Investigation on the physicochemical properties of poly (ethylene-co-vinyl acetate)/mesoporous silica nanocomposites: Effects of content and surface functionalization

Abstract

In this study, poly (ethylene-co-vinyl acetate)/mesoporous silica EVA/SBA-15 nanocomposites, containing 0.5, 1.5, and 2.5 wt% of unfunctionalized and functionalized SBA-15 were prepared by melt blending in an internal mixer. Mesoporous silica was synthesized through the sol-gel method and modified by hexadecyltrimethoxysilane (HDTMS). Several characterizations were performed; including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), mechanical properties, dynamic mechanical analysis (DMA), and dielectric study to characterize the physicochemical properties of elaborated materials. The results revealed the successful synthesis and functionalization of mesoporous silica, as confirmed by the FTIR and SEM. The crystallinity of the nanocomposites decreased and the elastic modulus increased with the incorporation of the mesoporous silica. Measurement of tensile properties shows that the tensile strength of the nanocomposite content of 1.5 wt% F-SBA-15 is 17.2% is higher as compared to pure EVA. DMA analysis validates the improvement in mechanical properties of the EVA/SBA-15 samples. SEM images displayed well-dispersed F-SBA-15 nanoparticles and enhanced interfacial adhesion between the phases. TGA indicates the enhancement of the thermal stability of nanocomposites as compared with the pure EVA matrix. The surface functionalization presented an approach to preparing nanocomposites with enhanced thermal stability and a low dielectric constant.