Preparation of highly exfoliated and transparent polycarbonate/clay nanocomposites by melt blending of polycarbonate and poly(methyl methacrylate)/clay nanocomposites

In this report, we introduce an industrially feasible method that involves melt blending of polycarbonate (PC) and in situ suspension polymerized exfoliated PMMA/clay (Na+MMT) nanocomposites to prepare highly exfoliated PC/clay nanocomposites. The rational behind this is that PC is well known to form miscible blend with low molecular weight PMMA. Thus, low molecular weight PMMA/clay exfoliated nanocomposites were prepared by suspension polymerization using pre-exfoliated clay (Na+MMT) in water media during the polymerization. The (80/20 w/w) PC/PMMA blends without and with Na+MMT showed single glass transition temperature (Tg), indicating complete miscibility of the polymers in the blend. The surface morphologies of the composites were studied by scanning electron microscopy (SEM). Wide-angle X-ray diffraction and transmission electron microscope (TEM) studies of the nanocomposites revealed delamination of the clay silicate layers in the PC matrix. The properties of the (80/20 w/w) PC/PMMA-Na+MMT nanocomposites were significantly higher than that of the pure PC. Moreover, retention of the optical transparency of PC in the nanocomposites could be due to the presence of unmodified clay (Na+MMT), which did not contain any organic modifier (quaternary ammonium salt) that could decompose during melt mixing of PC at high temperature (similar to 280 degrees C). (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012