Investigation Into the Effect of Fumigation By Ethylene Oxide On the Color of Cotton

In order to determine the effect of ethylene oxide treatments on the physical properties of cotton fiber, mainly color, cottons of varying color characteristics where sourced and fumigated. Commercial quarantine treatments were carried out for 5 hours at 50^oC and for 24 hours at 21^oC, and the cottons were then tested by various methods to detect any differences. It was found that ethylene oxide treatments had no effect on physical properties such as length, strength and Micronaire of the fiber. The treatments did however result in a permanent change in the color value and subsequently the color grade of USDA Upland cottons. In most cases the reflectance value (Rd) decreased while the yellowness (+b) remained unaffected, which in essence means that the fiber has become darker. These changes in the reflectance values will result in the HVI instrument wrongly classifying the cotton one grade higher (i.e. worse). Color change detected in the Pima cotton did not appear to be permanent, and damage by ethylene oxide on Australian Upland cotton appeared not to be as apparent as noted with USDA calibration cottons. Further work is required to better understand the observed effects of the ethylene oxide fumigation treatments.