Thermal decomposition of dialdehyde cellulose and its nitrogen-containing derivatives

A series of dialdehyde cellulose samples with varied aldehyde content were prepared, and they were further converted to nitrogen-containing derivative s by Schiff base reaction with hydroxylamine or hydrazine. Thermal decompos ition of these compounds in nitrogen was studied by thermogravimetry/differ ential thermal analysis (TG/DTA). While the decomposition of unmodified cel lulose in nitrogen started at about 280 degreesC and rapid weight loss occu rred at 300-330 degreesC, the introduction of dialdehyde groups to cellulos e resulted in significant shifts of decomposition to the lower temperature side. The samples of high degree of substitution showed two-step decomposit ion at around 220 and 280 degreesC, indicating a basic change in the mode o f decomposition. The nitrogen-containing derivatives showed changes in ther mal decomposition similar to that of dialdehyde cellulose, hut the samples with high degrees of substitution, above similar to 70%, showed an explosiv e decomposition at 151-162 degreesC. This anomalous phenomenon stems charac teristic to the chemical structures involving C=N-N or C=N-O groups. (C) 20 01 Elsevier Science B.V. All rights reserved.