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Article: Quiescent nonisothermal crystallization kinetics of isotactic polypropylenes.
- Article from:
- Polymer Engineering and Science
- Article date:
- May 1, 1995
- Author:
CopyrightCOPYRIGHT 1995 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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INTRODUCTION
In polymer processing, crystallization behavior is influenced by two competitive effects, namely, cooling rate and crystallization rate. The cooling rate is controlled by the heat transfer from the polymer sample to its surroundings, i.e., by the cooling medium, its agitation and the mass of the polymer. The crystallization rate, on the other hand, is enhanced by the presence of molecular orientation. The effect of molecular orientation can be very large, but it is difficult to measure and quantify. Spruiell and White (1) have introduced the concept of continuous cooling transformation (CCT) curves, which are well known in the metallurgy and solid state ...