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J. L. Halary, D. Bauchiere, P. L. Lee, L. Monnerie

Study of model systems as a powerful tool for producing reliable structure — property relationships in epoxy networks

Polimery 1997, No 2, 86


DOI: dx.doi.org/10.14314/polimery.1997.086


Summary

Series of epoxy-amine networks were designed to separate the effects on the properties of chain rigidity and of architectural characteristics, i.e., cross-linkdensity and extender type. Glass transition temperature (Tg) was shown to increase with the increasing cross-link density and rigidity of the epoxide and amine residues, but these effects were not completely decoupled. In addition, inspection of non-stoichiometric systems revealed the occurrence of peculiar effects in the presence of unreacted epoxide moieties. A general correlation between the values of the rubbery modulus and Tg has been proposed. As regards the sub-Tg β-transition, the on set of the process has been shown to occur at the same temperature irrespective of chain stiffness and cross-link density as a result of short-range cooperativity of the hydroxypropyl ether motions. As a consequence of practical interest, the higher cross-link densities lead to the lower Young moduli at room temperature.


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