Thermal studies on cellulose cyclohexenephosphonate in air

Abstract

The flame retardancy of the cellulose cyclohexenephosphonate (CCHP) has been investigated by the kinetics of thermal degradation using differential thermal analysis (DTA) and thermogravimetry (TG) from ambient temperature to 700°C in dynamic air. Various parameters such as energy, entropy and free energy of activation have been calculated using the Broido method and transition state theory. For the decomposition stage of thermal degradation, the activation energy of CCHP has been found to be 133.83 kJ mol^-¹ which is lower than that of cellulose (187.0 kJ mol^-1). Higher char yield of CCHP as compared to cellulose leads to the conclusion that CCHP is a good flame retardant. The IR spectra of the chars of modified cellulose indicate formation of compounds containing C=O, C=C and P=O groups. The mechanism of thermal degradation of CCHP has been proposed.