Improvement in Tanning Properties of Natural Leather Through Surface Modification Assisted by CO2 Low-Temperature Plasma

Low temperature plasma (LTP) technology is a green, solvent free, clean, efficient environment-friendly surface treatment technology. The pioneering works were carried out by applying LTP to surface modification of natural leather in order to improve the chrome tanning exhaustion rate. The effects of different treatment time on tanning exhaustion rate, microstructure, chemical compositions, mechanical and organoleptic properties of leather were studied. The optimal CO2 plasma treatment time is about 10 min, at which the chrome tanning exhaustion rate increases from 78.49% to 91.82% compared with untreated leather. The SEM results show that some micro-pores, fissures, deep ravines and filamentous fibers can be observed due to the surface etching effect. From the XPS analysis, compared with the untreated leather, the O1s concentration and the O1s/C1s ratio of the 10min LTP modified leather both increase from 18.75% to 28.85% and from 0.258 to 0.479, respectively. The results show that appropriate LTP process can effectively improve the chrome tanning exhaustion rate, which reduces the emission of heavy metal chromium in waste liquor and also has a good synergistic effect on improving the comprehensive performance of leather such as hydrothermal stability, physical-mechanical and organoleptic properties. The LTP modification technology may be a new potential method for cleaner high-exhaustion chrome tanning technology.