Influence of Stabilizers with Secondary Amine Groups on the Thermal and Thermoxidative Decomposition of Polyepichlorohydrin

Abstract The thermal and thermoxidative destruction of epichlorohydrin elastomers, stabilized with secondary amine groups containing antioxidants has been studied, using TG and DSC methods, chromatographic and IR-spectrometric analysis of gaseous products of the destruction and also elementary analysis, gel-content and viscometric measurements on the polymers. The elimination of chlorine atoms is not important in the process of polyepichlorohydrin destruction. Most important are the scission of the main chains, producing drastic decreases of the intrinsic viscosities of the polymers, and also the formation of carbonyl groups on the macromolecules. The first destruction step is accompanied by substantial changes of the molecular weights, the weight loss being not important. The secondary amine-type stabilizers do not influence the thermal destruction, but have a good inhibiting activity on the thermoxidative destruction of polyepichlorohydrin, increasing the temperature at which this process occurs. At relatively high temperatures (about 150°C) the secondary amines react with CH2CI groups of the polymer. In the case of difunctional aminic antioxidants these reactions yield crosslinked polymers.