What is Polyvinyl Alcohol?
Polyvinyl alcohol, also known as PVA, PVOH or PVAL, is a water soluble crystalline polymer that has excellent film forming, emulsifying and adhesive properties. It is produced by the polymerization of vinyl acetate to polyvinyl acetate followed by an alcoholysis reaction to PVA. The extent of the alcoholysis reaction will result in a specific degree of hydrolysis for the PVA.
Uses of Polyvinyl Alcohol
- Paper coatings as a size press film former
- Board coatings as a protein replacement
- Water-soluble film useful for dissolvable packaging
- Textile sizing agent
- Paper adhesive when combined with boric acid in spiral tube winding and solid board production
- Release liners
- Inkjet coating binder
- Optical brightener carrier
- Mold release for casting, such as epoxies
- Additive in offset printing fountain solutions
- Sacrificial coating layer
S-1500 Series Polyvinyl Alcohol
Degree of Hydrolysis
The degree of hydrolysis is the ratio of hydrophilic alcohol groups and hydrophobic acetate groups. The ratio contributes to the water resistance of the dried film. The fully hydrolyzed PVA has better water resistance than the partially hydrolyzed PVA.
Degree of Polymerization
The degree of polymerization is the expression of the size of the polymer and the molecular weight of the polymer. As the degree of polymerization is increased, you see:
- Higher solution viscosity
- Increased adhesion strength of the film
- Better solvent resistance
- Higher tensile strength of the film
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