基于胶原湿热稳定性热力学本质的统一鞣革理论的构建及实证研究

Comprehensive the related principle of tanning chemistry, polymer physics and physical-chemistry, a unified tanning theory was constructed based on the thermo-dynamical nature of collagen’s hydrothermal shrinkage, the main points are as below: ① The function of tanning agents is displacing or merging some of the supra-molecular water so that a supra-molecular matrix could be formed around the triple helices of collagen and a “core—shell” structure is constructed. ② Tanning process does not alter the mechanism of hydrothermal shrinkage: its thermo-dynamical nature lies on the breaking of hydrogen bonds which provide the stability of the triple helices of collagen, the breaking of hydrogen bonds induces collagen’s conformational transfer and the collapse of “core—shell” structure, shrinkage is the appearance in macroscopic. The shrinkage temperature is determined by △H and △S during this process, i.e., Ts = △H/△S. ③ The“core—shell” structure formed by a good tanning should be long in average and rigid ; so that the △S is small and the △H is large during the collapse of “core—shell” structure, so that a higher Ts could be obtained.. For the confirming experiments: ① the tested samples from different tanning agents and tanning systems will be prepared systematize and scientifically. ② Hydrothermal isometric tension (HIT) method will be adopted to analysis the density and the stability of the cross-linking bonds between collagen molecules; the changing of chemical bonds between collagen molecules before and after shrinkage will be determined by high performance NMR and FTIR; the thermo-dynamical parameters during the shrinkage process will be accurately measured by DSC with varying-temperature techniques. ③Molecular dynamics simulation (MDS) was applied to confirm the new theory. ④ Guiding by the new unified tanning theory, 1- 2 tanning systems with Ts＞100℃ are intended to be developed.

综合鞣制化学、高分子物理和物理化学原理，基于胶原湿热收缩的热力学本质，构建统一的鞣革理论。要点有：①鞣剂的作用是取代部分超分子水，在胶原三股螺旋（芯）周围形成超分子基质（壳）而构成“芯—壳”结构单元。② 鞣制并不改变胶原的湿热收缩机制，其实质还是由于维持三股螺旋结构稳定的氢键破坏，发生构象转变而引起“芯—壳”结构塌陷；收缩温度决定于此过程的焓变和熵变，即Ts = △H/△S。③ 好的鞣革形成的 “芯—壳”结构单元尺寸大且均匀，“壳”的刚性强；这样， “芯—壳”结构塌陷引起的△S小，而△H大，因而Ts就高。.实证研究包括：①科学严谨地制备被测样品。②采用HIT分析维持胶原湿热稳定的化学键密度和类型；用高分辨NMR、FTIR表征收缩前后胶原化学键的变化；变温DSC技术测量胶原湿热收缩过程的热力学参数。③采用分子动力学模拟方法对理论进行验证。④在新理论指导下研发1～2种Ts＞100℃的鞣法。

综合鞣制化学、高分子物理和物理化学原理，基于胶原湿热收缩的热力学本质，构建统一的鞣革理论。要点有：①鞣剂的作用是取代部分超分子水，在胶原三股螺旋（芯）周围形成超分子基质（壳）而构成“芯—壳”结构单元。② 鞣制并不改变胶原的湿热收缩机制，其实质还是由于维持三股螺旋结构稳定的氢键破坏，发生构象转变而引起“芯—壳”结构塌陷；收缩温度决定于此过程的焓变和熵变，即Ts = △H/△S。③ 好的鞣革形成的 “芯—壳”结构单元尺寸大且均匀，“壳”的刚性强；这样， “芯—壳”结构塌陷引起的△S小，而△H大，因而Ts就高。.实证研究包括：①科学严谨地制备被测样品。②采用HIT分析维持胶原湿热稳定的化学键密度和类型；用高分辨NMR、FTIR表征收缩前后胶原化学键的变化；变温DSC技术测量胶原湿热收缩过程的热力学参数。③采用分子动力学模拟方法对理论进行验证。④在新理论指导下研发1～2种Ts＞100℃的鞣法。