Preparation And Study On The Structure And Properties Of Wool Keratin Films

The wool resource is shortage. It is estimated that a large amount of wool wastes were disposed every year. These wastes include wool byproducts of the wool textile industry, poor quality raw wools not fitting for spinning, and many other animal fibers. These wastes are abundant in keratin. Therefore, recently the study of reused protein material is very active, but there have been few reports on regenerated wool keratin. In the present work, the keratin extracted from wool is used to form blend films, and the structure is studied, which give an academic reference on the potential application of keratin in the field of degradable plastics, biomedicine and cosmetics film, and provide a new way to reuse other protein wastes.Firstly, the method of extracting keratin from wool was selected, three different methods were used, and the rate of solubility, concentration of keratin solution, surface morphology of wool residue and stability of keratin solution were compared and analyzed. The results showed that by using urea / sodium sulfide / SDS method to dissolve wool, not only the wool scale has been ruptured and dissolved, but solvents may diffuse into the wool fibers, and partial cortex has been dissolved. The rate of solubility achieved 48.48%, and the mass fraction of keratin solution was 1.59%. The stability of wool keratin extracted in this method is better than the other methods. Based on the study, in this paper, the urea / sodium sulfide / SDS method is used to dissolve wool for the future experiments.Secondly, the wool keratin solution was cast to obtain pure keratin film, and the basic structure of pure keratin film was determined. Compared with wool fiber, the pure keratin film showed a decrease in the amount ofα-helix structure, whileβ-sheet and random coil conformations increased. Compared with wool fiber, the crystallinity and the thermal stability of keratin decreased.Thirdly, PVA solution and fibroin solution were used to mix with keratin solution in different proportions, the rheological properties of the keratin/PVA and keratin/fibroin blends were studied, and then keratin/PVA and keratin/fibroin blended films were formed. And the surface morphology, molecular structure, aggregation structure, thermal property, mechanical property and dissolved rate in the hot-water were researched. The results showed that the keratin/PVA films appeared two-phase macro level, keratin/fibroin films with uniform and dense structure. With the increase of PVA or fibroin content, the structural characteristics of blended films were shifted from keratin type to PVA type or fibroin type, the intermolecular interaction formed between keratin and fibroin. When the keratin and PVA or keratin and fibroin were blended in the ratios of 30:70～20:80, the mechanical properties of blended films had greatly improved. The addition of PVA or fibroin can help to improve the wet stability of blended films.Finally, the degradation performance of keratin/PVA blended films were researched and analyzed, the weight loss, basic structure and surface morphology were tested. The results indicated that the weight loss of films degraded in enzyme solution is higher than films degraded in PBS solution, the keratin was partial degraded.