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Permeability of A Liquid Crystalline Epoxy

Published online by Cambridge University Press:  15 March 2011

Jianxun Feng
Affiliation:
Department of Materials Science & Engineering, University of Florida, PO Box 116400, Gainesville, Florida 32611
Elliot P. Douglas
Affiliation:
Department of Materials Science & Engineering, University of Florida, PO Box 116400, Gainesville, Florida 32611
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Abstract

This paper presents a comparison of moisture permeation in liquid crystalline and conventional epoxy systems. The permeability is obtained using a dynamic method. It is found that both epoxy systems exhibit Fickian behavior. The liquid crystalline epoxy network exhibits higher barrier properties for moisture transport than the conventional epoxy network. The efficient chain packing within the smectic mesophase of the liquid crystalline thermoset (LCT) is suggested as the main factor for this difference. The stoichiometry has a large effect on the moisture permeation. The diffusion coefficient decreases monotonically with increasing amine/epoxide functional ratio. The permeability (P) and solubility coefficient (S) reach a minimum at a functional ratio of one. The mechanism of the permeation is described in terms of the two-phase morphology present and hydrogen bonding between absorbed water and the network.

Type
Research Article
Copyright
Copyright © Materials Research Society 2002

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References

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