Enhancing toughness and thermomechanical properties of random 3D E-glass fibre/epoxy composites through epoxy resin modification using APTMS

In this study, γ-Aminopropyl trimethoxy silane (APTMS) was incorporated into epoxy resin to enhance the adhesion between E-glass fibres and the epoxy matrix, and to improve the thermomechanical properties of the resulting composite. Composite samples containing 3D randomly oriented short glass fibres were fabricated using a cast-in-place method followed by vacuum processing. Scanning Electron Microscopy (SEM) analysis confirmed improved interfacial bonding between the E-glass fibres and epoxy due to APTMS treatment. Dynamic Mechanical Thermal Analysis (DMTA) revealed that the storage modulus increased by 78.32% as compared to that of unmodified composite. The glass transition temperature (Tg) increased to 88.41 °C, relative to 73.63 °C for unmodified composite. The loss factor (tan delta) increased by approximately 11.42% as compared to that of unmodified composite. Thermogravimetric Analysis (TGA) indicated enhanced thermal stability within the temperature range of 25 °C to 300 °C. The ultimate flexural and tensile strengths improved by approximately 61.32, and 73.25% as compared to that of unmodified composite, respectively, at the optimal concentration (4 wt% APTMS). Finally, a numerical model based on the finite element method (FEM) simulation was established to model the glass-epoxy interfacial and flexural behavior of the fabricated composite.