Dependence of Elastic-Strength Properties of Epoxy Polymers on Moisture Content in the Process of Natural Climatic Aging in Conditions of a Temperate Continental Climate

The article provides the results of studying changes in the sorption and elastic-strength characteristics of polymer samples based on modified epoxy resin and various types of hardeners exposed to natural climatic aging. Field exposure of samples was carried out on test benches of the scientific research laboratory of Environmental and Meteorological Monitoring, Construction Technologies and Examinations of Ogarev National Research Mordovia State University (moderate continental climate). We established that field climatic aging of samples of the studied compounds lasting maximum 18 months is accompanied by a decrease in the limit moisture saturation. We proposed to use the indicator of irreversible weight loss of epoxy polymer samples as a criterion for evaluating field climatic aging of polymer samples. We analyzed the effect of exposure duration on the change of the dependence of the tensile strength and elongation at maximum load at extreme humidity. We established that the greatest decrease in mechanical strength, regardless of the hardener used, is observed for samples in the dried state. The decrease in mechanical strength of samples in the dried state after 18 months of field exposure reaches 36%. At the same time, it is also accompanied by a multiple drop in elongation by 1.5–2 times at maximum load. We found that mechanical strength of samples based on amine-type hardeners in a moisture-saturated state virtually does not change, regardless of the climatic aging duration. To clarify the synergetic and neutralizing effects arising during field climatic aging, we proposed to study the full moisture content range of the samples under study. We stated the main criteria for evaluating field climatic aging of polymer samples in terms of their moisture content.