Overview of Polyvinyl Acetate
The first thing that arises in our mind is what polyvinyl acetate is. We have come across many chemical compounds, but have you ever come across this compound, polyvinyl acetate? When numerous monomeric vinyl acetate (CH3COOCH=CH2) units are combined, they create a material known as polyvinyl acetate. It is possible to use polyvinyl acetate directly or modify it chemically to create other significant polymeric materials.
Let’s learn more about this interesting chemical compound. Further, we will discuss the uses of polyvinyl acetate, why PVA glue is used, polyvinyl acetate properties, and much more.
Properties of Polyvinyl Acetate
The properties of polyvinyl acetate include:
Chemical symbol of Polyvinyl Acetate
Instead of being crystalline, polyvinyl acetate is an amorphous polymer.
Polyvinyl acetate, the toughest of the polyvinyl esters, adheres well to most surfaces.
Polyvinyl acetate can be dissolved in various solvents besides water because it does not cross-link and so becomes insoluble.
Polyvinyl acetate is an organic compound made of non-crystalline or viscous material and can be either natural or artificial.
It won't turn yellow as some other thermoplastics do.
One formulation for slow drying contains 5 to 15% polyvinyl acetate and ethyl alcohol (ethanol). The same quantity of polyvinyl acetate is combined with acetone to provide a fast-drying alternative (dimethyl ketone).
Low cost, good biodegradation resistance, almost invisible bond line, high initial tack, softening at 30-45 °C, and poor creep resistance under load.
Uses and Applications of Polyvinyl Acetate
Some important uses and applications of polyvinyl acetate include:
Polyvinyl Acetate Glue
It is compatible with various other paint chemicals and can be used as a resinous component of latex paints.
The lamination of metal foils can be done using polyvinyl acetate.
As a thermosetting adhesive, non-emulsified or waterless polyvinyl acetate is helpful.
Alkali can be used to treat polyvinyl acetate, which eventually produces polyvinyl alcohol and alkali acetate. Polyvinyl alcohol can be converted into various esters or can generate acetals when it reacts with aldehydes like butyraldehyde or formaldehyde.
When it comes to filling gaps, polyvinyl acetate works okay.
PVA glue is used as it functions well as a dust-proofer, primer, bonding agent, and high-performance sealer. PVA dries quickly at room temperature and sets best when there is good airflow. When you clamp the components being glued, the seal is the strongest. It has an extremely strong binding strength and dries quickly. Stronger PVA glues have a maximum strength of 4000 PSI, while regular PVA glue has an average strength of roughly 3000 PSI.
PVA is used in various industries, including the textile, paper, and food packaging sectors. This is because of its great chemical and thermal stability and its inexpensive cost of production.
Dissolvable plastic PVA, also known as PVOH, is used in various products, such as dishwashers, and laundry pods.
Summary
In this article, we learned that Polyvinyl acetate (CH3COOCH=CH2) is an amorphous polymer. It can be dissolved in various solvents besides water because it does not cross-link and so becomes insoluble. The toughest of the polyvinyl esters adheres well to most surfaces. As we have discussed, polyvinyl acetate is an amorphous polymer with several uses.
We also learned that polyvinyl acetate is used in our everyday needs. It is used as glue, filling gaps, laminating metal foils, and much more. With these advantages, polyvinyl acetate also has disadvantages. It can irritate the respiratory tract and cause coughing when inhaled. It may cause eye and skin irritation when absorbed through the skin. Let’s wrap up this article here only.
FAQs on Uses of Polyvinyl Acetate
1. What exactly is Polyvinyl Acetate (PVA)?
Polyvinyl Acetate, commonly known as PVA, is a synthetic thermoplastic polymer. It is created through the polymerisation of vinyl acetate monomers. It is typically an amorphous, or non-crystalline, material known for its strong adhesive properties and is a key ingredient in many common glues.
2. What are the most common uses of Polyvinyl Acetate in everyday products?
Polyvinyl Acetate has a wide range of applications due to its versatility and low cost. Some of its most common uses include:
- Adhesives: It is the primary component in white glue, wood glue, and bookbinding adhesives.
- Paints: It serves as a resinous binder in water-based or latex paints, improving their durability and finish.
- Textile Industry: Used as a sizing agent to stiffen and protect threads during weaving.
- Paper Coatings: Applied to paper to give it a glossy finish and increase its strength.
3. What are the key chemical properties that make Polyvinyl Acetate useful?
The utility of Polyvinyl Acetate stems from several key properties. It exhibits excellent adhesion to a variety of porous surfaces like wood, paper, and cloth. It is relatively resistant to biodegradation and does not yellow with age like some other plastics. While insoluble in water, it can be dissolved in a range of organic solvents like acetone and ethanol, allowing for different formulations for fast or slow drying applications.
4. How is Polyvinyl Acetate different from Polyvinyl Alcohol (PVOH)?
While their names are similar, Polyvinyl Acetate (PVA) and Polyvinyl Alcohol (PVOH) have a crucial difference in water solubility. PVOH is actually made from PVA through a process called hydrolysis. Polyvinyl Acetate itself is not water-soluble, which is why it's used in durable paints and glues. In contrast, Polyvinyl Alcohol is water-soluble, making it ideal for products like dissolvable laundry and dishwasher pods.
5. Why is PVA glue one of the most popular adhesives for wood and paper crafts?
PVA glue is highly effective for wood and paper because its polymer chains are suspended in a water-based emulsion. When applied, the water penetrates the porous fibres of the wood or paper. As the water evaporates, the polymer chains are drawn together and interlock with the material's fibres, creating a very strong, durable bond that is often stronger than the material itself.
6. What is the chemical formula and structure of Polyvinyl Acetate's repeating unit?
The chemical formula for the repeating monomer unit in Polyvinyl Acetate is C₄H₆O₂. The polymer structure consists of a long vinyl backbone of carbon atoms, with acetate groups [−OOCCH₃] attached to every second carbon atom. The general formula for the polymer is written as -(C₄H₆O₂)n-.
7. Is Polyvinyl Acetate used in the food industry?
Yes, Polyvinyl Acetate has specific, regulated uses in the food industry. It is often used as a component of chewing gum base due to its rubbery texture. It can also be used as a glaze on fresh fruits and vegetables to provide a protective, shiny coating. Its use as a food additive is governed by food safety authorities.
8. What are the potential health and safety considerations when working with Polyvinyl Acetate?
While generally safe in its final, cured form (like dried glue), the liquid emulsion or dust from Polyvinyl Acetate can be an irritant. As per safety guidelines, inhalation of its vapours or dust may irritate the respiratory tract. Direct contact with the liquid form may also cause mild skin or eye irritation. Therefore, it is advisable to work in a well-ventilated area and avoid direct contact with eyes or prolonged contact with skin.
