate cement based on a frit-sintered mixture of ZnO, SiO₂, MgO, and Bi₂O₃ oxides, with the addition of phosphorous slag and an aqueous solution of orthophosphoric acid as the mixing liquid, was [...] Read more.

The feasibility of producing high-quality zinc phosphate cement based on a frit-sintered mixture of ZnO, SiO₂, MgO, and Bi₂O₃ oxides, with the addition of phosphorous slag and an aqueous solution of orthophosphoric acid as the mixing liquid, was demonstrated. The raw materials used for zinc phosphate cement preparation were investigated using various physicochemical analysis methods. It was found that the phosphorous slag contains silicon oxide (37.6%), aluminum oxide (4.49%), calcium oxide (42.4%), magnesium oxide (2.19%), as well as fluorine (1.94%) and calcium fluoride (4.91%). The slag predominantly consists of an amorphous glassy phase with minor inclusions of crystalline components. During the sintering process, the addition of 1.5–3.0 wt.% phosphorous slag to the frit promotes the formation of low-melting eutectics due to the presence of fluorides, resulting in a 100 °C reduction in the sintering temperature. An optimal zinc phosphate cement powder composition was developed, comprising: ZnO—83.0%, MgO—9.0%, SiO₂—3.5%, Bi₂O₃—3.0%, and phosphorous slag—1.5%. The resulting sintered product exhibited a whiteness of 97.8%, which exceeds that of the reference sample by 2.6%. Upon mixing the powder with the mixing liquid, zinc ions are released first, initiating a chemical reaction that leads to the formation of zinc, magnesium, and aluminum phosphates. The compressive strength of the resulting composite cements ranged from 101.8 to 111.9 MPa, fully complying with the requirements for cement grade as specified in GOST 31578-2012. Full article

► Show Figures

Figure 1

24 pages, 9175 KiB

Open AccessArticle

Investigating the Effects of H₂ Additions to Helium and Argon Shielding Gases on TIG-Welded AISI 316L Stainless Steel

by Samir Khrais, Tariq Darabseh, Awsan Mohammed and Ahmad Abdel Al

J. Compos. Sci. 2025, 9(5), 199; https://doi.org/10.3390/jcs9050199 - 22 Apr 2025

Abstract

Adding hydrogen (H₂) to shielding gas in Tungsten Inert Gas (TIG) welding has garnered attention for its potential to enhance weld quality. This study explores the effects of H₂ and helium (He) content on AISI 316L stainless steel welding, focusing [...] Read more.

Adding hydrogen (H₂) to shielding gas in Tungsten Inert Gas (TIG) welding has garnered attention for its potential to enhance weld quality. This study explores the effects of H₂ and helium (He) content on AISI 316L stainless steel welding, focusing on their influence on weld bead geometry, microstructural properties, and mechanical properties. The H₂ (1.5%, 3%, 4.5%) and He (10%, 20%, 30%) concentrations were evaluated in a shielding gas primarily composed of argon (Ar). The study underscores the need for precise gas blend control to balance enhanced performance with material safety. These findings offer insights into optimizing welding parameters for AISI 316L, with implications for broader applications in industries demanding high quality. The result shows that H₂ (1.5–3.0%) improves penetration, geometry, and surface finish, while He (10–20%) enhances arc stability and smoothness; however, excessive levels of H₂ (>4.5%) cause defects. Optimal mechanical properties (UTS: 714.54 MPa, YS: 449.03 MPa, hardness: 93.34 HRB, impact toughness: 34.45 J) are achieved with 3% H₂, 30% He, and 150 A arc current. Full article

(This article belongs to the Special Issue Welding and Friction Stir Processes for Composite Materials)

► Show Figures

Figure 1

20 pages, 6548 KiB

Open AccessArticle

Research on the Relative Displacement Distribution of a Composite Plate with Built-In FBG Sensors

by Aliya Kalizhanova, Ainur Kozbakova, Murat Kunelbayev, Timur Kartbayev and Gulzhan Kashaganova

J. Compos. Sci. 2025, 9(5), 198; https://doi.org/10.3390/jcs9050198 - 22 Apr 2025

Abstract

The paper studies the distribution of relative displacement of a composite plate with integrated fiber Bragg gratings. The analysis of the methods for manufacturing composite plates with embedded optical fibers containing FBG sensors, as well as the spectral characteristics of the gratings under [...] Read more.

The paper studies the distribution of relative displacement of a composite plate with integrated fiber Bragg gratings. The analysis of the methods for manufacturing composite plates with embedded optical fibers containing FBG sensors, as well as the spectral characteristics of the gratings under various bending conditions, are performed. The effect of sensor arrangement on the accuracy of determining stresses and relative elongations of the material is experimentally studied. The features of spectral shifts that occur under non-uniform stresses are revealed, which can reduce the accuracy of measurements when using interrogators. The patterns of change in the central wavelength of Bragg gratings depending on the type and magnitude of plate bending are established. The research results confirm that the use of a network of embedded FBG sensors allows one to accurately determine the areas of maximum deformations, as well as the nature and magnitude of bending of composite structures. The data obtained can be used to develop more accurate systems for monitoring the stress–strain state of composite materials. Full article

(This article belongs to the Section Fiber Composites)

► Show Figures

Figure 1

25 pages, 5601 KiB

Open AccessArticle

Photocatalytic Degradation of Acetaminophen by g-C₃N₄/CQD/Ag Nanocomposites from Aqueous Media

by Ali Toolabi, Mahsa Tahergorabi, Jamal Mehralipour, Neda Seyedi and Negin Nasseh

J. Compos. Sci. 2025, 9(5), 197; https://doi.org/10.3390/jcs9050197 - 22 Apr 2025

Abstract

Ternary g-C₃N₄/CQD/Ag photocatalysts were synthesized via deposition of carbon quantum dots (CQDs) and silver nanoparticles (Ag) onto graphitic carbon nitride (g-C₃N₄) for efficient acetaminophen degradation. The nanocomposites exhibited enhanced photoresponse and broad-spectrum photocatalytic activity under [...] Read more.

Ternary g-C₃N₄/CQD/Ag photocatalysts were synthesized via deposition of carbon quantum dots (CQDs) and silver nanoparticles (Ag) onto graphitic carbon nitride (g-C₃N₄) for efficient acetaminophen degradation. The nanocomposites exhibited enhanced photoresponse and broad-spectrum photocatalytic activity under both UV (254 nm, 250 W) and Xenon (>420 nm, 500 W) irradiation. Characterization by XRD, FTIR, SEM, PL, and EDX elucidated the material’s composition, structure, morphology, and optical properties. Optimized photocatalytic degradation of acetaminophen (50 mg/L) was achieved at pH 7 with 0.6 g/L catalyst loading and 60 min irradiation, yielding degradation efficiencies of 87.5% (UV) and 85.3% (Xenon). Radical quenching experiments and GC-MS analysis identified hydroxyl radicals as the primary reactive species and revealed a gradual decrease in intermediate toxicity during mineralization. This study demonstrates the superior photocatalytic performance of the ternary g-C₃N₄/CQD/Ag nanocomposites compared to binary systems for effective acetaminophen removal. Full article

(This article belongs to the Section Carbon Composites)

► Show Figures

Figure 1

20 pages, 19306 KiB

Open AccessArticle

Integrated Development of Mechanical Strength and Thermoelectric Properties in Cement Composites Incorporating Graphene Oxide and Manganese Dioxide

by Jude Shalitha Perera, Anuradha Silva, Priyan Mendis, Shanaka Kristombu Baduge, Aathavan Kuhanandha, Lochlan Hau and Philip Trinh

J. Compos. Sci. 2025, 9(4), 196; https://doi.org/10.3390/jcs9040196 - 21 Apr 2025

Abstract

Cement-based thermoelectric materials are gaining popularity among materials scientists due to their robust mechanical characteristics and suitability for thermal energy harvesting in building applications. However, despite advancements in the development of these materials, a significant knowledge gap persists regarding their mechanical characterisation. This [...] Read more.

Cement-based thermoelectric materials are gaining popularity among materials scientists due to their robust mechanical characteristics and suitability for thermal energy harvesting in building applications. However, despite advancements in the development of these materials, a significant knowledge gap persists regarding their mechanical characterisation. This research aimed to enhance the thermoelectric performance of cement composites through the incorporation of graphene oxide (GO) and manganese dioxide (MnO₂), while ensuring adequate compressive strength was maintained. An experimental investigation was conducted to simultaneously assess both properties of cement composites using identical specimens. Additionally, microstructural analysis of the samples was performed to further understand the integrated development of these two properties. To evaluate the integrative properties, a Pareto analysis was performed to identify the Pareto-optimal solutions for specific applications. Additionally, a new index, termed the Thermoelectric Strength Index (TSI), was developed to compare materials in applications where both thermoelectric efficiency and mechanical robustness are important. The findings indicated that while both GO and MnO₂ enhanced the thermoelectric properties of cement, their reactions with the cement phases produced distinct relationships with compressive strength, especially when GO and MnO₂ were added together. The TSI demonstrated that MnO₂ was superior for simultaneously enhancing mechanical strength and thermoelectric performance, with the 7.5 wt.% formulation yielding the best results. This study demonstrates the complex interrelationship between the mechanical strength and thermoelectric properties of the investigated fillers, underscoring the necessity for a holistic approach in the development of thermoelectric cement composites. Full article

(This article belongs to the Special Issue Mechanical Properties of Composite Materials and Joints)

► Show Figures

Figure 1

19 pages, 6866 KiB

Open AccessArticle

Experimental Investigation on Mechanical Properties of Glass Fiber–Nanoclay–Epoxy Composites Under Water-Soaking: A Comparative Study Using RSM and ANN

by Manjunath Shettar, Ashwini Bhat, Nagaraj N. Katagi and Mandya Channegowda Gowrishankar

J. Compos. Sci. 2025, 9(4), 195; https://doi.org/10.3390/jcs9040195 - 21 Apr 2025

Abstract

Fiber-reinforced polymer composites are exposed to severe environmental conditions throughout their intended lifespan. It is essential to investigate how they age when exposed to cold and hot water to increase the durability of fiber-reinforced polymer composites. This work uses a hand lay-up process [...] Read more.

Fiber-reinforced polymer composites are exposed to severe environmental conditions throughout their intended lifespan. It is essential to investigate how they age when exposed to cold and hot water to increase the durability of fiber-reinforced polymer composites. This work uses a hand lay-up process to create composites with different weight percentages of glass fiber, nanoclay, and epoxy. ASTM guidelines are followed for performing tensile and flexural tests. The input parameters, varying wt.% of glass fiber and nanoclay, are continuous, and the aging condition is deemed a categorical factor. The mechanical properties are considered as response variables (output). The mechanical properties are optimized using Response Surface Methodology (RSM), while Artificial Neural Networks (ANNs) provide a reliable predictive model with high correlation coefficients. The findings demonstrate that ANNs outperform RSM in flexural strength prediction, whereas RSM offers greater accuracy for tensile strength modeling. SEM analysis of the fracture surfaces reveals the causes of specimen failure under tensile load, with distinct differences between dry, cold, and boiling water-soaked specimens. Full article

(This article belongs to the Section Composites Modelling and Characterization)

► Show Figures

Figure 1

19 pages, 7457 KiB

Open AccessArticle

Preparation and Photoelectric Properties of Nanostructured Native Oxide of Gallium Monoselenide with Applications in Gas Sensors

by Veaceslav Sprincean, Alexandru Macovei, Liviu Leontie, Aurelian Carlescu, Silviu Gurlui and Mihail Caraman

J. Compos. Sci. 2025, 9(4), 194; https://doi.org/10.3390/jcs9040194 - 19 Apr 2025

Abstract

Using the Bridgman technique, GaSe single crystals were obtained which were mechanically split into plane-parallel plates with a wide range of thicknesses. By heat treatment in air at 820 °C and 900 °C, for 30 min and 6 h, micro- and nanocomposite layers [...] Read more.

Using the Bridgman technique, GaSe single crystals were obtained which were mechanically split into plane-parallel plates with a wide range of thicknesses. By heat treatment in air at 820 °C and 900 °C, for 30 min and 6 h, micro- and nanocomposite layers of Ga₂Se₃–Ga₂O₃ and β–Ga₂O₃ (native oxide) with surfaces made of nanowires/nanoribbons were obtained. The obtained composite Ga₂Se₃–Ga₂O₃ and nanostructured β–Ga₂O₃ are semiconductor materials with band gaps of 2.21 eV and 4.60 eV (gallium oxide) and photosensitivity bands in the green–red and ultraviolet-C regions that peaked at 590 nm and 262 nm. For an applied voltage of 50 V, the dark current in the photodetector based on the nanostructured β–Ga₂O₃ layer was of 8.0 × 10⁻¹³ A and increased to 9.5 × 10⁻⁸ A upon 200 s excitation with 254 nm-wavelength radiation with a power density of 15 mW/cm². The increase and decrease in the photocurrent are described by an exponential function with time constants of τ_1r = 0.92 s, τ_2r = 14.0 s, τ_1d = 2.18 s, τ_2d = 24 s, τ_1r = 0.88 s, τ_2r = 12.2 s, τ_1d = 1.69 s, and τ_2d = 16.3 s, respectively, for the photodetector based on the Ga₂Se₃–Ga₂S₃–GaSe composite. Photoresistors based on the obtained Ga₂Se₃–Ga₂O₃ composite and nanostructured β–Ga₂O₃ layers show photosensitivity bands in the spectral range of electronic absorption bands of ozone in the same green–red and ultraviolet-C regions, and can serve as ozone sensors (detectors). Full article

(This article belongs to the Special Issue Advanced Composite Materials from Natural and Synthetic Sources: Fabrication, Characterization and Practical Application, Volume II)

► Show Figures

Figure 1

21 pages, 9241 KiB

Open AccessArticle

Theoretical/Experimental Study of the Heavy Metals in Poly(vinylalcohol)/Carboxymethyl Starch-g-Poly(vinyl imidazole)-Based Magnetic Hydrogel Microspheres

by Joaquín Alejandro Hernández Fernández, Jose Alfonso Prieto Palomo and Carlos A. T. Toloza

J. Compos. Sci. 2025, 9(4), 193; https://doi.org/10.3390/jcs9040193 - 18 Apr 2025

Abstract

Heavy metal contamination of water is a critical environmental problem due to its toxicity and persistence in ecosystems. In this study, magnetic hydrogel spheres composed of carboxymethylated starch modified with poly(1-vinylimidazole) (CMS-g-PVI) and polyvinyl alcohol (PVA), combined with Fe₃O₄ nanoparticles, [...] Read more.

Heavy metal contamination of water is a critical environmental problem due to its toxicity and persistence in ecosystems. In this study, magnetic hydrogel spheres composed of carboxymethylated starch modified with poly(1-vinylimidazole) (CMS-g-PVI) and polyvinyl alcohol (PVA), combined with Fe₃O₄ nanoparticles, were synthesized and characterized to evaluate their efficiency in adsorbing metal ions such as Cu²⁺, Pb²⁺, and Cd²⁺. Structural characterization by FT-IR spectroscopy confirmed the successful integration of all functional components into the hydrogel matrix. Additionally, scanning electron microscopy (SEM) revealed a rough and porous surface morphology favorable for adsorption and an average bead diameter of 3.2 mm, influenced by the stirring rate during synthesis. Adsorption studies demonstrated maximum capacities of 82.4 mg·g⁻¹ for Cu²⁺, 66.5 mg·g⁻¹ for Pb²⁺, and 51.8 mg·g⁻¹ for Cd²⁺, with optimal removal efficiencies at pH 6.2 and 5.7. From a theoretical perspective, density functional theory (DFT) calculations using the B3LYP/6-311+G(d,p) method allowed the optimization of molecular structures and analysis of electronic properties. The total dipole moment (TDM) of the CMS-g-PVI/PVA system reached 20.81 Debye. A significant reduction in the HOMO-LUMO energy gap was observed upon metal adsorption, with values of 0.0308 eV for Cu²⁺, 0.0175 eV for Pb²⁺, and 0.0235 eV for Cd²⁺, confirming strong interactions between the hydrogel matrix and the metal ions. The combined experimental and computational approach provides a comprehensive understanding of the adsorption mechanisms and supports the development of efficient materials for water decontamination. Full article

► Show Figures

Figure 1

14 pages, 1706 KiB

Open AccessArticle

Thermal Stabilization Activities of Metal Oxide γ-Irradiated Styrene–Isoprene–Styrene Nanocomposites

by Traian Zaharescu, Ademar B. Lugāo, Violeta Mangalagiu and Radu Mirea

J. Compos. Sci. 2025, 9(4), 192; https://doi.org/10.3390/jcs9040192 - 17 Apr 2025

Abstract

This study provides insights into the stabilization effects of certain oxides (CeO₂, Cr₂O₃, Cd₂O₃, In₂O₃, MnO₂, MgO, Nd₂O₃, and Pr₂O₃ [...] Read more.

This study provides insights into the stabilization effects of certain oxides (CeO₂, Cr₂O₃, Cd₂O₃, In₂O₃, MnO₂, MgO, Nd₂O₃, and Pr₂O₃) in styrene–isoprene–styrene triblock copolymers with respect to neat materials. This study was performed via chemiluminescence (CL), which allowed for the determination of the main parameters characterizing the interphase coexistence: the oxidation induction times, oxidation rates, and onset oxidation temperatures. The improvement in the thermal performances of the pristine and γ-ray-processed samples at a moderate dose was highlighted differently due to the electronic interactions on the particle surface. While the non-isothermal CL measurements pointed to a weaker evolution of oxidation in the studied composites at a higher temperature range over 160 °C, the isothermal CL determinations revealed a delayed start of oxidation, slower oxidation rates, and greater activation energies in the nanocomposite aging patterns. The different individual behaviors of the investigated formulations were ascribed to the dissimilar electronic interactions between the particles and the surrounding matrix, where the oxidation initiators were formed by the molecular fragmentation of the polymer macromolecules. The kinetic features illustrate the influence of the peculiarities due to the electronic interactions. The higher resistance shown by the irradiated samples compared with the non-processed compositions demonstrates the stabilization efficiency of the fillers studied. Full article

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

► Show Figures

Graphical abstract

15 pages, 6304 KiB

Open AccessArticle

Composite Film Based on Polyethylene and Plant Waste

by Natalia Igorevna Cherkashina, Dmitry Sergeevich Romanyuk, Darya Alexandrovna Sinebok, Sergey Ivanovich Gorodov, Artem Yurievich Ruchiy, Roman Alekseevich Barinov and Daria Viktorovna Silchenko

J. Compos. Sci. 2025, 9(4), 191; https://doi.org/10.3390/jcs9040191 - 16 Apr 2025

Abstract

This study presents the development of a composite film based on low-pressure polyethylene (LPPE) and sunflower husk. The sunflower husk was pretreated with a 4% NaOH solution. Composite films with a thickness of 200 ± 0.20 µm were obtained, containing 40–60 wt.% sunflower [...] Read more.

This study presents the development of a composite film based on low-pressure polyethylene (LPPE) and sunflower husk. The sunflower husk was pretreated with a 4% NaOH solution. Composite films with a thickness of 200 ± 0.20 µm were obtained, containing 40–60 wt.% sunflower husk. The main mechanical properties, water absorption, and surface morphology of the films were analyzed using scanning electron microscopy (SEM). Thermogravimetric (TG) and differential scanning calorimetry (DSC) curves were obtained for sunflower husk, polyethylene, and composite films. The optimal composition of the film components (wt.%) was determined as follows: LPPE—50–55%, sunflower husk—45–50%. The composite film containing 50 wt.% sunflower husk exhibited the following properties: tensile resistance—3.9 ± 0.18 MPa, relative elongation at break—6 ± 0.28%, tensile strain—21 ± 1.02%, modulus of elasticity—108 ± 5.32 MPa, and water absorption over 24 h—2.4%. Full article

(This article belongs to the Section Polymer Composites)

► Show Figures

Figure 1

23 pages, 8743 KiB

Open AccessArticle

Energy-Absorbing Performance of Metallic Thin-Walled Porous Tubes Filled with Liquid Crystal Elastomers Under Dynamic Crush

by Xu’an Hu, Shaohua Niu, Yanxuan Wu, Bingyang Li, Zhen Li and Jun Wang

J. Compos. Sci. 2025, 9(4), 190; https://doi.org/10.3390/jcs9040190 - 16 Apr 2025

Abstract

Metallic thin-walled porous tubes have been widely applied in energy absorption fields due to their unique mechanical properties. Inspired by foam-filled structures, liquid crystal elastomers as a new category of metamaterials were filled in metallic thin-walled porous tubes to obtain a novel composite [...] Read more.

Metallic thin-walled porous tubes have been widely applied in energy absorption fields due to their unique mechanical properties. Inspired by foam-filled structures, liquid crystal elastomers as a new category of metamaterials were filled in metallic thin-walled porous tubes to obtain a novel composite energy-absorbing structure that can improve energy-absorbing capabilities. By means of experiments and numerical simulations, this paper investigated deformation modes and the energy-absorbing performance of metallic thin-walled porous tubes filled with liquid crystal elastomers under dynamic crush. Moreover, the effects of geometric parameters on deformation modes and the energy-absorbing performance of the metallic thin-walled porous tubes filled with liquid crystal elastomers were analyzed. The results show that liquid crystal elastomers can enhance energy-absorbing capabilities under dynamic crush and geometric parameters can affect deformation modes, further affecting the energy-absorbing performance of metallic thin-walled porous tubes filled with liquid crystal elastomers. Full article

(This article belongs to the Section Composites Applications)

► Show Figures

Figure 1

15 pages, 3551 KiB

Open AccessArticle

Response Surface Methodology-Based Optimization for Enhancing the Viability of Microencapsulated Lactobacillus plantarum in Composite Materials

by Rafael González-Cuello, Joaquín Hernández-Fernández and Rodrigo Ortega-Toro

J. Compos. Sci. 2025, 9(4), 189; https://doi.org/10.3390/jcs9040189 - 15 Apr 2025

Abstract

Probiotics have gained prominence and consumer appreciation due to their potential health benefits. However, maintaining their viability and stability during gastric transit remains a challenge. This study aims to enhance the viability of microencapsulated Lactobacillus plantarum in composite microcapsules exposed to simulated gastric [...] Read more.

Probiotics have gained prominence and consumer appreciation due to their potential health benefits. However, maintaining their viability and stability during gastric transit remains a challenge. This study aims to enhance the viability of microencapsulated Lactobacillus plantarum in composite microcapsules exposed to simulated gastric juice. The independent variables investigated were low-acyl gellan gum (LAG), bacterial cellulose (BC), and calcium concentrations. The microcapsules were prepared using the internal ionic gelation method. The resulting microcapsules exhibited a uniform size distribution, with a diameter of approximately between 15 to 120 μm, making them suitable for food applications. Response surface methodology (RSM) based on the Box–Behnken design was successfully employed to optimize the concentrations of LAG, BC, and calcium. Under optimal conditions—0.63% w/v LAG, 17.91% w/v BC, and 25.12 mM Ca—the highest L. plantarum viability reached 94.28% after exposure to simulated gastric juice, with an R² value of 99.64%. These findings demonstrate the feasibility of developing multicomponent microcapsules that effectively protect probiotic bacteria against gastric fluids, offering a promising alternative for the food industry in designing probiotic-enriched food systems. Full article

(This article belongs to the Special Issue Advances in Biocomposite Materials for Regenerative Medicine and Biomedical Applications)

► Show Figures

Figure 1

24 pages, 10743 KiB

Open AccessArticle

Investigation of Diffusion of Different Composite Materials on the Damage Caused by Axial Impact Adhesive Joints

by Dudu Mertgenç Yoldaş and Mehmet Fatih Yoldaş

J. Compos. Sci. 2025, 9(4), 188; https://doi.org/10.3390/jcs9040188 - 14 Apr 2025

Abstract

In this study, the effects of exposure to seawater on the material properties of glass fiber-reinforced polymer (GFRP) and carbon fiber-reinforced polymer (CFRP) samples were investigated. The samples were stored in seawater with a salinity of 3.3–3.7% and a temperature of 23.5 °C [...] Read more.

In this study, the effects of exposure to seawater on the material properties of glass fiber-reinforced polymer (GFRP) and carbon fiber-reinforced polymer (CFRP) samples were investigated. The samples were stored in seawater with a salinity of 3.3–3.7% and a temperature of 23.5 °C taken from the Aegean Sea in September for different periods (1, 2, 3, 6 and 15 months). The samples prepared in accordance with the ASTM D5868-01 standard were subjected to axial impact testing. In the first stage of this study, moisture retention percentages were determined, and, then, axial impact tests were performed. In the tests, a total of 36 samples bonded with single-lap adhesive were subjected to 30 Joule impact energy, and their mechanical strength was evaluated. In line with the experimental results, moisture absorption and axial impact energy values were compared in order to determine the most durable composite material connection, and the most durable connection was selected by evaluating the mechanical properties. Damage analysis on the samples was performed at the DEU Science and Technology Application and Research Center with ZEISS GEMINI SEM 560. (Oberkochen, Germany). The fracture surfaces of the CFRP and GFRP samples after gold coating were examined in detail with a scanning electron microscope, and their interface properties and internal structures were observed. The fracture toughness of GFRP specimens increased from 4.6% in a dry environment to 27.96% after 15 months in seawater. CFRP specimens increased from 4.2% in a dry environment to 11.96% after 15 months in seawater, but the increase was less pronounced compared to GFRP. According to the experimental results, CFRP samples exhibited superior mechanical performance compared to GFRP samples. Full article

(This article belongs to the Collection Editorial Board Members’ Collection Series: Fibre Composite Materials)

► Show Figures

Figure 1

19 pages, 40454 KiB

Open AccessArticle

Shining a Light on Carbon-Reinforced Polymers: Mg/MgO and TiO₂ Nanomodifications for Enhanced Optical Performance

by Lukas Haiden, Michael Feuchter, Andreas J. Brunner, Michel Barbezat, Amol Pansare, Bharath Ravindran, Velislava Terziyska and Gerald Pinter

J. Compos. Sci. 2025, 9(4), 187; https://doi.org/10.3390/jcs9040187 - 12 Apr 2025

Abstract

This study examines the intrinsic optical enhancements of carbon fiber-reinforced polymers (CFRPs) achieved through the integration of magnesium oxide (MgO) nanoparticles, as well as Mg/MgO and titanium dioxide (TiO₂) thin films onto carbon fibers. Integration was performed by quasi-continuous electrophoretic deposition [...] Read more.

This study examines the intrinsic optical enhancements of carbon fiber-reinforced polymers (CFRPs) achieved through the integration of magnesium oxide (MgO) nanoparticles, as well as Mg/MgO and titanium dioxide (TiO₂) thin films onto carbon fibers. Integration was performed by quasi-continuous electrophoretic deposition (EPD) and physical vapor deposition (PVD), respectively. Employing a customized electrophoretic cell, EPD facilitated uniform MgO nanoparticle deposition onto unsized carbon fibers, ensuring stable nanoparticle dispersion and precise fiber coating. As a result, the fibers exhibited increased ultraviolet (UV) reflectance, largely attributed to the optical properties of the protective MgO layer. In parallel, PVD enabled the deposition of Mg/MgO and TiO₂ thin films with tailored thicknesses, providing precise control over key optical parameters such as reflectivity and interference effects. Mg/MgO coatings demonstrated high UV reflectivity, while TiO₂ layers, with their varying refractive indices, generated vibrant colors in the visible (Vis) range through thickness-dependent light interference. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) assessed the quality, thickness, and uniformity of these thin films, and UV/Vis spectroscopy confirmed the influence of deposition parameters on the resulting optical performance. Post-lamination analyses revealed that both EPD and PVD modifications significantly enhanced UV reflectivity and allowed for customizable color effects. This dual strategy underscores the potential of combining EPD and PVD to develop advanced CFRPs with superior UV resistance, decorative optical features, and improved environmental stability. Full article

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

► Show Figures

Figure 1

17 pages, 5233 KiB

Open AccessArticle

Anisotropy and Strain Rate Sensitivity of Additively Manufactured Polymer Composites in Tension and Compression: Effects of Type and Orientation of Fibres

by Md Niamul Islam, Konstantinos P. Baxevanakis and Vadim V. Silberschmidt

J. Compos. Sci. 2025, 9(4), 186; https://doi.org/10.3390/jcs9040186 - 11 Apr 2025

Abstract

Comprehensive analysis of the anisotropic nature of additively manufactured (AM) parts caused by their fabrication method requires attention, as current quasi-static experiments on AM specimens are used to determine strength and stiffness. This study investigates the anisotropic mechanical behaviour of AM polymer composites [...] Read more.

Comprehensive analysis of the anisotropic nature of additively manufactured (AM) parts caused by their fabrication method requires attention, as current quasi-static experiments on AM specimens are used to determine strength and stiffness. This study investigates the anisotropic mechanical behaviour of AM polymer composites reinforced with short and continuous carbon fibres, examining various filament orientations, loading directions and strain rates. Utilising the fused deposition modelling (FDM) technique, nylon and carbon fibres were fabricated into composites with controlled orientations. Mechanical tests were conducted in different directions to assess the tensile and compressive properties of these composites, with results showing enhanced tensile strength and stiffness in continuous-fibre (CF) composites compared to short-fibre (SF) ones, particularly in longitudinal orientations. The compressive behaviour revealed complex effects of type and orientation of reinforcing fibres, with CF composites demonstrating superior stiffness but lower strength than SF composites in specific orientations. Strain rate sensitivity analysis for the least anisotropic (quasi-isotropic) cases indicated that tensile strength decreased slightly with the increased strain rate while compressive strength increased. These findings underline the critical effect of fibre orientation and type on mechanical properties and suggest potential applications of AM composites in scenarios demanding tailored anisotropic behaviours, including structural optimisation and numerical modelling for various loading conditions. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, 3rd Edition)

► Show Figures

Figure 1

13 pages, 9205 KiB

Open AccessArticle

Fracture Behavior of Additively Manufactured Carbon Fiber Reinforced Acrylonitrile-Styrene-Acrylate Containing Cracks and Notches

by Sergio Cicero, Sergio Arrieta, Fabrizia Devito, Borja Arroyo and Fulvio Lavecchia

J. Compos. Sci. 2025, 9(4), 185; https://doi.org/10.3390/jcs9040185 - 11 Apr 2025

Abstract

Within the context of the increasing use of additive manufacturing techniques and the corresponding need to understand the behavior of 3D-printed materials, this paper analyzes the fracture behavior of additively manufactured carbon fiber reinforced (10 wt.%) acrylonitrile-styrene-acrylate (ASA) with three different raster orientations [...] Read more.

Within the context of the increasing use of additive manufacturing techniques and the corresponding need to understand the behavior of 3D-printed materials, this paper analyzes the fracture behavior of additively manufactured carbon fiber reinforced (10 wt.%) acrylonitrile-styrene-acrylate (ASA) with three different raster orientations (90/0, 45/−45, 30/−60). The analyzed material (ASA-CF10) combines the remarkable resistance to weathering agents typical of ASA with the enhanced mechanical properties resulting from the inclusion of carbon fiber reinforcement. The analysis is performed on single-edge-notched bending (SENB) specimens containing different types of defects, from cracks to U-notches with notch radii of 0.5 mm, 1 mm and 2 mm. When compared to non-reinforced ASA, the fracture resistance is noticeably higher (nearly double) for the reinforced material in all raster orientations. The notch effect, defined as the increase in the fracture resistance when the notch radius increases, is analyzed through the Theory of Critical Distances (TCD), and it is mostly higher in the reinforced material than in the pristine polymer. These observations are supported by Scanning Electron Microscopy analyses. Full article

(This article belongs to the Special Issue Editorial Board Members' Collection Series: Mechanical Analysis of Composite Materials)

► Show Figures

Figure 1

22 pages, 7094 KiB

Open AccessArticle

Development of Cement-Free Binder Systems Based on Metallurgical Waste: Hardening by Forced Carbonation

by Nikolay Lyubomirskiy, Tamara Bakhtina, Alexey Gusev, Aleksandr Bakhtin, German Bilenko and Wolfgang Linert

J. Compos. Sci. 2025, 9(4), 184; https://doi.org/10.3390/jcs9040184 - 11 Apr 2025

Abstract

This article explores the possibility of using metallurgical waste slags formed during the smelting of cast iron and steel as cementless binders that harden due to forced carbonization and the subsequent hydration processes of some minerals that form the basis of these slags. [...] Read more.

This article explores the possibility of using metallurgical waste slags formed during the smelting of cast iron and steel as cementless binders that harden due to forced carbonization and the subsequent hydration processes of some minerals that form the basis of these slags. This study presents the results of multi-objective optimization using statistical methods of mathematical experimental design, with the purpose of obtaining a carbonized material with good mechanical and physical properties. As a result of the research, carbonized stone with compressive strength up to 116.5 MPa was obtained. Water absorption by weight is within the range of 6.0–17.0%, and quantitative CO₂ binding was 6–11.9%, depending on the type of slag. A pilot batch of wall product samples (hollow bricks and paving elements of various territories) was manufactured under production conditions. During the tests, we found that the compressive strengths of products based on BOF and EAF slags were 96.3 and 81.1 MPa, respectively, and that of bricks based on BS slag was 37.1 MPa. A comprehensive analysis of the performance properties of products from the pilot batch showed that these samples meet the requirements of national standards. Full article

(This article belongs to the Section Composites Applications)

► Show Figures

Figure 1

28 pages, 16181 KiB

Open AccessArticle

Investigating the Potential of Using Walnut Shell Particles for Manufacturing Cement-Bonded Particle Boards

by Anas El Hamri, Yassine Mouhib, Hassan Chkala, Oussama Oulhakem, Mohammed Chigr and Nour-Eddine El Mansouri

J. Compos. Sci. 2025, 9(4), 183; https://doi.org/10.3390/jcs9040183 - 10 Apr 2025

Abstract

In the search for eco-friendly and resource-efficient alternatives to conventional building materials, agricultural residues are gaining increasing attention as reinforcements in cement-based composites. This study investigates the potential of walnut shell particles (WSPs), a lignocellulosic bio-product, as a sustainable reinforcing agent in walnut [...] Read more.

In the search for eco-friendly and resource-efficient alternatives to conventional building materials, agricultural residues are gaining increasing attention as reinforcements in cement-based composites. This study investigates the potential of walnut shell particles (WSPs), a lignocellulosic bio-product, as a sustainable reinforcing agent in walnut shell cement boards (WSCBs). Using super white cement (SWC) as a binder, boards were manufactured with WSP content ranging from 10% to 50% by weight, targeting a density of 1300 kg/m³, a 10 mm thickness, and a water-to-cement ratio of 0.6:1. The mixtures were cold-pressed at ambient temperature using a hydraulic press at 3 MPa for 24 h, followed by curing for 28 days under ambient conditions. Physical properties such as density, water absorption, and thickness swelling were assessed, along with mechanical performance, through flexural testing. Fracture surfaces and internal microstructures were examined using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Functional groups and chemical reactions were monitored using FTIR, while thermal analysis (TGA and DSC), as well as measurements of thermal conductivity and resistance, provided comprehensive insights into the thermal behavior, insulating performance, and energy efficiency potential of the boards. Results demonstrate that the board with 30% WSP exhibited an optimal balance of physical and mechanical properties, achieving a 24 h water absorption of 14.05% and a modulus of rupture (MOR) of 6.53 MPa, making it suitable for non-structural applications. The board with 50% WSP exhibited the best thermal insulation performance, with a low thermal conductivity of 0.079 W/m·K. These findings highlight the potential of recycled agricultural materials in enhancing building materials’ performance, contributing to sustainable, eco-friendly construction practices. Full article

(This article belongs to the Special Issue Advancements in Sustainable Cement-Based Composites: Innovations in Performance, Durability, and Environmental Impact)

► Show Figures

Graphical abstract

24 pages, 3714 KiB

Open AccessArticle

Comparison of Bending Properties of Sandwich Structures Using Conventional and 3D-Printed Core with Flax Fiber Reinforcement

by Viktor Brejcha, Martin Böhm, Tomáš Holeček, Miloš Jerman, Klára Kobetičová, Ivana Burianová, Robert Černý and Zbyšek Pavlík

J. Compos. Sci. 2025, 9(4), 182; https://doi.org/10.3390/jcs9040182 - 9 Apr 2025

Abstract

The growing demand for sustainable composites has increased interest in natural fiber reinforcements as alternatives to synthetic materials. This study evaluates the bending properties of sandwich structures with flax fibers and 3D-printed lightweight foaming PLA cores compared to conventional designs using glass fibers [...] Read more.

The growing demand for sustainable composites has increased interest in natural fiber reinforcements as alternatives to synthetic materials. This study evaluates the bending properties of sandwich structures with flax fibers and 3D-printed lightweight foaming PLA cores compared to conventional designs using glass fibers and traditional cores. Three-point bending tests (EN 310) and density profile analysis showed that, despite its lower density, the 3D-printed foaming PLA core achieved a modulus of elasticity of 2269.19 MPa and a bending strength of 31.46 MPa, demonstrating its potential for lightweight applications. However, natural fibers influenced resin absorption, affecting core saturation compared to glass fibers. The use of bio-based epoxy and foaming PLA contributes to a lower environmental footprint, while 3D printing enables precise material optimization. These findings confirm that 3D-printed cores offer a competitive and sustainable alternative, with future research focusing on further optimization of internal structure to enhance mechanical performance. Full article

(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2024)

► Show Figures

Figure 1

Journal Description

Journal of Composites Science

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Topical Collections

Further Information

Guidelines

MDPI Initiatives

Follow MDPI