The effect of talc on the crystal orientation in polypropylene/ethylene-propylene rubber/talc polymer blends in injection molding

The effect of talc on the b-axis orientation of the polypropylene crystals In polypropylene (PP)/ethylene-propylene rubber (EPR)/talc blends of infect ion molding was examined using the X-ray diffraction method. The b-axes of the PP crystals were most strongly oriented in the thickness direction for the injection molded PP/EPR/talc blends. The b-axis orientation In the thic kness direction of injection moldings was promoted by increasing the concen tration of talc, by reducing the particle size, or by purifying the talc. T he dependence of the specimens' rigidity on talc content, particle size, an d purity was also investigated. The rigidity depended on the degree of b-ax is orientation. The results of our investigation suggest that increasing th e orientation of the PP crystals that are near talc particles may improve t he rigidity.