Polyvinyl Alcohol Powder Knowledge

Polyvinyl alcohol powder is a white or light yellow granular powder with a specific gravity of 1.2 to 1.3 .

(generally a total alcoholysis product is 1.295 and a partial alcoholysis is mainly 1.275). 

The PH value of the aqueous solution is 6 to 8.88% The alcoholysis polyvinyl alcohol is 5.5 to 7.5.

The solubility of polyvinyl alcohol powder varies with the degree of polymerization, degree of alcoholysis, and water temperature. Generally, those with a high degree of polymerization and alcoholysis can be dissolved at higher temperatures; on the contrary, those with a low degree of polymerization and alcoholysis have good dissolution properties at low temperatures. 

The viscosity of its aqueous solution is also affected by the degree of polymerization. The degree of polymerization is high and the viscosity is also high. 

For example, the degree of polymerization above 1500 is high viscosity, 1000-1500 is medium viscosity, and below 1000 is low viscosity.

In addition, polyvinyl alcohol used as fabric finishing slurry can be selected according to the characteristics of the fabric fibers at high temperature and low viscosity. For cellulose fiber fabrics, polyvinyl alcohol with a full alcoholysis and moderate polymerization degree is more suitable. Fully alcoholyzed polyvinyl alcohol can be made into a slurry with higher viscosity, which has a good affinity for hydrophilic fibers, and partially alcoholized polyethylene has a high adhesion to hydrophobic fibers (such as polyester, nylon, etc.) , but easily soluble in water and easier to remove. 

For blended fabrics of cellulose fibers and hydrophobic synthetic fibers, a fully alcoholized and partially alcoholized polyvinyl alcohol slurry should be used in an appropriate mixing ratio. 

The film formed by partial alcoholysis of polyvinyl alcohol is soft, good elasticity, and slightly hygroscopic; 

while the film formed by completely alcoholyzed polyvinyl alcohol is harder, and has less wettability.