Polyvinyl acetate

Polyvinyl acetate

IUPAC name poly (1-acetyloxiethylene)
Other names PVAc, PVA
Identifiers
CAS number	9003-20-7^Y
PubChem	7758
KEGG	C12282^N
Jmol-3D images	Image 1
SMILES C=COC(C)=O
Properties
Molar mass	86.09 g/mol/unit
Hazards
MSDS	MSDS
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Polyvinyl acetate, PVA, PVAc, poly(ethenyl ethanoate), is a rubbery synthetic polymer with the formula (C₄H₆O₂)_n. It belongs to the polyvinyl esters family with the general formula -[RCOOCHCH₂]-. It is a type of thermoplastic.^[1]

It should not be confused with the related polymer polyvinyl alcohol, which is called PVA also (PVAc could be considered a technically correct abbreviation for polyvinyl acetate and would aid in avoiding such confusion).

Polyvinyl acetate is a component of a widely-used type of glue, referred to variously as wood glue, white glue, carpenter's glue, school glue or PVA glue.

1 Preparation
2 Discovery
3 Properties
4 Applications and uses
5 See also
6 References

Preparation

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

Discovery

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

The monomer, vinyl acetate, was on an industrial scale first produced by 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.

Properties

The degree of polymerization of polyvinyl acetate typically is 100 to 5000. 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.

Applications and uses

As an emulsion in water, PVAc emulsions 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 "carpenter's glue" or PVA glue.
as paper adhesive during paper packaging converting
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.
for handcrafted works.
as envelop adhesives,
as wallpaper adhesive

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

PVAc can also be used as coating to protect cheese from fungi and humidity.

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.^[5]
Polyvinyl acetate phthalate (PVAP): Polyvinyl acetate is partially hydrolyzed and then esterified with phthalic acid.

References

^ Murray, G. T. (1997), Handbook of materials selection for engineering applications, CRC Press, p. 242, ISBN 9780824799106, http://books.google.com/books?id=NC-AXM9U6qsC&pg=PA242.
^ See:
(1) Deutsche Reichs Patent no. 281687 (4 July 1913), an abstract of which appears in the Journal of the Society of Chemical Industry (London), vol. 34, page 623 (1915);
(2) Deutsche Reichs Patent no. 281688 (2 April 1914);
(3) British patent no. 15271 (25 June 1914.);
(4) 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, page 1185 (1917).
^ Rutherford John Gettens and George Leslie Stout, Painting Materials: A Short Encyclopaedia (Princeton, New Jersey: D. Van Nostrand, 1942),page 74.
^ Young, M.E., M. Murray and P. Cordiner (1999). "Stone consolidants and chemical treatments in Scotland". Robert Gordon University, Building Research Establishment and Historic Scotland. http://www2.rgu.ac.uk/schools/mcrg/miconsol.htm. Retrieved 2009-07-30.
^ H. Staudinger, K. Frey, W. Stark, Ber. Deut. Chem. Ges. 1927, 60, 1782.