CRYSTALLIZATION AND MELTING BEHAVIOR OF A STEREOBLOCK ISOTACTIC POLYPROPYLENE

The crystallization and melting behaviour of a stereoblock isotactic polypropylene were analyzed using the dilatometric method. The samples were crystallized at different temperatures and at each temperature the crystallization kinetics were noted. The melting temperature was obtained as a function of the crystallization temperature according to the Hoffmann and Week equation. The obtained results show that the chain microstructure plays a significant role in the melting behaviour; the effect was related to the crystal thickness, as determined mainly by the length of the stereoregular sequences.