The Research On Preparation Of Filling Agents By Waste Wool

Waste wool, cattle hair, pig hair, feather and hair are commonly hair wastes and theirmain ingredient is keratin which is a very valuable renewable resources. Statistics show thatChina’s annual production of hair waste is more than four million tons, but people do not takeadvantage of these resources due to various reasons. As a result, a serious of resources waswasted and our living environment was polluted simultaneously. Therefore, the recycling ofhair waste has a very important economic and social value.This paper focus on the recycling of hair wastes for preliminary exploration. Thepreparation process conditions of keratin and leather filler material were investigatedrespectively. On the one hand, the keratin extracted from hair wastes could be used as rawmaterials for protein industries; on the other hand, through further processing, the keratin canbe used to synthesize leather filler materials to meet the demand of leather tanning industry.The keratin was extracted from waste wool by combinational method of acid-alkali. Theinfluence extent of different temperature, time, the dosage of hydrochloric acid, sodiumhydrogen sulfite and sodium hydroxide on the wool hydrolysis could be distinguished by theyield of keratin. The optimum conditions were as follows：the temperature was85℃，thehydrolysis time was130min, the liquid to solid ratio was1.2, and the dosage of sodiumbisulfite and sodium hydroxide was26%and30%respectively. The molecular weightdistribution of the hydrolyzate is as follows:1000Daltons or less account for29.01%,1000~3500Daltons account for53.12%,3500~7000Daltons account for2.66%, and the molecularweight above7000Daltons representing15.21%. Finally, the obtained keratin wascharacterized by infrared spectroscopy (IR) and the characterization results were comparedwith the wool IR spectrum to determine the consistency between them.The protein was precipitated gradually at the time of the pH of the solution was adjustingto its isoelectric point. And was then filtered, dried, milled, to obtain a higher purity keratinpowder.Keratin and ethanolamine was added to the reactor according to the proportion of2:1andstirred for20min at the temperature of110℃for further degradation and activation of keratin, then the keratin was purified by trichloromethane and the the purified keratin wasobtained.The activated keratin was acylated by maleic anhydride. The influence of temperature,time and the amounts of maleic anhydride on the acylation process could be distinguished bythe quantity of carbon-carbon double bond(C=C) in acylate. It is determined through a seriesof experiments that the optimum conditions were as follows：the temperature was76℃, theacylated time was126min, and the proportion of maleic anhydride and keratin was1:2. Afteracylation, the C=C of maleic anhydride were introduced into the polypeptide chain, then thereaction products were purified. Finally, the acylate was determined by IR.The keratin acylate was graft by acrylic acid, while this reaction requires a catalyst tooccur. The influence extent of different, graft time, and the dosage of acrylic acid and catalyston the acylation process could be distinguished by grafting efficiency and grafting percentage.It is achieved through a series of single-factor experiments that the optimum conditions wereas follows：m (acrylic)/m (acylate)=1.1, the dosage of catalyst was10%of the total mass ofthe monomers, the reaction temperature was74℃, the graft time was130min. Infraredspectroscopy shows that carbon-carbon double bond in acylate was disappeared and carboxylcontent was increased which indicating that the addition reaction with acrylic acid wassuccessfully and acrylic copolymer was obtained.Leather filling tests were performed by modified keratin filler，and its filling effects werecompared with the commodities fillers. Experimental results show that the modified filler maysignificantly increase the thickness and fullness and decrease the location difference of leather,while the leather softness, tensile strength, shrinkage temperature etc. were lesser than theeffect of commodities filler. In addition, multiple parallel experiments show that theperformance of homemade keratin filler materials wasn’t stabile enough, and its standarddeviation was larger than others.It is concluded from SEM that the homemade fillers and industrial fillers all have a goodeffect on separating fibers and increasing thickness of leather. And in terms of fiber dispersion,the homemade fillers was a bit poor than industrial fillers. However, as a new product, itsperformance was barely satisfactory.