Synthesis, characterization and development of high performance siloxane-modified epoxy paints

Abstract

Diglycidyl ether of bisphenol A (DGEBA) epoxy was modified with hydroxyl-terminated poly dimethyl siloxane (HPDMS), through ring opening addition polymerization reaction. The structural elucidation of the siloxane-modified epoxy resin (ESR) was carried out by FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. The physico-chemical characterization of the synthesized resin (ESR) was done by standard methods. DGEBA and ESR, were subjected to paint formulation with the help of TiO 2, Fe 2O 3 and lemon chrome pigments. The formulated paint systems were cured at room temperature with polyamide (PA) used as curing agent. The DGEBA–PA and siloxane-modified epoxy–polyamide (ESR–PA) paints were applied on mild steel strips. The physico-mechanical and anticorrosive performance of the coated panels was evaluated by standard methods. Thermal analysis of DGEBA–PA, epoxy siloxane/PA systems was carried out by thermogravimetric analysis (TGA). The effect of siloxane incorporation and the role of PA as a curing agent on the coating properties of these paint systems was also investigated. The ESR–PA system was found to exhibit good thermal and corrosion resistance performance.