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Crystallinity and lateral crystallite size of different UHMW PE materials
Author(s) -
Hofmann D.,
Schulz E.,
Fanter D.,
Fuhrmann H.,
Bilda D.
Publication year - 1991
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.1991.070420332
Subject(s) - triclinic crystal system , crystallite , crystallinity , orthorhombic crystal system , materials science , crystallography , polyethylene , crystal structure , composite material , chemistry
Nascent high‐molecular‐weight (UHMW) polyethylene (PE) samples of different origins show a rather high crystallinity of about 70–75% and contain both a major portion of orthorhombic extended chain crystallites and a minor portion of triclinic crystallites. The triclinic content is greater the higher the molecular weight of the sample and the higher the activity of the used catalyser. A melting / recooling treatment results in a reduction of crystallinity by about 15–25% and disappearance of the triclinic phase. Further, an irreversible conversion of nascent orthorhombic extended chain crystallites to orthorhombic folded chain crystallites of increased lateral dimensions and crystalline perfections takes place during the melting / recooling treatment. The results are compared to those obtained for lower‐molecular‐weight PE samples and for high‐strength / modulus PE fibers of different origins.