Polyvinyl alcohol (PVA), also known as PVAL or PVOH, is an artificial polymer composed of vinyl and alcohol groups. As an organic compound, it possesses adhesive properties that make it highly versatile. This water-soluble, crystalline polymer is flammable due to the presence of the alcohol group, and while typically non-corrosive, it can cause mucous membrane irritation.
Unlike other vinyl polymers formed by polymerizing their corresponding monomers, PVA is produced by entirely or partially hydrolyzing polyvinyl acetate to remove acetone chemicals.
Polyvinyl alcohol finds use in the production of drugs, acetic acid, perfumes, dyes, flavoring agents, and more. PVA manufacturers create PVA for various uses, including packing and papermaking, and it’s also found in regular white or wood glue. Due to its unique properties, polyvinyl alcohol is resistant to oils, solvents, and grease.
Properties Of Polyvinyl Alcohol
PVA has several properties that make it a helpful polymer in many applications. Some of the properties include the following:
- High flexibility and tensile strength: Polyvinyl alcohol has a high degree of flexibility and tensile strength, making it an ideal material for use in textiles, adhesives, and films.
- It’s water-soluble and odorless: PVA is soluble in water, forming a clear solution. It’s also odorless, which makes it suitable for use in applications where odor is a concern.
- High melting point: Polyvinyl alcohol has a melting point of about 200 degrees Celsius, which makes it a stable material even in high temperatures.
- Polyvinyl alcohol is ductile but also flexible and robust: This means PVA can be stretched without breaking. It’s also strong and flexible, making it suitable for various applications.
- It also works as a high oxygen barrier: PVA is an adequate oxygen barrier. This makes it useful for packaging applications where it’s crucial to protect the contents from oxygen.
- Repellent to grease and water: It’s water resistant and repellent to oil, making it useful in applications where these properties are desirable.
- Polyvinyl alcohol is an atactic polymer: PVA molecules are randomly oriented. This property affects its mechanical properties as well as other characteristics.
- Reactivity: PVA reacts with butyraldehyde and formaldehyde, making it helpful in producing adhesives and resins.
Overall, the unique properties of PVA make it a versatile and valuable material in a wide range of applications.
Benefits Of Polyvinyl Alcohol
Polyvinyl alcohol offers several benefits in industrial and commercial applications due to its unique properties. Some of the benefits of PVA include:
- Protective coating: PVA is a popular material for producing protective coatings. It provides a transparent and durable coating that can protect various substrates, including metal, plastic, and wood, from corrosion, abrasion, and other types of damage.
- Vapor barrier: PVA is a highly effective vapor barrier. Its water resistance and film-forming properties make it ideal for preventing water vapor penetration into structures, which can cause moisture damage, mold growth, and other problems.
- Excellent film former: Polyvinyl alcohol is a great film former, meaning it can create thin films with superior properties such as transparency, flexibility, and tensile strength. These films are often used to produce packaging materials, coatings, and adhesives.
- Removable: It’s a water-soluble polymer that can be easily removed from substrates with water. This property makes it an ideal material for temporary coatings, such as those used for protecting delicate surfaces during transportation or storage.
- Water-based solution: PVA can be easily dissolved in water to form a water-based solution, making it an eco-friendly and cost-effective alternative to solvent-based coatings and adhesives. This makes it suitable for home use, where you’ll encounter many benefits of water-soluble glue.
These properties make it versatile for various industrial and commercial applications, including packaging, coatings, adhesives, and construction materials.
Uses Of Polyvinyl Alcohol
Polyvinyl alcohol is an artificial water-soluble polymer with numerous uses. These uses include the following:
1. Used As A Raw Material For The Manufacture Of Other Polymers
PVA is primarily utilized in the industry as an essential ingredient for producing various polymers. For example, vinyl nitrate (PVN) is used in propellants and plastic explosives. PVA is also used in producing polyvinyl acetate (PVAc), polyvinyl butyral (PVB), and polyvinyl formaldehyde (PVF). The production of PVB, which serves as a plastic interlayer for safety glass in aircraft and automobiles, is the most effective use of PVA.
2. PVA Is Used In The Manufacturing Of Adhesives
PVA is commonly used in producing adhesives due to its strong adhesive properties and compatibility with many substrates. It is a popular choice for bonding wood and wood-based products, as well as paper, cardboard, textiles, and other materials. PVA adhesives are available in various strengths and levels of water resistance, making them suitable for indoor and outdoor use.
They’re also utilized in creating laminates and composites, allowing for the bonding of different materials to form a sturdy and long-lasting structure. Overall, PVA adhesives are a versatile and effective bonding solution for various industries, including woodworking, paper, packaging, textiles, and more.
3. Dissolvable And Water-Soluble Packaging
PVA films are used in various products that require a water-soluble film. These include laundry detergent, cleaning agents, swimming pool chemicals, inks, pigments, water treatment substances, and agricultural products. Once in the water, the PVA film will dissolve, allowing the main product to create a mixture with the water.
4. Coating Of Different Elements
PVA is also utilized as a coating material for multiple food products and is considered generally safe for consumption. One of the primary industrial applications of PVA is in the production of food packaging. A thin and water-resistant PVA film is developed to prevent moisture formation in food products. Its crosslinking density and ability to resist moisture add to its usefulness in this area.
Polyvinyl alcohol is also increasingly used in the pharmaceutical industry to coat medicinal tablets. Its diverse chemical properties have demonstrated its potential for various health applications, particularly pharmaceuticals. However, it’s adamant that you use food-grade PVA when making products for human consumption.
5. Used In 3D Printing Media
PVA’s ability to dissolve in water makes it a highly suitable filament for creating supports in 3D printing. This is especially advantageous in parts with overhangs or delicate areas where using acrylonitrile butadiene styrene (ABS) supports isn’t feasible.
PVA’s significant benefit as a support material is its water solubility. You can soak the printed output in water for a few hours. Once dissolved, the polyvinyl alcohol leaves behind clean, unmarred lines in the overhanging regions of the object being produced.
Polyvinyl alcohol is a versatile and widely used synthetic polymer with various unique properties that make it valuable in multiple industrial and commercial applications. PVA is a water-soluble, non-toxic, and biodegradable material with high flexibility, tensile strength, and elasticity.
Its properties make it a suitable material for packaging, textiles, adhesives, coatings, and other industries. PVA’s chemical properties are also used in the health and pharmaceutical industry. While PVA has some limitations, its many advantages make it a useful and widely used material in various fields.
Paige Glassman is a chemistry blogger based in Amsterdam, Netherlands, with expertise in polymers and their applications. She spends most of her time writing articles and technical reports. She likes to cook and bake to experiment with new recipes during her free time.