Degradable Silyl Ether-Based Thermoset Under Acidic Condition

Recently, as plastic usage increases, the environmental pollution due to plastic waste is becoming severe. Incomplete degradation of waste plastics produces microplastics, which are difficult to remove by their small sizes. Microplastics, harmful to human health, flow into the marine ecosystem and accumulate in the human body. Many researches are being conducted to develop degradable polymers. However, thermosetting plastics such as epoxy resin used in various industrial fields are still challenging to degrade. In this study, we developed a degradable epoxy thermoset using silyl ether derivative as a curing agent that easily hydrolyzed under acidic or basic conditions. The synthesized silyl ether derivatives were mixed with bisphenol A and formed network structures through thermal curing. To compare the effects of degraded behaviors on the chemical structures of curing agents, we used several types of silyl ether derivatives having different functional groups. The weight loss of the cross-linked epoxy network immersed in HCl solution for a certain time was observed the degradable behavior. As a result, it was confirmed that the crosslinked epoxy network was completely degraded. In addition, curing agents having more sterically hindered functional groups exhibit a slow degraded rate. The results suggest that curing agents containing silyl ether bonds can form the degradable epoxy network, and the rate of degradation can control by chemical structure.