Polyvinyl alcohol, sometimes known as PVA, PVOH, or PVAL, is a synthetic polymer that dissolves in water. It is a white powder produced by the polymerization of vinyl acetate monomers. This material plays various roles in commercial and industrial industries such as paper industry, textile, and printing.
This compound has the highest production volume among water-soluble synthetic polymers.
Physical and Chemical Properties:
Polyvinyl alcohol comes in the form of granules or white cream-colored powder. Its aqueous solutions are pure in terms of pH, acidic to neutral. The combination with the chemical formula CH2CHOH is non-toxic, non-flammable, and odorless. Another feature of this material is that it is resistant to fats, oils, and solvents.
|Molar mass||44.05 g·mol−1|
|Appearance||Colorless, white or cream, amorphous powder|
|pH||5,0 to 6,5 (4 % solution)|
|Melting Point||200 °C (392 °F; 473 K)|
|Boiling point||644 °F at 760 mm Hg approximately|
|Solubility||Soluble in water; sparingly soluble in ethanol|
|Flash Point||175 °F (79 °C)|
|color||white or cream-colored|
|Chemical Structure Depiction|
PVA Production Process:
The key raw material in the production of the product is vinyl acetate monomer. PVA is obtained by polymerization of vinyl acetate monomer and then by partial hydrolysis. In this hydrolysis, the ester group in PVAc is replaced by the hydroxyl group. The process is completed by the presence of sodium hydroxide as a catalyst.
Applications and Uses of PVA:
- Polyvinyl alcohol is used in the paper industry to make the paper as a compactor.
- Used in the textile industry to produce fabrics.
- One of the main uses of this material is in food packaging.
- Used as emulsion and stabilizer in PVC or PVAc adhesive formulations and all types of coatings.
- This compound is used as an aid in the polymerization of the suspension.
- Used as a protective colloid to disperse polyvinyl acetate.
- Production of artificial tears and eye drops for lubrication
- Production of gloves resistant to chemical raw materials.
- Used to produce vinyl fiber. No oil is needed to produce these fibers.
- Used in photographic film.
- Today, PVA-based polymers are widely used in the production of additives.
- In medicine, it is used as an embolic agent in uterine fibroids (UFE).
- Polyvinyl alcohol is used as an emulsifier in the cosmetics industry.
- It is also used in agricultural industries to increase soil adhesion and prevent soil erosion and the production of chemical fertilizers, pesticides, and herbicides.
Sterile Polyvinyl alcohol Eye drops:
One of its uses is in the form of eye drops, which are also called artificial tears. This substance is used to treat burning and dry eyes; Especially if the dryness is due to reduced tear production in the eye. This drop lubricates the surface of the eye and makes it easier to open and close the eye.
This drop can be obtained both with a doctor’s prescription and without a prescription from pharmacies.
Application of PVA in the Preparation of Adhesives:
Among the two common adhesives available called polyvinyl acetate and PVA, you should note that the type of polyvinyl acetate turns yellow after a while and loses its adhesive properties.
- PVA adhesives are water-soluble and do not turn yellow over time and are used for adhesives paper and other items;
- Among the properties of PVA, the following can be mentioned;
- It does not turn yellow over time;
- Remains flexible;
- It will not affect the pH balance of products;
- It dries easily and with high transparency;
- Does not produce harmful fumes.
Because the composition of polyvinyl alcohol has a wider application in many industries, the issue of its toxicity and dangerousness is very important.
If this polymer enters the environment, it decomposes gradually and slowly.
This compound is flammable. Dust from this polymer scattered in space may irritate the eyes and respiratory system.
People who deal with this substance need to use special glasses, masks, and work clothes.
- Skin Contact: Immediately flush skin with water.
- Inhalation: move the person to the fresh air.
- Eye Contact: Rinse eyes with water for at least 15-20 minutes.
- Ingestion: Do not induce vomiting. Get medical aid immediately. Call a poison control center.
Packing and storage:
Store in a cool, dry place. Store in a tightly closed container.