Abstract: The melting points(T_m),crystalline temperature(T_c)and crystallinity(X_c)of propylene/α-olefin(pentene-1,octene-1 and decene-1)copolymers have been investigated. The results show that the T_m,T_c and X_c of the copolymers are lower than those of propylene homopolymer,indicating that lower α-olefin incorporation in copolymer has strongly hampered the crystallization of propylene.From critical crystalline sequence length of several propylene/α-olefin copolymers,it can be seen that a long chain α-olefin has much stronger effect on crystallization of PPthan a short α-olefin does.

Key words: Propylene/α-olefin copolymer, Crystalline behavior, Critical crystalline sequence length