Bulk and solution crystallization kinetics of isotactic polybutene-1

✍ Scribed by K.S. Sastry; R.D. Patel

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 527 KB
• Volume: 8
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(72)90082-1

✦ Synopsis

The crystallization kinetics of an unfractionated sample of isotactic polybutene-i have been studied from the melt and from dilute solutions in amyl acetate by the dilatometric method. The kinetics of bulk crystallization followed the Avrami equation for most of the transformation with a deviation towards the end of the crystallization process. The Avrami exponent is found to be temperature dependent with the value of n ~ 3 at high undercooling (indicating a homogeneous nucleation process) and n ~ 4 at lower undercooling (indicating a heterogeneous nucleation process). The temperature coefficients of the rate constants indicate a nucleation controlled process of crystallization.

When amyl acetate is used as a diluent, the crystallization was found to follow the Avrami formulation only at a high undercooling, while at the other temperatures it is applicable only to part of the transformations. The excess interracial free energy and the lateral free energy have been evaluated for the polymer in amyl acetate.