Abstract: Blends of PP/ethyleneoctene block copolymer (OBC) were prepared containing a rare earth compounds (WBGⅡ) as a βnucleating agent. The effects of WBGⅡ on crystalline behavior, crystalline form, crystal morphology and mechanical properties of the blends were studied. With increasing OBC content, the notched impact strength and elongation at break of PP/OBC blends increased significantly, while tensile and flexural strengths of blends decreased. The PP/OBC blend containing 1.0 % WBGⅡ masterbatch and 15 % OBC gave rise to a βphase melting peak at 152 ℃, and a βform content of 21.94 %. The crystallization temperature of the blends increased by 10.88 ℃, notched impact strength and the elongation at break increased by 264.82 % and 367.66 %, respectively, compared with neat PP.

Key words: polypropylene, rare earth βnucleating agent, mechanical property