Polybenzoxazine-modified epoxy resin: thermal properties and coating performance

Abstract

Abstract In this investigation, a sample of epoxy resin was modified with different weight ratios (2, 5, 10, 15, and 20%) of a benzoxazine and thermally cured to form films; EB02, EB05, EB10, EB15, and EB20, respectively. The curing reaction of the benzoxazine molecules and epoxy prepolymer was monitored by the Fourier transform infrared (FTIR) spectroscopic analysis. The examination of anticorrosion performances of the individual films by the method of electrochemical impedance spectroscopy (EIS), was achieved by, respectively, coating the films on stainless steel (SS) substrates. The water absorption behavior of the individual films also was examined by water sorption (WS) analysis. The water intake of the tested modified-epoxy resin shows a linear dependence on the amount of polybenzoxazine in each of the samples. Better coating performances are seen, from the EIS results of modified epoxy films in comparison to the pure epoxy resin. However, the EB20 shows outstanding corrosion prevention property with excellent hydrophobicity.