ISOTHERMAL GROWTH OF ONE SPHERULITE AROUND CIRCULAR OBSTACLES IN A POLYPROPYLENE FOIL

Growth of one spherulite within a thin foil of polypropylene around on e circular obstacle or around combinations of circular obstacles is in vestigated. For each obstacle there exists a region of shadow, seen fr om the nucleus of the spherulite, which influences the growth of the s pherulite. Within any region of shadow the growth fronts are evolvents of the obstacle's boundary, because the spherulite grows isotropicall y. When two growth fronts belonging to one spherulite meet each other inside the shadow, an intrinsic grain boundary is formed for each obst acle. Additionally, growth of one spherulite around a rectangular obst acle and a spherical obstacle is investigated.