Improvement in Tanning Properties of Natural Leather through Surface Modification assisted by CO2 Low-Temperature Plasma

Abstract

Low temperature plasma (LTP) technology is a green, solventfree,clean, efficient environment-friendly surface treatmenttechnology. The pioneering works were carried out by applyingLTP to surface modification of natural leather in order toimprove the chrome tanning exhaustion rate. The effects ofdifferent treatment time on tanning exhaustion rate, microstructure,chemical compositions, mechanical and organolepticproperties of leather were studied. The optimal CO2 plasmatreatment time is about 10 min, at which the chrome tanningexhaustion rate increases from 78.49% to 91.82% compared withuntreated leather. The SEM results show that some micro-pores,fissures, deep ravines and filamentous fibers can be observeddue to the surface etching effect. From the XPS analysis,compared with the untreated leather, the O1s concentration andthe O1s/C1s ratio of the 10min LTP modified leather bothincrease from 18.75% to 28.85% and from 0.258 to 0.479,respectively. The results show that appropriate LTP process caneffectively improve the chrome tanning exhaustion rate, whichreduces the emission of heavy metal chromium in waste liquorand also has a good synergistic effect on improving thecomprehensive performance of leather such as hydrothermalstability, physical-mechanical and organoleptic properties. TheLTP modification technology may be a new potential method forcleaner high-exhaustion chrome tanning technology.