Homogenization of blends of polypropylene and ethylene-propylene rubber under shear in the presence of inorganic fillers☆

The possibility of homogenization of blends of PP with EPR under shearing conditions on Bridgman anvils at rotation angles of 100 to 1500° under 0·5–20 kbar pressure in the presence of inorganic fillers has been studied at 20°. Radio thermoluminescence structural analysis showed that the introduction into the blend of active inorganic fillers (Aerosil, asbestos or carbon black, from 5 to 30 weigth %) allowed a 2–4 fold reduction in the minimum pressure needed for the formation under shear of a kinetically stable polymeric composition, with a single glass transition temperature.