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.