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The stress optical behavior of PET fibers and films
Author(s) -
Ward I. M.,
Bleackley M.,
Taylor D. J. R.,
Cail J. I.,
Stepto R. F. T.
Publication year - 1999
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.11622
Subject(s) - birefringence , photoelasticity , materials science , shrinkage , stress (linguistics) , orientation (vector space) , optics , principal stress , monte carlo method , composite material , statistical physics , physics , geometry , mathematics , solid mechanics , philosophy , statistics , shear stress , linguistics
The use of stress‐optical measurements to characterize oriented PET fibers is reviewed. The implications of a molecular network for the development of orientation in spun fibers, cold drawn and hot drawn fibers are also considered. Early research made use of the Kuhn and Grün theory of photoelasticity, and their model has been shown by many workers to be a useful starting point for understanding the development of molecular orientation in PET provided that it is suitably modified for high chain extension at high draw ratios. The principal thrust of recent research at Leeds has been to explore the applications of more precise molecular modelling using the Monte Carlo rotational isomeric state model developed by Stepto and Taylor, and applying it to the development of optical birefringence with strain, as well as the shrinkage stress. It has been shown that the Kuhn and Grün theory, where the actual network is replaced by a model network of freely jointed random links, cannot provide a consistent description of the shrinkage stress and the optical birefringence.