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polyvinyl alcohol[¦päl·i′vīn·əl ′al·kə‚hȯl]
a white solid polymer, [—CH2— CH(OH)—]n, having a degree of polymerization n up to 5,000 and containing as much as 68 percent crystalline phase in the form of microcrystalline formations. Polyvinyl alcohol is nontoxic.
The only practical solvent for polyvinyl alcohol is water. Polyvinyl alcohol does not dissolve in organic solvents and is especially resistant to the action of oils, fats, gasoline, and other hydrocarbons, as well as to the action of dilute acids and alkalies. In industry, polyvinyl alcohol is produced by the saponification of polyvinyl acetate in a methanol solution in the presence of strong acid and alkaline catalysts. Polyvinyl alcohol that contains up to 30 percent residual vinyl acetate monomeric units (solvars or soviols) can be obtained by controlling the degree of saponification.
Polyvinyl alcohol is used in the manufacture of fibers and films. It is also utilized as an emulsifier, thickener, and adhesive. Special brands of polyvinyl alcohol with low molecular weights are important in the food industry and medicine. They are used, for example, as plasma substitutes during blood transfusions and also in drug production.
World production of polyvinyl alcohol in 1973 was about 220,000 tons.
REFERENCESSee references under .
S. S. MNATSAKANOV