The spontaneous igniting behaviour of oil-contaminated cotton

The incidence of spontaneous ignition in bales of raw cotton and piles of cotton cloth during processing and laundering suggests that self-heating reactions occur within, which raise internal temperatures to greater than 300–350°C when ignition can occur. The cause of these self-heating reactions is not well understood, but believed to be associated with the presence of waxy deposits on raw cotton and oily surface contaminants on cotton cloth generally. This study shows that contamination of pure cotton with refined cotton, peanut and rapeseed oils can promote ignition of 102 mm cubes of fabric at temperatures below 200°C. Thermal analyses (DTA and TGA) have been used to demonstrate that the source of internal exothermic activity is oxygen-dependent and a low temperature (229–246°C) exotherm for each oil-contaminated cotton has been identified. Cursory kinetic analysis shows that the activation energy for this exotherm is 61 kJmol−1 for cotton seed, 88 kJmol for rape seed and 56 kJmol−1 for peanut oil-contaminated cotton.