INFLUENCE OF CLAY ON THE MORPHOLOGY AND PHASE SEPARATION BEHAVIOR OF POLY（METHYL METHACRYLATE）/POLY（STYRENE-co- ACRYLONITRILE） BLENDS

The effect of clay on the morphology and phase-separation behavior of poly（methyl methacrylate）/poly（styrene- co-acrylonitrile） （PMMA/SAN） blends and the variation of clay dispersion have been investigated. With the evolution of phase separation in PMMA/SAN, most of the clays are first located at the boundaries between PMMA and SAN, and then gradually move to the PMMA-rich domain, owing to the affinity of clay to PMMA. The introduction of clay causes the increase of binodal and spinodal temperatures of PMMA/SAN and enlarges their metastable region, indicating the phase stabilizing effect of clay on the matrix. But the influence of clay on the cloud points obviously depends on the composition of PMMA/SAN. The selective adsorption of PMMA on the clay results in the difference between the composition of surface layer and that of polymer matrix. Hence, the clay plays the role of an agent changing the conditions of phase structure formation.