Extraction Of Feather Keratin And Preparation And Properties Of Its Composite Materials With Cellulose

In recent years, due to the shortage of resources and the dual pressures of environmental pollution, more and more researchers began to pay attention to development and utilization of natural renewable resources. In China, there are a large number of discarded feather each year,which the main component is keratin. Cellulose is the largest reserve natural polymer in nature, if the feather keratin and cellulose can be scientifically developed and biodegradable biobased material is created, the problem of resources' shortage and environmental pollution can be solved effectively. In this paper, there are the following aspects of the study:Firstly, keratin was extracted from the disposable chicken feather using L-cysteine as reducing agent. Then, it was re-dissolved in the sodium carbonate-sodium bicarbonate buffer,and the pure keratin membrane and fiber were fabricated by doctor-blade casting process and wet spinning method, respectively. Scanning electron microscopy(SEM), Fourier transform infrared(FT-IR) spectroscopy, X-ray diffraction(XRD) and Thermogravimetric analysis(TGA) were used to characterize the structure and properties of raw chicken feather, keratin powder, keratin membrane and fiber. Compared with the raw chicken feather, the regenerated keratin materials retain its chemical structure and thermal stability, their relative crystallinity is a little different depend on the shaping method, which leads to the difference in moisture regain. The mechanical results show that tensile strength of the keratin membrane reaches3.5MPa, have potential application in biomedical fields. However, the keratin fiber presents low tenacity, i.e.0.5cN/dtex, this problem should be solved in order to apply the new fiber for textile and material science.Secondly, regenerated cellulose membranes were dried by four drying method: Air drying, Freeze drying, Vacuum drying and Oven drying respectively. SEM, FT-IR, XRD,TGA, Nanoindenter and Universal testing machine were used to investigate the difference of structures and properties of the four kinds of cellulose membranes. The results show that cellulose membranes prepared from vacuum drying and oven drying present smooth and stiff surface,but there are also some flaws on the surface. Freeze drying membranes present loose structure without any flaws, which makes its mechanical properties superior to membranes obtained from other drying methods. The results of nanoindenter show that freeze drying and oven drying membranes present the excellent elasticity modulus and hardness, it is mainly due to the high temperature evaporates the water in membranes quickly, and the cellulose macromolecules closed to each other to form the compact microstructure.Finally, keratin / cellulose composite membranes and fibers were prepared by blending keratin and cellulose in ionic liquid. The composite membrane materials with different composition ratios were characterized by SEM, FT-IR, XRD, TGA and Universal Testing Machine. The composite fibers were prepared by the best combination of two kinds of polymers in the membrane material. The morphology and mechanical properties of the composites were explored. The use of ionic liquid can successfully prepare fine keratin /cellulose composite materials. The experimental results show that the highest crystallinity of the composite membrane is obtained when the ionic liquid: cellulose: keratin 95: 5: 3, and thetensile breaking strength is the highest, up to 102.53 MPa. Pure cellulose film tensile elongation at break up to 17.07%, once the keratin added, it will be a sharp decline. The thermal stability of the composites after addition of keratin is significantly higher than that of pure cellulose and pure keratin, which was also the characteristic of the composites. Keratin /cellulose composite fiber has fineness uniformity and good mechanical properties, but other properties of composite fibers also need further study.