关键词: 羊毛角蛋白, PVA, 静电纺丝, 纳米纤维膜, 口罩

Abstract: Air is an important element of human living environment,and air quality has draw more and more attention. While China's industry is developing rapidly, air pollution problems are also intensifying. Tiny particles in the air have a great impact on human health, and wearing a mask is a convenient and effective solution. The air filtration material in the mask can filter most harmful substances in the air. At present, common air filtration materials are mainly composed of ultrafine glass fiber materials and meltblown electret nonwoven materials. The glass fiber is brittleness and easy falling off and the characteristics restrict its wide application. The meltblown electret nonwoven material is greatly affected by the environment, which makes its filtration efficiency unstable. Electrospun nanofiber membrane has the advantages of controllable fiber morphology and diameter, large specific surface area, high porosity and narrow pore size distribution.These properties indicated electrospun nanofibers possess excellent performance in PM2.5 particles filtration. In addition, China is rich in wool resources, and a large number of waste wool is produced every year. The main constituent of wool is keratin, which has excellent biodegradability, high permeability and good biocompatibility. Adding keratin to the electrospun nanofiber membrane can improve fiberous membranes’ performance, and make good use of waste wool resources.
In the present study, the composite fiberous membranes consisted of wool keratin and polyvinyl alcohol (PVA) are prepared by electrospinning technology and applied to the filter element material of medical masks. First, keratin is extracted from wool fibers by acid-base method, and centrifuged to obtain keratin precipitates. Keratin is then added to the prepared PVA solution and mixed well. The mixed solution is prepared into keratin/PVA nanofiber membranes by electrospinning technology. There are different concentrations of Keratin and PVA. Both the physical and chemical properties of fiberous membranes with different concentrations were analyzed by scanning electron microscopy，Fourier transform infrared spectroscopy, dust filtration and other tests. The results of fiberous morphology indicates that when the concentration of keratin is constant, the diameter of the prepared fiber is increase with increasing the mass fraction of PVA solution. When the mass fraction of PVA solution is constant, the higher the concentration of keratin, the smaller the diameter of the prepared nanofiber. Infrared spectroscopy test shows that wool keratin and PVA are stably combined by hydrogen bonds. Contact angle test shows that adding keratin can significantly improve the hydrophilicity of filter element material. The air filtration efficiency test shows that when the concentration of PVA solution is 6% and the ratio of keratin to PVA is 30:70, the filtration efficiency is the highest, reaching to 97.17%.
This fiber membranes prepared by electrospinning has good filtration performance. Keratin has the advantages of excellent biodegradability, high permeability and good biocompatibility. The addition of keratin/PVA nanofiber membrane is conducive to improving the filtration efficiency of medical masks. Keratin/PVA nanofiber membrane has broad application prospects in air filter materials. However, electrospinning fiber membrane still has problems such as long preparation time and low yield at present. Therefore, in future research, the preparation process should be optimized to make the electrospinning fiber membrane output steady and efficiently. And the influence of different structures of fiber membrane should be explored to further expand application field of electrospinning fiber membrane.

Key words: wool keratin, polyvinyl alcohol, electrospinning, nanofiber membrane, masks