Preparation Of Oxidized Cellulose Cross-linked Modified Wool Keratin Materials And Its Properties

Wool keratin is the most important component of wool fiber,and it has entered the field of human research because of its good biocompatibility,biodegradability and regenerability.In this paper,the keratin was extracted from wool yarn by the reduction method(R)and the molten urea method(U),and the two keratin proteins were analyzed by infrared spectroscopy and molecular weight.The keratin solubility and viscosity were used as evaluation indexes to explore the solvent and solvent ratio required for the keratin re-dissolution process.The results shows that both keratin proteins retain a complete amide structure with molecular weights of17-54 KD and 14.4-25 KD,respectively.The keratin re-dissolution process shows that keratin has the best solubility in 88%formic acid or 0.08 mol.L~-11 NaOH solvent,and keratin could also be dissolved in 0.08 mol.L~-11 NaOH with DMSO or DMF,and 88%of formic acid in a complex solvent with DMSO or DMF,but with the addition of DMSO or DMF,the solubility is reduced.The keratin extracted by R method and U method were modified by self-made oxidized cellulose with average particle size of 0.893?m and aldehyde group content of 64.17%.Then the modified keratin films and aerogels were prepared and characterizated.The results shows that when the content of oxidized cellulose in the composite membrane is 15%,the tensile strength of the two modified membranes reach the maximum of 4.49 MPa(R method)and 3.90 MPa(U method),which is increased compared with the pure keratin membrane 5.24 and 5.96 times;the elongation at break increased from 32.50%to 73.33%(R method),and 25.73%increased to54.86%(U method).SEM characterization confirms that the texture and surface of the two modified membranes are gradually reduced,the surface is smooth,and oxidized cellulose and keratin achieves good compatibility.Infrared spectra shows that the aldehyde peak disappeares in the modified membrane,and a new C=N stretching vibration absorption peak in the Schiff base appeares,indicating that the oxidized cellulose in the composite membrane is chemically crosslinked with keratin.The swelling ratio,relative weight loss rate and water content of the modified keratin membrane are reduced,and the water resistance is greatly improved.For modified aerogels:when the volume fraction of modifier is 10%,the compressive strength and compressibility of the two modified aerogels are the largest,and the maximum pressure is 1times and 2.15 times of that the aerogel alone;SEM observation shows that the density and porosity of the modified aerogel increased with the increase of oxidized cellulose content;XRD shows that the aerogel crystallinity decreased after the modifier.However,the mechanical properties of the modified membrane and aerogel have not reach a high level and need further study.