An investigation of the kinetics of cellulose degradation under non-isothermal conditions

The degree of polymerization (DP) of a polymer system subjected to non-isothermal depolymerization is examined kinetically with a preliminary application to the study of cellulose degradation. An equation for the time dependence of the DP observed under non-isothermal degradation using a linear temperature ramp is derived from the relevant isothermal kinetic equations. An iterative computer-based method of fitting non-isothermal degree of polymerization (NlDP) data is also presented. The activation energy and the Arrhenius A-factor associated with the depolymerization process can be varied independently to achieve an optimized fit to experimental NIDP data and may be used to calculate the predicted lifetime of the polymer in service. The potential of NIDP data analysis to quickly deliver these kinetic parameters is identified and the confidence ranges in the predicted lifetimes derived from NIDP data analyses appear to be similar to those derived from isothermal analyses of DP data. Experimental NIDP data support the notion that the prolonged degradation of cellulose does not produce oligomers of DP much less than ca. 200. (C) 1998 Elsevier Science Limited. All rights reserved.