A study on the thermal decomposition temperature (TDT) and critical ambient temperature (CAT) of cotton
Cotton is a flammable material and some cottons would decompose or even self-ignite at bad storage and transport conditions. This paper studied the spontaneous combustion of cotton from the aspect of thermal decomposition temperature (TDT) and critical ambient temperature (CAT). From Fourier transform infrared spectroscopy analysis and chromatographic and mass spectrometric analysis, significant thermal decomposition was detected at the temperature of 210 ° C, which indicated that the TDT of cotton was around 210 ° C. From TG analysis and small-scale CAT test, activation energy of cotton and CAT of small cotton stack were obtained. Then, CATs of the cotton stacks with different dimensions were calculated based on Frank-Kamenetskii theory. With the dimensions l increased from 0.2 to 3.2 m, the CATs of cotton decreased from 195.0 to 137:9° C. The TDT of cotton was higher than these CATs, and the differences between TDT and CAT of cotton varied from almost 15-70 ° C (with the dimensions l increased from 0.2 to 3.2 m). As the experiments and calculation of the CATs were very complicated and time-consuming, the CATs of cotton can be estimated if the TDT was known. The result of this paper was especially meaningful for evaluating the risk of spontaneous combustion of cotton and speculating the reason of cotton fire.