Poly(methyl methacrylate-co-styrene)/silicate nanocomposites synthesized by multistep emulsion polymerization

Abstract

Exfoliated poly(methyl methacrylate-co-styrene) [P(MMA-co-ST)]/silicate nanocomposites were synthesized through a multistep emulsion polymerization. The methyl methacrylate monomers were polymerized first and then the styrene monomers were polymerized. The nanocomposites had core-shell structures consisting of PMMA (core) and PS (shell); these structures were confirmed by H-1 NMR spectroscopy and TEM, respectively. P(MMA-co-ST) copolymers showed two molecular weight profiles and two glass transition temperatures (T-g) in GPC and DMA measurements. At 30 degreesC, the nanocomposites exhibited 83 and 91% increases in their storage moduli relative to the neat copolymer because the silicate layers were dispersed uniformly in the polymer matrix.