Polyvinyl acetate

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Polyvinyl acetate
Polyvinyl acetate
Identifiers
CAS number 9003-20-7 YesY
PubChem 7758
KEGG C12282 YesY
Jmol-3D images Image 1
Properties
Molecular formula (C4H6O2)n
Molar mass 86.09 g/mol/unit
Density 1.19g/cm3 (25 C)
Hazards
MSDS MSDS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
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 also called PVA.

Polyvinyl acetate is a component of a widely used glue type, commonly referred to as wood glue, white glue, carpenter's glue, school glue, Elmer's glue (in the US), or PVA glue.

Preparation[edit]

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[edit]

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

The monomer, vinyl acetate, was first produced on an industrial scale 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[edit]

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

Under alkaline conditions, boron compounds such as boric acid or borax cause the polymer to cross-link, forming tackifying precipitates or Slime.

Microbial degradation[edit]

A number of microorganisms can degrade polyvinyl acetate; most commonly, damage is caused by filamentous fungi however there are also algae, yeasts, lichens and bacteria have also been shown to degrade polyvinyl acetate. [4]

Applications and uses[edit]

As an emulsion in water, aPVAc 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.[5] 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.
  • in handcrafts
  • as envelope adhesive
  • as wallpaper adhesive
  • as a primer for drywall

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[citation needed].

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

See also[edit]

References[edit]

  1. ^ Murray, G. T. (1997), Handbook of materials selection for engineering applications, CRC Press, p. 242, ISBN 978-0-8247-9910-6. 
  2. ^ 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).
  3. ^ Rutherford John Gettens and George Leslie Stout, Painting Materials: A Short Encyclopaedia (Princeton, New Jersey: D. Van Nostrand, 1942),page 74.
  4. ^ Francesca Cappitelli; Claudia Sorlini (2008). "Microorganisms Attack Synthetic Polymers in Items Representing Our Cultural Heritage". Applied Environmental Microbiology 74. PMC 2227722. 
  5. ^ 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. Retrieved 2009-07-30. 
  6. ^ H. Staudinger, K. Frey, W. Stark, Ber. Deut. Chem. Ges. 1927, 60, 1782.