PYROLYSIS DECOMPOSITION KINETICS OF CELLULOSE-BASED MATERIALS BY CONSTANT HEATING RATE MICROPYROLYSIS

Fibrous, powdered fibrous, and acid-washed celluloses, newsprint, and paper dunnage were examined by Pyromat micropyrolysis to determine vol atile organic compound evolution kinetic parameters. For the cellulose samples, the interpolated T-max values (temperature of maximum evolut ion rate for a constant heating rate) indicate the fibrous cellulose i s the least reactive. The fibrous cellulose samples have activation en ergies and frequency factors around 43 kcal/mol and 5 x 10(12) s(-1). A three-parameter nucleation kinetic model gave the best fits to the r eaction profile, which is narrower than a first-order reaction. Newspr int and dunnage were also examined. The interpolated T-max values indi cate that dunnage is more reactive than the newsprint, and both are mo re reactive than the cellulose samples. Newsprint and paper dunnage ha ve energy distributions that are similar but shifted from each other. Because of the diversity in chemical structure in the papers, the best fits were found using a discrete energy distribution method, which us es parallel first-order reactions. The newsprint has a principal activ ation energy of 43 kcal/mol and a frequency factor of 5 x 10(12) s(-1) , consistent with cellulose being the predominant component. The dunna ge has a principal activation energy of 40 kcal/mol and a frequency fa ctor of 9 x 10(11) s(-1) Pyrolysis-MS measurements indicate that the d ifference between the total mass loss and organic evolution profiles i s only a few degrees and cannot account for the 15-20 degrees C differ ence between decomposition temperatures measured by Pyromat and some T GA results in the literature.