Microwave Irradiation: An Innovative Routine to Promote Goat Skin Chrome Tanning Process

Abstract

The chemical reaction with microwave assistant has faster rate, higher yield and milder condition. In order to study the influence of microwave on chrome tanning process, the chrome tanning with microwave heating (MW) was carried out at different initial pH and terminal pH regraded as experimental samples and with water bath heating (WB) at corresponding condition was control in the study. The shrinkage temperature, chrome content and chrome distribution of wet blue were determined to obtain the influence of microwave on tanning effect. In addition, the pickled skins were modified by esterification and deamination and then the modified skins were tanned under microwave to know whether microwave would affect the combination sites between collagen and chromium complex or not. The results showed that microwave had positive effect on chrome tanning process, representing as higher shrinkage temperature and chrome content as well as more uniform chrome distribution for leather. Especially, the shrinkage temperature of MW leather exceeded 100°C when tanning terminal ending pH was only 3.3, indicating the tanning with microwave assistance could complete under a lower pH than the usual. Moreover, the combination sites between collagen and chromium of MW leather were the same as WB, indicating the effect of microwave could not change the combination sites. In sum, microwave could promote chrome tanning and make it finish at a milder condition, which might innovate the tanning technology and provide a new chrome tanning method in the future.