Preparation Of Keratin Films Reinforced By Wool And Study On Their Structure And Properties

The wool resource is shortage while the applications of thick and short wool areignored. It is estimated that a large amount of wool wastes were disposed every year. Thesewastes are abundant in keratin. At the same time, there have been few reports onregenerated wool keratin. A homogeneous composite made of keratin and wool wasprepared in this study, and the structure was studied, which give an academic reference onthe potential application of keratin in the field of biomedicine, degradable wrapper, andcosmetics film, and provide a new way to reuse other keratin wastes.Firstly, urea/sodium sulfide/SDS method was used to dissolve wool, then the woolkeratin solution was achieved, which was cast to obtain pure keratin film, and the basicstructure of pure keratin film was determined. There are α-helix structure, β-sheet andrandom coil conformations in the pure keratin film, as same as in wool fiber. Comparedwith wool fiber, the crystallinity of keratin decreased.Secondly, keratin solution and PVA solution were mixed in different proportions, thendifferent contents wool fiber were cast into keratin/PVA mixed solution, and variouswool/keratin/PVA homogeneous composite films were formed. The surface morphology,molecular structure, aggregation structure, thermal property, mechanical property and airpermeability were studied. The results showed that the keratin/PVA films showedtwo-phase macro level, and the join of wool fiber made composite films unflatness. Withthe increase of PVA content, the structural characteristic of blended films was shifted fromkeratin type to PVA type. When the keratin and PVA were blended in the ratios of20:80,the mechanical properties of blended films were greatly improved. The join of wool fiberdecreased the mechanical properties of composite films. With the high content of PVA,8%-16%of wool fiber in the composite films had better flexibility than those had no woolfiber ones. The contents of PVA or wool fiber had no obvious influence in air permeabilityof the composite films.Finally, the influence of fiber length in the mechanical properties of composite filmswas discussed. The results indicated that composite films with longer fiber had better mechanical properties than those with shorter fiber ones.