Synthesis and characterization of exfoliated poly(styrene-co-methyl methacrylate)/clay nanocomposites via emulsion polymerization with AMPS

Abstract

A method was described for synthesis of exfoliated poly(styrene-co-methyl methacrylate)/clay nanocomposites through an emulsion polymerization with reactive surfactant, 2-acrylamido-2-methyl-1-propane sulfonic (AMPS) which made the polymer end-tethered on pristine Na-MMT. AMPS widened the gap between clay layers and facilitates comonomers penetrate into clay. Silicate layers affect the composition of comonomers, for example A0.3M10S10T5 showed the elevated composition of MMA end tethered on silicate when compared to the feed ratio and polar methyl methacrylate (MMA) was considered to have the stronger interaction with clay layers than styrene. The exfoliated structure of extracted nanocomposite was confirmed by XRD and transmission electron microscopy. The onset of thermal decomposition for nanocomposites shifted to a higher temperature than that for neat copolymer. The dynamic moduli of nanocomposites increase with clay content. Dynamic storage modulus and complex viscosity increased as the clay content increased. In low frequency region all prepared nanocomposites exhibited apparent low-frequency plateaus in the linear storage modulus. Complex viscosity showed shear-thinning behavior as the clay content increases.