马桑皮植鞣剂与铝盐结合鞣制性能及机理

Tanning performance and mechanism of Coriaria nepalensis bark vegetable tanning agent combined with aluminum salt

摘要:

以提取于马桑皮的植物鞣剂为原料，与铝盐进行绵羊酸皮结合鞣制，优化鞣制工艺并建立基于马桑皮鞣剂的植铝结合鞣制方法，对鞣制后皮革性能及鞣制机理进行研究。结果表明，当马桑皮鞣剂用量为酸皮质量的15%、Al3(SO4)2•18H2O用量为酸皮质量的20%、渗透pH为4.0、结合pH为4.5的条件下，皮革收缩温度可达110.5 ℃。皮革表观性能良好，增厚率为82.2%，抗张强度为10.0 MPa，撕裂强度为52.5 N/mm，断裂伸长率为76.8%，优于橡椀植物鞣剂结合鞣制的皮革。鞣制后皮革胶原纤维变粗，形成紧密的网状结构。马桑皮植物鞣剂能充分渗透至皮革胶原纤维中，并与其产生氢键交联。在结合鞣制时，铝盐与皮革胶原纤维中结合的单宁类成分产生络合，使交联作用增强，从而显著提高成革的热稳定性能和机械性能。

Abstract:

The vegetable tanning agent extracted from Coriaria nepalensis bark was used as raw material, and the combined tanning of pickled sheep skin was carried out with aluminum salt. The tanning process was optimized to establish a combined tanning method of Coriaria nepalensis bark tanning agent, and the leather performance and tanning mechanism were studied. The results of the experiment show that when the amount of vegetable tanning agent is 15%, the amount of Al3(SO4)2•18H2O is 20%, the penetration pH is 4.0, and the combined pH is 4.5, the shrinkage temperature of the tanned leather can reach 110.5 ℃. The tanned leather has good appearance properties, and thickness increase rate is 82.2%, tensile strength is 10.0 MPa, tear strength is 52.5 N/mm, elongation at break is 76.8%, which is better than the leather tanned by the combination of a commercially available valonia vegetable tanning agent. After tanning, the collagen fibers of the leather become thicker and form a tight network structure. The Coriaria nepalensis bark vegetable tanning agent and aluminum salt can fully penetrate into the collagen fibers of the leather and produce hydrogen bond cross-linking with them. During the combined tanning process, the aluminum salt is complexed with the tannins combined in the leather collagen fibers, which enhances the cross-linking effect, thereby significantly improving the thermal stability and mechanical properties of the tanned leather.