尿素对皮胶原热降解行为的影响及其可逆性

Influence of Urea Process on Thermal Degradation Behavior of Collagen Fibers

采用热重法（TG）和微分热重分析法（DTG）研究了经过不同浓度尿素溶液处理的皮胶原纤维的热降解行为，用Coats—Redfem法计算了其热降解活化能，得到未处理皮胶原纤维和不同浓度尿素溶液处理后的皮胶原纤维的热降解活化能范围为82．8～239．2kJ／mol。皮胶原纤维的热降解活化能随尿素浓度的增大先减小后增大，在浓度为3．0mol／L时活化能最小，浓度很大（〉6．0mol／L）时活化能与未处理皮胶原纤维的接近。尿素浓度较低（3．0mol／L）时，水洗前后皮胶原纤维的热降解活化能变化较大；浓度很高（9．0mol／L）时，水洗前后活化能变化不大。水洗后皮胶原纤维的热降解活化能和未经过尿素处理的皮胶原纤维基本相同，说明水洗后皮胶原纤维的内部结构已回复到原来的状态，尿素对皮胶原纤维的作用是可逆的。

The thermal degradation behaviors of the collagen fibers processed by urea were analyzed with thermogravimetry （TG） and differential thermogravimetry analysis （DTG）. The thermal degradation activation energies of different urea processed samples were calculated by Coats -Redfern method, and the thermal degradation activation energies were found to be in the range of 82.8 Ll/mol -239.2 kJ/mol. The results show that with increasing the urea concentration, the thermal degradation activation energy of the collagen fibers increased followed by a decreasing. The lowest value is found at the urea conceatration of 3.0 mol/L. The thermal degradation activation energy of the sample processed at a higher urea concentration solution （〉6.0mol/L） is almost the same as the sample without a urea - processed history. The urea processed samples are water washed to obtain urea processed - water washed samples, and the samples are studied for thermal degradation behaviors. Obvious changes are found in thermal degradation activation energies between samples before and after water washing when the urea concentration （3.0mol/L） is at a low level. When the urea concentration is high （9.0mol/L）, the change in thermal degradation activation energy of samples before and after water washing is small. No matter whether the urea Concentration is high or low, the thermal degradation activation energy of the samples recovered their original level, indicating that the internal structure of the collagen fibers has reverted to their original state and the influence of urea process on the collagen fibers is reversible.