Preparation And Characterization Of High Keratin Content Keratin/PEO Nanofibers

Keratin is a kind of fibrous protein which derived from animal skin and its derivatives.It has been widely used in the filter materials,biomedical materials and pharmaceuticals fields because of so many excellent characteristics,such as cell affinity,low immunity,good biocompatibility and biodegradability.The dominant component of human hair fibers is keratin.Thousands of tons of human hair fibers can be produced by more than one billion Chinese.Serious damage to natural ecosystem and severe energy lose will be occur if human hair fibers are directly abandent.Therefore,the development and utilization of natural keratin fibers have a huge economic and social benefits.In this text,reduction was selected and keratin was extrated from human hair with the mixture system of 2-mercaptoethanol/urea/sodium dodecyl sulphate.The dissolution rate of keratin human hair fiber was as high as 68.4%.Comparative analysis of FTIR spectra,thermal stability and X-ray diffraction between human hair and keratin powder showed that 2-mercaptoethanol act as a reducing agent can break the disulfide bonds in keratin molecules to form keratin consist of cystine residues.Compared with human hair fiber,?-helix structure in keratin molecular decreased,and?-sheet structure increased.Crystallinity and thermal stability improved with a certain degree.Keratin solution and poly(ethylene oxide)(PEO)were blened at different mass ratio and keratin/PEO nanocomposite membrane were prepared by electrospinning.The optimized process parameters of spinning keratin/PEO nano fibers were detennined as voltage 20KV,perfusion speed 0.3ml/h,and receiving distance 13cm.The study on the morphology,molecular structure,thermal properties and crystallinity of the blended nanofibers showed that the diameters of keratin/PEO nanofibers decreased gradually with the increase of keratin content,and the average diameter decreased from 310nm(keratin/PEO = 30/70)to 82nm(keratin/PEO = 90/10).The fiber homogeneity was enhanced and the characteristic peaks of keratin were strengthened steadily.The structural characteristics were gradually changed from PEO to keratin.In addition,the addition of PEO can break the self-assembled structure of keratin to form a more stable secondary structure,thus improving the stability of nanofibers.It was also found that the highest blending ratio of keratin/PEO was 80/20 when the nanofibers without beaded and well-formed nanofibers were obtained.In order to improve the content of keratin in the keratin/PEO blends,EGDE and glutaraldehyde were used to modify the blended solution.It was found that cross-linking could effectively enhance the spinnability of the solution.The effect of EGDE was ideal,and the ratio of keratin/PEO was as high as 90/10.To solve water-soluble defects of keratin nanofiber material,keratin/PEO nanofiber membranes were post-treated by heat treatment and genipin cross-linking and then SEM,contact angle,FTIR,XRD and TG were investigated.The results showed that water resistance,crystallinity and thermal properties of the nanofibers after heat treatment and cross-linking with genipin were improved.The nanofibers were insoluble in water,the contact angle increases,but the nanofibrous membranes still have good hydrophilicity.