Research On Woolkeratin Extraction And Itsanti-felting Application

China is one of the top wool produced and used countries in the world. Every year, a largenumber of unspinnable wool fibers are abandoned in wool textile industry. At the same time, withthe improvement of people’s living standard, the number of abandoned wool textiles is increasingsharply. This is not only a waste of resources, but also a pollution of environment. Nowadayspeople pay more and more attention to environmental protection and the reuse of textiles isbecoming one of the most important parts. The extraction of wool keratin from the abandonedwool fibers can turn “waste” into “wealth”, which is in accordance with the growing trend towardsgreen and sustainable development. Wool keratin, one kind of natural green bio-material, hasalready attracted much concern. The development of efficient, economical and eco-friendly woolkeratin extraction technology has turned out to be an important research subject.This paper used the superheated water method, enzyme method and reductive method for theextraction of wool keratin. By the modern analysis methods, the structure and properties of keratinextracted by the three methods were compared. The application of wool keratin obtained byreductive method in anti-felting finishing of wool fabric was also discussed. The finishing processwas optimized and the optimal anti-felting finishing process was determined. At the same time,through testing amino acid content of wool fabric and observing SEM photographs of wool fabric,the mechanism of anti-felting process was discussed.Superheated water is emerging as a green solvent in recent years. In use of the uniqueproperties of water in the superheated condition, the keratin which is insoluble and hard todegrade can be dissolved in superheated water without using any additional chemicals. In thispaper, waste wool was degraded by superheated water to extract keratin. Sodium dodecyl sulfatepolyacrylamide gel electrophoresis(SDS-PAGE), MALDI-TOF-MS, Fourier transform infraredspectroscopy with attenuated total internal reflectance mode measurement(FTIR-ATR), wide-angle X diffraction (WAXD), Thermogravimetry (TG) and Amino Acid Analysis were usedto analyze the structure and properties of the obtained keratin (S-keratin). And the S-keratin wascompared with the keratin obtained by enzyme method (E-keratin) and reductive method(R-keratin). The results indicated that the solubility of wool and the yield of S-keratin were89.15%and81.46%respectively. The molecular weight distribution was <1.6kD, indicating thatthe disulfide bonds in S-keratin were partly broken, and the S-keratin showed peptide. The proteinmolecular weight of E-keratin was about10kD. The reductive method got large molecular weightkeratin, and the molecular weight distribution was between40kD and55kD. In addition,S-keratin’s thermal stability was a little poor comparing with E-keratin and R-keratin.Because the keratin extracted by reductive method was with large molecular weight and itscoarse solution without dialysis could be directly used in wool fabric finishing. So it waseconomical, practical, easy to industrialize. Therefore, the application of keratin coarse solutionobtained by reductive method in anti-felting finishing of wool fabric was also discussed in thispaper. Different processes were discussed in anti-felting finishing of wool fabric. The optimalfinishing conditions were obtained by analyzing the effect of anti-felting. The results indicatedthat the reductive pretreatment showed positive effect on anti-felting finishing. The shrinkage ofwool fabric treated with the optimal conditions decreased from16.84%to1.82%, satisfied withthe specification of TWC TM31. The treated wool fabric showed good strength retention.Under the optimal finishing process, through observing the SEM photographs of wool fabricand testing amino acid content of wool fabric in the hydrolysate, we analyzed content changes ofdisulfide bond in the pretreated fabrics and treated fabrics by R-keratin to explore the mechanismof keratin anti-felting finishing. SEM photographs showed that keratin had obvious accumulationin wool fiber surface, which could reduce the directional friction effect of wool scale layer and getant-felting effect. The analysis results of amino acid content showed that cystine content of thepretreated fabric reduced from4.19%of the original fabric to2.78%. And the cystine content ofthe treated fabrics by R-keratin rose to3.28%. It showed that the presence of reducing agent coulddestroy the disulfide bond of wool fabric to a certain extent and generated reactive sulfydryl.Under the keratin solution finishing, a part of the reactive sulfydryl of keratin and disulfide bondof the wool fabric took place exchange reaction and generated stable chemical bonds ofKeratin-S-S-Wool. Therefore durable finishing effect was achieved.