The initial activation energy at zero conversionEo of thermooxidative decomposition has been taken as a measure of thermal stability of polycarbonates (PC) andEo has been correlated with the relative hydrolysis raterh as a measure of their hydrolyse resistance. It is suggested that both decomposition processes are initiated by the same mechanism,
the attack of hydrolytic agent onto ester C−O bonds. The following values ofEo have been found:
187 (PC-M)>87 (PC-A)>43 (PC-C) kJ/mol, and they are correlated with values ofrh being 0.01 (PC-M)<1 (PC-A)<4.4 (PC-C). It has been found, using a computer modeling technique, that bothEo andrh depend on the minimized energy of conformations.