複合材料 リサイクルを目的としたアミン硬化エポキシ樹脂の硝酸による分解

Abstract

Three kinds of epoxy resins were decomposed by nitric acid in order to establish a recycling method of epoxy resin. Specimens were immersed in 80°C nitric acid (4M and 6M) and decomposed products were recovered. The molecular weight distributions and chemical structures of the products were analyzed by using Size Eliminated Chromatograph and FT-IR, respectively. For the case of bisphenol A type epoxy resin cured with amine, a derivative of monomer was formed due to the decomposition at C-N bonds. The derivative of monomer was dissolved in nitric acid and was extracted with ethyl acetate. 2, 4, 6-trinitrophenol, which was produced by the breakage of main chain and subsequent nitration, was also recovered. Nitric acid attacked the C-N bonds in bisphenol F type epoxy resin cured with amine more selectively because of the existence of methylene group in the main chain. The yield of recovered decomposed product which contained derivative of the monomer of bisphenol F type epoxy resin was more than the case of bisphenol A. With regard to tetraglycidyl diamino diphenyl methane (TGDDM) resin cured with diamino diphenyl methane (DDM), the chemical structure of cured resin is symmetric and repetitive. Hence, decomposed product of TGDDM/DDM was recovered as a nearly single compound of 2, 4, 6-trinitroaniline.