Performance study of an epoxy–polythiol curing system for local insulating spraying based on the imbalance stoichiometric ratio

• Published in: Materials letters Vol. 351; p. 135123
• Main Authors: Zhang, Zhongyuan, Gao, Fengsheng, Li, Le, Wei, Liwei, Su, Zheng, Li, Haoyi, Liu, Yifan, Liu, Hechen, Liu, Yunpeng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2023
• Subjects: Dielectrics; Epoxy resin; Microstructure; Polythiol; Stoichiometric ratio; Epoxy resin; Polythiol; Dielectrics; Microstructure; Stoichiometric ratio
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2023.135123

•Enhancing the dielectric strength of air gaps in transmission line towers.•Application of an epoxy–polythiol coating on a cross-arm for the enhancement.•Effect of different stoichiometric ratios of polythiol on coating performance. An epoxy–polythiol coating on a cross arm is an effective method to enhance the dielectric strength of air gaps in transmission line towers and reduce the occurrence of bird-related faults. However, epoxy–polythiol dual-component raw materials could not achieve the prescribed stoichiometric ratio of 1:1, affecting the protective performance of the formed insulation layer. This study characterizes the cured systems of epoxy–polythiol with imbalance stoichiometry using Fourier-transform infrared spectroscopy and scanning electron microscopy. Tests were conducted to analyze parameters of the epoxy–polythiol curing system, including breakdown strength, cure time, thermal conductivity, water absorption rate, and mechanical properties. Results demonstrate that nonstoichiometric conditions reduce the curing time, breakdown strength, thermal conductivity, and water absorption of the epoxy–polythiol curing system. However, a slight increase in the equivalent amount of the curing agent improves the mechanical properties of the cured products.