【作者】 马金辉；

【导师】 付丽红；

【作者基本信息】 山东轻工业学院 ， 皮革化学与工程， 2007， 硕士

【摘要】 研究了有机酸、有机酸盐的脱铬机理和工艺。采用酸、碱、盐、机械相结合的方法,对皮革含铬固体废弃物进行松散、脱铬,制备丝状胶原纤维。采用扫描电子显微镜（SEM）对制得的纤维进行表征,结果表明,胶原纤维的三股螺旋结构基本保持完好,局部被破坏,其原因是被碱、酸水解所致。研究了葡萄糖浓度、溶液温度、时间对Ca（OH）₂溶解度及灰液组成和pH的影响。结果表明,葡萄糖和Ca（OH）₂反应生成的葡萄糖化钙能极大的提高Ca（OH）₂的溶解度;葡萄糖分解物聚合使溶液变黄、pH值降低、Ca（OH）₂溶解度降低。从络合物解聚、氢离子（H⁺）取代和有机酸根阴离子取代三方面探讨了有机酸的脱铬机理,认为H⁺的取代和有机酸阴离子的取代起主要作用。水解作用是配聚作用的基础,铬主要是以羟配络合物的形式存在,氧配聚络合物比较少。羟配聚络合物和氧配聚络合物都很稳定,均不容易接受质子,仅靠铬配合物的解聚作用,脱铬效果比较差。高浓度的H⁺与羧基结合力强,可以封闭胶原的电离羧基,削弱胶原羧基与铬络合物结合,将铬络合物取代达到脱铬的目的。草酸根和柠檬酸根可以取代胶原羧基离子且与铬有很强的配位亲和力,生成稳定的有机酸铬络合物。研究了草酸和柠檬酸盐脱铬时,反应产物草酸铬络合物和柠檬酸铬络合物的最大吸收波长、脱铬时溶液pH值变化,确定了草酸和柠檬酸盐脱铬的工艺条件。脱铬后制备的丝状胶原纤维的干热收缩温度是185℃,终点收缩温度是225℃,其最终收缩率为44%。更多还原

【Abstract】 Adopting the method of combination of acid, alkali, salt and machinery, the chrome shavings are relaxed and dechromed, as a result, the threadlike collagen fibers are prepared. The threadlike collagen fibers prepared are characterized, and the result indicates that the triple helix structure basically keep in good condition, but the partial sites are destroyed, of which the reason is that the collagen fibers are hydrolized by aicds or alki.The effects of the glucose concentration、the temperature of solution and the time for the solubility of Ca（OH）₂, the constitution of lixivium and the pH value of the solution are investigated. The results indicate that, the C6H12O6·Ca（OH）₂ produced by both Ca（OH）₂ and glucose can advance the solubility of Ca（OH）₂ evidently; After decomposition of glucose, it polymerizes to the result that the color of solution turns yellow, at the same time, the solubility of Ca（OH）₂ and the pH value of solution decline.The mechanism of organic acid on the dechroming from chrome shavings is studied in terms of the depolymerization of complex, the replacement of H⁺ and the replacement of organic acid radical anion. It is found that both the replacement of H⁺ and the replacement of organic acid anion take an important part in the course of the dechroming of organic acid.The maximum absorbed wavelength and variation of the pH of the solution of the reaction product of dechroming of oxalic acid and citrate from chrome shavings are chromium oxalic and chromium cirtrate, and the technological conditions of the dechroming with oxalic acid citrate from chrome shavings are determined.After dechroming the dry heat shrinkage temperature of the threadlike collagen fibers is 185℃, and the terminal poit shinkage temperature is 225℃, and eventually, the rate of shinkage is 44%.更多还原