On the thermo-oxidative and thermal degradation of polymers based on diphenyl ether☆

It was found by TGA that the onset of decomposition of polyphenoxyphenylenemethylenes (PPPM) based on diphenyl ether occurs in the temperature range 390–400°. The effect of the nature and the amount of the hardening catalyst on the thermo-oxidative degradation of PPPM was investigated. It is shown that the most stable polymers are those hardened in the presence of stannic chloride and sulphuric acid. The optimum amount of catalyst is 0·5-1% on the mass of polymer. The thermo-oxidative degradation of PPPM is found to be a first order reaction. The effective energy of activation for the degradation process in air is 14±2 kcal/mole, compared with 28 kcal/mole in an inert gas.