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The viscoelastic behavior of isotactic polypropylene fibers
Author(s) -
Laible Roy C.,
Morgan Henry M.
Publication year - 1962
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1962.070062104
Subject(s) - tacticity , polypropylene , materials science , viscoelasticity , composite material , yarn , stress relaxation , polymer , creep , polymerization
The stress‐strain properties of isotactic polypropylene yarn have been studied over a wide range of strain rates up to 2,000,000% per minute. The testing equipment used included the Instron, three pneumatic and pneumatichydraulic type of high speed testers, the falling weight method, the rotating disc longitudinal impact and ballistic techniques. Evaluation of the behavior of polypropylene at strains of 2, 6, 12, and 16% shows the existence of two relaxation peaks, one at τ = 10 −2 sec. and the other at about 10 2 sec. with a plateau of little time dependency in between. The data, especially at the shorter testing times, can be well represented by a single mechanical model composed of two Maxwell units in parallel. Information concerning the ultimate properties of isotactic polypropylene yarn was also obtained. The work‐to‐rupture values for polypropylene at most strain rates exceed those characteristic of any other available textile material.