Lifetime prediction and kinetic parameters of thermal decomposition of cashew gum by thermal analysis

The thermal decomposition kinetics of cashew gum, an exudate polysaccharide from A. occidentale L., has been investigated by thermogravimetric analysis in nitrogen and air atmospheres and non-isothermal conditions. The heating rates were of 5, 10, and 20 K min−1 and gas flow of 20 mL min−1. The NETZSCH Thermokinetics 3 software estimated the activation energy and pre-exponential factor with Friedman and Ozawa–Flynn–Wall methods. Multivariate nonlinear regression analysis was applied to estimate a probable mechanism and lifetime prediction and to describe the thermal decomposition. The results obtained showed that the energy activation is dependent on the conversion degree for both atmospheres. For nitrogen, the most appropriate kinetic model was estimated with two consecutive stage reactions (FnF1 model). For air, the best model was estimated with six stages consecutive and completive reactions (FnFnFnFnFnFn model).