Decomposition of Epoxy Resin in Supercritical Isopropanol

This paper reports the decomposition of an amine-cured bisphenol A diglycidyl ether (DGEBA) epoxy resin in supercritical isopropanol in a flow reactor with and without potassium hydroxide (KOH). The decomposition process was monitored by the change of the refractive index of the exit solution with time. The product distribution was analyzed using gas chromatography-mass spectroscopy (GC-MS) and compared with those obtained from the decomposition in supercritical 1-butanol and pyrolysis processes. This study indicated that thermolysis played a key role in cleaving the chemical bonds of the epoxy resin, and that supercritical isopropanol reduced char formation, because of the rapid removal of the primary decomposition products from the reaction zone to lessen secondary reactions. KOH reduced the initial decomposition temperature of the epoxy resin, but it also promoted the Guerbet reaction of isopropanol to form complex alcohols.