Supermolecular structure of poly(propylene-co-ethylene)/poly(ethylene-co-vinyl acetate) blends irradiated with fast electrons. SEM, SAXS and DSC studies

The present study concerns extruded polymer films from blends of i-PP-co-ethylene (PP) and poly(ethylene-co-vinyl acetate) (EVA), irradiated with fast electrons. SEM studies of the blends indicate a droplet type structure of the minor component. A co-continuous type structure was supposed for the blends with composition 50/50 wt.%. For the blends EVA/PP 40/60 wt.%, one-dimensional order and coalescence of EVA droplets are observed. The analyses of SAXS data show that this two component system could be examined as a one component, two-phase structure. The shape of the correlation function and the coincidence of the degree of crystallinity, calculated by means of SAXS and DSC, confirm this suggestion. The irradiation mainly affects the amorphous phases. The long period slightly decreases after irradiation as a result of crosslinking that mainly occurs in the amorphous part. At the same time, the thickness of crystal lamellae does not change with composition and irradiation dose. The crystallization process of irradiated samples differs from that of unirradiated ones.