Journal of Composites Science

24 pages, 3469 KiB

Open AccessArticle

Application of DFT and Experimental Tests for the Study of Compost Formation Between Chitosan-1,3-dichloroketone with Uses for the Removal of Heavy Metals in Wastewater

by Joaquín Alejandro Hernández Fernández, Jose Alfonso Prieto Palomo and Rodrigo Ortega-Torod

J. Compos. Sci. 2025, 9(2), 91; https://doi.org/10.3390/jcs9020091 - 19 Feb 2025

Abstract

The environment presently contains greater amounts of heavy metals due to human activities, causing toxicity, mutagenicity, and carcinogenicity. This study evaluated a chitosan (CS) composite material combined with 1,3-dichlorocetone to extract heavy metals from affected waters, integrating experimental and computational analyses. The synthesis [...] Read more.

The environment presently contains greater amounts of heavy metals due to human activities, causing toxicity, mutagenicity, and carcinogenicity. This study evaluated a chitosan (CS) composite material combined with 1,3-dichlorocetone to extract heavy metals from affected waters, integrating experimental and computational analyses. The synthesis of chitosan, obtained from shrimp waste chitin, reached a yield of 85%. FTIR analysis confirmed key functional groups (NH₂ and OH), and XRD showed high crystallinity with peaks at 2θ = 8° and 20°. The physicochemical properties evaluated included a moisture content of 7.3%, ash content of 2.4%, and a deacetylation degree of 73%, consistent with commercial standards. Chitosan exhibited significant solubility in 1.5% acetic acid, moderate solubility in water, and insolubility in NaOH, demonstrating its versatility for environmental applications. In adsorption tests, heavy metal concentrations were reduced by CS derivatives, with Cr and Pb dropping to 0.03 mg/L, and Cu and Zn to less than 0.05 mg/L. CS cross-linked with 1,3-dichlorocetone proved the most efficient, outperforming other derivatives such as glutaraldehyde and epichlorohydrin. Computational analysis evaluated key molecular interactions using DFT and the B3LYP/LANLD2Z method. The band gap energies (HOMO–LUMO) decreased to 0.09753 eV for Zn and 0.01485 eV for Pb, indicating high affinity, while Cd showed lower interaction (0.11076 eV). The total dipole moment increased remarkably for Zn (14.693 Debye) and Pb (7.449 Debye), in contrast to Cd (4.515 Debye). Other descriptors, such as chemical hardness (η), reflected a higher reactivity for Zn (0.04877 eV) and Pb (0.00743 eV), which favors adsorption. The correlation between experimental and computational results validates the efficiency and selectivity of CS/1,3-dichlorocetone for removing heavy metals, especially Pb and Zn. This material stands out for its adsorbent capacity, sustainability, and economic viability, positioning it as a promising solution for wastewater remediation. Full article

(This article belongs to the Special Issue Characterization and Modeling of Composites, 4th Edition)

16 pages, 1006 KiB

Open AccessSystematic Review

Composite Dust Toxicity Related to Restoration Polishing: A Systematic Review

by Kamila Kucharska, Anna Lehmann, Martyna Ortarzewska, Jakub Jankowski and Kacper Nijakowski

J. Compos. Sci. 2025, 9(2), 90; https://doi.org/10.3390/jcs9020090 - 18 Feb 2025

Abstract

An integral part of daily dental practice is preparing and polishing placed composite restorations. When these procedures are performed, significant amounts of composite dust are released from the grinding material. This systematic review aims to enhance the existing body of knowledge, encourage further [...] Read more.

An integral part of daily dental practice is preparing and polishing placed composite restorations. When these procedures are performed, significant amounts of composite dust are released from the grinding material. This systematic review aims to enhance the existing body of knowledge, encourage further dialogue, and expand the understanding of composite dust and its related risks. Following inclusion and exclusion criteria, twelve studies were included. Several studies highlight that composite dust contains nanoparticles capable of deep lung penetration, posing significant health risks to both dental staff and patients. Inhalation of composite dust can lead to respiratory diseases such as pneumoconiosis. Studies have shown that water cooling during composite grinding reduces dust emissions but does not eliminate them completely. Researchers suggest that thermal degradation of the composite material, not just filler particles, may be the source of the nanoparticles. In vitro studies have shown the toxicity of composite dust to bronchial and gingival epithelial cells, especially at high concentrations. Further research is needed on the health effects of composite dust and the development of effective methods to protect staff and patients. Full article

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

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21 pages, 12291 KiB

Open AccessArticle

Energy Absorption Mechanisms of Riveted and Assembled Double-Trapezoidal Auxetic Honeycomb Core Structures Under Quasi-Static Loading

by Zhenhua Tian, Shaoqing Shi, Yu Liao, Wenkang Wang, Lei Zhang and Yingjie Xiao

J. Compos. Sci. 2025, 9(2), 89; https://doi.org/10.3390/jcs9020089 - 14 Feb 2025

Abstract

Auxetic honeycomb structures, known for their exceptional mechanical properties, are widely used as sacrificial layers to protect critical targets from extreme explosive loads. However, conventional double arrowhead auxetic honeycomb-core structures (DA-AHSs) encounter significant interfacial connectivity challenges, and scaling auxetic honeycombs with alternative cellular [...] Read more.

Auxetic honeycomb structures, known for their exceptional mechanical properties, are widely used as sacrificial layers to protect critical targets from extreme explosive loads. However, conventional double arrowhead auxetic honeycomb-core structures (DA-AHSs) encounter significant interfacial connectivity challenges, and scaling auxetic honeycombs with alternative cellular microstructures introduces further complexity. To overcome these issues, riveted and assembled double-trapezoidal auxetic honeycomb-core structures (DT-AHSs) were developed as a replacement for DA-AHSs. The deformation modes and energy absorption mechanisms of DT-AHSs were analyzed through theoretical methods and quasi-static testing. The results show that DT-AHSs energy absorption primarily relies on the yield deformation of the longer inclined walls and rotational deformation of the shorter inclined walls. Additionally, the shorter walls support auxetic behavior by stabilizing the deformation of the longer walls. These findings provide a basis for further exploration of the protective potential of DT-AHSs. Full article

(This article belongs to the Section Composites Applications)

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19 pages, 18754 KiB

Open AccessArticle

The Design and Characterization of an Artificial Soil Substrate Made from Sand-Washing Slurry

by Biqin Dong, Xu Wu, Penghui Wang, Rongxin Peng and Yanshuai Wang

J. Compos. Sci. 2025, 9(2), 88; https://doi.org/10.3390/jcs9020088 - 13 Feb 2025

Abstract

The global reserve of sand has significantly decreased, and sand washing is predominantly favored due to its simplicity and low operational costs, but this method poses significant environmental risks like landslides, making its reuse essential for sustainability. In view of this challenge, based [...] Read more.

The global reserve of sand has significantly decreased, and sand washing is predominantly favored due to its simplicity and low operational costs, but this method poses significant environmental risks like landslides, making its reuse essential for sustainability. In view of this challenge, based on the composite preparation method, an innovative approach was proposed to prepare an artificial soil substrate from sand-washing slurry. The physical and vegetative feasibility performance, including strength, density, water absorption, retention, electrical conductivity (EC), and pH; and microstructural characteristics, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR) of the artificial soil substrate with different proportions of cement and foaming agent were measured. Increasing the cement content to 30% of un-crushed artificial soil substrate specimens improved strength, whereas 40% reduced it due to the diminished pore-filling effect. Water absorption rates ranged from 29.22% to 36.68%, increasing with more foaming agent and decreasing with more cement, while the water retention time was 12–14 days, and incorporating foaming agent significantly increased water absorption. Leachate pH ranged from 11.99 to 12.18, and reduced to 7.82–8.28 with 5% phosphoric acid. The EC of the artificial soil substrate decreased by 88.64% to 93.59% after 10 wet–dry cycles, aligning with the standard. Artificial-soil-substrate-predominant products include calcite, quartz, and dolomite, with a pronounced silica content and soil substrate porosity ranging from 27.96% to 51.80%. From the microstructural test, calcium silicate hydrate gel, produced by cement hydration, effectively bound the sand-washing slurry, thereby improving strength. Full article

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11 pages, 5433 KiB

Open AccessArticle

Thermodynamic Analysis on Complex Oxides Formed by Aerodynamic Heating for Ultrahigh-Temperature Ceramic Matrix Composites

by Mizuki Tsuganezawa, Yutaro Arai and Ryo Inoue

J. Compos. Sci. 2025, 9(2), 87; https://doi.org/10.3390/jcs9020087 - 13 Feb 2025

Abstract

The oxidation and recession of carbon-fiber-reinforced ultrahigh-temperature ceramic matrix composites (C/UHTCMCs) fabricated via reactive melt infiltration (RMI) using Zr-Ti alloys with three different compositions are evaluated via an arc-jet tunnel test at temperatures above 2000 °C for 60 s. Thermodynamic evaluations show that [...] Read more.

The oxidation and recession of carbon-fiber-reinforced ultrahigh-temperature ceramic matrix composites (C/UHTCMCs) fabricated via reactive melt infiltration (RMI) using Zr-Ti alloys with three different compositions are evaluated via an arc-jet tunnel test at temperatures above 2000 °C for 60 s. Thermodynamic evaluations show that the recession of the UHTCMCs is prevented by the formation of a solid solution of ZrTiO₄ on their exposed surface. Because an increase in the Zr content increases the melting temperature of ZrTiO₄, the recession of the composites increases as the Zr content in the infiltrated alloys decreases. UHTCMCs fabricated with Zr-20at%Ti showed the least recession (<5%). Full article

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14 pages, 4163 KiB

Open AccessArticle

Non-Destructive Evaluation of Impact-Damaged Sandwich Composites: Influence of Fiber Type

by Jaime Santos, Paulo N. B. Reis, Mario Santos and Ana M. Amaro

J. Compos. Sci. 2025, 9(2), 86; https://doi.org/10.3390/jcs9020086 - 12 Feb 2025

Abstract

This study deals with the evaluation of impact-damaged sandwich composites using different fiber types (carbon, glass, and Kevlar), where the outer layers, or “skins”, were made from the same type of fiber, while the inner layer, or “core”, consisted of a different fiber [...] Read more.

This study deals with the evaluation of impact-damaged sandwich composites using different fiber types (carbon, glass, and Kevlar), where the outer layers, or “skins”, were made from the same type of fiber, while the inner layer, or “core”, consisted of a different fiber type, with the aim of improving the damage resistance and tolerance of composite materials. To achieve this goal, the following research question was formulated: can the type of core fiber used in sandwich composites primarily determine their structural response under impact? To obtain a consolidated answer, various configurations manufactured were subjected to low-velocity impact tests to induce damage. The next step involved evaluating the extent and distribution of damage across various samples using ultrasonic C-scan techniques, along with assessing the impact bending stiffness (IBS) property, a widely recognized method for measuring the structural response of composites. It was observed that the different composite configurations presented distinct absorbed energy and, consequently, different damages, which was confirmed by the IBS and the C-scan methods. The glass–carbon–glass (GCG) sandwich composite demonstrated superior performance in mitigating damage compared to the other sandwich designs. The core material was verified as the main factor influencing the response of the sandwich composite. Full article

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

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12 pages, 2555 KiB

Open AccessArticle

Highly Stable and Temperature-Independent Humidity Sensor Based on PEO/PVA Polymer Composite

by H. M. Zeeshan Yousaf, Mazhar Javed, Muhammad Mehran Bashir, Rayyan Ali Shaukat and Hasan Mahmood

J. Compos. Sci. 2025, 9(2), 85; https://doi.org/10.3390/jcs9020085 - 12 Feb 2025

Abstract

Traditional humidity sensors frequently face challenges, especially in environments with fluctuating temperatures, which can compromise their efficiency, stability, and reliability. Therefore, there is an urgent demand to fabricate low-cost and high-performance temperature-independent humidity sensors. In this work, for the first time, highly stable [...] Read more.

Traditional humidity sensors frequently face challenges, especially in environments with fluctuating temperatures, which can compromise their efficiency, stability, and reliability. Therefore, there is an urgent demand to fabricate low-cost and high-performance temperature-independent humidity sensors. In this work, for the first time, highly stable and reliable temperature-independent humidity sensors have been proposed based on a PEO/PVA polymer composite. Four sensors were fabricated containing weight ratios of PEO/PVA as 50:50%, 40:60%, 60:40%, and 70:30%, respectively. All of the fabricated sensors were electrically characterized at three different temperatures, 30 °C, 35 °C, and 40 °C, to investigate the impedance response. The proposed sensor based on a PEO/PVA (40:60%) composite presents a remarkable and optimized temperature-independent performance in the range of 0–60%RH. Apart from this, the response and recovery time (9 s/16 s) of the temperature-independent humidity sensor based on PEO/PVA (40:60%) were investigated. Finally, the sensor showed long-term stability for 90 days, ensuring the reliability of the proposed device. These remarkable performances of the proposed sensor based on PEO/PVA with a weight ratio of (40:60)% can open a new gateway for low-range temperature-independent humidity sensors for various real-time applications. Full article

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Schematic representation of the preparation of the PEO/PVA polymer-composite-based active layer and fabrication of humidity sensor. Full article ">Figure 2
Detailed schematic of the automatic humidity and temperature measurement setup with controlled environment chamber and auto data logging. Full article ">Figure 3
(a–c) SEM image of PEO/PVA (40:60%) polymer composite at the magnification of 20 µm, 10 µm, and 50 µm; (d) EDS mapped image; (e) C K series; O K series and Si K series; (f) atomic weight percentage and elemental analysis of PEO/PVA (40:60%) polymer composite; and (g) FTIR spectrum of PEO/PVA (40:60%) polymer composite. Full article ">Figure 4
Impedance response of the sensors with PEO/PVA with different concentrations: (a) 40:60, (b) 60:64, (c) 50:50, (d) 70:30, and (e) hysteresis curve of the PEO/PVA (40:60) polymer-composite-based temperature-independent humidity sensor. Full article ">Figure 5
(a) Reproducibility of the PEO/PVA (40:60) polymer-composite-based temperature-independent humidity sensor; (b) reproducibility of the PEO/PVA (60:40) polymer-composite-based temperature-independent humidity sensor; (c) response and recovery time of the PEO/PVA (40:60) polymer-composite-based temperature-independent humidity sensor; and (d) repeated cycles of the response and recovery time of the PEO/PVA (40:60) polymer-composite-based temperature-independent humidity sensor. Full article ">

16 pages, 3202 KiB

Open AccessArticle

Kinetic Analysis of the Cracking Behavior in Methanol-Treated Poly(methyl methacrylate)/Functionalized Graphene Composites

by Bing-Hong Yang, Shou-Yi Chang, Yulin Zhang, Fuqian Yang and Sanboh Lee

J. Compos. Sci. 2025, 9(2), 84; https://doi.org/10.3390/jcs9020084 - 11 Feb 2025

Abstract

Structural degradation in liquid environments can hinder the applications of polymer composites as structural materials. In this work, we study the impacts of methanol on surface cracking and the propagation of pre-formed cracks in UV-irradiated poly(methyl methacrylate)/functionalized graphene (PMMA/FG) composites, followed by the [...] Read more.

Structural degradation in liquid environments can hinder the applications of polymer composites as structural materials. In this work, we study the impacts of methanol on surface cracking and the propagation of pre-formed cracks in UV-irradiated poly(methyl methacrylate)/functionalized graphene (PMMA/FG) composites, followed by the uptake of three different crack-generated solvents, namely 1-butanol, cyclohexanol, and 2EA, respectively. The density of surface cracks increases with the increase in the uptake of the crack-generated solvent. The dependence of the nominal diffusivity for the surface cracking on temperature follows an Arrhenius-like law. The methanol in the composites enhances the uptake of the crack-generated solvent, accompanied by the desorption of methanol, and accelerates the initiation and propagation of surface cracks. The activation energy for the initiation of surface cracks shows an increasing dependence on the Hansen solubility distance from methanol. The progression of the pre-formed crack length with time follows a parabolic law. The nominal diffusivity of the crack-generated solvent for the propagation of the single-crack is greater in the healing zone than in the crack-free zone; the corresponding activation energies exhibit an opposite trend. Increasing the fraction of functionalized graphene and decreasing the UV-irradiation dose cause increases in the energy barriers that need to be overcome for the surface cracking and propagation of preexisting cracks. Full article

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

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17 pages, 4866 KiB

Open AccessArticle

Polymer-Derived Carbon Matrix Composites with Boron Nitride Nanotube Reinforcement

by Okunzuwa Austine Ekuase, Qiang Wu, Jin Gyu Park, Jizhe Cai, Zhiyong Liang and Zhibin Yu

J. Compos. Sci. 2025, 9(2), 83; https://doi.org/10.3390/jcs9020083 - 11 Feb 2025

Abstract

This study explored the use of boron nitride nanotubes (BNNTs) as reinforcing fillers to enhance the mechanical properties of polymer-derived carbon matrix composites. BNNT-reinforced carbon matrix composites containing 0.5–5 wt% BNNTs were fabricated with pyrolysis conducted at different temperatures. X-ray diffraction and Raman [...] Read more.

This study explored the use of boron nitride nanotubes (BNNTs) as reinforcing fillers to enhance the mechanical properties of polymer-derived carbon matrix composites. BNNT-reinforced carbon matrix composites containing 0.5–5 wt% BNNTs were fabricated with pyrolysis conducted at different temperatures. X-ray diffraction and Raman spectroscopy revealed enhanced crystallinity and reduced defects in carbon matrix composites with BNNT addition. At 1200 °C pyrolysis temperature, sample shrinkage decreased from 28% in the control sample without BNNT addition to 12% with 5 wt% BNNTs, demonstrating BNNTs’ significant influence on the matrix. The density increased by 20.1% with 5 wt% BNNTs. Mechanical testing demonstrated an enhancement in the failure strain from 0.7% to 0.8% and an 87.8% increase in the work of fracture with 5 wt% BNNTs. Furthermore, the flexural strength and modulus improved by 68.7% and 55.6%, respectively, at this BNNT concentration. Increasing the pyrolysis temperature to 1500 °C further boosted the mechanical properties, with the flexural strength increasing by 283.7% and the flexural modulus by 528.6% when comparing samples containing 5 wt% BNNTs to those without BNNT reinforcement. Samples processed at 1500 °C with 5 wt% BNNT composition exhibited optimal performance. Full article

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

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14 pages, 5400 KiB

Open AccessArticle

Graphene Oxide–Antibiotic Coatings with Improved Resistance to Microbial Colonization for Arthroplasty Implants

by Gheorghe Iosub, Adelina-Gabriela Niculescu, Valentina Grumezescu, Gabriela Dorcioman, Oana Gherasim, Valentin Crăciun, Dragoș Mihai Rădulescu, Alexandru Mihai Grumezescu, Miruna Silvia Stan, Sorin Constantinescu, Alina Maria Holban and Adrian-Radu Rădulescu

J. Compos. Sci. 2025, 9(2), 82; https://doi.org/10.3390/jcs9020082 - 10 Feb 2025

Abstract

In this study, we investigated the biocompatibility and antibacterial efficiency of hydroxyapatite/graphene oxide/ceftazidime (HAp/GO/CFZ) coatings obtained by the Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technique for arthroplasty implants. The coatings were evaluated for their ability to inhibit biofilm formation by model opportunistic pathogens, specifically [...] Read more.

In this study, we investigated the biocompatibility and antibacterial efficiency of hydroxyapatite/graphene oxide/ceftazidime (HAp/GO/CFZ) coatings obtained by the Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technique for arthroplasty implants. The coatings were evaluated for their ability to inhibit biofilm formation by model opportunistic pathogens, specifically Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, for 24, 48, and 72 h. A significant reduction in the biofilm formation was demonstrated by coating surfaces, which led to a diminution of approximately 4 logs in the CFU/mL values compared to controls. These findings suggested that HAp/GO/CFZ coatings have the potential to prevent infections associated with arthroplasty implants, thereby improving patient outcomes and implant longevity. Full article

(This article belongs to the Special Issue Advances in Laser Fabrication of Composites)

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ATR-FTIR spectra of HAp/GO/CFZ DC and MAPLE coatings obtained at different laser fluences. Full article ">Figure 2
Typical SEM micrographs of HAp/GO/CFZ coatings obtained by MAPLE at (a1) 300, (b1) 400, and (c1) 500 mJ/cm2 laser fluences, and the corresponding EDS spectra (a2,b2,c2). Full article ">Figure 3
SEM micrographs with corresponding EDS maps of HAp/GO/CFZ coatings obtained by MAPLE at different laser fluences. Full article ">Figure 4
XRD patterns for HAp/GO/CFZ coatings obtained at 500 mJ/cm2.. Full article ">Figure 5
Cell viability (MTT assay) and LDH release levels of human fetal osteoblasts after 72 h (results are calculated as means ± standard deviation of three independent experiments and shown relative to control; * p < 0.05 compared to control). Full article ">Figure 6
Morphology of human fetal osteoblasts after 72 h of incubation by cytoskeleton staining (green: F-actin filaments labeled with FITC, and blue: nuclei labeled (with DAPI), where (a) control; (b) reference; (c) HAp/GO/CFZ coated surfaces (500 mJ/cm2 laser fluence). Full article ">Figure 7
Graphic representation of S. aureus and E. coli biofilm development on HAp/GO/CFZ-coated surfaces (500 mJ/cm2 laser fluence) compared to uncoated control. Full article ">

48 pages, 7112 KiB

Open AccessReview

Biobased Hydrophobic Solutions for Natural Textiles—Moving Beyond PFAS

by Petra Jerič, Blaž Likozar and Uroš Novak

J. Compos. Sci. 2025, 9(2), 81; https://doi.org/10.3390/jcs9020081 - 10 Feb 2025

Abstract

In order to achieve hydrophobic properties in textiles, per- and poly-fluoroalkyl substances (PFAS) are often used. These chemicals represent a class of synthetic compounds that have found wide application in numerous industries because of their advantageous properties, such as hydrophobicity, lipophobicity, chemical inertness, [...] Read more.

In order to achieve hydrophobic properties in textiles, per- and poly-fluoroalkyl substances (PFAS) are often used. These chemicals represent a class of synthetic compounds that have found wide application in numerous industries because of their advantageous properties, such as hydrophobicity, lipophobicity, chemical inertness, remarkable lubricity, non-stickiness, exceptional fire resistance, resistance to high temperatures, and high resistance to various weathering conditions. However, recent scientific research has demonstrated that these compounds possess persistent, accumulative, and highly mobile properties that make them an environmental hazard. Since the toxicity of PFAS is now recognized, ongoing research has been initiated to explore new substitutes. This comprehensive review focuses on the exploration of natural-based hydrophobic coatings for natural textiles, which include materials such as natural waxes, fatty acids, naturally occurring polymeric compounds (including proteins, carbohydrates, complex aromatic polymers, and polymers like natural rubber), and other naturally occurring substances. The role of each compound in the hydrophobic coating is also highlighted. This review aims to evaluate the potential of natural compounds as viable replacements for PFAS, focusing on their efficiency and durability. Full article

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14 pages, 4932 KiB

Open AccessArticle

Metallic Multimaterials Fabricated by Combining Additive Manufacturing and Powder Metallurgy

by Mayank Kumar Yadav, Riddhi Shukla, Lixia Xi, Zhi Wang and Konda Gokuldoss Prashanth

J. Compos. Sci. 2025, 9(2), 80; https://doi.org/10.3390/jcs9020080 - 10 Feb 2025

Abstract

Nature has created a unique combination of materials, and the design and material compositions used in nature are not successfully employed for industrial applications. Metallic multimaterials (MMMs) are a unique class of materials that combine the properties of various metallic constituents (both matrix [...] Read more.

Nature has created a unique combination of materials, and the design and material compositions used in nature are not successfully employed for industrial applications. Metallic multimaterials (MMMs) are a unique class of materials that combine the properties of various metallic constituents (both matrix and reinforcement(s)) to improve the functionality, performance in real-time, and application spectrum. Accordingly, this study explores the fabrication perspective of MMMs by combining both additive manufacturing (AM) and powder metallurgical (PM) routes. Ti6Al4V structures were fabricated via the laser powder-bed fusion (LPBF) process, and the reinforcement powders were added into the spark plasma sintering (SPS) mold where the Ti6Al4V structures were placed. Different reinforcement compositions including Mg, Al, Fe, Ni, and Cu were explored. Since the present study is focused on the variation of hardness, the hardness profile of the MMM composite was explored showing a sinusoidal trend. This study stands as a testimonial of fabricating MMM composites via a combination of AM and PM processes. Full article

(This article belongs to the Special Issue Metal Composites, Volume II)

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Schematic illustration of the composite manufacturing process: (a1) additive manufacturing of the lattice using LPBF process, (a2) fabricated metal lattice precursor, (b1) spark plasma sintering of the composite by placing the precursor inside the spark plasma sintering mold, and (c1) structure of the fabricated metallic bimetal. Full article ">Figure 2
Scanning electron microscopy–energy dispersive spectroscopy area maps showing the individual constituents present in the metallic multimaterials (MMMs): (a) Ti6Al4V-Mg MMM composite—bimetal composite, (b) Ti6Al4V-Mg-Al composite—trimetal composite, and (c) Ti6Al4V-Mg-Ti-Fe composite—multimaterial composite. Full article ">Figure 3
X-ray diffraction patterns of the different metallic multimaterial composites fabricated by the combination of additive manufacturing and powder metallurgical processes. Full article ">Figure 4
Scanning electron microscopy images (both secondary electron (BE) and back-scattered (BSD) modes) showing the microstructure of the Ti6Al4V–Mg–Al–Fe metallic multimaterial composite. Full article ">Figure 5
Hardness profile plot observed for the Ti6Al4V–Mg–Al–Fe metallic multimaterial composite fabricated by combining additive manufacturing and powder metallurgical processes. Full article ">Figure 6
Scanning electron microscopy–energy dispersive spectroscopy area maps showing the individual constituents present in the 316L SS–Ti–Cu–Ni metallic multimaterial composite. Full article ">

22 pages, 6852 KiB

Open AccessArticle

Experimental Assessment of the Strength and Microstructural Properties of Fly Ash-Containing Basalt Fiber-Reinforced Self-Compacting Sustainable Concrete

by Ala Abu Taqa, Usama A. Ebead, Mohamed O. Mohsen, Mervat O. Aburumman, Ahmed Senouci, Walid Maherzi and Deya Qtiashat

J. Compos. Sci. 2025, 9(2), 79; https://doi.org/10.3390/jcs9020079 - 9 Feb 2025

Abstract

This study investigates the influence of basalt fiber on the rheological, mechanical, and microstructural properties of sustainable self-compacting concrete (SCC) incorporating fly ash and microsilica as supplementary cementitious materials (SCMs). Various SCC mixes were prepared, incorporating five different volume fractions of basalt fiber [...] Read more.

This study investigates the influence of basalt fiber on the rheological, mechanical, and microstructural properties of sustainable self-compacting concrete (SCC) incorporating fly ash and microsilica as supplementary cementitious materials (SCMs). Various SCC mixes were prepared, incorporating five different volume fractions of basalt fiber (0.05%, 0.1%, 0.5%, 1%, and 1.5%), along with a control mix. The rheological properties of fresh SCC were evaluated using slump flow and V-funnel flow tests. Subsequently, the mechanical properties, including compressive strength, splitting tensile strength, and flexural strength, were measured after 28 days of curing. Additionally, microstructural analysis was conducted using scanning electron microscopy (SEM) on fractured specimen surfaces. The results indicated that the inclusion of basalt fiber adversely affected the flowability of fresh SCC mixes, with increased fiber volume. However, the hardened concrete exhibited significant improvements in mechanical properties with the addition of basalt fibers. The optimal performance was observed in the SCC70-85/0.10 mix specimens, which demonstrated a 69.90% improvement in flexural strength and a 23.47% increase in splitting tensile strength compared with the control specimen. SEM analysis further revealed enhanced microstructural density in the concrete matrix containing basalt fiber. A two-factor analysis of variance (ANOVA) with repetitions was conducted to evaluate the effects of varying basalt fiber concentrations on the compressive, flexural, and tensile strengths of SCC mixes. The ANOVA results indicated significant effects for both SCC grade and basalt fiber concentration, demonstrating that each factor independently affected the compressive, tensile, and flexural strengths of SCC. These findings suggest that the incorporation of basalt fibers holds promise for extending building lifespans and enhancing concrete quality, representing a valuable advancement in structural engineering applications. Full article

(This article belongs to the Special Issue Novel Cement and Concrete Materials)

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22 pages, 13197 KiB

Open AccessArticle

Effects of Polyphosphoric Acid on Physical, Rheological, and Chemical Properties of Styrene-Butadiene-Styrene (SBS)-Modified Asphalt Binder

by Amjad H. Albayati, Mazen J. Al-Kheetan, Aliaa F. Al-ani, Yu Wang, Ahmed M. Mohammed and Mustafa M. Moudhafar

J. Compos. Sci. 2025, 9(2), 78; https://doi.org/10.3390/jcs9020078 - 9 Feb 2025

Abstract

High temperatures combined with heavy traffic load necessitate asphalt binder modification to enhance its performance and durability. This research examines the effects of polyphosphoric acid (PPA) on the physical, rheological, and chemical properties of styrene-butadiene-styrene (SBS)-modified asphalt binders. Asphalt binders were prepared by [...] Read more.

High temperatures combined with heavy traffic load necessitate asphalt binder modification to enhance its performance and durability. This research examines the effects of polyphosphoric acid (PPA) on the physical, rheological, and chemical properties of styrene-butadiene-styrene (SBS)-modified asphalt binders. Asphalt binders were prepared by adding 3% SBS and varying PPA dosages of 0.3%, 0.6%, and 0.9% by weight of asphalt cement. The experiment investigated the physical properties (penetration, softening point, ductility, viscosity, and specific gravity), the rheological properties (the performance grading (PG), multi-stress creep recovery (MSCR), and linear amplitude sweep (LAS)), and the microstructure and chemical composition of the modified asphalt binder. The results demonstrated impressive improvements in rutting resistance and stiffness. Adding 3% SBS and 0.9% PPA increased the rutting factor (G*/sin δ) by 165% and the high-temperature PG from 74.2 °C to 93.6 °C compared to the virgin asphalt binder. However, the optimum fatigue resistance was obtained by adding 0.3% PPA to the SBS asphalt binder. The microstructure and composition analysis revealed that using SBS and PPA together enhanced binder homogeneity and reduced voids. Lastly, an Overall Desirability (OD) analysis suggested the 3% SBS and 0.3% PPA to be the most effectively balanced formulation for the demand of high temperature and heavy traffic conditions. However, further field studies are recommended to validate the results under real-world conditions. Full article

(This article belongs to the Special Issue Advanced Asphalt Composite Materials)

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12 pages, 4013 KiB

Open AccessArticle

Effect of Turmeric Staining and Bleaching Treatment on Color Stability and Surface Hardness of Different Dental Composite Resins

by Mitsu Patel, Jimin Lee, Marc Hayashi, Reuben H. Kim and Mijoo Kim

J. Compos. Sci. 2025, 9(2), 77; https://doi.org/10.3390/jcs9020077 - 8 Feb 2025

Abstract

This study investigated the susceptibility of nine composite resins to turmeric staining, evaluated bleaching efficacy for color recovery, and assessed surface hardness throughout these processes. Disc-shaped specimens (8 mm × 2 mm, n = 3/group) were subjected to daily 20 min turmeric solution [...] Read more.

This study investigated the susceptibility of nine composite resins to turmeric staining, evaluated bleaching efficacy for color recovery, and assessed surface hardness throughout these processes. Disc-shaped specimens (8 mm × 2 mm, n = 3/group) were subjected to daily 20 min turmeric solution immersion for two weeks, followed by two weeks of daily 3 h applications of 16% carbamide peroxide bleaching. Color measurements included spectrophotometric analysis for ΔE values (threshold ΔE > 3.3 for clinical significance) and VITA Classic shade assessment at baseline, post-staining, and post-bleaching intervals. Surface hardness was evaluated using a Vickers hardness tester. Results showed significant color changes in all materials except HA after turmeric exposure, with FS exhibiting the highest staining susceptibility (ΔE = 24.6 ± 2.69) and HA showing minimal change (ΔE = 1.9 ± 0.85). VITA Classic shade evaluation revealed varying patterns; some materials maintained their initial shade designation despite significant ΔE changes (FS, CM), while others showed substantial shade shifts with successful recovery post-bleaching (HA, OM). Bleaching effectiveness varied across materials, with PO, VEP, and FS demonstrating substantial recovery in ΔE values, although FS retained clinically noticeable discoloration post-bleaching (ΔE = 7.6 ± 0.89). Surface hardness analysis revealed three distinct groups: high (80–90 HV: FS, CA, VPO), intermediate (55–70 HV: VEP, OM), and low (40–47 HV: PO, AE, HA, CM). For patients with high exposure to chromogenic foods, such as turmeric, material selection requires careful consideration of staining susceptibility, with HA and OM demonstrating superior color stability and recovery characteristics in this study. Full article

(This article belongs to the Section Composites Applications)

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12 pages, 6745 KiB

Open AccessArticle

Influence of Heat Treatment on Microstructure and Wear Properties of TiC/FC250 Composites

by Yujin Lim, Jaeseong Choi, Seungchan Cho, Junghwan Kim, Sangmin Shin and Ilguk Jo

J. Compos. Sci. 2025, 9(2), 76; https://doi.org/10.3390/jcs9020076 - 8 Feb 2025

Abstract

Metal matrix composites (MMCs) produced through the unique liquid pressing infiltration (LPI) process exhibit significant industrial potential. In this study, TiC/FC250 metal matrix composites were fabricated using the liquid pressing infiltration process, and the effects of austempering and quenching–tempering heat treatments on the [...] Read more.

Metal matrix composites (MMCs) produced through the unique liquid pressing infiltration (LPI) process exhibit significant industrial potential. In this study, TiC/FC250 metal matrix composites were fabricated using the liquid pressing infiltration process, and the effects of austempering and quenching–tempering heat treatments on the microstructure and wear characteristics were investigated in comparison to as-cast specimens of both the FC250 gray cast iron matrix material and the TiC/FC250 metal matrix composites without heat treatment. The results indicated that the quenching–tempering heat treatment effectively enhanced the dry sliding friction and wear characteristics compared to the as-cast condition. The heat-treated specimens, under optimal conditions, demonstrated superior properties compared to other heat treatments and the matrix material. Although the metal matrix composites were successfully produced via the liquid pressing infiltration process and optimal heat treatment, some graphite morphology transformed from a flake to a spherical shape due to the high temperature and slow cooling rate during the process. With the quenching–tempering heat treatment, the wear resistance increased by approximately 41.53% in the matrix material and by 53.38% in the metal matrix composites compared to the as-cast specimens. The TiC/FC250 metal matrix composite heat-treated under optimal conditions exhibited an approximate 58.28% reduction in the friction coefficient compared to the FC250 gray cast iron. Full article

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XRD pattern of FC250 matrix and TFC composites with different heat treatments. Full article ">Figure 2
Scanning electron microscopy images of (a–c) FC matrix, and (d–f) TFC composites with different heat treatment. The white arrow indicates graphite. Full article ">Figure 3
EPMA mapping analysis of specimens before heat treatment: (a) FC-AS (b) TFC-AS. The white arrow represents graphite. Full article ">Figure 4
Hardness variation of FC and TFC metal matrix composites under different heat treatment conditions. Full article ">Figure 5
Wear surface microscopy on the wear tracks of (a–c) FC, and (d–f) TFC metal matrix composites before and after heat treatment. Full article ">Figure 6
High-magnification SEM images of the wear tracks of (a–c) FC250 matrix, and (d–f) TFC metal matrix composites with different heat treatment conditions. The red circle indicates the area where debris has broken off. Full article ">Figure 7
Average friction coefficient of FC250 matrix and TFC composites with different heat treatment. Full article ">

17 pages, 4583 KiB

Open AccessArticle

Numerical Analysis and Life Cycle Assessment of Type V Hydrogen Pressure Vessels

by Mohd Shahneel Saharudin, Syafawati Hasbi, Santosh Kumar Sahu, Quanjin Ma and Muhammad Younas

J. Compos. Sci. 2025, 9(2), 75; https://doi.org/10.3390/jcs9020075 - 7 Feb 2025

Abstract

The growing concern about greenhouse gas emissions and global warming has heightened the focus on sustainability across industrial sectors. As a result, hydrogen energy has emerged as a versatile and promising solution for various engineering applications. Among its storage options, Type V composite [...] Read more.

The growing concern about greenhouse gas emissions and global warming has heightened the focus on sustainability across industrial sectors. As a result, hydrogen energy has emerged as a versatile and promising solution for various engineering applications. Among its storage options, Type V composite pressure vessels are particularly attractive because they eliminate the need for a polymer liner during manufacturing, significantly reducing material usage and enhancing their environmental benefit. However, limited research has explored the pressure performance and life cycle assessment of these vessels. To address this gap, this study investigates the pressure performance and carbon emissions of a Type V hydrogen pressure vessel using four composite materials: Kevlar/Epoxy, Basalt/Epoxy, E-Glass/Epoxy, and Carbon T-700/Epoxy. The results reveal that Carbon T-700/Epoxy is the most suitable material for high-pressure hydrogen storage due to its superior mechanical properties, including the highest burst pressure, maximum stress capacity, and minimal deformation under loading. Conversely, the LCA results, supported by insights from a large language model (LLM), show that Basalt/Epoxy provides a more sustainable option, exhibiting notably lower global warming potential (GWP) and acidification potential (AP). These findings highlight the trade-offs between mechanical performance and environmental impact, offering valuable insights for sustainable hydrogen storage design. Full article

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

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23 pages, 7096 KiB

Open AccessArticle

Establishing Benchmark Properties for 3D-Printed Concrete: A Study of Printability, Strength, and Durability

by Alise Sapata, Māris Šinka, Genādijs Šahmenko, Lidija Korat Bensa, Lucija Hanžič, Katarina Šter, Sandris Ručevskis, Diāna Bajāre and Freek P. Bos

J. Compos. Sci. 2025, 9(2), 74; https://doi.org/10.3390/jcs9020074 - 7 Feb 2025

Abstract

This study investigates the fresh state and hardened state mechanical and durability properties of 3D-printed concrete. The mechanical tests focused on its anisotropic behavior in response to different load orientations. Compressive, flexural, and splitting tensile strengths were evaluated relative to the print layers [...] Read more.

This study investigates the fresh state and hardened state mechanical and durability properties of 3D-printed concrete. The mechanical tests focused on its anisotropic behavior in response to different load orientations. Compressive, flexural, and splitting tensile strengths were evaluated relative to the print layers orientation. Results showed that compressive strength varied significantly, achieving 85% of cast sample strength when the load was applied parallel to the print layers ([u] direction), 71% when the load was applied perpendicular to the print object’s side plane ([v] direction), while only reaching 59% when applied perpendicular to the top plane ([w] direction). Similar trends were observed for flexural strength, with average values reaching 75% of cast sample strength when the load was applied perpendicular to the print layers ([v.u] and [w.u] directions), but decreasing to 53% when the load was applied parallel to print layers ([u.w] direction), underscoring the weaknesses at interlayer interfaces. The splitting tensile strength remained relatively consistent across print orientations, reaching 90% of the cast sample strength. Durability assessment tests revealed that 3D-printed concrete exhibits reduced resistance to environmental factors, particularly at the layer interfaces where the cold joint was formed, which are prone to moisture penetration and crack formation. These findings contribute valuable insights into the mechanical and durability properties of 3D-printed concrete, emphasizing the importance of print orientation and interlayer bonding in its performance. This understanding helps guide the optimal use of 3D-printed elements in real-life applications by aligning load or exposure to environmental factors with the material’s strength and durability characteristics. Full article

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

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17 pages, 2785 KiB

Open AccessArticle

Zn-Ferrite and Hematite Dispersed by SBA-15 Silica Grains: Visible Light-Driven Photocatalytic Activity for Advanced Oxidation Process on Amoxicillin

by Aya Jezzini, Anne Davidson, Gilles Wallez, Jean-Marc Grenèche, Tayssir Hamieh and Joumana Toufaily

J. Compos. Sci. 2025, 9(2), 73; https://doi.org/10.3390/jcs9020073 - 5 Feb 2025

Abstract

Nanoparticles of ZnFe₂O₄ and hematite with varied sizes and distributions were synthesized using the two-solvent method (cyclohexane, water) on SBA-15 silica batches. Calcination is performed in air at 700 °C (2 °C/min) with rapid quenching produced catalysts with distinct nanoparticle [...] Read more.

Nanoparticles of ZnFe₂O₄ and hematite with varied sizes and distributions were synthesized using the two-solvent method (cyclohexane, water) on SBA-15 silica batches. Calcination is performed in air at 700 °C (2 °C/min) with rapid quenching produced catalysts with distinct nanoparticle configurations, namely, internal zinc ferrite and external hematite. The choice of precursor was critical, and nitrate salts yielded only zinc ferrite nanoparticles, while chloride salts produced a mixture of hematite and zinc ferrite. The photocatalytic activity of these materials was evaluated under visible light irradiation from an LED lamp, using O₂ from air as an oxidizing agent without the addition of H₂O₂. Samples enriched with external hematite nanoparticles from chloride precursors achieved the highest activity, decomposing 30% of AMX in 225 min. In contrast, nitrate-derived samples with predominantly internal zinc ferrite nanoparticles exhibited lower catalytic activity. Characterization via TEM, XRD, N2 sorption, and Mössbauer spectroscopy confirmed the structural and magnetic properties of the nanoparticles. Mössbauer spectra, particularly at 12K and under a magnetic field, demonstrated the presence of hematite nanoparticles, distinguishing them from isolated Fe (III) cations. Zinc ferrite nanoparticles exhibited specific magnetic ordering, with Fe ions occupying tetrahedral and octahedral sites. The results demonstrate the critical role of nanoparticle, composition, and positioning in optimizing photocatalytic efficiency for water decomposition. Full article

(This article belongs to the Section Composites Manufacturing and Processing)

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20 pages, 2521 KiB

Open AccessArticle

A Bayesian Network Framework to Predict Compressive Strength of Recycled Aggregate Concrete

by Tien-Dung Nguyen, Rachid Cherif, Pierre-Yves Mahieux and Emilio Bastidas-Arteaga

J. Compos. Sci. 2025, 9(2), 72; https://doi.org/10.3390/jcs9020072 - 5 Feb 2025

Abstract

In recent years, the use of recycled aggregate concrete (RAC) has become a major concern when promoting sustainable development in construction. However, the design of concrete mixes and the prediction of their compressive strength becomes difficult due to the heterogeneity of recycled aggregates [...] Read more.

In recent years, the use of recycled aggregate concrete (RAC) has become a major concern when promoting sustainable development in construction. However, the design of concrete mixes and the prediction of their compressive strength becomes difficult due to the heterogeneity of recycled aggregates (RA). Artificial-intelligence (AI) approaches for the prediction of RAC compressive strength

{(f}_{c})

need a sizable database to have the ability to generalize models. Additionally, not all AI methods may update input values in the model to improve the performance of the algorithms or to identify some model parameters. To overcome these challenges, this study proposes a new method based on Bayesian Networks (BNs) to predict the

f_{c}

of RAC, as well as to identify some parameters of the RAC formulation to achieve a given

f_{c}

target. The BN approach utilizes the available data from three input variables: water-to-cement ratio, aggregate-to-cement ratio, and RA replacement ratio to calculate the prior and posterior probability of

f_{c}

. The outcomes demonstrate how BNs may be used to forecast both forward and backward, related to the

f_{c}

of RAC, and the parameters of the concrete formulation. Full article

(This article belongs to the Special Issue Novel Cement and Concrete Materials)

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28 pages, 2319 KiB

Open AccessReview

Advancements in Free-Standing Ferroelectric Films: Paving the Way for Transparent Flexible Electronics

by Riya Pathak, Gopinathan Anoop and Shibnath Samanta

J. Compos. Sci. 2025, 9(2), 71; https://doi.org/10.3390/jcs9020071 - 5 Feb 2025

Abstract

Free-standing ferroelectric films have emerged as a transformative technology in the field of flexible electronics, offering unique properties that enable a wide range of applications, including sensors, actuators, and energy harvesting devices. This review paper explores recent advancements in the fabrication, characterization, and [...] Read more.

Free-standing ferroelectric films have emerged as a transformative technology in the field of flexible electronics, offering unique properties that enable a wide range of applications, including sensors, actuators, and energy harvesting devices. This review paper explores recent advancements in the fabrication, characterization, and application of free-standing ferroelectric films, highlighting innovative techniques such as multilayer structures and van der Waals epitaxy that enhance their performance while maintaining mechanical flexibility. We discuss the critical role of these films in next-generation devices, emphasizing their potential for integration into multifunctional systems that combine energy harvesting and sensing capabilities. Additionally, we address challenges related to leakage currents, polarization stability, and scalability that must be overcome to facilitate commercialization. By synthesizing current research findings and identifying future directions, this paper aims to provide a comprehensive overview of the state-of-the-art in free-standing ferroelectric films and their impact on the development of sustainable and efficient flexible electronic technologies. Full article

(This article belongs to the Section Composites Applications)

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A schematic diagram illustrating the laser lift-off process. This figure is intended to provide a general overview of the methodology and does not depict specific experimental parameters. Full article ">Figure 2
A schematic representation of the wet etching process for fabricating free-standing ferroelectric films. Full article ">Figure 3
Interfaces connected by Van der Waals gap. Full article ">Figure 4
Comparison of remnant polarization (Pr) of substrate intact and free-standing ferroelectric films. Full article ">Figure 5
Roadmap of domain wall motion in free-standing films. The orange color represents the ferroelectric film. Full article ">Figure 6
(a–c): Schematic illustration of an energy harvesting mechanism where bending the substrate induces mechanical strain in the ferroelectric layer, leading to the switching of polarization domains. Arrows indicate the direction of polarization of each domain. Full article ">Figure 7
Integration of free-standing films in multifunctional devices. Full article ">

15 pages, 2601 KiB

Open AccessArticle

Physicochemical Studies of Opoka as a Raw Material Component of Sodium Silicate Mixture for Subsequent Synthesis of Foam Glass Material Based on It

by Bibol Zhakipbayev, Alexandr Kolesnikov, Samal Syrlybekkyzy, Leila Seidaliyeva, Akmaral Koishina and Lyailim Taizhanova

J. Compos. Sci. 2025, 9(2), 70; https://doi.org/10.3390/jcs9020070 - 4 Feb 2025

Abstract

The present article presents the results of physical and chemical studies of opoka. In particular, the opoka was subjected to chemical analysis, X-ray phase, differential thermal analysis, scanning microscopy, and X-ray energy dispersive elemental microanalysis. The opoka was studied with the aim of [...] Read more.

The present article presents the results of physical and chemical studies of opoka. In particular, the opoka was subjected to chemical analysis, X-ray phase, differential thermal analysis, scanning microscopy, and X-ray energy dispersive elemental microanalysis. The opoka was studied with the aim of using it as an available raw material for obtaining a sodium silicate mixture and, in the future, developing an energy-saving technology for obtaining a building heat-insulating and sound-insulating foam glass material based on it, using synthesis. As a result of the studies, the chemical composition of the opoka was determined, which is 69–80% represented by silica. The elemental composition of the opoka was established, which is represented by 94.25% oxides of Si, Al, and Fe. The presence of such oxides makes it an ideal raw material component of a silicate-sodium mixture for the subsequent synthesis of foam glass material from it. Experimental exploratory studies on the synthesis of foam glass based on opoka have been carried out. The experimentally obtained sample of foam glass material consists of 93.37% Si, Al, Mg, and Na oxides, has a porous structure with a pore size of 2–5 microns, an average density of 375 kg/m³, thermal conductivity of 0.063 W/(m °C) at 25 °C, and noise absorption of 51.6 Db. Full article

(This article belongs to the Section Composites Manufacturing and Processing)

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15 pages, 4027 KiB

Open AccessArticle

Thermal, Mechanical, and Microstructural Properties of Novel Light Expanded Clay Aggregate (LECA)-Based Geopolymer Concretes

by Tinkara Marija Podnar and Gregor Kravanja

J. Compos. Sci. 2025, 9(2), 69; https://doi.org/10.3390/jcs9020069 - 4 Feb 2025

Abstract

The construction sector’s reliance on traditional cement significantly contributes to CO₂ emissions, underscoring the urgent need for sustainable alternatives. This study investigates fine (0–4 mm), rounded, uncoated, porous-surfaced lightweight expanded clay aggregate (LECA)-based geopolymers, which combine the low-carbon benefits of geopolymers with [...] Read more.

The construction sector’s reliance on traditional cement significantly contributes to CO₂ emissions, underscoring the urgent need for sustainable alternatives. This study investigates fine (0–4 mm), rounded, uncoated, porous-surfaced lightweight expanded clay aggregate (LECA)-based geopolymers, which combine the low-carbon benefits of geopolymers with LECA’s lightweight and insulating properties. Geopolymers were synthesized using lignite-rich fly ash with varying ratios of LECA to aggregate. Mechanical testing revealed that the reference mixture without LECA (REF-GEO) achieved the highest compressive strength of 37.89 ± 0.75 MPa and flexural strength of 7.62 ± 0.11 MPa, while complete substitution of the aggregate with LECA (LECA-100%) reduced the compressive strength to 17.31 ± 0.88 MPa and flexural strength to 3.41 ± 0.11 MPa. The density of the samples decreased from 2.06 g/cm³ for REF-GEO to 1.31 g/cm³ for LECA-100%, and thermal conductivity dropped significantly from 1.15 ± 0.07 W/mK to 0.38 ± 0.01 W/mK. Microstructural analysis using XRD and SEM-EDX highlighted changes in the material’s internal structure and the increase in porosity with higher LECA content. Water vapor permeability increases over time, particularly in samples with higher LECA content. These findings suggest that LECA-based geopolymers are suitable for low-load or non-structural elements. They are ideal for sustainable, energy-efficient construction that requires lightweight, insulating, and breathable materials. Full article

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

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12 pages, 970 KiB

Open AccessArticle

Enhanced Photocatalytic Hydrogen Generation from Methanol Solutions via In Situ Ni/Pt Co-Deposition on TiO₂

by Mst. Farhana Afrin, Mai Furukawa, Ikki Tateishi, Hideyuki Katsumata, Monir Uzzaman and Satoshi Kaneco

J. Compos. Sci. 2025, 9(2), 68; https://doi.org/10.3390/jcs9020068 - 2 Feb 2025

Abstract

TiO₂ is widely utilized as an excellent photocatalyst in energy production. However, its rapid electron and hole recombination confers poor photocatalytic activity. Cocatalysts are essential for increasing photocatalytic efficacy by introducing improved electron transmission and enlarging the active site. Herein, the photocatalytic [...] Read more.

TiO₂ is widely utilized as an excellent photocatalyst in energy production. However, its rapid electron and hole recombination confers poor photocatalytic activity. Cocatalysts are essential for increasing photocatalytic efficacy by introducing improved electron transmission and enlarging the active site. Herein, the photocatalytic degradation of aqueous methanol solution to generate hydrogen was studied with the simultaneous in situ deposition of metals (M = Ag, Cu, Ni, Pd, and Pt) on the TiO₂ surface. Adding methanol to water and incorporating a bimetallic cocatalyst enhanced hydrogen production by reducing the electron–hole pair recombination. The studied metal ions could be reduced by the conduction band electrons of TiO₂ for the in situ simultaneous deposition of metal. The larger work function value of the studied metals favored the Schottky junction formation, which contributed to increasing photocatalytic efficiency. Among these simultaneous metal-deposited photocatalysts, maximal photocatalytic hydrogen production was achieved with NiPt/TiO₂. The optimal component was 0.01 wt.% Ni/1.0 wt.% Pt for TiO₂. The hydrogen evolution with NiPt/TiO₂ was approximately 341 and 1.3 times better than that with pure TiO₂ and Pt/TiO₂, respectively. A potential reaction pathway for photocatalytic hydrogen production from an aqueous methanol solution over NiPt/TiO₂ photocatalyst has also been proposed. Full article

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

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22 pages, 5276 KiB

Open AccessArticle

Development of Doum Palm Fiber-Based Building Insulation Composites with Citric Acid/Glycerol Eco-Friendly Binder

by Hicham Elmoudnia, Younoussa Millogo, Paulina Faria, Rachid Jalal, Mohamed Waqif and Latifa Saâdi

J. Compos. Sci. 2025, 9(2), 67; https://doi.org/10.3390/jcs9020067 - 2 Feb 2025

Abstract

This study focuses on the development of an insulation biocomposite using Doum palm (Chamaerops humilis) fibers reinforced with a natural binder based on citric acid and glycerol. The main objective is to optimize the thermal conductivity and mechanical properties of the biocomposite as [...] Read more.

This study focuses on the development of an insulation biocomposite using Doum palm (Chamaerops humilis) fibers reinforced with a natural binder based on citric acid and glycerol. The main objective is to optimize the thermal conductivity and mechanical properties of the biocomposite as a function of fiber preparation (short or powdered fibers) and binder content (20%, 30% and 40%), and relate them to the bonding of the fibers and the binder. The obtained results suggest that the addition of the binder greatly enhances the density, compressive strength and Young’s modulus of biocomposites. More specifically, the addition of 20% by weight of the citric acid/glycerol binder improves the bond between fibers, whether they are short fibers or powders. This leads to an increase in the mechanical properties, with Young’s modulus reaching (212.1) MPa and compressive strength at (24.3) MPa. On the other hand, the results show that these biocomposites also have acceptable thermal insulation performance, achieving a thermal conductivity of (0.102) W/(m·K), making them suitable for a variety of applications in sustainable buildings and for refurbishment. Full article

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22 pages, 13498 KiB

Open AccessArticle

A Study on the Relationship Between the Pore Characteristics of High-Performance Self-Compacting Concrete (HPSCC) Based on Fractal Theory and the Function of the Water–Binder Ratio (W/C)

by Guihong Xu, Mingwei He, Li He, Yongsheng Chen, Li Duan and Weiguo Jiao

J. Compos. Sci. 2025, 9(2), 66; https://doi.org/10.3390/jcs9020066 - 2 Feb 2025

Abstract

The mechanical properties of High-Performance Self-Compacting Concrete (HPSCC) are strongly influenced by its pore structure, but the impact of varying water–binder ratios (W/C) on this relationship remains unclear. To address this, the present study investigates HPSCC with W/C ratios ranging from 0.19 to [...] Read more.

The mechanical properties of High-Performance Self-Compacting Concrete (HPSCC) are strongly influenced by its pore structure, but the impact of varying water–binder ratios (W/C) on this relationship remains unclear. To address this, the present study investigates HPSCC with W/C ratios ranging from 0.19 to 0.23, aiming to elucidate the connection between pore structure, fractal characteristics, and mechanical performance. Through a combination of compressive strength testing, low-temperature nitrogen adsorption, and Scanning Electron Microscopy (SEM) observations, this study reveals key insights. First, compressive strength initially increases with a decreasing W/C ratio but plateaus beyond W/C = 0.21, identifying an optimal range for balancing strength and workability. Second, the pore structure of HPSCC is characterized by cylindrical, ink-bottle, and planar interstitial pores, with significant fractal characteristics. Notably, the fractal dimension decreases as the W/C ratio increases, indicating reduced pore complexity and improved homogeneity. Finally, a strong linear correlation (R² > 0.9) between the W/C ratio, fractal dimension, and compressive strength provides a predictive tool for assessing HPSCC performance. This study concludes that the internal pore structure is a critical determinant of HPSCC strength, and the identified optimal W/C ratio range offers guidance for mixture designs. Additionally, fractal dimension analysis emerges as a novel method to evaluate HPSCC’s microstructural quality, enabling predictions of long-term performance and durability. These findings contribute to the scientific basis for designing high-performance concrete materials with improved mechanical properties and durability. Full article

(This article belongs to the Special Issue Novel Cement and Concrete Materials)

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18 pages, 5155 KiB

Open AccessArticle

Antibacterial UV-Curable Gel with Hydroxyapatite Nanoparticles for Regenerative Medicine in the Field of Orthopedics

by Julia A. Burunkova, Valeria V. Semykina, Vera E. Sitnikova, Dmitry M. Dolgintsev, Faliya F. Zaripova, Alina A. Ponomareva, Diana R. Mizina, Attila Csick, Sandor Kokenyesi and Anton Zhilenkov

J. Compos. Sci. 2025, 9(2), 65; https://doi.org/10.3390/jcs9020065 - 1 Feb 2025

Abstract

The development and analysis of the properties of a new material based on UV-curable acrylate monomers with silicon-containing hydroxyapatite and zinc oxide nanoparticles as an antibacterial component and gelatin was carried out. Using this material in orthopedics and dentistry is very convenient because [...] Read more.

The development and analysis of the properties of a new material based on UV-curable acrylate monomers with silicon-containing hydroxyapatite and zinc oxide nanoparticles as an antibacterial component and gelatin was carried out. Using this material in orthopedics and dentistry is very convenient because it covers any surface geometry of metal implants and hardens under ultraviolet light. In this work, sorption properties, changes in porosity, and mechanical properties of the material were investigated. The conditions for obtaining hydroxyapatite (HA) nanoparticles and the presence of silicon oxide nanoparticles and organic for the shell in an aqueous medium were studied for the pH of the medium, the sequence of administration and concentration of the material components, as well as antibacterial properties. This polymer material is partially resorbable. That supports not only the growth of bone cells but also serves as a protective layer. It reduces friction between organic tissues and a metal implant and can be a solution to the problem of the aseptic instability of metal implants. The material can also be used to repair damaged bones and cartilage tissues, especially in cases where the application and curing procedure is performed using laparoscopic methods. In this work, the authors propose a simple and quite cheap method for obtaining material based on photopolymerizable acrylates and natural gelatin with nanoparticles of HA, zinc oxide, and silicon oxide. The method allows one to obtain a composite material with different nanoparticles in a polymer matrix which retain the requisite properties needed such as active-sized HA, antibacterial ZnO, and structure-forming and stability-improving SiO2 nanoparticles. Full article

(This article belongs to the Section Biocomposites)

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14 pages, 5278 KiB

Open AccessArticle

Microwave Synthesis of Luminescent Recycled Glass Containing Dy₂O₃ and Sm₂O₃

by Achanai Buasri, Apichaya Boonpanya, Arraya Yangderm, Thanaporn Kensopha and Vorrada Loryuenyong

J. Compos. Sci. 2025, 9(2), 64; https://doi.org/10.3390/jcs9020064 - 1 Feb 2025

Abstract

This research studied the recycling of borosilicate glass wastes from damaged laboratory glassware. The luminescent glasses were prepared by doping glass waste powder with rare earth ions, namely, dysprosium ions (Dy³⁺) and samarium ions (Sm³⁺), as well as co-doping [...] Read more.

This research studied the recycling of borosilicate glass wastes from damaged laboratory glassware. The luminescent glasses were prepared by doping glass waste powder with rare earth ions, namely, dysprosium ions (Dy³⁺) and samarium ions (Sm³⁺), as well as co-doping with Dy³⁺ and Sm³⁺ at a concentration of 2% by weight. The sintering process was conducted in a microwave oven for a duration of 15 min. The photoluminescence spectra of the doped glasses were obtained under excitation at 401 nm and 388 nm. The results showed that the emission characteristics depended on the doping concentrations of Dy³⁺ and Sm³⁺ and the excitation wavelengths. Upon excitation at 401 nm, the co-doped glasses exhibited the maximum emission peak of Sm³⁺ at 601 nm (yellowish and orange region in the CIE chromaticity diagram) due to the energy transition from ⁴G_5/2 to ⁶H_7/2. When excited at 388 nm, however, the emission spectra of the co-doped glasses were similar to the characteristic emission peaks of Dy³⁺ (white region in the CIE chromaticity diagram), but the peak position exhibits a red shift. This could be attributed to an increase in the amount of non-bridging oxygens (NBOs) by co-doping. Full article

(This article belongs to the Special Issue Trends and Challenges in Developing and Processing Composite Materials)

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18 pages, 7322 KiB

Open AccessArticle

Optimization of 3D Printing Parameters for Enhanced Mechanical Strength: Effects of Glass Fiber Reinforcement and Fill Ratio Using RSM and ANOVA

by Hussein Hadi Jawad, Naser Kordani, Abbasali Bagheri and Hamed Aghajani Derazkola

J. Compos. Sci. 2025, 9(2), 63; https://doi.org/10.3390/jcs9020063 - 1 Feb 2025

Abstract

This research aimed to provide valuable insights for future studies and enhance manufacturing processes by investigating the effect of incorporating fibers into 3D printing to improve the mechanical properties of fabricated components. The experimental design was carried out using Design-Expert software, employing the [...] Read more.

This research aimed to provide valuable insights for future studies and enhance manufacturing processes by investigating the effect of incorporating fibers into 3D printing to improve the mechanical properties of fabricated components. The experimental design was carried out using Design-Expert software, employing the Central Composite Design (CCD) methodology. Seventeen experiments were conducted, with predefined input parameters, layer height, filler ratio, and printing speed, analyzed through the Response Surface Methodology (RSM) using Design-Expert version 12. An Analysis of Variance (ANOVA) revealed that the filler ratio had the most significant effect on fracture strength. The influence of different printing parameters printing speed, layer height, and filler ratio on the mechanical properties and print quality was systematically investigated. The results indicated that the filler ratio was the most critical factor, with a 100% fill ratio yielding the highest tensile strength. Conversely, a 50% fill ratio significantly reduced production costs, but at the expense of mechanical performance. Thus, if strength is the primary requirement, a higher fill ratio is recommended. The effect of printing speed was found to be less significant compared to layer height and filler ratio. The maximum recorded tensile strength was 540.65 N, achieved with a layer height of 0.5 mm, a 100% fill ratio, and a printing speed of 8 mm/s. In contrast, the lowest recorded tensile strength was 389.93 N, observed with a layer height of 0.4 mm, a 50% fill ratio, and a printing speed of 4 mm/s. After applying a transformation function, the data showed good alignment with the normal distribution on the probability plot, indicating that the assumption of normality was satisfied. Additionally, the incorporation of glass fibers significantly enhanced the mechanical strength of the printed samples. Full article

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

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18 pages, 4260 KiB

Open AccessArticle

Influence of Synthesis Conditions on the Structure, Composition, and Electromagnetic Properties of FeCoSm/C Nanocomposites

by Dmitriy Muratov, Lev Kozhitov, Irina Zaporotskova, Alena Popkova, Evgeniy Korovin, Sergey Boroznin and Natalia Boroznina

J. Compos. Sci. 2025, 9(2), 62; https://doi.org/10.3390/jcs9020062 - 1 Feb 2025

Abstract

New materials are actively being developed for use in various fields of electronics, as they can significantly improve the performance of electronic devices and prevent adverse effects. Such materials include nanocomposites, which include nanoparticles of magnetic metals and alloys in a non-magnetic polymer [...] Read more.

New materials are actively being developed for use in various fields of electronics, as they can significantly improve the performance of electronic devices and prevent adverse effects. Such materials include nanocomposites, which include nanoparticles of magnetic metals and alloys in a non-magnetic polymer or carbon matrix. For the first time, we synthesized FeCoSm/C nanocomposites and studied the effect of synthesis conditions on their structure, composition, and electromagnetic properties. Thermogravimetric (TG) analysis and differential scanning calorimetry (DSC) analysis of the heating processes of nanocomposite precursors allowed optimizing the mode of IR processing of precursors. X-ray phase analysis (XPA) showed that nanoparticles of a solid-metal solution based on the FeCo structure are formed, and at temperatures above 700 °C, the formation of SmCo5-x alloy nanoparticles is also possible. As the synthesis temperature increases, the average size of nanoparticles of alloys containing Sm increases. The effect of the metal ratio in the precursor on the structure, composition, and electromagnetic properties of FeCoSm/C nanocomposites is analyzed. It has been established that the most promising of all the studied materials are those obtained at a temperature of 700 °C with a metal ratio of Fe:Co:Sm = 50:40:10. Full article

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

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J. Compos. Sci., Volume 9, Issue 2 (February 2025) – 41 articles

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