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Rheological characterization of ethylene vinyl acetate copolymers
Author(s) -
Arsac A.,
Carrot C.,
Guillet J.
Publication year - 1999
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/(sici)1097-4628(19991209)74:11<2625::aid-app9>3.0.co;2-g
Subject(s) - vinyl acetate , copolymer , viscoelasticity , rheology , ethylene vinyl acetate , materials science , glass transition , polymer chemistry , polyethylene , time–temperature superposition , dynamic mechanical analysis , molar mass distribution , chemical engineering , polymer , composite material , engineering
A series of ethylene vinyl acetate (EVA) copolymers was studied by dynamic mechanical spectroscopy to understand the relative influence of composition, structure, and molecular weight distribution on their rheological behavior in the melt. The examination of their viscoelastic properties in a large temperature range showed that the glass transition temperature is nearly independent on their composition because of the statistical nature of the copolymers, though some long sequence of polyethylene homopolymer may exist at low vinyl acetate (VA) content. The successful use of the time temperature superposition for oscillatory experiments in the melt confirmed the previous remarks, because the application of the Williams Landel Ferry (WLF) equation leads to a unique set of WLF coefficient, whatever the composition of the EVA. This enables the comparison of the rheological behavior in the melt at the same temperature, in the same free volume condition, and at last it was shown that in the terminal zone, the molecular weight distribution is more influent on the behavior of EVA copolymers than their composition. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2625–2630, 1999