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Article: Nonisothermal Crystallization Kinetics of Polytetrafluoroethylene.
- Article from:
- Polymer Engineering and Science
- Article date:
- June 1, 2000
- Author:
CopyrightCOPYRIGHT 2000 Society of Plastics Engineers, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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An analysis of the crystallization kinetics of polytetrafluoroethylene (PTFE) under nonisothermal conditions is presented. A simple method is proposed to remove the limits of the Ozawa theory. The Avramic exponent, n, can be reasonably well determined from the nonisothermal crystallization exotherm. An n value of [tilde] 1.49 was obtained for PTFE, which indicates the formation of one-dimensional crystallites (fibrillar type) after thermal nucleation or two-dimensional crystallites (discs) after athermal nucleation. Both these morphologies were experimentally observed. For PTFE crystallization from the melt, activation energy was obtained as 34 kcal/mol. This is much ...