Polyvinyl acetate ( PVA, PVAc, poly(ethenyl ethanoate)), commonly known as wood glue (a term that may also refer to 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 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
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 fungus; however, algae, , , and bacteria can also degrade polyvinyl acetate.
Discovery
Polyvinyl acetate was discovered in
Germany in 1912 by
Fritz Klatte.
[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);
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British patent no. 15271 (25 June 1914.);
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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).
The monomer, vinyl acetate, was first produced on an industrial scale by the addition of acetic acid to acetylene in the presence of a mercury(I) salt acting as a catalyst,[Rutherford John Gettens and George Leslie Stout, Painting Materials: A Short Encyclopaedia (Princeton, New Jersey: D. Van Nostrand, 1942), page 74.] 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 (free-radical vinyl polymerization of the
monomer vinyl acetate).
Applications
As a dispersion in water (usually an emulsion), PVAc preparations are used as
for
porosity materials, particularly for
wood,
paper, and
cloth, and as a consolidant for porous building stone, in particular
sandstone.
PVAc is considered a food-safe material,
and is thus used often in such applications (e.g., in food packaging material).
Uses:
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As wood glue, PVAc is known as "white glue" and the yellow as "carpenter's glue".
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As paper adhesive during paper packaging conversion.
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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.
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In handicrafts.
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As envelope adhesive.
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As wallpaper adhesive.
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As a primer for drywall and other substrates.
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As a gum base in chewing gum.
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As an adhesive for Rolling paper.
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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 in , 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 hydrolysis 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.
[H. Staudinger, K. Frey, W. Stark, Ber. Deut. Chem. Ges. 1927, 60, 1782.]
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Polyvinyl acetate phthalate (PVAP): Polyvinyl acetate is partially hydrolyzed and then esterified with phthalic acid.
See also
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Ethylene vinyl acetate
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International Klein Blue
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Elmer's Products
