PHOSPHORUS-CONTAINING EPOXY FOR FLAME RETARDATION .4. KINETICS AND MECHANISM OF THERMAL-DEGRADATION

The kinetics and mechanisms of thermal degradation of a phosphorus-con taining epoxy based on bis-(3-glycidyloxy)phenylphosphine oxide (BGPPO ) and 4,4'-diaminodiphenylsulfone (DDS) were studied. Two and four sta ges were found for BGPPO/DDS degradation in nitrogen and air, respecti vely. The degradation activation energies calculated from the methods of Kissinger, Friedman and Ozawa were obtained. The first stage of deg radation, which results from the decomposition of phosphorous groups, showed lower activation energy than the other stages. Furthermore, via FTIR and TG-FTIR investigations, the degradation of this phosphorus-c ontaining epoxy was determined to begin by the breaking of P-Ph bonds, followed by dehydration reactions breaking P-O-C bonds, and eliminati on of propyl groups. Therefore, the degradation of the epoxy resulted in high char yields and residues with high phosphorus contents. (C) 19 96 Elsevier Science Limited.