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Structure–property relationships for styrene crosslinked polyesters. I. Network structure and rubbery elastic modulus
Author(s) -
Bellenger V.,
Mortaigne B.,
GrenierLoustalot M. F.,
Verdu J.
Publication year - 1992
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.1992.070440411
Subject(s) - styrene , materials science , polyester , copolymer , polymer chemistry , dynamic mechanical analysis , elastic modulus , modulus , composite material , polymer
Ten unsaturated polyester prepolymers differing by the nature of the diol, by the maleate/phthalate molar ratio, or by the chain length, were crosslinked by about 40% by weight of styrene and then analyzed by IR spectrophotometry, solid state NMR, and rubbery elasticity measurements. The spectrometric measurements revealed a practically complete conversion of the styrene/fumarate copolymerization. The rubbery elastic modulus varies in a complex way with the presumed network structure. A non‐ideality factor f was defined from the current theories; f is a decreasing function of the average number of flexible bonds between crosslinks. The networks based on dimeric diols display a practically ideal behavior. The influence of dangling chains, corresponding essentially to polyester chain ends, is taken into account by the Graessley's formula in which trifunctional and tetrafunctional crosslinks are distinguished. A method for the estimation of the nature and weight fraction of dangling chains was proposed.