Thermal degradation of bis(azidomethyl)oxethane oligomer

Abstract

The kinetics, composition of products, and mechanism of thermal degradation of the bis(azidomethyl)oxethane oligomer in different media (vacuum, argon, air) in the temperature range 150 to 210°C has been studied by thermogravimetry, volumetry, IR spectroscopy, and mass spectrometry. It has been shown that the kinetic parameters of degradation are practically independent of the medium wherein the degradation proceeds. The process obeys the first-order kinetics and may be described by the Arrhenius equation k = 1014.1 ± 1.1exp[−161 400 ± 4600)/RT] s−1. Mass spectrometric analysis provides evidence that nitrogen prevails in gaseous reaction products. A comparison of the IR spectra of the initial oligomer and the solid residue of its thermolysis testifies that azide groups are destroyed, while the backbones of polymer heterochains remain intact. The closeness of kinetic and activation parameters for the reaction under study to those available for aliphatic azides, the data on the composition of gases being formed, and the structure of the solid residue of thermolysis allow one to suggest that the mechanism of oligomer thermal degradation involves elimination of a nitrogen molecule in the rate-determining stage of the process and subsequent crosslinking of macrochains.