Thermally Initiated Free-Radical Oxidation of Cellulose

Publisher Website
Google Scholar
Abstract
Purified cotton cellulose was heated in the resonant cavity of the electron spin resonance spectrometer in static nitrogen, flowing nitrogen, and flowing air and in vacuum. The formation of free radicals in the samples of cotton was monitored at temperatures below 300°C. Cotton was treated with chemical additives and then heated in static nitrogen at atmos pheric pressure. At the same temperature of heating, a much greater concentration of free radicals was formed in purified cotton heated in static nitrogen than in cotton heated in flowing nitrogen or in vacuum. The rate of free-radical forma tion in cotton heated in flowing nitrogen was constant throughout the heating period. Cotton, heated at the same tem peratures and times in flowing air or in static nitrogen, showed a greater concentration of free radicals than cotton heated in flowing nitrogen. The effects of additives or the application of vacuum on the apparent energy of activation for the formation of free radicals in heated cotton were also investigated. The amount of char formed during pyrolysis, as indi cated by the intensity of the free-radical signal, was much greater for samples which contained additives or which were allowed to trap decomposition products than for untreated cotton purged free of volatile decomposition products, as they were formed.

This publication has 8 references indexed in Scilit: