Abstract: PP/SEPS blends containing αnucleating agent(α-NA) were prepared by melt mixing process. And the particle size and distribution of dispersed phase were measured by scanning electron microscopy. The interparticle distance in the blends with different content of α-NA was calculated according to a percolation model, and the effect of content of α-NA on the critical interparticle distance was described quantitatively. It was found that the higher the content of α-NA, the greater the inter-particle distance, and the easier the brittle-ductile transition.

Key words: α-nucleating agent, polypropylene, brittle-ductile transition