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Article: Blends, hydrogen bonds, and orientation: understanding the role of interactions.
- Article from:
- Polymer Engineering and Science
- Article date:
- February 1, 2004
- Author:
CopyrightCOPYRIGHT 2004 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
Two main phenomena are known to result in the final observed orientation of a polymer: first, initial deformation, and second, relaxation towards an equilibrium state, which can occur both during and after deformation.
The first theory relating orientation to deformation was proposed by Kuhn and Grun (1). This approach was developed to describe an elastomer network during deformation, and does not take into account interactions of a chain with its neighbors. According to this theory. the orientation factor
<[P.sub.2] (cos [theta])>, often abbreviated
<[P.sub.2]>, varies with deformation ratio [lambda] (ratio of final to initial length of deformed sample) as
<[P.sub.2](cos[theta])> = ...
<[P.sub.2](cos[theta])><[P.sub.2](cos[theta])>