a method for extruding polypropylene containing vinylidene chloride polymers . according to the present invention , the polymers are extruded using extrusion equipment coated with a fluoropolymer . this method improves the processability , alleviates thermal degradation of the pvdc , improves the extrudate quality by reducing discoloration and voids in surfaces of the extruded product and protects the equipment by reducing the corrosive wear .