ISSN:
1572-8943
Keywords:
diffusion coefficient
;
DMA
;
TGDDM epoxy
;
water sorption
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The diffusive and dynamic mechanical behaviour of an epoxy system containing tetraglycidyl-4,4′-diaminodiphenylmethane and a multifunctional Novolac glycidyl ether cured with 4,4′-diaminodiphenylsulfone was studied after water sorption. The diffusion of water was performed at 100% relative humidity, by immersion of specimens in water at 20, 40, 70 and 100°C. In all sorption experiments, the water diffusion followed Fick's law. Diffusion coefficients and saturated water concentrations were estimated for these temperatures. The activation energy for diffusion was determined from the relationship linking the diffusion coefficient and the reciprocal of the absolute temperature. The value obtained was 45.7 kJ mol-1. Dynamic mechanical analysis of samples immersed in water at 25 and 100°C, and with various water contents, showed a shift in Tg〉 (defined by the tanδ peak) to lower temperatures over the glass transition region, and a slight decrease in the dynamic storage modulus in the presence of water as a result of a plasticization effect.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1010174910232
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