IN-SITU POLYMERIZATION PREPARATION OF BLENDS OF POLY(METHYL METHACRYLATE) AND POLY(STYRENE-CO-ACRYLONITRILE)

The in situ polymerization of methyl methacrylate (MIMA) with poly(sty rene-co-acrylonitrile) (SAN) was studied. The PMMA/SAN in situ polymer ization blends obtained were examined by differential scanning calorim etry (DSC), dynamic mechanical analysis (DMA), thermogravimetric analy sis (TGA), tensile tests and scanning electron microscopy (SEM). The b lends with compositions of 95/5, 80/20, 70/30, and 60/40 in weight rat ios were miscible and had a single phase structure. However, the 90/10 PMMA/SAN in situ polymerization blend obtained was inhomogeneous and had a two-phase structure; polymerization-induced phase separation occ urred during the preparation process of the blend. Both tensile streng th and elongation at break increase with increasing SAN content up to 30 wt %. The degradation temperature and thermal stability of PMMA inc reased remarkably on incorporation of SAN up to 30 wt %.