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This study investigates the performance of vinyl ester composites reinforced with areca fruit fiber, microcrystalline cellulose, and silane coupling-grafted recycled PET bottle waste foam under conditions of water and heat-accelerated aging. The reinforcement, areca fiber and recycled PET foam were surface-modified using 3-aminopropyltrimethoxysilane (3-APTMS) to enhance interfacial bonding. The composites were fabricated using a manual hand layup process and subjected to aging tests. According to results the APS2 composite had enhanced heat conductivity at 0.17W/mk and decreased flame propagation speed at 10.99mm/min after being exposed to saltwater. Similarly, after being exposed to rainwater, the ARP2 composite developed a temperature conductivity of 0.16W/mk, a flexural strength of 80.3MPa, a tensile strength of 37.4MPa, and a flame propagation speed of 10.97mm/min. SEM analysis of silane-treated vinyl ester composites reinforced with areca fibers and microcrystalline cellulose reveals improved interfacial bonding and filler dispersion, enhancing the composite’s mechanical integrity. These findings confirm that the application of silane coupling agents significantly enhances the thermal stability, water resistance, and overall durability of the composites, making them suitable for demanding applications requiring high mechanical strength, effective thermal management, and robust fire resistance, particularly under challenging environmental conditions.

This study investigates the mechanical, fatigue, water absorption, and flammability properties of polyethylene terephthalate (PET) core-pineapple fiber sandwich composites reinforced with silane-treated neem fruit husk (NFH) biosilica additives. The novel approach includes modifying the fiber’s surface and incorporating biosilica to enhance environmental resistance. The composites were prepared using a hand layup method, followed by silane treatment of the biosilica, pineapple fiber, PET core and vinyl ester resin. Subsequently, to evaluate environmental impacts on composite’s performance, sandwich composites were subjected to temperature aging at 40^∘C and 60^∘C in a hot oven for 30 days and warm water aging at the same temperatures in tap water with pH 7.4. According to the results, adding 1%, 3%, and 5 vol.% silane-treated biosilica significantly improved the mechanical properties. The composite with 3% biosilica (L2) showed a tensile strength of 120.8MPa, flexural strength of 194.4MPa, compression strength of 182.4MPa, rail shear strength of 20.21MPa, ILSS of 23.14MPa, hardness of 85 Shore-D, and Izod impact strength of 6.56 J. Even under temperature and water aging conditions, the composites showed only minimal reductions in properties, highlighting the efficacy of the silane treatment. The temperature-aged L2 composite had a tensile strength of 104MPa, flexural strength of 172.8 MPa, compression strength of 164MPa, and ILSS of 22.5MPa, while the water-aged L2 composite exhibited a tensile strength of 96MPa, flexural strength of 152.8MPa, compression strength of 146.4MPa, and ILSS of 21.4MPa. Scanning electron microscope (SEM) analysis confirmed uniform dispersion of biosilica particles, critical for improved performance, though higher concentrations led to agglomeration and stress points. The composites also demonstrated excellent flame retardancy, maintaining a UL-94 V-0 rating with decreased flame propagation speeds, specifically 9.05mm/min for L2. These findings underscore the potential of silane-treated biosilica as a reinforcing additive to enhance the durability and performance of composites in adverse conditions.

Ethylene Propylene Diene Monomer (EPDM) composites filled with 0–400 phr ${\mathrm{\text{PbWO}}}_4$ (PWO) were prepared by conventional process using a two-roll mill. Surface treatment of the fillers coated with KH570 was conducted to enhance the wettability and lubrication of fillers in the polymer matrix. According to SEM images and mechanical test, both micro- and submicro-fillers disperse homogeneously in the matrix, and adhesion of submicro-fillers to the matrix is stronger than that of micro-fillers. The submicro-PWO composites had better tensile strength and elongation at break than those composites containing micro-PWO powder, but a relatively higher hardness. The photon shielding test was performed to determine the radiation shielding properties of these composites, which showed that attenuation of gamma-rays for the submicro-PWO composites was substantially enhanced compared to micro-PWO reinforced composites.

This experiment chooses A356 aluminum matrix composites containing 55% SiC particle reinforcing phase as the parent metal and Al–Si–Cu–Zn–Ni alloy metal as the filler metal. The brazing process is carried out in vacuum brazing furnace at the temperature of 550°C and 560°C for 3 min, respectively. The interfacial microstructures and fracture surfaces are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy spectrum analysis (EDS). The result shows that adequacy of element diffusion are superior when brazing at 560°C, because of higher activity and liquidity. Dislocations and twins are observed at the interface between filler and composite due to the different expansion coefficient of the aluminum alloy matrix and SiC particles. The fracture analysis shows that the brittle fracture mainly located at interface of filler and composites.

In this study, a novel AA7075-TiO₂ metal matrix composite was machined utilizing a biosilica mixed EDM technique and the surface roughness and material removal rate are optimized. The biosilica particles are produced from waste maize cobs and then silane-treated. The optimization of process variables wasperformed using Taguchi grey relational approach with a process variable of peak current, gap voltage and pulse-on time. Results revealed that the gap voltage is the most important process variable, since it has a larger max-min difference of 0.25. In order to create a high MRR of 11.6mm³/min and a surface roughness of 2.25 m, the maximum GRG of 0.79 for Trial 1 (A2B1C3) represents the most ideal process variable group. The best results appear to be obtained with a peak current of 10 A, a gap voltage of 20V, and a pulse-on time of 140$\mu$s. The new GRG, however, is around 2.51% better than the anticipated optimized process variables of A2B1C3 with an old GRG of 0.79, according to the confirmation research. The new MRR of 11.89mm³/min and the surface roughness of 2.30s with a GRG of 0.81 are based on the optimized new process variables (A1B1C3).