Composites of poly(vinyl acetate) filled with calcium carbonate: Microscopy, diffractometry and thermophysical properties

Calcium carbonate (CaCO3) is used as filler in poly(vinyl acetate)(PVAc) co mposites to enhance the mechanical properties. The filler is often commerci ally surface treated with stearic acid to optimize the interfacial bonding and wetting. The effects of the interface on properties were studied using scanning electron microscopy (SEM) of films with initial and deformed morph ologies. Plasticizing additives cause a significant change in the appearanc e of the films and a reduction in the glass transition temperature of the m atrix from 40 degrees C to approximate to 18 degrees C, which was not alter ed by further addition of the filler. A PVAc composite fracture surface sho ws the particles adhering well to the matrix, suggesting good adhesion and reinforcement. The SEM study is complemented by WAXD, SEM/X-SEM, XPS. and t hermal analysis.