Depolymerization of polycarbonate in critical region of methanol

Depolymerization of polycarbonate in critical region of methanol was studied in absence of catalysts and in a batch-type autoclave at reaction temperature of 220—260℃ and with reaction time of 5—45?min. The main liquid products were demethyl carbonat (DMC) and bisphenol-A(BPA), which were identified and quantified by GC/MS and GC/FID. In critical region of methanol at 240℃ for reaction time of 30?min, the yield of DMC and BPA reached 91.75% and 90.03%, respectively. Gel Permeation Chromatography was used to measure the number-average molecular weight ((Mn)) of solid products. Based on the experiments, mechanism of methanolysis was proposed in this paper.