Chemiluminescence during thermal and thermo-oxidative degradation of cellulose

The chemiluminescent phenomena during thermal and thermo-oxidative degradation of cellulosic material and model substances were found to originate in at least three relatively independent processes. The low-temperature chemiluminescent phenomenon typical of samples previously irradiated with an incandescent 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°C typical of pre-oxidised samples can be associated with decomposition of peroxide groups present in the sample. An intense chemiluminescence at temperatures approaching 200°C was found to correlate with polymer chain scissions, resulting in the decrease in the degree of polymerisation determined by viscometry. The results show that the chemiluminescence approach may shed new light on the radical degradation mechanisms of cellulose and related polyhydroxylated polymers.