Green solvents, such as propylene carbonate (PC), can be used in leather processing to improve the efficiency of chrome tanning and reduce wastewater. Here we report a combined small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) study on PC and its efficacy as a carrier medium during chrome tanning. SAXS analysis on the collagen structure of chrome tanned leather using PC, compared to conventionally tanned leather using water, showed an increase in Cr uptake in addition to the more uniform penetration of Cr through the leather cross-section. The increased binding of Cr to the collagen matrix drives the decreased hydration environment of the collagen triple helix. Furthermore, DSC studies show a uniform hydrothermal stability for the PC samples due to the more even distribution of Cr through the collagen matrix. Understanding the mechanisms by which chrome tanning occurs in non-aqueous solvents can guide us towards a more sustainable future for the leather industry.

中文翻译：

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碳酸亚丙酯铬鞣过程中胶原结构的变化

绿色溶剂（例如碳酸亚丙酯（PC））可用于皮革加工，以提高铬鞣的效率并减少废水。在这里，我们报告了P​​C的小角度X射线散射（SAXS）和差示扫描量热法（DSC）的组合研究，以及其在铬鞣制过程中作为载体介质的功效。与使用水进行常规鞣制的皮革相比，使用PC进行铬鞣制皮革的胶原结构的SAXS分析显示，除了铬在皮革横截面上的渗透更均匀之外，铬的吸收量也有所增加。Cr与胶原蛋白基质结合的增加驱动了胶原蛋白三螺旋的水合环境降低。此外，DSC研究表明，由于Cr在胶原蛋白基质中分布更均匀，因此PC样品具有均匀的水热稳定性。