Polyvinyl Alcohol PVA Fiber has excellent properties as following:
The Solubility: Polyvinyl Alcohol is dissolved in water, the higher the temperature, the greater the solubility is, but it is almost insoluble in organic solvents. And the PVA solubility with the degree of hydrolysis and polymerization degree varies. Part of the alcohol solution and the low degree of PVA dissolved fase, and completely alcohol solution and the high degree of polymerization of PVA is dissolved slowly. General rule, the effect on the solubility of Polyvinyl Alcohol PVA, alcoholysis degree is greater than the degree of polymerization. The Polyvinyl Alcohol PVA dissolution process is carried out in stages, namely: pro and wetting a swelling of an unlimited swelling a dissolution.
Film-Forming Properties: Polyvinyl Alcohol is easy film formation, excellent in the mechanical properties of the film, the tensile strength of the film with the degree of polymerization, the degree of alcoholysis rise enhanced.
Adhesiveness Properties:Polyvinyl Alcohol PVA has a good adhesion with hydrophilic cellulose. Generally, the degree of polymerization, the higher the degree of alcoholysis, the stronger the bond strength.
Thermal Stability: When the Polyvinyl Alcohol PVA powder is heated to about 100℃, the appearance of it is gradually changed. PVA part alcoholysis begins to melt at about 190℃, decomposition occurs at 200℃. PVA is fully alcoholysis begins to melt at about 230℃, 240℃ decomposition. Pyrolysis experiment shows that: the lower the degree of polymerization, the faster weight reduction. The higher the degree of hydrolysis, the shorter the decomposition time.
Currently, the medical use PVA with PVA 0588, PVA 1788, PVA 124 and other specifications, the degree of alcoholysis of the former two kinds of specifications are (88±2)(m01)％, average degree of polymerization is set to 500 to 600 and 1700 to 1800, PVA 124 alcoholysis degree is 98 to 99(m01)％, average degree of polymerization is 2400 to 2500.
The development of new pharmaceutical excipients, dosage optimization is one of the strategies to promote the mission of the current development of Chinese medicine with the international standards. Polyvinyl Alcohol PVA has a synthetic convenience, safety and low toxicity, easy to control product quality, cheap, easy to use features. Therefore, Polyvinyl Alcohol PVA is a good potential for development of pharmaceutical excipients again.