Optimization of mechanical properties of epoxy-based hybrid nanocomposite: Effect of using nano silica and high-impact polystyrene by mixture design approach

Abstract

Epoxy resins have tight three-dimensional molecular network structures; because of this reason, these materials are brittle in nature and have pore resistance in front of crack propagation. In the present study, to overcome this issue, the optimized mixture proportions of epoxy-based hybrid nanocomposite with different composition of nano silica as nano reinforcement, high-impact polystyrene as thermoplastic phase and hardener were determined by applying the simplex-centroid mixture design method to achieve the ultimate tensile, flexural, compression and impact strength. Results revealed that the best mixture occurs in 2.67wt.% of HIPS, 4.01wt.% of nano SiO2 and 28phr of hardener. Experimental results indicate that new ternary nanocomposite improved ultimate tensile, compression and impact strength up to 59.5%, 45% and 414% compared to those of the neat epoxy resin respectively, although they did not show enhanced flexural strength. The tensile and flexural elongations at break were improved up to 71% and 83% larger than those of neat epoxy, respectively, but compression strain did not change considerably. Correlation between the morphology of the nanocomposite and its mechanical properties was noted when using the SEM technique. EDX analysis used to indicate homogeneous combination of Silica nano particles in matrix and show solvent evaporated completely under vacuum situation.