Chemiluminescence during thermal and thermo-oxidative degradation of cellulose

The chemiluminescent phenomena during thermal and thermo-oxidative degradat ion of cellulosic material and model substances were found to originate in at least three relatively independent processes. The low-temperature chemil uminescent phenomenon typical of samples previously irradiated with an inca ndescent light source and dependent on both temperature and composition of the surrounding atmosphere during irradiation is attributed to the decay of charge-transfer complexes between oxygen and hydroxyl and/or ether groups in cellulose. A peak in chemiluminescence during dynamic experiments at 135 degrees C typical of pre-oxidised samples can be associated with decomposi tion of peroxide groups present in the sample. An intense chemiluminescence at temperatures approaching 200 degrees C was found to correlate with poly mer chain scissions, resulting in the decrease in the degree of polymerisat ion determined by viscometry, The results show that the chemiluminescence a pproach may shed new light on the radical degradation mechanisms of cellulo se and related polyhydroxylated polymers. (C) 2000 Elsevier Science Ltd. Al l rights reserved.