An Evaluation of the Effects of Type and Temperature of Aqueous Media on the Compressive Strength of Glass-Epoxy Composites

Abstract

Epoxy systems reinforced with E-glass fibers, exposed to 100 h in three separate media were subjected to compressive mode of deformation. The difference in weight, i.e., before and after exposure to 100 h, following immersion in media was noted. Compared to the data obtained at room temperature in plain water (i.e., PR), the absorption levels in plain water containing a small proportion of dilute HCl at room temperature (i.e., PAR) were lower while samples in plain water at elevated (50 C) temperature (i.e., PH) show higher absorption. The compression strength and fractographic features, noted on the compression failed samples, are reported in this work. The experiment reveals that the media exposed samples generally exhibit lower strengths compared to the dry (i.e., unexposed) samples. Among the media exposed samples, the PAR set shows a small rise in strength while the PR and PH sets display a lowering of values. These changes have been attributed to various factors like medium ingress into samples inducing an alteration in the response of the interface regions, presence of either lengthy or fragmented fibers and resin smear on the fibers. In PAR case, the lower diffusion helps first in lowering the extent of its recording a decrement in strength vis-à-vis the dry case and this trend may be countered by the size of the Cl being different and in the end a small rise in strength is recorded. The fractographic features reveal interface separation, either scattered debris or a cleaner surface of fibers or adherence of resin on fibers region as well as appearance or otherwise of long or short fibers depending on whether the tests were done on unexposed samples or on the ones subjected to immersion in a specific aqueous medium.