Crystallinity and chain stem length dependence of yield kinetics in polyethylene

Autor: Jevan Furmanski, Leon Govaert, Jonathan Schaefer, Joseph A. Throckmorton, Johannes A. W. van Dommelen
Přispěvatelé: Group Govaert, Processing and Performance, Group Van Dommelen, Mechanics of Materials
Rok vydání: 2022
Předmět:
Zdroj: Journal of Polymer Science, 60(22), 3085-3098. Wiley
ISSN: 2642-4169
2642-4150
DOI: 10.1002/pol.20220265
Popis: Researchers have long sought to predict the mechanical behavior of polyethylene from its microstructure. In particular, the yield strength and yield kinetics have been reported to be dependent on crystallinity and crystal thickness, but the relative importance of these two microstructural attributes has not been shown. In the present work, a series of microstructures was obtained through a combination of controlled quench rates from the melt and inclusion of various amounts of hexene comonomer. The yield strength for a wide range of strain-rates was linearly dependent on the crystallinity, and independent of crystal thickness (chain stem length), both measured by Raman spectroscopy. Similarly, yield kinetics described by a Ree-Eyring two-process stress activated model showed linear dependence on crystallinity and no dependence on crystal thickness. The results of the present work call into question models of yield kinetics dependent on screw dislocation nucleation, which depend on crystal thickness.
Databáze: OpenAIRE
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