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Polyvinyl alcohol

Tab PVA vhy-E Tab PVA thy-E
Tab PVA ghy-E

*on request

Further polyvinyl alcoholes:

  • Fine particle grades,
  • low foaming grades,
  • low ash grades,
  • tackified grades.

Polyvinyl alcohol cannot be produced directly by polymerization of the monomer, because the monomeric vinyl alcohol (enol) relocates and stabilizes immediately under proton excursion to the acetaldehyde (ethanal).

Technically the polyvinyl acetate dissolved in methanol is transformed into polyvinyl alcohol by hydrolysis (alcoholysis). Caustic soda is used as a catalyst.

The technical application properties depend particularly from the molar mass and from the part of the acetyl groups available in the macromolecule (degree of hydrolysis).

Polyvinyl alcohol is a crystalline polymer which is branched out insignificantly due to his processing method. The melting point and glass transitions temperature depends on the hydrolysis degree and the molar mass also still from the distribution of the acetyl groups (statistical or in blocks) the tacticity and the water content of the polymer.

The films made of polyvinyl alcohol are rice-firm and viscous-elastic. They are oil and heat-resistant. As plasticizers can be used polyols, as for example glycerol and ethylene glycol.

With decreasing degree of polymerization and degree of hydrolysis the solving-rate in water increases. Polyvinyl alcohol can be dissolved by strewing in water and stirring at 90°C.

In dissolved form polyvinyl alcohol must be conserved. The viscosity depends on the molar mass, the degree of hydrolysis, the concentration and the temperature.

Through sulphates polyvinyl alcohol solutions can be felled. Boric acid can be set in as thickeners.

Through processing with chromates polyvinyl alcohol becomes insoluble in water.

Physical properties:
 

  • Appearance:
  • Specific gravity:
  • Bulk density:
  • Glas transition temperature:
  • Melting point:
  • Light stability:
  • Effect of organic solvents:
  • Toxicity: 

 

white to ivory (granule or powder)
1,23 - 1,31 g·cm
-3
0,5 - 0,7 g·cm-3
approx. 60°C (partially hydrolyzed), approx. 85°C (fully hydrolyzed)
approx. 180 - 190°C (partially hydrolyzed), approx. 230°C (fully hydrolyzed)
excellent
resistant to most solvents
non-toxic