Infrared dichroism study of the relaxation of selected segments along a stretched polymer chain and comparison with theoretical models

The differences in chain relaxation as a function of segmental position along a deformed chain have been elucidated by studying linear isotopically labeled block polystyrenes. Films from three different copolymers have been stretched at constant strain rate and various temperatures. The orientation...

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Bibliographic Details
Published in:Macromolecules 1988-08, Vol.21 (8), p.2404-2412
Main Authors: Tassin, Jean Francois, Monnerie, Lucien, Fetters, Lewis J
Format: Article
Language:English
Subjects:
Applied sciences
Exact sciences and technology
Miscellaneous
Organic polymers
Physicochemistry of polymers
Properties and characterization
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Summary:The differences in chain relaxation as a function of segmental position along a deformed chain have been elucidated by studying linear isotopically labeled block polystyrenes. Films from three different copolymers have been stretched at constant strain rate and various temperatures. The orientation of the different blocks has been measured by infrared dichroism. End blocks appear to relax faster than the overall chain, the relaxation of which is still more rapid than that of the central block. The kinetics of the relaxation are sensitive to the length of the end block and the total molecular weight of the copolymer. The relative relaxation of chain ends with respect to the average orientation has been compared to the predictions of the Doi--Edwards model of chain relaxation. Good agreement has been obtained, without any adjustable parameter, when refraction, chain length fluctuations, and reptation processes have been considered. 37 ref.--AA
ISSN:0024-9297
1520-5835
DOI:10.1021/ma00186a018