栲胶及其降解产物-金属Matrix及鞣性研究（一）

Study on Extracts and its Degradated Products-metal Matrix and Their Tanning Properties（ Ⅰ ）

制革近百年来，研究者一直在为探索多鞣剂鞣法机理而不懈努力，传统理论用键能高低以及配位场理论解释皮革的高湿热稳定性，认为皮胶原的湿热稳定性取决于鞣剂和皮胶原形成的横向交联键的强度和数量。但结合鞣本身是一个复杂的反应过程，随着对鞣制理论的深入研究，关于多鞣剂结合鞣赋予皮革高湿热稳定性，出现了不能用传统理论圆满解释的现象。有研究表明，一些没有鞣性的或鞣性很弱的物质与单宁结合鞣时可以产生较高的湿热稳定性；鞣剂与胶原纤维间的交联度不是决定成革收缩温度的唯一因素。如果多种鞣剂之间能够形成某种稳定结构的化合物填充于胶原纤维间，支撑纤维构象，在皮胶原受热时，只要这些配合物结构不被破坏，则对胶原纤维的支撑就不会改变，胶原纤维的构象转变就会受阻，宏观上就表现为成革收缩温度的提高。我们将这种多鞣剂之间形成的稳定化合物定义为配合物（Matrix）。本文化文验证了Matrix的存在及其结构特征，并对此研究了传统结合鞣与对应组分Matrix鞣革的收缩温度及耐热稳定性。 本论文从生产实践的角度出发，主要对比研究了栲胶及降解产物-金属配合物Matrix及栲胶-金属盐分步鞣革的鞣革性能。选择未改性的荆树皮栲胶、落叶松栲胶、橡槐栲胶以及荆树皮栲胶氧化降解产物Wat-1、Wat-2（Wat-2的降解程序大于Wat-1，平均分子量小于Watr-1）作为有机配体；选择金属盐硫酸铬、硫酸铝作为金属离子中心配体。鞣革方法为传统的先植后铬、先植后铝分步结合鞣以及Matrix溶液鞣革。即栲胶及降解产物与金属盐在一定条件下混合并充分反应，形成Marix溶液，用此溶液来鞣革。 结果表明，栲胶及降解产物-金属络合反应溶液中有沉淀产生。栲胶及降解产物与硫酸铬反应较为温和，未见有大量沉淀产生；栲胶及降解产物与硫酸铝混合后，发生较为剧烈的络合反应，溶液中迅速产生大量沉淀。 紫外光谱的实验结果表明，在一定条件下栲胶及春降解产物-金属盐的混合溶液中的确有新的化合物生成。通过对比反应前后的红外吸收光谱，结合表明栲胶及栲胶降解产物Wat-1、Wat-2与硫酸铬、硫酸铝的配合物中看到C-0-M中金属配位键的吸收峰，并可能有环的结构存在，也证实了栲胶及降解产物与硫酸铬、硫酸铝确实形成了配合物Matrix。 收缩温度及DSC测定结构表明，栲胶及降解产物在不同程度上提高了皮胶原的耐热稳定性。栲胶及降解产物Wat-1与硫酸铬、硫酸铝配合反应生成的配合物Matrix与浸酸猪皮作用后发现，以Matrix溶液鞣革，得革的收缩温度和相变温度均低于相应组合按照栲胶-金属顺序分步鞣革的收缩温度和相就温度。推测可能是因为分子尺寸的关系，Matrix分子过大难以向皮内渗透。但分子量较小的收缩温度和耐热稳定性均高于同组分以及栲胶War-1分步鞣革的结果。从而在一定程度上证明皮胶原产生高相应温度即协同效应的主要起因是皮胶原纤维间的“多支撑稳定结构”-Matrix。

Abstract：Inhundreds of years, a lot of efforts had been done to research the mechanism of multi-tannages, Hydrothemmal stability of collagen had been explained by traditional theory of bond energy and number between tanning agents and collagen gibres through some operations, But as multi-tannages is a very complicated process, with the deepening research on tanning theory, there have being more and more facts than can not be explained perfectly through ,tradituonal ,theory. Some tesearches showed that some materials which can hardly combine with collagen also give high shrinkage temperature（TS）to leathers. In addition, synergistic effect had been tanning agents and collagen fibers is not the onhy contributor to the hydrothermal stability of leather, If some kinds of stable compounds with property size exist between collagen fibers at right posigions and support the formation of collagen fibers.when the collagen,fibers are heated the structure of the compounds does not be destroyed, thus the conformation of the collagen fibers will remain the same. That is to say the collagen fibers will not shrink and the high Ts will be achieved. The compounds with stable structure was defined as ＂Matrix＂. From view of practical operation, extract-metal matrixes were studied in this paper. Unmodified extracts inclding wattle extracts, larch extracts,valonia extract and wattle oxidzing degradation products Wat-1, Wat-2（the latter one was higher oxidizing degree products and lower average molecular weight）and metal salts Cr2（SO3）3, A12（SO4）3 were chosen as the reactant. The results showed that the there were sedimedts when extract reacted with metals. More sediments could be seen in the reacting system of extract-Al（Ⅲ） The structure of matrix was analyzed by UV and FT-IR. The results of UV confirmed that in the condition of experiments, matrix of extract-metal existed. By contrast of the spestras of FT-IRpeaks of matrix of extract-metal existed, By contrast of the spestras of FT-IR peaks of matrix of extract-Cr（Ⅲ） andextract Al（Ⅲ）reflecting the absorption of the metal ion of C-O-M can be seen. DSC results demonstrated the influence of different tannage system to the hydrothermal stability of collagen fibers.The reacting system of matrix of wattle extract, larch extract, valonia extract and Wat-1 could not give higher hydrothemal stability than corresponding dombination tannages. It was confired that the size of molecular may be the main reason, matrix with big molecular size could hardly penetrate into the pickled pig skin. In the contrast wattle extract oxidzing modefied products Wat-2 which has smaller molecular size than unmodified and Wat-1 was used in the study. However higher Ts and hydrothermal stability were achieved by matrix of Wat-2 with Cr（Ⅲ）amd Al（Ⅲ）than leathers tanned by combination tannage Thus the contribution of Matrix to the hydrothermal stability of collagen fibers could be proved in some extent.