Study On The Compatibility Of PVA/SF Blend System And The Properties Of The Membranes

As a water-soluble macromolecule, PVA has the characteristics of good hydrophilic property, good biological compatibility, and degradable. It has strict linear structure, well flexibility, stable chemistry property and good filming property. So PVA can be used as biology medical material. SF is a kind of natural protein fiber with no virulence, stimulation and susceptibility to the base. With the good biological compatibility, it is applied as biology medical material. However, the shortage of its mechanical property limits its application. While the membranes prepared by the mixtures of PVA and SF can present the advantages of both components, so as to improve the physiological function and mechanical property of two materials. In order to improve the compatibility of two materials, the compatibility of the mixtures of different solvents and that of under the circumstance of sodium ethyl xanthate had been compared in this article. Structures and properties of the membranes prepared by different mixtures had been studyed in three following aspects:(1) The compatibility of PVA/SF mixture with different solvents and the property of membranes. Two different solvents which were H₂O and LiBr/C₂H₅OH/H₂O were adopted in this article to get PVA/SF mixtures, and prepared the PVA/SF blend membranes separately. By analyzing the compatibility of mixtures, physical appearances, structures and thermal properties of the membranes, it was found that the compatibility of two components of ternary solvent improved in certain degree compared with the blend system of H₂O solvent. Especially with small quantity of SF, the two phase structure could hardly be found in these membranes. It was proved that in the system of PVA/SF, the solvent of SF and its quantity affected the compatibility of two components. The structures and properties of the PVA/SF blend membranes were characterized with the solubility in water, thermal weight analysis, x-ray diffraction, the strength and elongation. The membranes with good compatibility were found improved in the aspects of thermal and mechanical properties.(2) The properties of PVA/SF blend membranes after the chemical treatment. The structures and properties of the PVA/SF blend membranes of LiBr/C₂H₅OH/H₂O ternary solvent after the chemical treatment with EtOH were investigated through the solubility in water, thermal weight analysis, x-ray diffraction, the strength and elongation. It was found that the molecules were ordered closer and neater in the membranes after chemical treatment. And the membranes after the chemical treatment with EtOH were found improved in the aspects of thermal and mechanical properties.(3) The compatibility of PVA/SF mixtures with sodium ethyl xanthate and the properties of the membranes. The membranes were prepared by the PVA/SF mixtures of H₂O solvent added the sodium ethyl xanthate. The compatibility of two components was also found improved in certain degree. However, the improvement was not as obvious as the changing of system solvent. It was proved that adding polarity functions into PVA/SF mixture systems can also improve the compatibility of two components. The characterized of the structures and properties of these membranes got the same results as former. The membranes with good compatibility had good thermal and mechanical properties.