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Length changes induced by sorption and desorption of moisture in glass-fiber reinforced polyester (GRP) composite and the effects of weathering

From National Research Council Canada

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  1. National Research Council of Canada
FormatText, Article
Subjectreinforced plastics; length; weathering; swelling; vapor pressure; moisture content; length change - sorbed water isotherm; swelling strain; matrix resin microheterogeneity
Abstract
The length change-sorbed water isotherm of GRP composite (23 degrees C) indicates that for equilibrium water contents higher than a certain critical value a marked decrease in the relative rate of swelling strain (delta L/L[0]) per unit rate of sorbed water (delta W/W[GRP]) occurs in both the control and the weathered material. The change in rate is attributed to the microheterogeneity of the matrix resin, which consists of a mixture of dense microgel particles ( highly cross-linked resin islands) embedded in a less dense continous resin phase (cross-linked to a lesser degree). At equilibrium concentrations lower than the critical value, most or possibly all of the sorbed water is contained in the less dense phase of the resin, which is more easily penetrated by the water. As this phase is less restrained because of fewer cross-links, it swells to a greater extent than the microgel phase, which absorbs most of the water above the critical concentration. The amount of linear swelling in the weathered sheet is lower than that of the control sheet. Weathering also results in lower rates of swelling below the critical value of equilibrium sorbed water content, but induces considerably higher rates above that value.
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  • Durability of Building Materials 1 (1982): 67–84.
LanguageEnglish
Peer reviewedYes
IdentifierDBR-P-1027
NRC numberNRCC 20147
NRC-IRC-2101
NPARC number20374111
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Record identifier4999ec8e-328c-4052-ab31-738284a4ccd0
Record created2012-07-23
Record modified2024-03-22
Date modified: