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Owing to the outstanding properties of boron carbide (B4C) particles, material researchers have shown potential in filler‐reinforced polymer composites. The present work studied the implication of B4C fillers on the mechanical and ballistic properties of glass fiber epoxy reinforced composites. Two different weight percentages of 2 and 4 wt% B4C fillers were used to modify the epoxy resin. The composite samples with glass fabric woven were made through compression molding. The results show that the tensile, flexural, interlaminar, impact strength and hardness of glass fiber composite were improved by addition of 2 wt% of B4C. The high‐velocity ballistic tests were conducted on the unfilled and B4C filler‐reinforced composites using a 9 mm parabellum projectile with an initial striking of 372 ± 15 m/s. The least back face signature (BFS) and highest specific energy absorption (SEA) were observed for 2 wt% B4C filler composite. Adding B4C filler enhanced matrix toughening and interfacial bonding between fiber and matrix. Matrix cracking and fiber breakage result in the least ballistic resistance for unfilled composite. Fracture behavior was studied on tensile, impact, and ballistic‐tested samples using scanning electron microscopy. The fractured surfaces of filler‐reinforced composite demonstrated good interfacial bonding, matrix hardening, and fiber pullouts. Highlights: The addition of B4C with epoxy up to 2 wt% improves the mechanical and ballistic properties of the composites.The least back face signature and highest specific energy absorption were observed for 2 wt% B4C filler composite.B4C filler enhanced matrix toughening and interfacial bonding between fiber and matrix.Failure of unfilled glass fiber composites is a combination of matrix cracking, fiber pullout, and interface debonding. [ABSTRACT FROM AUTHOR]

2024 aluminum alloy has high strength, processing performance, and good damage tolerance performance, but it is prone to intergranular corrosion and pitting. Therefore, the development of corrosion protective coatings is essential for the aluminum alloy. In this paper, cerium ion (Ce3+) was doped into chitosan‐modified montmorillonite (Ce‐CS‐MMT) by ion exchange method, and the corrosion protective performance of Ce‐CS‐MMT epoxy coating (Ce‐CS‐MMT/EP) was investigated. The electrochemical analysis of aluminum alloy in cerium‐containing solution showed the corrosion inhibition efficiency reached 95.52%. The result indicates the corrosion inhibition effect of cerium‐containing solution was better than pure NaCl solution and MMT solution. The corrosion study of the coating illustrates that the protection rate of Ce‐CS‐MMT/EP reached 95.82%, which was higher than that 91.83% of Ce‐MMT/EP. The result indicates the resistance of charge transfer was greater and the better shielding effect for electrolyte corrosion ions than MMT and Ce‐MMT epoxy coatings, and the corrosion protective performance was excellent. [ABSTRACT FROM AUTHOR]

This study delineates the dependence of thermophysical behavior of acid‐epoxy vitrimers on their formulation. The stress relaxation due to the bond exchange reaction and the glass transition temperature of acid epoxy vitrimers are investigated, with respect to the influence of catalyst content and acid chain length. This is carried out for a range of dicarboxylic acids and catalyst concentrations formulated and characterized using calorimetry and dynamic mechanical analysis. The influence of acid chain length on the bond exchange rate, topological transition, and glass transition temperatures of the vitrimers is found to be significant. The activation energy of the exchange reaction varies over a wide range from 73 to 104 kJ/mol and the topology freezing temperature from 66 to 136°C with the behavior governed by the interplay between crosslinking density, network flexibility and density and distance of functional groups, with an increase of catalyst concentration leading to lower topological transition temperature and the dependence on chain length showing non‐monotonic behavior. The glass transition decreases by about 30°C as the carbon chain length increases from 6 to 14 carbons due to enhanced monomer flexibility and is not affected by the concentration of catalyst. [ABSTRACT FROM AUTHOR]

The exothermic nature of acrylate photopolymerizations enables room temperature 3D printing of a quaternary formulation that incorporates an acrylate monomer, and an epoxy/thiol‐ene system (ETES). The latter comprises an epoxy monomer, a multifunctional thiol and a tetraallyl functionalized ditertiary amine curing agent. Pristine ETES necessitates temperatures of 85–95 °C for curing. Several mechanisms operate simultaneously during this process: homopolymerization of acrylates, thiol‐acrylate photopolymerization, thiol‐ene photopolymerization between the double bonds of curing agent and the multifunctional thiol, the Michael addition between thiolates derived from ETES and the double bonds of acrylates, and the anionic polymerization of the epoxy resin via the tertiary amine groups. To optimize the quaternary formulations for printing, parameters, such as reactivity, exothermicity, and viscosity, was explored. Subsequently, the thermal and viscoelastic properties of the printed cross‐linked polymers derived from these formulations were analyzed using Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA) and Thermogravimetric Analysis (TGA). The polymers derived from quaternary formulations exhibited lower crosslinked density compared to those obtained from the pristine acrylates. This reduction in crosslink density contributes to the improved toughness of the hybrid polymers. [ABSTRACT FROM AUTHOR]

The increasing responsibility to sustain the environment ecofriendly paves the way to the development of materials with bio or synthetic waste. The goal of this study is to produce uniform dispersion of bio-ceramic Habesha eggshell particles (ESPs) in an epoxy matrix and to investigate damping characteristics under dynamic mechanical analysis for lightweight applications. Lightweight composites were fabricated by dispersing the 70 μm ESPs in varied weight percentages of 2.5, 5, 7.5, and 10, achieved through a novel pulverization process, in the epoxy matrix using a magnetic stirrer. The XRD investigation revealed a reduction in the crystallinity index with decreasing peaks as the eggshell fraction rose. The addition of 10% ESPs increased the heterogeneity in composites thus enhancing the thermal stability with the shift of glass transition temperature to the scale of 6.9 °C. The increased area under the loss modulus curve observed for a higher percentage of ESPs acknowledges the improved heat absorption capacity and 35% improvement in damping characteristics. Few theoretical models were employed to acknowledge the strengthening mechanism to uphold the thermal stability of the composite. The theoretical results show a minimal error percentage compared to the experimental results. The inclusion of ESPs in the epoxy matrix promises better thermal stability and damping characteristics. [ABSTRACT FROM AUTHOR]

AbstractThermosets, before hardening, consist of independent macromolecules similar to thermoplastics, however, chemical curing of these macromolecules via heat or radiations may form irreversibly crosslinked macromolecular networks between their main chains. Graphene quantum dots are inimitable spherical nano-entities having the advantages of extremely small sizes, of 5-10 nm, very high surface area, surface/edge effects, quantum confinements and a range of physical characteristics including semiconductivity, fluorescence and magnetic properties. Similar to other nanocarbons (like graphene, fullerene or nanodiamonds), graphene quantum dots have been examined as noteworthy nanofillers to enhance the essential physical features of various macromolecular matrices, such as thermosets, thermoplastics and rubbers. Consequently, this review article was intended to systematically discuss the existing scientific state of graphene quantum dots reinforced thermosetting macromolecular matrices for the formation of high performance nanomaterials. According to the literature reports, the type, amount and molecular weight of these macromolecules seemed to affect the epoxy-quantum dots interactions and physical properties, like strength and heat stability of the resulting nanomaterials. Moreover, including graphene quantum dots in thermosetting matrices, like epoxies, hyperbranched polyesters and hyperbranched polyurethanes, has positively influenced the engineering aspects (mainly mechanical and thermal attributes) of the resulting nanocomposites owing to their interactions, compatibility and interfacial tendencies toward these matrices. Principally, epoxy/graphene quantum dots nanocomposites have been fabricated and investigated for the effects of graphene quantum nano-entities on the physical property enhancements of these irreversibly crosslinked macromolecules due to their mutual matrix-nanofiller interfaces. As per our analysis, the literature hitherto on the graphene quantum dots reinforced thermosetting matrix nanocomposites has disclosed significant property improvements of these macromolecules and their promising technological applications for high performance anticorrosion coatings, electromagnetic interference shields and biomedical fields. [ABSTRACT FROM AUTHOR]

Highlights Establishing a robust interfacial bond between hexagonal boron nitride (h‐BN) plates and the epoxy matrix is essential for enhancing heat transfer, which is difficult because of h‐BN's low‐surface energy, tendency to clump together, and the chemical inertness of the epoxy matrix. This research shows different techniques for treating the surface of h‐BN fillers by applying acids and thermal processes to activate the surface. The silanization process was used to increase the silane content on the surface of activated h‐BN in order to make it more compatible with the epoxy matrix. X‐ray photoelectron spectroscopy analysis revealed silicon peaks (Si2s peak at 150.1 eV and Si2p peak at 100.3 eV) in the spectrum of silane‐treated samples. Heat treatment resulted in the production of more oxygen molecules on the shell of h‐BN compared to the acid treatment. Here, the primary focus was on examining how surface treatment affects thermal conductivity (TC) performance in both in‐plane and through‐thickness paths. There was an increase in the epoxy's TC perpendicular to the plane, going from 0.21 to 0.47 (W/mK), showing a remarkable 123.8% enhancement by adding 10 wt% of silane‐modified‐thermal treated h‐BN particles. The improvement resulted from effectively silanizing the exterior boundary of h‐BN particles, enhancing connection and distribution in the epoxy matrix. Surface modification of h‐BN‐epoxy composites improves TC, leading to better heat conduction in thermal management systems, benefiting industries like aerospace, automotive, and energy systems. Silanization of h‐BN for better filler‐matrix bonding leading to improved heat transfer Boosting thermal conductivity in the through‐thickness direction with surface‐modified h‐BN Significant improvement in through‐thickness thermal conductivity with treated h‐BN. Thermal treatment of h‐BN produced better oxygenation than acid treatment. Application in aerospace and automotive through improved heat transfer. [ABSTRACT FROM AUTHOR]

Self-healing composites are smart materials that can self-detect and prevent micro crack propagation and any catastrophic failure in the composite structure. In this study, dicyclopentadiene (DCPD) monomer was encapsulated with urea formaldehyde (UF) by in situ polymerization. These microcapsules were mixed with epoxy, chopped carbon fiber (CF), and multi-walled carbon nanotubes (CNT) to make self-healing composite. Both microcapsules and the composite specimens were extensively tested for their physical, thermal, and mechanical properties. The average diameter and shell thickness of the microcapsules were 268 µm and 805 nm, respectively. DMA analysis suggested that the microcapsules have a glass transition temperature (Tg) of 85°C. FTIR analysis confirmed the presence of CF, multi-walled carbon nanotubes (MWCNT), and other constituents in the composite. The tensile strength of the self-healing composites was tested as per ASTM standards. The incorporation of MWCNT in the composites has significantly improved the tensile strength of the composite without compromising on the self-healing efficiency (90%) compared the unmodified samples (72%). The encouraging results of higher glass transition temperature (85°C) combined with an improved healing efficiency (90%), can be considered as the novelties of this work. As the test results of microcapsules and composite specimens were encouraging, they can find applications in making composite structures for aerospace, windmills, and marine applications. The experimental observations and test results are discussed in detail. [ABSTRACT FROM AUTHOR]

Owing to their ability to provide thermal conduction as well as electrical insulation properties that are required for modern electronic devices and electrical systems, nano-fillers incorporated epoxy composites are being widely investigated. In this study, epoxy composites have been reinforced with boron nitride nanosheets (BNNSs) to achieve enhanced thermal conductivity and dielectric properties. Further, their change as a function of BNNSs concentration (weight %) has been investigated. BNNSs are synthesized using the bottom-up approach, while the nanocomposites of epoxy and BNNSs are fabricated with the help of a process involving stirring and ultrasonication. The results reveal that the incorporation of BNNSs leads to enhancement of thermal conductivity of the nanocomposites and it increases with an increase in the loading of BNNSs. The increase in thermal conductivity is 1.93 W/mK with 15 weight % of BNNSs, that is ~ 865% improvement over the pure epoxy. Also, an approximately 123% increase in dielectric constant has been observed. These results demonstrate the potential of BNNSs as nano-fillers in preparing epoxy nanocomposites with better thermal management and energy storage capacity. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine experimentally the higher material parameter g$g$ of a metamaterial with a triangular substructure and to verify a higher‐gradient elasticity model for beams with internal substructures or microstructures. The investigations of the higher‐gradient elasticity models of Bernoulli‐Euler and Timoshenko beams with a periodic triangular substructure in Khakalo et al. show that the bending stiffness strongly depends on the geometrical parameters of the lattice structure. To achieve this goal, beams with triangular substructures were additively manufactured using fused deposition modeling and stereolithography. They were experimentally investigated in tensile and bending tests. Three different types of beams with triangular substructures were produced, consisting of one, two and four layers of triangular beams, using two different materials: Polylactide and epoxy resin. The higher material parameter g was quantitatively determined based on the experimental results using inverse analysis. The results are valid for these specific variations of the substructure and can adequately represent the elastic size effects. In addition, this study investigates the relationship between the bending stiffness and the geometric parameters of the lattice structure as well as the influence of the curing time on the elastic properties of epoxy resin. The experiments involved testing the triangular beams under tensile and bending loads. The numerical and experimental results were compared using digital image correlation. Based on the experimental data, a higher gradient material parameter representing the geometric structure of the lattice was determined. [ABSTRACT FROM AUTHOR]

In this study, two different Al2O3-TiO2 and SiO2-TiO2 hybrid TiO2 particles were synthesised by using silica (SiO2) and alumina (Al2O3) to suppress the photocatalysis of TiO2. Key variables such as the concentration of the hybridization material (C), heating temperature (Th), and calcinating temperature (Tc) were selected with performance measured by photodegradation rate. The Taguchi L9 orthogonal array, a systematic approach used in the design of experiments (DOE), confirmed A333 (Al2O3-TiO2) achieved 99% photodegradation suppression with photodegradation rate reduced significantly from 0.01305 min-1 to 0.00009 min-1 and improved yellowing resistance by 63%, while S323 (SiO2-TiO2) achieved 75% suppression with photocatalysis activity decreased from 0.01305 min-1 to 0.0033 min-1 and 42% improved resistance. X-ray Diffraction (XRD) analysis showed A333 had a higher rutile phase (40.1% vs. 10.2% for S323), and Fourier Transform Infra Red (FTIR) and Field Emission Scanning Electron Microscopy (FESEM) analyses revealed A333's rougher surface and lower surface area compared to S323 and pure TiO2. Overall, A333 effectively suppressed photocatalysis and improved yellowing resistance of epoxy thin film. [ABSTRACT FROM AUTHOR]

Nanodiamond has been categorized among remarkable zero dimensional nanocarbon. This carbon nanoparticle has been applied as important nanofiller in the polymeric matrices. This state-of-the-art review article portrays fundamentals, physical properties, and prospects of nanodiamond filled thermosetting matrices. Among thermosets, most research efforts have been reported on the nanodiamond filled epoxy and polyurethane matrices. Consequently, the epoxy/nanodiamond and polyurethane/nanodiamond nanocomposites have been designed. The nanodiamond nanoparticle addition in polymers caused microstructural variations and enhancements in mechanical, thermal, wear, adhesion, and related advanced features. The property improvement was observed due to the nanofiller dispersion, matrix-nanofiller interactions, and interface formation. Type of thermosetting polymer, curing agent, nanodiamond content, nanodiamond functionalities, and processing method define the final nanocomposite architecture, morphology, and ensuing characteristics. Consequently, the high-tech epoxy/nanodiamond nanocomposites and polyurethane/nanodiamond nanocomposites exposed capability toward technological relevance like coatings, microwave absorption, and biomedical. As few thermosetting matrices have been used with the nanodiamond nanofillers so far, more comprehensive future efforts are needed to disclose the actual potential of thermosetting polymer/nanodiamond nanocomposites. [ABSTRACT FROM AUTHOR]

The success of composite materials is attributed to the nature of bonding at the nanoscale and the resulting structure-related properties. This study reports on the interaction, electronic, and optical properties of diamond nanothread/polymers (cellulose and epoxy) and boron nitride nanotube/calcium silicate hydrate composites using density functional theory modeling. Our findings indicate that the interaction between the nanothread and polymer is due to van der Waals-type bonding. Minor modifications in the electronic structures and absorption spectra are noticed. Conversely, the boron nitride nanotube–calcium silicate hydrate composite displays an electron-shared type of interaction. The electronic structure and optical absorption spectra of the diamond nanothread and boron nitride nanotube in all configurations studied in the aforementioned composite systems are well maintained. Our findings offer an electronic-level perspective into the bonding characteristics and electronic–optical properties of diamond nanothread/polymer and boron nitride nanotube/calcium silicate hydrate composites for developing next-generation materials. [ABSTRACT FROM AUTHOR]

This study investigates the correlation between the interface structure and macroscopic dielectric properties of polymer-based nanocomposite materials. Utilizing bisphenol-A (BPA) epoxy resin (EP) as the polymer matrix and the commonly employed layered phyllosilicate montmorillonoid (MMT) as the nanometer-scale dispersive phase, nano-MMT/EP composites were synthesized using composite technology. The microstructure of the composite samples was characterized through XRD, FTIR, SEM, and TEM. Changes in the morphology of the nanocomposite interface were observed with varying MMT content, subsequently impacting dielectric polarization and loss. Experimental measurements of the dielectric spectrum of the nano-MMT/EP were conducted, and the influence of the material interface, at different nano-MMT contents, on the dielectric relaxation was analyzed. The study delves into the effect of the nanocomposite interface structure on ion dissociation and migration barriers, exploring the ionic conductivity of nano-MMT/EP. Lastly, an analysis of the impact of different nano-MMT contents on the dielectric conductivity is presented. From the experimental results, the arranging regularity of polymer molecules in the interface area raises. In the matrix, the ion migration barriers decrease significantly. The higher the MMT content in the interface, the lower the migration barrier is. Until the MMT content exceeds the threshold, the agglomerated micro-particles form, which decreases the polymers' space distribution regularity, and the ions migration barrier raises. According to the changes in the rule of the ions migration barrier with the composite interface structure content, the reason for dielectric conductivity changes can be judged. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) are extensively utilized in the fabrication of high-performance composites due to their exceptional mechanical, electrical, and thermal characteristics. To investigate the mechanical properties of CNTs filled polymers accurately and effectively, a 3D modeling approach that incorporates the microstructural attributes of CNTs was introduced. Initially, a representative volume element model was constructed utilizing the modified nearest neighbor algorithm. During the modeling phase, a corresponding interference judgment method was suggested, taking into account the potential positional relationships among the CNTs. Subsequently, stress–strain curves of the model under various loading conditions were derived through finite element analysis employing the volume averaging technique. To validate the efficacy of the modeling approach, the stress within a CNT/epoxy resin composite with varying volume fractions under different axial strains was computed. The resulting stress–strain curves were in good agreement with experimental data from the existing literature. Hence, the modeling method proposed in this study provides a more precise representation of the random distribution of CNTs in the matrix. Furthermore, it is applicable to a broader range of aspect ratios, thereby enabling the CNT simulation model to more closely align with real-world models. [ABSTRACT FROM AUTHOR]

Metal corrosion is a challenge for the world with heavy impacts on the economy. Study on the development of effectiveness anticorrosion additives is a promising strategery for the protection industry. This research focuses on the modification of hydrotalcite Mg−Al (HT) loading tannic acid (TA) with 3‐(trimethoxy silyl) propyl methacrylate organo‐silane (TMSPM) for applicating as an anti‐corrosion additive for epoxy coating on the steel substrate. The suitable ratio of HT and modifiers was investigated and the suitable content of modified HT in epoxy matrix was found based on mechanical properties of the epoxy‐based coating. The characteristics of modified HT were assessed through infrared (IR) spectroscopy, X‐ray diffraction pattern (XRD), scanning electron microscopy (SEM), thermal gravimetry analysis (TGA), water contact angle (WCA), dynamic light scattering (DLS). Detailly, HT‐TA3‐S3 shows good stability in distilled water when HT/TA was modified with TMSPM which makes Zeta potential decreases significantly. Besides, SEM analysis presented HT‐TA‐S has a cylindrical shape about of 500 nm. Moreover, the crystallite size of HT/TA after being modified by TMSPM decreases sharply. All of these prove successfully synthesize HT loading TA with modified TMSPM. Water contact angle (WCA) decreases in case of loading TA and increases in case of modifying with TMSPM (WCA changed from HT (116.3°) to HT‐TA (102.4°) and HT‐TA‐S (120.1°) which indicates the increased hydrophobicity of the sample. The obtained results showed HT/TA was modified successfully with TMSPM. The modification affected the size distribution and surface properties of HT nanoparticles while it did not impact on the crystal structure of HT. After incorporating modified HT/TA into the epoxy coating, the adhesion of coating to steel substrate was improved significantly. Consequently, the adhesion of epoxy/3 wt. % modified HT/TA coating was increased 3 times as compared to epoxy neat (from 0.76 MPa to 2.77 MPa). In addition, the relative hardness and gloss retention of epoxy/3 wt. % modified HT/TA coating reached the maximum values as compared to the others. Owing to salt spraying results, the epoxy/3 wt. % modified HT/TA exhibited an excellent anticorrosion ability for the steel substrate. All the above results show the potential of HT nanoparticles loading TA modified with TMSPM as anticorrosive additives for protective coatings on steel substrates. [ABSTRACT FROM AUTHOR]

Recently, bio-composites have attracted much attention due to their potential applications in various industries. The most notable benefits are the product's low cost, biodegradability, lightweight, availability, and ability to solve environmental issues. The present research utilizes ash gourd (Benincasa hispida) peel, a food waste, as a filler material to produce epoxy (EP) composites. The effect of ash gourd peel particle percentage (ranging from 0 to 25 wt.%) was studied on the developed composites' mechanical and thermal properties and water absorption behavior. The maximum tensile strength, flexural strength, and shore D hardness were 47.52 MPa, 2409.17 MPa, and 79.6respectively, when the ash gourd peel was 5% by weight in the composite. It was observed that the mechanical characteristics of manufactured bio-composites are negatively affected by the high concentration of ash gourd peel particles in the epoxy matrix. Also, increasing ash gourd peel particle fraction increases the water absorption of composites when immersed in distilled, sea, and tap water. The composite with 5% filler by weight absorbs water at a minimal rate when immersed in seawater. Thermogravimetric analysis was conducted to investigate the newly developed composite's thermal behavior. In addition, a morphological examination of the fractured surfaces was carried out with assistance from a scanning electron microscope. The work presents ash gourd peel particles as the potential alternative to be used as filler in composites. [ABSTRACT FROM AUTHOR]

The mechanical properties of fiber metal laminates (FML) are influenced by several various factors. Interface adhesion plays a particularly crucial role in interlaminar strength. Enhancing the interlaminar strength of carbon fiber reinforced aluminum laminate (CARALL) composites present a persistent challenge due to inherent weaknesses between metal and composite elements. Therefore, this study focuses on improving the interlaminar performance of CARALL composites by introducing cellulose paper interlayer at the metal/composite interface. The cellulose paper interlayer offers the advantage of being cost-effective and sustainable. Cellulose paper-interleaved CARALL composites were fabricated by vacuum bagging method and exhibited noteworthy improvements in mechanical properties. Comparative analysis with pristine samples revealed substantial enhancements, including a 15% increase in tensile strength, a remarkable 42% improvement in flexural strength, and a significant enhancement in mode-I fracture toughness by 65%. Furthermore, the cellulose paper interleaving played a crucial role in stabilizing fracture formation at the fiber-matrix interface, with mode II fracture toughness witnessing a 3% increase. Visual examination revealed the underlying toughening processes occurring in the interfacial area. This innovative approach of interleaving laminated composites with cellulose paper emerges as a sustainable and effective strategy, demonstrating the potential to fortify and toughen the interlaminar zones of CARALL composites. [ABSTRACT FROM AUTHOR]

Adhesives play an important role in modern society's production and daily life. Developing robust and sustainable adhesives remains a great challenge. Here we report a sustainable epoxy-vitrimer adhesive with high adhesive strength (about 10 MPa) and reusability (82% strength after 3 times). This adhesive can be fabricated from commercially available products through a straightforward hot-pressing method without the need of solvents. The adhesive process is also simple, requiring only 30 min at 180 °C. In addition, the vitrimer adhesive has the advantages of both erasability for reuse and excellent water resistance. This work provides a facile strategy to fabricate high-strength adhesive that ensures reusability, recyclability, low cost of raw materials, and simple processing technology. Simultaneously, it expands the range of potential applications for epoxy vitrimers. [ABSTRACT FROM AUTHOR]

Realizing multiple locked shapes in pre-oriented liquid crystal elastomers (LCEs) is highly desired for diversifying deformations and enhancing multi-functionality. However, conventional LCEs only deform between two shapes for each actuation cycle upon liquid crystal-isotropic phase transitions induced by external stimuli. Here, we propose to regulate the actuation modes and the locked shapes of a pre-orientated epoxy LCE by combining dynamic covalent bonds with cooling-rate-mediated control. The actuation modes can be adjusted on demand by exchange reactions of dynamic covalent bonds. Derived from the established actuation modes, such as elongation, bending, and spiraling, the epoxy LCE displays varied locked shapes at room temperature under different cooling rates. Various mediums are utilized to control the cooling rate, including water, silicone oil, and copper plates. This approach provides a novel way for regulating the actuation modes and locked shapes of cutting-edge intelligent devices. [ABSTRACT FROM AUTHOR]

The main objective of this study is to investigate the effect of curing temperature on the mechanical properties of hemp fiber reinforced polymer (HFRP) composites. In this study, hemp fiber was considered as a reinforcement and epoxy resin with hardener as a matrix. The mercerization process was used to remove contaminants from the fiber surface. The overall volumetric fraction used was 40% fiber and 60% matrix. One composite sample was cured at open temperature (27 ± 3 °C) for 15 days and others at elevated temperatures such as 80, 120 and 160 °C for various durations such as 1, 2, and 3 h (h). Different mechanical tests were performed under ASTM standards to examine the mechanical performance of HFRP composites. The tensile and compressive properties such as Young's modulus, tensile and compressive strengths are higher in the specimens cured at 120 °C for 3-h. The flexural strength and stiffness are maximum in the composites cured at 80 °C for 3-h. The maximum interlaminar shear strength representing the composite's resistance to delamination is observed at 120 °C for 3-h curing condition. The Fourier transform infrared (FTIR) study identifies that the chemical treatment has reduced the impurities present on the fiber surface. Scanning electron microscopic (SEM) studies indicate better fiber/matrix adhesion in specimens cured at elevated temperatures than those cured at open temperature. Finally, this study emphasizes that curing at elevated temperature (120 °C for 3-h) improves the mechanical performance of the NFRP composites. [ABSTRACT FROM AUTHOR]

A comparative study on three types of fireproofing coatings (namely, cementitious, sodium silicate, and epoxy) was made to determine their effectiveness in protecting steel structures. The effects of these coatings on the external protection of steel were structurally, thermally, and mechanically studied. The prepared cementitious coatings endured the heat until 1200 °C for 1 h showing dimensions stability without deformation nor cracking during firing. Both crushing strength (CS) and bulk density measurements decreased from 69 to 18 kg/cm2 and from 1.62 to 1.00 g/cm3 'respectively' with increasing both perlite and vermiculite percentages. Six of the prepared 48 sodium silicate and epoxy coatings succeeded in bearing heat until 900 °C for 3.5 h sustaining the steel substrates' temperature below 60 °C following the Underwriters Laboratory-94 (UL-94) standard. This protective effect was due to the formation of a hard glassy phase on the steel surface isolating it from the heat by the action of the applied constituents. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) thermograms for these succeeded samples revealed that they gave a high residual weight ranging from 63 to 88% when tested from room temperature up to 900 °C. Performing the scanning electron microscopy (SEM) test revealed that physical blending between both the binder and additives (other coating ingredients') has occurred. The results concluded that the used ingredients, which have low prices, compared to the imported ones, and are locally available, are recommended for the fire protection of steel. [ABSTRACT FROM AUTHOR]

In this study, glass fiber and flax fiber reinforced with epoxy and ZnO nanofiller were used to create composites utilizing the hand layup method. The purpose of this study is to develop a novel hybrid polymer‐matrix composite that can be employed in various application areas such as aerospace, sports, medical equipment, railways, etc. The fabricated composite was made with epoxy as a matrix material reinforced with nano‐ZnO, glass fiber, and flax fiber. Six fiber layers with varying fiber orientations were inserted into the matrix in a specific stacking order. The results show the maximum tensile, flexural, impact, and ILSS as the values of 264.74 MPa, 492.12 MPa, 595.72 J/m, and 50.05, respectively. Along with the mechanical properties, Physical characterization such as density, void content, thickness swelling, moisture content, and water absorption tests were conducted. FE‐SEM test was conducted to check the uniformity of nanoparticles in the matrix material and the breakdown of fibers. [ABSTRACT FROM AUTHOR]

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Frontal polymerization has great potential in complementing additive manufacturing processes such as direct ink writing as a continuous cure synchronized to the printing speed can overcome issues such as sagging. To study the incorporation of frontal polymerization into a potential printing process, a frontally polymerizable DGEBA epoxy resin has been developed for both UV and thermal initiation. Through frontal polymerization alone, full conversion is observed with a starting glass transition of 150°C for both initiation methods. Resulting thermal behavior is shown to have little dependence on either initiation irradiance or temperature utilized and much greater dependence on initiator concentration in the resin. Mechanical behavior is maximized by varying initiator concentration and cure conditions achieving tensile stress of 75 MPa and K1C of 1.2 MPa‐m1/2. Shelf stability of the resin proves promising with no viscosity change after 12 weeks of room temperature storage. Future studies will concern adapting the resin for both direct ink writing and continuous fiber additive manufacturing applications. Highlights: Frontal polymerization of EPON 826 using RICFPUtilized a tetrakis borate containing diaryliodonium cationic initiatorStable and polymerizable after 12 weeksResin printed and frontally cured using UV initiation [ABSTRACT FROM AUTHOR]

In this work, mild steel as a substrate was coated by electrodeposition in a bath mixed with nickel sulfate (NiSO4·6H2O), nickel chloride (NiCl4·6H2O), and boric acid (H3BO3) using nanocomposite cetyltrimethylammonium bromide, hBN, and epoxy with hardener. The experiments were designed using the Taguchi method through the L9 orthogonal array to reduce the number of experiments. The input parameters for the design of experiments were taken: the time (min), voltage (V), and the hBN concentration (wt-%). The coated samples were tested for their tribological, corrosion, and adhesion performance using pin-on-disc, electro-impedance spectroscopy, and cross hatch tester, respectively. The tribological results reveal that the coated sample of 3 wt-% hBN concentration at 3 mV voltage and 30-minute deposition time shows the lowest friction coefficient (∼0.42) among all the samples, indicating its superior wear resistance and corrosion resistance. Further, the same sample also outperformed the others, demonstrating the high adhesion (adhesion scale of 5 B) of coating with the substrate. Moreover, the surface was characterized using X-ray diffraction, Fourier transforms infrared, goniometer, and scanning electron microscopy. [ABSTRACT FROM AUTHOR]

The aim of this research was to develop a lightweight, asbestos-free brake friction material using sisal, jute, and sisal/jute hybrid composites along with fillers and frictional additives. Sisal, jute, and sisal/jute hybrid fiber–reinforced epoxy polymer-filler-based composites were prepared using a compression molding process, and their mechanical and tribological properties were evaluated as per ASTM standards. The results were compared with commercial brake friction material. The study found that the compressive strength of sisal, jute, and hybrid composites increased by 21%, 11.6%, and 16.65%, respectively, while the hybrid composite (S3 + J3) exhibited nearly equivalent compressive strength. The impact strength, hardness, and water and oil absorption behavior of the hybrid composite exhibited the same performance as that of commercial brake pads. A pin-on-disc experiment was conducted and the results showed that wear loss and coefficient of friction decreased with an increased weight percentage of fiber. Scanning electron microscopy images depicted uniform dispersion, distribution, and defect-free laminates with a uniform wear track. Overall results suggest the potential use of these composites in brake pad applications. Therefore, this study presents the development of sisal-jute fiber epoxy filler–based hybrid composites for lightweight applications, which can be used as a substitute for asbestos in brake pads. [ABSTRACT FROM AUTHOR]

A dual-material 3D printing technique is developed to rationally construct namrsilica/carbon black/epoxy (SiO2/CB/EP) composites through alternately arranging nano-silica/epoxy (SiO2/EP) composites with high strength and carbon black/epoxy (CB/EP) composites with high conductivity. According to the rheological properties, the epoxy composites with 11. 6 wt. % SiO2 and 10 wt. % CB exhibits excellent printability. A stable diameter of 400 μm was achieved through controlling the extrusion pressure and printing speed. The SiO2/CB/EP composites show an excellent manufacturing accuracy and a highly ordered 3D structure as verified by the optical and micro-CT images. The tensile, compres-sive and bending strengths of the SiO2/CB/EP composites were 35 MPa, 64 MPa and 120 MPa, respectively, indicating that there is no attenuation compared to those of the SiO2/EP composites. Moreover, the electromagnetic interference shielding effectiveness of the composites is as high as 25 dB on the basis of the microwave absorbing mechanism. [ABSTRACT FROM AUTHOR]

In this work, epoxy was added into commercial Sn-3.0Ag-0.5Cu (SAC305) solder paste to enhance the thermal cycling reliability of the joint. The microstructure and fracture surface were observed using a scanning electron microscope/energy dispersive spectrometer (SEM/EDS), and a shear test was performed on the thermally cycled joint samples. The results indicated that during the thermal cycling test, the epoxy protective layer on the surface of the epoxy-enhanced SAC305 solder joint could significantly alleviate the thermal stress caused by coefficients of thermal expansion (CTE) mismatch, resulting in fewer structural defects. The interfacial compound of the original SAC305 solder joints gradually coarsened due to the accelerated atomic diffusion, but epoxy-enhanced SAC305 solder joints demonstrated a thinner interfacial layer and a smaller IMC grain size. Due to the reduced stress concentration and the additional mechanical support provided by the cured epoxy layer, epoxy-enhanced SAC305 solder joints displayed superior shear performance compared to the original joint during the thermal cycling test. After 1000 thermal cycles, Cu-Sn IMC regions were observed on the fracture surfaces of the original SAC305 solder joint, exhibiting brittle fracture characteristics. However, the fracture of the SAC305 solder joint with 8 wt.% epoxy remained within the solder bulk and exhibited a ductile fracture mode. This work indicates that epoxy-enhanced SAC305 solder pastes display high thermal cycling reliability and could meet the design needs of advanced packaging technology for high-performance electronic packaging materials. [ABSTRACT FROM AUTHOR]

Europium-hydroxyapatite (Eu-HA) nanocomposite was developed via continuous hydrothermal synthesis. Eu+3 ions partially replaced the Ca+2 ions within hydroxyapatite molecular structure. High quality Eu-HA nanorods of 20 nm width and 6 μm lengths were verified via TEM micrographs. Eu-HA maintained the crystalline structure of HA with minimum change; material studio software confirmed the partial replacement of Ca+2 by Eu+3. XPS analysis demonstrated Eu+3 content of 6.91 atom %. Ca/P ratio was found to be 1.405 and 0.118 for virgin HA and Eu-HA respectively; this was ascribed to the partial replacement of Ca+2 with Eu +3. The EDAX mapping verified the uniform dispersion of Eu ions within Eu-HA structure. Eu-HA nanocomposite was uniformly distributed in silica sol-gel matrix; subsequently it was applied on AZ31 magnesium alloy. The corrosion performance of Eu-HA sol-gel coating nanocomposite (Eu–S) was evaluated using different electrochemical techniques including Potentiodynamic Polarization (PDP), Electrochemical Impedance Spectroscope (EIS), and Electrochemical Noise (EN) in aerated 0.1 M NaCl solution. Corrosion protection was assessed to that of neat silica sol-gel coating (NSG). Pitting was detected over the whole NSG coated sample, after few hours of immersion in the corrosive solution. EuS coated AZ31 withstand up to 144 h without any sign of corrosion or delamination. EIS analysis with PDP parameters suggested the formation of protective layer; that is responsible for the corrosion resistance. Europium has unique ability to form a protective oxide layer acting as a barrier layer that could prevent the penetration of corrosive electrolyte to the underlying metal substrate. [ABSTRACT FROM AUTHOR]

This study investigates the impact of Acacia catechu (AC) gum filler at various volume percentages (5%, 10%, 15%, 20%, 25%, 30%, and 35%) on the mechanical and dynamic mechanical behaviour of epoxy composites. The AC filler was subjected to ball milling and subsequent reinforcement with epoxy resin through ultrasonication. The results indicate that incorporating up to 20% v/v of Acacia catechu gum filler into the epoxy resin enhances the tensile strength (16.12 MPa), flexural strength (14.36 MPa), fracture toughness, and low-velocity impact strength of the composite material. However, exceeding 20% volume fraction of the filler diminishes the mechanical properties. Viscoelastic properties were evaluated using a dynamic mechanical analyser, revealing that incorporating up to 20% Acacia catechu improves the storage modulus and decreases the damping factor. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were employed for characterisation. FTIR spectroscopy identified O–H groups from cellulose, represented by a broad peak at 3567 cm−1 in AC. A peak at 3400 cm−1 in 20% AC blended epoxy suggests intramolecular and intermolecular hydrogen bonding interactions, with -OH groups from AC particles serving as catalysts. Morphological behaviour of the fibre with epoxy was examined through SEM analysis. [ABSTRACT FROM AUTHOR]

There has been great interest in developing high‐performance, sustainable and eco‐friendly materials. This study presents an innovative development and research of the mechanical properties of dog bone–reinforced epoxy composites to determine their suitability for biomedical applications. Good surface compatibility for the matrix and reinforcement was the target, complementing the structural compatibility needed for such applications. Hand‐lay open mould technique was used to fabricate the composites with varying weight percentage of dog bone particles (DBPs), and mechanical properties (tensile strength, Young's modulus, percentage elongation and flexural strength) were determined. The results show that the developed composites' mechanical properties were enhanced, and the tensile strength of 21.10 MPa–27.97 MPa, Young's modulus of 1531.00 MPa–1732.90 MPa, ductility of 2.10%–2.60% and flexural strength of 27.53 MPa–35.67 MPa were recorded for the biocomposites. Energy‐dispersive X‐ray spectroscopy (EDS) revealed the main elements' contents of the DBPs as calcium (50.3%), carbon (20.77%) and oxygen (11.76%). Scanning electron microscopy (SEM) examination of the fractured surfaces revealed the homogeneous distribution of the dog bone particulates within the epoxy matrix, which caused the property enhancement. The findings of this research underline the potency of processed animal waste as filler materials. [ABSTRACT FROM AUTHOR]

Highlights This study meticulously investigated the effect of two carbon allotrope nanofillers, two‐dimensional graphene nanoplatelets (GnPs) and one‐dimensional multi‐wall carbon nanotubes (MWCNTs) individually, at various loadings on the kinetics of curing of the epoxy (EP)/vinyl ester (VE) based interpenetrating polymer network (IPN) system, with a mass ratio of 1:1. The IPN system is including a liquid epoxy resin based on bisphenol A which has been cured by methyltetrahydrophthalic anhydride (MTHPA) in the presence of 1‐methyl imidazole (Mi) as an accelerator and a vinyl ester resin based on bisphenol A which has been cured by methyl ethyl ketone peroxide (MEKP). The curing behavior of all prepared nanocomposites under non‐isothermal conditions was studied using DSC at four heating rates. Two different isoconversional approaches were applied to evaluate the reaction kinetics, that is, the Friedman and the advanced Vyazovkin methods. The obtained activation energy curves for all samples revealed a complex curing behavior involving three stages: early IPN stage, IPN growth stage, and late IPN stage. Then, the activation energy values for each reaction step were determined based on the Friedman method. The presence of GnPs showed no catalytic effect on the reaction of VE with MEKP. In contrast, incorporating MWCNT nanoparticles considerably decreases the activation energy values of the reaction of ring opening of epoxides with MTHPA‐Mi and the reaction of esterification of the hydroxyl groups of VE with MTHPA. MWCNTs reduce activation energy in curing reactions for EP/MTHPA‐Mi and VE/MTHPA. GnPs do not catalyze VE/MEKP reaction unlike MWCNTs. Combining MWCNTs and GnPs enhances properties of IPN nanocomposites. Curing process includes early, growth, and late IPN stages impacting activation energy. SEM analysis reveals better dispersion of GnPs in IPN nanocomposites with MWCNTs. [ABSTRACT FROM AUTHOR]

A precise prediction of the cure-induced shrinkage of an epoxy resin is performed using a finite element simulation procedure for the material behaviour. A series of experiments investigating the cure shrinkage of the resin system has shown a variation in the measured cure-induced strains. The observed variation results from the thermal history during the pre-cure. A proposed complex thermal expansion model and a conventional chemical shrinkage model are utilised to predict the cure shrinkage observed with finite element simulations. The thermal expansion model is fitted to measured data and considers material effects such as the glass transition temperature and the evolution of the expansion with the degree of cure. The simulations accurately capture the exothermal heat release from the resin and the cure-induced strains across various temperature profiles. The simulations follow the experimentally observed behaviour. The simulation predictions achieve good accuracy with 2–6% discrepancy compared with the experimentally measured shrinkage over a wide range of cure profiles. Demonstrating that the proposed complex thermal expansion model affects the potential to minimise the shrinkage of the studied epoxy resin. A recommendation of material parameters necessary to accurately determine cure shrinkage is listed. These parameters are required to predict cure shrinkage, allow for possible minimisation, and optimise cure profiles for the investigated resin system. Furthermore, in a study where the resin movement is restrained and therefore able to build up residual stresses, these parameters can describe the cure contribution of the residual stresses in a component. [ABSTRACT FROM AUTHOR]

This study focuses on enhancing the thermal properties and shape recovery performance of shape memory polymers (SMPs) through the application of carbon-based fillers. Single and mixed fillers were used to investigate their effects on the glass transition temperature (Tg), thermal conductivity, and shape recovery performance. The interaction among the three-dimensional (3D) structures of mixed fillers played a crucial role in enhancing the properties of the SMP. These interactions facilitated efficient heat transfer pathways and conserved strain energy. The application of mixed fillers resulted in substantial improvements, demonstrating a remarkable 290.37% increase in thermal conductivity for SMPCs containing 60 μm carbon fiber (CF) 10 wt% + graphite 20 wt% and a 60.99% reduction in shape recovery time for SMPCs containing CF 2.5 wt% + graphite 2.5 wt%. At a content of 15 wt%, a higher graphite content compared to CF improved the thermal conductivity by 37.42% and reduced the shape recovery time by 6.98%. The findings demonstrate that the application of mixed fillers, especially those with high graphite content, is effective in improving the thermal properties and shape recovery performance of SMPs. By using mixed fillers with high graphite content, the performance of the SMP showed significant improvement in situations where fast response times were required. [ABSTRACT FROM AUTHOR]

In this paper, new epoxy resin/rubber powder/hollow beads three-phase composites were prepared by designing the incorporation of fly ash hollow beads with different mass fractions (5%, 10%, 15%, and 20%) as new reinforcing phases into epoxy resin/rubber powder two-phase composites with 5% mass fraction of carbon black rubber powder. Quasi-static compression tests were conducted at room temperature to test the compressive properties of the oxygen resin/rubber powder/hollow beads composites. Calculate the energy absorption properties and energy absorption efficiency of the composites from the compression curves. Fracture characteristics of compressed material specimens with microscopic morphology were observed by scanning electron microscopy. By systematically analyzing the effect of fly ash hollow beads content on the mechanical properties of epoxy resin/rubber powder/hollow beads three-phase composites, it was found that fly ash hollow beads as reinforcing materials can effectively improve the brittleness and yield strength of epoxy resin/rubber powder as well as the energy-absorbing properties and efficiency of the composites. The energy absorption properties of the epoxy resin/rubber powder/hollow beads composites increased and then decreased with the increase in the mass fraction of fly ash hollow beads. In the epoxy resin/rubber powder/hollow beads composites, the most significant performance was observed when the mass fraction of fly ash was 10%. [ABSTRACT FROM AUTHOR]

The presented study provides an overview of the current research achievements and the emerging market of bio-based thermosetting polymers. Environmental attributes related to bio-based polymers trigger a steadily growing interest in this novel and promising field. Due to their importance among thermosets in terms of composite applications and quantity, this review focusses on epoxy and unsaturated polyester resins. Current studies are mainly concerned with alternative renewable raw materials to substitute fossil content and their synthesis to improve their end-properties. A common target is the increase of bio-based content within the cured resin. In spite of today's efforts in research, the recent market review reveals only few commercially available bio-based thermosetting resin systems. However, they are commonly suited for a broad variety of processing methods and applications with bio-contents up to 75%. [ABSTRACT FROM AUTHOR]

Dimethylformamide (DMF), a polar solvent, is commonly used for preparing graphene/epoxy nanocomposites. While previous research has commonly predominantly highlighted the improvement in physio-mechanical properties of these nanocomposites, the effect of DMF on processing and its direct influence on the final characteristics of MXene/epoxy nanocomposites have not been investigated. This unexplored link between DMF dosage, MXene concentrations, and the final composite properties presents an exciting direction for future research. In this study, a fixed dosage of DMF was used with varying MXene concentrations to fabricate the nanocomposites. To assess the reliability of DMF dosage on the characteristics of the fabricated nanocomposites, various evaluation techniques were employed, including dispersion evaluation, mechanical tests, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), electromagnetic interference (EMI) shielding, and surface roughness measurements. The research outcomes revealed that as MXene concentration increased, the characteristics of the MXene/epoxy nanocomposites, improved across the board, indicating their potential for use in energy storage applications. [ABSTRACT FROM AUTHOR]

The production of multipurpose sustainable fillers is a matter of great interest, and biochar can play a pivotal role. Biochar is a biomass-derived carbon source that can act as a versatile platform for the engineering of fillers as neat or functionalized materials. In this work, we investigate the utilization of 800 °C annealed Miscanthus-derived biochar as a filler for the production of epoxy composites with promising mechanical and electrical properties. We also used it in the production of an iron-rich hybrid filler in order to fine-tune the surface and bulk properties. Our main findings reveal that hybrid composites containing 20 wt.% biochar exhibit a 27% increase in Young's modulus (YM), reaching 1.4 ± 0.1 GPa, while the ultimate tensile strength (UTS) peaks at 30.3 ± 1.8 Mpa with 10 wt.% filler, a 27% improvement over pure epoxy. However, higher filler loadings (20 wt.%) result in decreased UTS and maximum elongation. The optimal toughness of 0.58 ± 0.14 MJ/m³ is observed at 5 wt.% filler content. For organic composites, YM sees a notable increase of 90%, reaching 2.1 ± 0.1 Gpa at 20 wt.%, and UTS improves by 32% with the same filler content. Flexural tests indicate an enhanced elastic modulus but reduced maximum elongation as filler content rises. Electromagnetic evaluations show that hybrid fillers maintain a primarily dielectric behavior with a negligible impact on permittivity, while biochar–epoxy composites exhibit increased conductivity at higher filler loadings, suitable for high-frequency applications. In light of these results, biochar-based fillers demonstrate significant potential for enhancing the mechanical and electrical properties of epoxy composites. [ABSTRACT FROM AUTHOR]

The mining and steelmaking industries, while vital for economic and social development, produce and dispose of waste that contributes to environmental instability and discomfort. In this context, this study aimed to develop novel polymer composites intended for Artificial Ornamental Stone (AOS) application by incorporating iron ore tailings (IOTs), quartzite waste (QTZ), and steel slag (SS) into an epoxy (EP) matrix. The chemical, mineralogical, physical, mechanical, morphological, and thermal properties of the materials were assessed. Three waste mixtures were proposed using the Modified Andreassen Curve method, each with 35, 45, and 55 v/v% of EP. The composite properties were evaluated, showing that the composite with QTZ, SS, and 55 v/v% EP exhibited the lowest porosity (0.3%), water absorption (0.1%), and highest flexural strength (41 MPa). The composite containing the three wastes with 55 v/v% EP presented 1.0% porosity, 0.4% water absorption, and 34 MPa flexural strength. Lastly, the composite with IOTs, QTZ, and 55 v/v% EP exhibited 1.1% apparent porosity, 0.5% water absorption, and 23 MPa flexural strength. Therefore, the polymer composites developed with IOTs, QTZ, SS, and EP demonstrated suitable properties for wall cladding and countertops, presenting a potentially sustainable alternative to reduce environmental impacts from the mining and steelmaking industries. [ABSTRACT FROM AUTHOR]

Objective: In this study, the developed bioactive dental implant (BDI) from epoxy resin (ER), hydroxyapatite (HA), and curcumin nanoparticles (CUNPs). Materials and methods: The prepared BDI were characterized using their physicochemical, mechanical, antimicrobial, bioactive, and biocompatibility study. The scanning electron microscopy (SEM) morphology of the BDI was observed HA mineralized crystal layer after being immersed in the stimulated body fluids (SBF) solution. Results: The mechanical properties of the BDI exhibited tensile strength (250.61 ± 0.43 MPa), elongation at break (215.66 ± 0.87%), flexural modulus (03.90 ± 0.12 GPa), water absorption (05.68 ± 0.15%), and water desorption (06.42 ± 0.14%). The antimicrobial activity of BDI was observed in excellent zone of inhibition against the gram-negative (15.33 ± 0.04%) and gram- positive (15.98 ± 0.07%) bacteria. The biocompatibility study of BDI on osteoblasts cell line (MG-63) was analyzed using MTT (3-[4, 5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. The results were observed 85% viable cells present in the BDI compared to the control (only ER) samples. Conclusions: Based on the research outcome, the BDI could be used for biomaterials application, particularly tooth dental implantation. [ABSTRACT FROM AUTHOR]

Abstract Epoxy is a widely used thermosetting resin recognized for its exceptional performance in adhesives, coatings, and various other applications, attributed to its high tensile strength, stiffness, electrical performance, and chemical resistance. Epoxy-clay nanocomposites are extensively employed across diverse industries. The physical and chemical properties of these nanocomposites are influenced by the processing methods, clay modifiers, and curing agents used during their preparation. In this study, epoxy/nanoclay composites based on Diglycidyl Ether Bisphenol-A (DGEBA) will be cross-linked using Isophorone Diamine (IPD), a cycloaliphatic amine, and Triethylenetetramine (TETA), a linear aliphatic amine. The initial phase of the research will assess the impact of different types of cross-linkers, both individually and in combination at various molar ratios (such as Isophorone Diamine: Triethylenetetramine (IPA: TETA) / 25:75 and 75:25), on the compressive strength of the epoxy mortar. In the subsequent phase, the epoxy formulation with an Isophorone Diamine: Triethylenetetramine (IPD: TETA / 75:25), which demonstrates the highest compressive strength, will be selected for further investigation. This formulation will be used to evaluate the effects of different weight percentages (3%, 5%, and 7%) of organically modified montmorillonite (OMMT). The prepared epoxy composites will be characterized using a range of techniques, including Fourier Transform Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). The epoxy/nanoclay composite with an IPD: TETA / 75:25 and 3 wt % OMMT is expected to show the highest compressive strength, which is 94 MPa.

Natural fibers play a crucial role in sandwich composites due to their biodegradability, ease of manufacturing, and ability to reduce pollution. The research aims to develop new biodegradable polymer composites using pine tree leaves (PTL) fillers loaded with epoxy through hand layup technique with different wt. % of PTL fillers. The molded composites were characterized to analyze the crystal size and plane orientations, surface morphology, thermal resistance, and presence of elemental compositions in the PTL filler-loaded epoxy composites through X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Energy dispersive analysis (EDX), Differential scanning calorimetry (DSC), and Thermogravimetric analysis (TGA). The 40 wt % of PTL epoxy composites showed a maximum tensile strength of 32 ± 0.5 MPa, a compressive strength of 15 ± 0.5 MPa, a flexural strength of 55 ± 0.5 MPa, and a Shore D hardness of 73 ± 0.5 SHN. The mechanical strength of 40 wt% PTL fillers loaded epoxy composite was enhanced by adding a single and double layer of E-glass fiber on the bottom and top of the PTL fillers loaded epoxy composite, achieving a maximum tensile strength of 76 ± 0.5 MPa. The 40 wt% PTL fillers loaded double E-glass fiber on the bottom and top of the PTL fillers loaded epoxy sandwich composite attained the maximum tensile strength of 156 ± 0.5 MPa, compressive strength of 29 ± 0.5 MPa, flexural strength of 220 ± 0.5 MPa, and Shore D hardness of 79 ± 0.5 SHN. The PTL fillers loaded and reinforced double E-glass fiber epoxy sandwich composite would be used in low-strength structural applications.

This study explores the effect of hybridization of both resin and reinforcement on mechanical properties of jute/cotton fiber-reinforced epoxy/polyester composite materials. Tensile, bending, and Charpy impact tests were conducted on the composites. Mechanical properties of the composites were observed to increase after hybridization. For reference, tensile strength of jute/epoxy/polyester and cotton/epoxy/polyester hybrid composites was observed to be 10.06% and 12.25% higher than jute/epoxy and cotton/epoxy composites, respectively. The existence of an interpenetrating polymer network between the two resins during hybridization causes enhancement in mechanical properties. The materials have applications in automobiles and aerospace due to their lightweight and improved strength. [ABSTRACT FROM AUTHOR]

Epoxy resins are widely used for their strength, chemical resistance, and adhesion, but they are naturally brittle. The objective of this study was to investigate the effects of the addition of a polyurethane (PU) base (polyol) and liquid silicone rubber (LSR (as toughening agents to the epoxy resin. This research focuses on developing a modified flexible epoxy resin by added the toughening agents to epoxy resin was evaluated in various weight ratios (3%, 6%, 9%, and 12%) with (1-methylethyl-1,1'-biphenyl, izoforon diamine) as a hardener. To evaluate the impact of strengthening materials, epoxy samples were tested before and after the addition the toughening agents above. Surprisingly, the mechanical properties exhibited significant improvement according to the results. In case of LSR/Epoxy, (tensile modulus, tensile strength, fracture toughness, and impact strength) were modified at 6wt% LSR. In case of PU/Epoxy, a mechanical property was modified depending on the addition percentage of PU. In conclusion, the 6wt% LSR is the best ratio to modified epoxy. In comparing to PU, each percentage modify a specific property, this difference take place because of the soft elastic flexible nature of PU.

Anticorrosion coatings are specialized products designed to protect metal surfaces from costly and dangerous corrosion, acting as barriers against corrosive organisms. Therefore, this study examined the physical and mechanical properties of epoxy resin in the presence of reactive diluents. Reactive diluents were synthesized based on styrene (St) and glycidyl methacrylate (GMA) through the free radical method using benzoyl peroxide (BPO) as a catalyst with various feed ratios of St and GMA. Diluents were characterized by Fourier Transform Infrared (FTIR) spectroscopy and Thermogravimetric Analyzer (TGA). Epoxy resins and hardener were at a ratio of 1:1, 1:0.5, and 1:0.3, respectively. The results showed that reactive diluents [Poly(St-co-GMA)] had an excellent dilution effect on epoxy resin with a decrease in epoxy resin viscosity from 8592 mPa-s to 1656, 680, and 430 mPa-s. Furthermore, the adhesion, tensile, and hardness properties contained 70% GMA and 30% St at a hardener ratio of 1:0.3. The increase in the mechanical properties was attributed to the reaction between modified epoxy resins with hardener.

In this study, epoxy/graphite composites were fabricated based on different weight fractions (0, 3, 6, and 9 wt.%) of graphite powder for bearing applications. The mechanical and tribological properties were assessed. Adhesive wear tests covered the severe regions, where the interface temperature (IFT) exceeded the heat distortion temperature (HDT) of the epoxy. Graphite additions improved elastic modulus and hardness but decreased fracture strain and toughness of the composites. The tribological behaviors in the mild wear region were improved as the graphite content increased. In the mild wear region, the increase in graphite additions showed a good improvement by reducing the specific wear rate (SWR) and coefficient of friction (COF). In the severe wear region, the neat epoxy and higher graphite concentrations exhibited a dramatic increase in SWR, whereas the lowest addition of 3 wt.% exhibited good wear performance. For epoxy, the reason was that IFT exceeded its HDT, while the aggregation of graphite particles was the main reason in the case of higher graphite concentrations. SEM examinations showed severe wear signs—high ploughing and fracture—when IFT exceeded the HDT. However, by reducing the IFT, graphite additions did not show such severe wear features due to the accelerated heat dissipation.

The present study aims to assess the impact of alfa and date palm natural fibers as reinforcement for epoxy, vinyl ester, and polyimide polymer (AlfaDate palm/epoxy, Alfa-Date palm/vinyl ester, and Alfa-date palm/polyimide) through a genetic approach. The study employs a genetic simulation rooted in the Weibull formalism, employing genetic operators such as selection, crossing, and mutation for a nuanced evaluation of the damage at the fibermatrix interface across the studied materials. The genetic algorithm results authentically capture the intrinsic behaviour of these materials, emphasising key mechanical properties like Young's Modulus, deformation, and stress at break. The obtained results highlight that the matrix showing the highest Young's modulus value at its fiber-matrix interface exhibits superior strength. These conclusions align with contemporary advancements in natural fiber-reinforced composite materials tailored for diverse industries and eco-friendly applications.

The current work aims to develop a new composite-based epoxy doped with calcinated clay for low and intermediate gamma-ray energy applications. The increased calcinated clay material concentration between 0 and 60 wt% enhances the constructed composites by 21.07%, from 1.139 ± 0.011 to 1.379 ± 0.013 g·cm−3. Moreover, new bonds have appeared in Fourier transform infrared analyses of fabricated composites, which confirm the diffusion and interactions between the calcinated clay material and epoxy resin. Furthermore, the impacts of the calcinated clay on the gamma-ray shielding properties were examined experimentally using the NaI (Tl) detector over an energy interval changing from 33 to 1,408 keV. The experimental examinations depict that the addition of calcinated clay with concentrations between 0 and 60 wt% enhances the developed composites’ linear attenuation coefficient by 67.9%, 24.5%, 35.9%, and 46.0% at gamma-ray energies of 81, 662, 1,275, and 1,408 keV, respectively. The improvement in the linear attenuation coefficient leads to a decrease in the required half-value layer for each composite, where it decreased between 4.82–3.87 cm (at 662 keV) and 7.63–5.22 cm (at 1,408 keV).