Remarkable enhancement of physical‐mechanical properties in unsaturated polyester resin composites using SiO ₂ @ CTBN hybrid particles

Abstract To improve the toughness of unsaturated polyester resin (UPR), core‐shell particles with a silica core and carboxyl‐terminated butadiene acrylonitrile (CTBN) rubber shell were synthesized and added to the UPR at 2, 5, and 10 wt%. Impact, tensile, bending, and dynamic mechanical analysis (DMA) were performed on the pure UPR and composites containing core‐shell particles (UPR/CSR). The impact analysis indicated that the addition of 2 wt% CSR particles increased the toughness by 34% compared to that of the pure UPR. However, due to the low modulus of the rubbery shell, the tensile, bending, and elastic moduli of the UPR/CSR composite decreased. To enhance the physical and mechanical properties of the UPR/CSR composite, a hybrid composite of UPR/CSR and gamma‐alumina (γ‐Al₂O₃) (as a regulator and reinforcer of the network) was manufactured, resulting in remarkable enhancements in the physical and mechanical properties. Additionally, variations in the curing kinetics of the pure UPR and UPR/CSR 2 composite at four heating rates were investigated for a more detailed examination of changes in the structure of the resin network. Highlights Synthesis of SiO ₂ @CTBN particles and fabrication of UPR/CSR composite. Significant increase in toughness of UPR/CSR composite compared to UPR resin. Significant increase in physical and mechanical properties of hybrid composite. Investigation of network structure and curing kinetic of UPR resin by DSC.