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Polyvinyl acetate (PVA) is a flexible and strong polymer used in glues, paints, and industrial adhesives. It is produced through free radical polymerization of vinyl acetate and is insoluble in water but soluble in alcohols, ketones, and esters. PVA is commonly used in the paper, textile, and cheese industries, as well as in machine coatings and lubricants. It is generally safe in small quantities, but prolonged exposure can cause respiratory problems and skin rashes.
Polyvinyl acetate is a thermoplastic polymer commonly used in glues, paints and many industrial adhesives. Polymers are essentially large molecules linked together in such a way that they are very strong and durable. Most plastics and synthetic materials contain them. Polyvinyl acetate, also commonly called “PVA” or “PVAc,” tends to be quite flexible and has a strong bonding ability, which is one of the main reasons it’s so popular in products like glue. It is made from vinyl acetate and has the chemical formula of (C4H6O2)n.
As did
PVA is normally produced through the free radical polymerization of vinyl acetate, which is also a polymer. Scientists first isolate this compound, then manipulate it to slightly change its structure. Most often this happens in water. Monomeric vinyl acetate molecules typically react when immersed in water and usually create a milky-white emulsion. The emulsion fluid can in most cases be instantaneously processed as a polyvinyl acetate polymer by removing it from the water and allowing it to stabilize at room temperature.
Physical properties
PVA is primarily a synthetic resin polymer. Due to its non-polar nature, it tends to be insoluble in water, oils, fats or gasoline. This makes it very resistant. On the other hand, it is soluble in alcohols, ketones and esters, so this shelf life is not limitless. In practice, this means that the polymer won’t erode or weaken when wet, but it probably shouldn’t be exposed to alcohol or related chemicals, at least not for long periods of time.
The compound has a molar mass of 86.09 grams per mole (g/mol). The ester groups in its structural lattice make it reactive with alkalis and leads to the formation of polyvinyl alcohol (PVOH, PVA or PVAL) and acetic acid (CH3COOH). Boron compounds such as borax and boric acid also react with the polymer in alkaline environments, leading to the formation of a precipitated borate-slime complex.
Use in glues
One of the most common places to find PVA is in glues. Polyvinyl acetate was first discovered by a German scientist, Dr. Fritz Klatte, in 1912 as a binding agent, and has since been used in a variety of environments involving porous materials such as wood and paper. Many different types of adhesives, from ordinary craft glues to construction solvents, depend at least in part on this polymer to be as strong as they are. It is also widely used for the production of glues in general, more commonly known as carpenter’s glue or white. Close examination of the ingredient list of most household adhesives will show PVA in some form.
Other common uses
PVA is also used in the paper and textile industries to produce coatings that give surfaces a shiny finish. It is also commonly part of the production of latex paints. In these settings it helps form a strong coating and carrier film. The compound is also used as a protective “shell” for the cheese to protect it from humidity and fungi.
Role in industry
Industrial manufacturers and producers also use PVA, but in these cases it is most commonly found in the form of a liquefied emulsion that can be added to machine coatings or coatings, or as a lubricant for certain mechanical tasks. The polymer typically has high resistance to UV and oxidation, making it a good choice for numerous outdoor and high-temperature applications. It is a polymer with good aging characteristics, but in some cases its sensitivity to water can be a problem. This is typically cured by formulating it with plasticizers to increase its reliability and stability.
When PVA is incorporated into emulsion coatings and adhesives, it is normally converted first to polyvinyl alcohol, which is a water-soluble polymer. This is done by partial hydrolysis. The result is stronger and more durable than if the compound had been isolated and used in its raw form.
Risks and precautions
There are not many known risks when the polymer is only used in small quantities, as is the case with most paint and bonding projects. The biggest problems usually come to people who work in laboratories and warehouses where the compound is actually produced in large quantities. Constant exposure to high volumes of PVA has been linked to respiratory problems and skin rashes. In most cases the symptoms disappear once exposure ends, but much depends primarily on individual tolerance and the duration of exposure.
