Epoxy Resins under Repeated Hygrothermal Conditions

In this paper, the effects of repeated hygrothermal conditions on an epoxy resin were investigated experimentally.The repeated hygrothermal conditions were obtained by immersing the samples in hot water then keeping them in drycondition followed by immersing in hot water for the second time reaching steady state condition at each section. The waterabsorption and desorption of the samples were obtained using gravimetric measurements and the resulting residualmechanical strengths were obtained by conducting tensile tests. The gravimetric results indicated that the maximum moistureuptake and absorption rate in the second absorption were higher compared to the first absorption. The mechanical testresults indicated that the residual strength reduced in the course of the first absorption section then it partially recovered asa result of water desorption and then further degraded due to the second absorption stage. The same trend was observed forthe resin stiffness.