A novel method to enhance the efficiency of aldehyde tanning agents via collagen amination.

The utilization of chromium free tanning agents generates lots of pollutants such as chromium containing wastewater and sludge. Besides, trivalent chromium may be converted into carcinogenic hexavalent chromium under certain conditions, causing permanent harm to the human body. Therefore, the promotion of chromium free tanning technology is extremely significant. In this study, it reports a green strategy to build a novel tanning system via the amination of collagen fibers. Leather collagen was aminated by diethanolamine to improve the positive charge and number of amino groups. This allowed the regulation of functional groups in collagen fibers and enabled the high employment of aldehyde tanning agents. On this matter, experimental work combined with molecular dynamics simulation was used to investigate the enhancement mechanism of amination. Collagen fibers aminated by diethanolamine achieved better aldehyde tanning effect than untreated collagen fibers, such as a higher shrinkage temperature (87.5 °C), dyeing absorption (74.6 %), and lower free formaldehyde content (160.8 mg/kg). This work provided a novel strategy for the establishment of a green and efficient chromium free tanning system.