Study On The Preparation And Performance Of Cellulose/keratin Composite Materials

Keratin and cellulose as the most abundant organic material resources on earth?were not used widely.At present?the application and development of cellulose/keratincomposite materials are still in infancy stage. The reason is that the keratin is notmeltable and not soluble in usual solvents due to the mechanically strongthree-dimensionally linked networks, which are built up by large number of disulfidebonds. A major drawback of cellulose material, which limits its utilization, is its lowstrength, although cellulose has been applied in some fields.In order to evaluate the mechanical properties of pure cellulose film and improvethe efficiency in keratin utilization?the composite films were made by mixing keratinsolution and cellulose solution using EGDE as crosslinker by cross-linking betweenmolecular chains. The comprehensive evaluation of chemical structure,thermalstability?surface morphology and mechanical strength were performed by FTIR,TGA,SEM and tensile machine. A series of experiments had been designed as follows:(1) Keratin was extracted from the wool by the chemical reduction method and theeffect of adding sodium dodecyl sulfonate(SDS) was studies.The results showed thatthe molecular weight of the keratin generally distributed from50to70kD; In thesecondary structure, the proportion of ?-helix structure decreased while the proportionof ?-sheet structure and random coil structure had increased; the yield of keratinincreased from56%to78%after the addition of SDS in the dialysate, without causingany effects on the molecular weight and structure of the extracted keratin.(2) Thedifferent composite films were prepared by mixing keratin solution andcellulose-NMMO solution using glutaraldehyde or EGDE as crosslinkers. The resultsshowed that the thermal stability and mechanical strength of pure cellulose usingmethanol as dialysate were better than the one using water as dialysate; Measurementsof these composite films without crosslinker showed testing shows that theirmechanical properties and thermal stabilities decreased gradually with increase inkeratin content. However, the mechanical properties and thermal stabilities ofchemically crosslinked films using EGDE as crosslinker improved significantly.(3) The cellulose/keratin composite fibers were prepared, in addition, the conditions ofkeratin-cellulose mixture spinning process and the rheological properties of spinningsolution were explored preliminary. The results showed that spinning solution werepseudo plastic fluid and the viscosity was enlarged with the increase of keratin;Thetensile strength of composite fibers were better than the one of pure cellulose fiber,but the elongation decreased.The tensile strength of composite films or fibers improved, which realized thepurpose of experiment. However, the selection and the amount of crosslinker needfurther research.