Thermal and spectral studies on cellulose arylthiophosphates in air

Abstract

The thermal behaviour of cellulose and cellulose arylthiophosphate samples have been studied using DTA and TG techniques from ambient temperature to 600°C in static air atmosphere. First exotherm in DTA curves of cellulose arylthiophosphate samples caused by the decomposition process has been found to be lower than that of pure cellulose. Broido method is used to obtained various kinetic and thermodynamic parameters from TG curves. For the decomposition stage of cellulose arylthiophosphate samples, the values of the activation energies are found to be in the range of 59.10-80.77 kJ mol^-1 and are lower than that of cellulose (218.73 kJ mol^-1). The EPR signals indicate the formation of very few free radicals during the thermal degradation of cellulose and cellulose arylthiophosphate samples. Higher char yield of cellulose arylthiophosphate samples as compared to cellulose lead to the conclusion that cellulose arylthiophophates are good flame retardants.