What is Polyvinyl Alcohol and what are its uses?

Polyvinyl Meaning Word poly means ‘many’ and vinyl is ‘ethenyl’ functional group. Formula of vinyl is -CH=CH2. When we remove one hydrogen atom from the ethylene or ethene molecule (H2C=CH2) we get vinyl group.

Polyvinyl Alcohol (PVA), also known as also known as PVOH, PVA, or PVAL, is a man-made or synthetic polymer made from the polymerization of vinyl acetate monomer. PVA polymer molecule contains vinyl and alcohol groups. It is a water-soluble polymer that is odorless, non-toxic, crystalline, bio-degradable,environment-friendly, and flammable in nature, and is resistant to grease, oils, and solvents. Presence of alcohol group in it makes it flammable. It is ductile but strong, flexible, and functions as a high oxygen and aroma barrier. PVA molecular weight or polyvinyl molecular weight ranges between 26,000-30,000. Its melting point is 185°C. It is insoluble in organic solvents but slightly soluble in ethanol. While other vinyl polymers are prepared by polymerization of its corresponding monomer, Polyvinyl Alcohol (PVA) undergoes either partial or complete hydrolysis of polyvinyl acetate to remove acetate groups. PVA is used in many industries, such as textile, paper industry, and food packaging industry because of its high chemical and thermal stability, and low manufacturing cost.   Chemical Structure of PVA PVA is not prepared by direct polymerization of vinyl acetate. Instead, it is prepared by hydrolysis of polyvinyl acetate (PVAc) through an alcohol (generally methanol) in presence of an alkaline catalyst. The properties of polyvinyl acetate depend upon the extent or degree of its hydrolysis, specifically whether it is full or partial, which in turn dictates its categorization into two groups, namely, partially hydrolyzed and fully hydrolyzed. Polymer contents affect the physical status of the resulting material: low polymer content results in a soft materials because the fluid moves freely through the matrix, whereas a higher polymer content results in considerable stiffening and strengthening of the material’s matrix It is used for a wide range of industrial and household applications as an adhesive, binder, emulsifier and thickener. Some common uses of PVA are:

• ● Making Paper: PVA is a bio-degradable imitation of natural polymers, used as a binder in the production of paper, helping to hold fibers together, and improve the strength of the paper. And particularly to make them more resilient to oils and grease
• ● Textiles: Polyvinyl Alcohol is a bio-degradable imitation of natural polymers used as a sizing agent in textile production that helps in stiffening and strengthening fabrics. And particularly to make them more resilient to oils and grease.
• ● Ceramics: PVA is used in the production of ceramics as a binder. It holds the ceramic particles together and improves the strength of the final products.
• ● Construction: The construction industry uses PVA as an adhesive that helps binding and sealing various building materials.
• ● Pharmaceuticals: PVA is used in the w as a binder and tablet dis-integrant in the manufacture of tablets, capsules and granules.
• ● Tissue Engineering Science: PVA-based materials are also applied in tissue engineering science
• ● Paint and Varnish – Polyvinyl alcohol can used as a binder in paints and varnishes, due to its ability to form a hard, durable film.
• ● Food Industry: Polyvinyl Alcohol is used in the food industry as a thickener and emulsifier in food products like sauces, jellies, and dressings. PVA is also used as a coating agent for food supplements and does not pose any health risks as it is not poisonous. One of the leading industrial uses for PVA is for food packaging, accounting for almost 31.4 percent of the global share. To combat moisture formation from foodstuff, PVA film is created to be thin and water-resistant. Its crosslinking density and resistance to moisture are added benefits to its usability in this area.
• ● Bio-medical Applications: PVA is used in biomedical applications for its compatibility. PVA composites, such as PVA gels, are used in different biomedical fields, such as in the manufacturing of contact lenses, artificial heart surgery, drug delivery systems, and wound dressings.
• ● Medical Devices: In medical devices, PVA is used as a biomaterial because of its highly favorable properties, such as biocompatibility, nontoxicity, non-carcinogenic, swelling properties, and bio-adhesive characteristics. This material is very useful and desirable for biomedical application and uses. Some non-implant and implant devices that are currently made of different PVA forms and HNTs.
• ● Freshwater Sports Fishing: In freshwater sports fishing PVA is added into bags that are filled with oil-based or dry fishing bait and attached to the hook. As PVA is soluble in water, when the bag lands on the bed of the water, it breaks down, leaving the hook bait surrounded by pellets and ground bait. This attracts fish to the hook bait, although the PVA does cause the plastic to dissolve in water.
• ● PVA Glue: As a glue it is used in making paper mache, decoupage project, mosaic, picture frame and attaching two pieces of wood together.
• ● PVA is also used as a film-forming agent, dispersant, a protective colloid, a lubricant in various applications like production of fibers and non-woven fabrics, as well as in adhesives, paints and coatings.
• ● PVA is a widely used thermoplastic polymer that is benign to living tissues, harmless, and nontoxic. This polymer is widely investigated because of its use in cross-linked products and nano-fillers.
• ● PVA has high strength and high optical transparency in water. Because of these desirable properties, PVA is used in packaging and as optical polarizer
• ● Polyvinyl alcohol is a resin, a natural or synthetic organic compound made of non-crystalline or viscous substance. Hence, it is often utilized as the starting point for the creation of other resins such as polyvinyl butyral (PVB) or polyvinyl formal (PVF). PVB has an adhesive quality and is a water-resistant, plastic film, which is often used to laminate safety glass for vehicles. PVF is commonly used to insulate wires.
• ● PVA films are used in packaging of different materials such as detergents, chemicals, disinfectants etc. in many industries.

Conclusion:

PVA is an artificial polymer that has been used in medical and other fields for years. Over the course of the last several years, the biodegradable polymer market has gone through a series of compilations and transformations in the world. In 2021, the polyvinyl alcohol global market was at an estimated USD 791.7 million. Due to stricter regulations regarding disposal and decreasing availability of landfills, there is a greater demand for sustainably packaged versions of the product. With the advent of new technology surrounding renewable natural polymers, polyvinyl alcohol has become a highly lucrative due to its biodegradable quality, under certain microbial conditions.