What Is Polyvinyl Acetate?
Polyvinyl acetate (PVA or PVAc) is a thermoplastic polymer with a chemical formula of (C4H6O2)n. It is normally manufactured by the free radical polymerization of vinyl acetate. The procedure involves the reaction of monomer molecules of vinyl acetate by submerging them into water. This results in the formation of a polyvinyl acetate emulsion that is milky white in color. The emulsion fluid can then instantly be processed as a polyvinyl acetate polymer in products comprising the PVAc as a constituent element.
PVAc is primarily a synthetic resin polymer, which, due its non-polar nature, is insoluble in water, oils, fats, or gasoline. On the other hand, it is soluble in alcohols, ketones, and esters. It has a molar mass of 86.09 grams per mole (g/mol). The ester groups in the structural lattice of polyvinyl acetate render it reactive with alkalis, and lead to the formation of polyvinyl alcohol (PVOH, PVA, or PVAL) and acetic acid (CH3COOH). Boron compounds like borax and boric acid also react with the polymer, under alkaline settings, leading to the formation of a complex borate-slime-precipitate.
Polyvinyl acetate was first discovered by a German scientist Dr. Fritz Klatte in 1912. Since its discovery, it has been employed widely as a binding material, due to its adhesive properties for porous materials like wood and paper. Other than its use as polyvinyl acetate glue, it is also used in paper and textile industry to produce PVA coatings that lend a shiny touch to surfaces. PVAc is commonly used in the manufacture of latex paints, where it helps in forming a tough coating and a supportive film. It is also widely used for the production of polyvinyl acetate adhesives, which are more commonly known as Elmer's glue, carpenter's glue, or white glue.
Industrial applications of PVAc normally use it in the form of a liquefied emulsion. Polyvinyl acetate polymer exhibits sound resistance to UV rays and oxidation. This renders it an effective polymer with good aging characteristics, yet its water sensitivity can be a problem. This is typically taken care of by formulating it with plasticizers to increase its reliability and stability.
When PVAc is incorporated into emulsion coatings and adhesives, it is normally converted to polyvinyl alcohol first, which is a water-soluble polymer. This is done by means of partial hydrolysis. On a lesser level, it is also used as a protective coating for cheese to render it safe from humidity and fungi.
Written by Amy Dyslex
