Enhancing Glass Transition Temperature of Poly(methylmethacrylate) by Incorporating Methacrylate-Functional Silane Grafted SiO2 Nanoparticles

Abstract

Nanocomposites attract the attention of researchers due to the increasing demand on materials having unique properties. Incorporation of nanoparticles into polymers considerably improves some materials properties such as thermal stability. In current study, PMMA/SiO₂ hybrid nanocomposites including ungrafted and grafted silica nanoparticles have been prepared. The surfaces of SiO₂ nanoparticles were grafted with 3-(methacryloyloxypropyl)trimethoxysilane (MPTS) and 3-(methacryloyloxypropyl)triethoxysilane (MPTES) by sol-gel technique. The structure, morphology and thermal properties of the obtained bulk materials were investigated by FTIR, SEM-EDX, TGA and DSC. Based on the studies of infrared spectroscopy, polymerization of MMA monomers was approved by following the intensity of acrylate group. Thermal characteristics of nanocomposite structures enhanced remarkably as SiO₂ nanoparticles were introduced to the polymer matrix and glass transition temperature T_g value reached to the highest (166°C) for MPTES@20% SiO₂-PMMA hybrid nanocomposite. According to SEM analysis, the most homogenous structure belonged to MPTES@20% SiO₂-PMMA hybrid nanocomposite.