A study of thermal degradation and oxidation of polymers by infrared spectroscopy. Part II. Polybenzyl

Abstract

The primary mode of degradation of polybenzyl at elevated temperatures in the presence of air has been found to be an oxidative attack on the methylene bridge. Initially the methylene bridge is oxidized to keto and hydroxyl groups. Later substantial amounts of acid anhydride and/or ester are formed. Extensive oxidation has been found to oxidize approximately 30% of the methylene bridge to keto groups and 20% to hydroxyl groups. This leaves approximately 50% not quantitatively accounted for specifically; however, the data indicate that the residual methylene groups are consumed primarily by the formation of anhydride and/or ester. While the polymer is initially thermoplastic, it becomes thermosetting as a result of oxidation. The course of the oxidation is followed by observing the growth of the infrared absorption bands arising from the various functional groups being generated as well as following the simultaneous decrease of the methylene absorption band.