Analysis of brittle–ductile transition of polypropylene/ethylene-octene 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 side-edge notched samples. The concept of interparticle distance (ID) and the surface-to-surface interparticle distance (τ) 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 (τ) getting from SALS have similar effects on charactering the toughness of the PP/EOC blends. But the surface-to-surface interparticle distance (τ) 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.