ABSTRACT

Wool is sensitive toward the effect of alkaline solutions which are usually used in the dissolution of wool fibers to regenerate keratin. In this investigation, the effect of different alkalis on the chemical composition and the secondary structure of wool was studied. Wool was treated with equivalent amounts of alkali metal hydroxides (lithium, sodium, and potassium hydroxides) as well as alkaline earth metal hydroxides (strontium and barium hydroxides). The effect of these alkalis on wool was monitored using amino acid analysis, elemental analysis, carboxylic content, acid, and base combining capacity, urea-bisulfite and alkali solubility, and FTIR spectroscopy. Further structure elucidation was conducted by thermo-gravimetric analysis, differential scanning calorimetry, and X-ray diffraction pattern. Scanning electron microscopy was used to assign the alteration of the fiber morphology of the alkali-treated wool. The results of this investigation indicate that the effect of the used alkalis on wool is not similar. Cystine, glycine, and the basic amino acids are the most affected species in the treated wool. Some elimination reactions were involved during alkaline treatment of wool; namely decarboxylation, desulphydration, and deamination. The secondary structure of wool treated with Sr(OH)₂ and Ba(OH)₂ was changed from the α-helical structure into the β-sheet form.

摘要

羊毛对碱性溶液的作用很敏感，碱性溶液通常用于溶解羊毛纤维以再生角蛋白。在本研究中，研究了不同碱对羊毛化学成分和二级结构的影响。用等量的碱金属氢氧化物（氢氧化锂、氢氧化钠和氢氧化钾）以及碱土金属氢氧化物（氢氧化锶和氢氧化钡）处理羊毛。使用氨基酸分析、元素分析、羧酸含量、酸和碱结合能力、尿素-亚硫酸氢盐和碱溶解度以及 FTIR 光谱来监测这些碱对羊毛的影响。通过热重分析、差示扫描量热法和 X 射线衍射图进行了进一步的结构解析。扫描电子显微镜用于确定碱处理羊毛纤维形态的变化。这项调查的结果表明，使用的碱对羊毛的影响并不相似。胱氨酸、甘氨酸和碱性氨基酸是处理过的羊毛中受影响最大的物种。羊毛碱处理过程中存在一些消除反应；即脱羧、脱硫和脱氨。Sr(OH)处理羊毛的二级结构 即脱羧、脱硫和脱氨。Sr(OH)处理羊毛的二级结构 即脱羧、脱硫和脱氨。Sr(OH)处理羊毛的二级结构₂和Ba(OH) ₂从α-螺旋结构转变为β-折叠形式。