Polyvinyl acetate
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| Polyvinyl acetate | |
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| Other names | PVAc, PVA |
| Identifiers | |
| CAS number | [] |
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| Properties | |
| Molecular formula | (C4H6O2)n |
| Molar mass | 86.09 g/mol |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references |
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Polyvinyl acetate (PVA or PVAc) is a rubbery synthetic polymer with the formula (C4H6O2)n.
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[edit] Preparation
Polyvinyl acetate (PVA or PVAc) is a rubbery synthetic polymer.
- (Homo)polymers are prepared by polymerization of vinyl acetate monomer.
- Copolymers are vinyl acetate (VAM) based polymers internally plasticized with for example ethylene (VAE) or acrylic (VAA).
Polyvinyl acetate is also the raw material to make Polyvinyl alcohol. Polyvinyl acetate is partially or completely hydrolysed.
[edit] Discovery
Polyvinyl acetate was discovered in Germany in 1912 by Dr. Fritz Klatte. On an industrial scale vinyl acetate is produced from ethyne, ethanoic acid and a mercury(I) salt.[1][verification needed]
[edit] Properties
The ester groups of the polyvinyl acetate are sensitive for alkali and will slowly convert PVAc into polyvinyl alcohol and acetic acid.
Under alkaline conditions, boron compounds, such as boric acid or borax causes the polymer to cross-link forming tackifying precipitates or slime.
[edit] Applications and uses
As an emulsion in water, PVAc emulsions are the adhesives for porous materials, particularly for wood, paper, and cloth.
- as wood glue PVAc is known as "white glue" and the yellow "carpenter's glue" or PVA glue.
- in paper converting as fast binding adhesive
- in bookbinding and book arts due to its flexible strong bond and non-acidic nature (unlike many other polymers).
- for handcrafted works.
To a lesser extent PVAc emulsion are used in paper coatings, paint and other industrial coatings. PVA can also be used as coating to protect cheese from fungi and humidity[citation needed].
