Polyvinyl acetate explained

Polyvinyl acetate should not be confused with Polyvinyl alcohol.

Polyvinyl acetate (PVA, PVAc, poly(ethenyl ethanoate)), commonly known as wood glue, PVA glue, white glue, carpenter's glue, school glue, or Elmer's Glue in the US, is a widely available adhesive used for porous materials like wood, paper, and cloth. An aliphatic rubbery synthetic polymer with the formula (C₄H₆O₂)_n, it belongs to the polyvinyl ester family, with the general formula −[RCOOCHCH₂]−. It is a type of thermoplastic.

Properties

The degree of polymerization of polyvinyl acetate is typically 100 to 5000, while its ester groups are sensitive to base hydrolysis and slowly convert PVAc into polyvinyl alcohol and acetic acid.

The glass transition temperature of polyvinyl acetate is between 30 and 45 °C depending on the molecular weight.

PVAc dispersions such as Elmer's Glue-All contain polyvinyl alcohol as a protective colloid. In alkaline conditions, boron compounds such as boric acid or borax cause the polyvinyl alcohol to cross-link, forming tackifying precipitates or toys, such as Slime and Flubber.

A number of microorganisms can degrade polyvinyl acetate. Most commonly, damage is caused by filamentous fungi; however, algae, yeasts, lichens, and bacteria can also degrade polyvinyl acetate.^[1]

Discovery

Polyvinyl acetate was discovered in Germany in 1912 by Fritz Klatte.^[2]

The monomer, vinyl acetate, was first produced on an industrial scale by the addition of acetic acid to acetylene with a mercury(I) salt,^[3] but it is now primarily made by palladium-catalyzed oxidative addition of acetic acid to ethylene.

Preparation

PVA is a vinyl polymer. Polyvinyl acetate is prepared by the polymerization of vinyl acetate monomer (free-radical vinyl polymerization of the monomer vinyl acetate).

Applications

As a dispersion in water (usually an emulsion), PVAc preparations are used as adhesives for porous materials, particularly for wood, paper, and cloth, and as a consolidant for porous building stone, in particular sandstone.^[4]

Uses:

• As wood glue, PVAc is known as "white glue" and the yellow as "carpenter's glue".
• As paper adhesive during paper packaging conversion.
• In bookbinding and book arts, due to its flexible strong bond and non-acidic nature (unlike many other polymers). The use of PVAc on the Archimedes Palimpsest during the 20th century greatly hindered the task of disbinding the book and preserving and imaging the pages in the early 21st century, in part because the glue was stronger than the parchment it held together.^[5]
• In handicrafts.
• As envelope adhesive.
• As wallpaper adhesive.
• As a primer for drywall and other substrates.
• As a gum base in chewing gum.^[6]
• As a water-soluble support material for 3D printing, usually for the fused filament fabrication method.^[7]
• As an adhesive for cigarette paper.^[8]
• As the coating layer on Gouda cheese.

The stiff homopolymer PVAc, but mostly the softer copolymer, a combination of vinyl acetate and ethylene, vinyl acetate ethylene (VAE), is also used in paper coatings, paint and other industrial coatings, as a binder in nonwovens in glass fibers, sanitary napkins, filter paper and in textile finishing.

Polyvinyl acetate is also the raw material to make other polymers like:

• Polyvinyl alcohol −[HOCHCH₂]−: Polyvinyl acetate is partially or completely hydrolysed to give polyvinyl alcohol. This reversible saponification and esterification reaction was a strong hint for Hermann Staudinger in the formulation of his theory of macromolecules.^[9]
• Polyvinyl acetate phthalate (PVAP): Polyvinyl acetate is partially hydrolyzed and then esterified with phthalic acid.

See also

• Ethylene vinyl acetate
• International Klein Blue
• Elmer's Products

Notes and References

1. 2227722 . Microorganisms Attack Synthetic Polymers in Items Representing Our Cultural Heritage . Francesca Cappitelli . Claudia Sorlini . Applied and Environmental Microbiology . 2008 . 74 . 3 . 18065627 . 10.1128/AEM.01768-07 . 564–569. 2008ApEnM..74..564C .
2. See:
   • Deutsches Reichspatent no. 281687 (4 July 1913), Journal of the Society of Chemical Industry (London), vol. 34, p. 623 (1915);
   • Deutsches Reichspatent no. 281688 (2 April 1914);
   • British patent no. 15271 (25 June 1914.);
   • Fritz Klatte and Adolf Rollett, "Plastic composition and process of producing it", U.S. Patent 1,241,738 (filed: July 3, 1914; issued: Oct. 2, 1917), an abstract of which appears in the Journal of the Society of Chemical Industry (London), vol. 36, p. 1185 (1917).
3. Rutherford John Gettens and George Leslie Stout, Painting Materials: A Short Encyclopaedia (Princeton, New Jersey: D. Van Nostrand, 1942), page 74.
4. Web site: Stone consolidants and chemical treatments in Scotland . Robert Gordon University, Building Research Establishment and Historic Scotland . Young. M. E.. Murray. M.. Cordiner. P. . 1999 . 2009-07-30 . https://web.archive.org/web/20161117184257/http://www2.rgu.ac.uk/schools/mcrg/miconsol.htm . 2016-11-17 . dead.
5. Web site: The Conservation of the Archimedes Palimpsest . . 2011 . February 22, 2018.
6. Amann . Manfred . Minge . Oliver . 2012 . Biodegradability of Poly(vinyl acetate) and Related Polymers . Advances in Polymer Science . 245 . 137–172 . 10.1007/12_2011_153. 978-3-642-27153-3 .
7. https://www.simplify3d.com/resources/materials-guide/pva/
8. Coggins . Christopher R. E. . Jerome . Ann M. . Lilly . Patrick D. . McKinney . Willie J. . Oldham . Michael J. . 2013 . A comprehensive toxicological evaluation of three adhesives using experimental cigarettes . Inhalation Toxicology . 25 Suppl 2 . 6–18 . 10.3109/08958378.2013.854430 . 1091-7691 . 24341843 . 6414435.
9. H. Staudinger, K. Frey, W. Stark, Ber. Deut. Chem. Ges. 1927, 60, 1782.