Degradation Properties of Sustained Release Membrane Composited of Water-Based Copolymer and Zeolite

The self-made slow-release membrane material with water-based copolymer (polyvinyl alcohol PVA, polyvinyl pyrrolidone PVP), zeolite and epoxy resin as raw materials was tested for degradation in buried soil. The effects of soil temperature T ( T 15 , T 25 , T 35 ) and moisture W ( W 60 , W 80 , W 100 ) on the degradability of membrane materials were investigated by a comprehensive experimental design, and a hydrothermal coupling model K ( T , W ) was established. The effects of degradation on the chemical structure, functional groups, and morphology of membrane materials were revealed by infrared spectroscopy and SEM electron microscopy. The results showed that the degradation degree of membrane material was an exponentially positive response to the increase in soil temperature and moisture. The degradation rate of membrane materials under different treatments was 13.7%-17.3%, and the maximum degradation rate was 17.3% under the T 35 W 100 condition. The determination coefficient R 2 of the constructed K ( T , W ) model reached 0.927, and the average relative error of the predicted degradation rate was 1.58%, indicating good accuracy of the model. The infrared spectrum showed that the -OH stretching vibration absorption peak of the degraded membrane becomes wider and the peak intensity increases; the absorption peak intensity of C-H, -CH 2 , and Si-O weakens; and the peak of the C=C absorption peak appears as a continuous staircase after degradation. The SEM electron microscopy showed there were differences in the pores and cracks of the membrane materials under different treatments, and the degradation was the most obvious under the T 35 W 100 condition.