On the degradation evolution equations of cellulose

Abstract

Cellulose degradation is usually characterized in terms of either the chain scission number or the scission fraction of cellulose unit as a function of degree of polymerisation (DP) and cellulose degradation evolution equation is most commonly described by the well known Ekenstam equations. In this paper we show that cellulose degradation can be best characterized either in terms of the percentage DP loss or in terms of the percentage tensile strength (TS) loss. We present a new cellulose degradation evolution equation expressed in terms of the percentage DP loss and apply it for having a quantitative comparison with six sets of experimental data. We develop a new kinetic equation for the percentage TS loss of cellulose and test it with four sets of experimental data. It turns out that the proposed cellulose degradation evolution equations are able to explain the real experimental data of different cellulose materials carried out under a variety of experimental conditions, particularly the prolonged autocatalytic degradation in sealed vessels. We also develop a new method for predicting the degree of degradation of cellulose at ambient conditions by combining the master equation representing the kinetics of either percentage DP loss or percentage TS loss at the lowest experimental temperature with Arrhenius shift factor function.