Analysis of brittle–ductile transition of polypropylene/ethyleneoctene copolymer blends by scanning electron microscopy and small angle laser light scattering

Blends of polypropylene (PP)/ethylene-octene copolymer (EOC) were studied. The influences of blend composition and mixing time on phase morphology development of the blends were investigated by scanning electron microscopy (SEM) and on-line small-angle light scattering (SALS) in detail. The toughness of the PP/EOC blends was investigated over wide ranges of EOC content and determined from the impact fracture energy of the sideedge notched samples. The concept of interparticle distance (ID) and the surface-to-surface interparticle distance (s) were introduced into this study to probe the size effect on the brittle–ductile transition (BDT) of PP/EOC blends. The results showed that ID based on the SEM photograph and the surface-to-surface interparticle distance (s) getting from SALS have similar effects on charactering the toughness of the PP/EOC blends. But the surface-to-surface interparticle distance (s) is more prone to character the BDT of PP/EOC blends than the ID value. On-line SALS can be applied to the research of BDT of PP/EOC blends