Polyvinyl alcohol (PVA) is an important polymer material with many excellent physical properties and wide applications.

Chemical definitions of 1 and polyvinyl alcohol

Polyvinyl alcohol (PVA) is a synthetic polymer material, which is formed by polycondensation of vinyl alcohol molecules. Its molecular formula is [CH2CH(OH)]n, where n represents the degree of polymerization, that is, the number of connections between single vinyl alcohol molecules.

2. Physical properties of polyvinyl alcohol

Polyvinyl alcohol has many physical properties, such as high elasticity, low air permeability, water resistance, moisture resistance, acid and alkali resistance, etc. These characteristics make PVA widely used in many fields, such as packaging, medical care, construction, agriculture and so on.

3. Preparation method of polyvinyl alcohol

PVA can be obtained by polymerization of aqueous solution of vinyl alcohol. In the process of polymerization, vinyl alcohol molecules will gradually form long chains, and condensation polymerization will be carried out through water molecules as the medium.

4. Environmental impact of polyvinyl alcohol

Polyvinyl alcohol is a biodegradable material, which can be decomposed in the natural environment. However, due to the wide application of PVA, it may have a certain impact on the environment, such as the formation of plastic pollution in rivers and oceans. It is necessary to manage and use PVA reasonably to reduce the impact on the environment.

The application of polyvinyl alcohol includes four fields: architecture, textiles, fibers and coatings.

1, construction field

The application of PVA in the construction field mainly plays a role in basic materials such as adhesives, and its consumption accounts for about 40% of the total PVA, which is also the most widely used field of PVA at present.

2. Textile field

PVA is also widely used in textile field because of its cohesiveness and film-forming property, which can be used for pure polyester or polyester cotton yarn.

3. Fiber field

PVA has also become an indispensable raw material for producing vinylon fiber, which is widely used in rubber products, coated cloth and other fields.

4. The field of coatings

PVA high barrier coating can be used for all kinds of common packaging, printing and plate sealing, such as BOPET, BOPP, BOPA, various PE and CPP. Especially on the sealing plate, it has excellent coating adaptability, which can better avoid the environmental pollution of residual solvent on the specific contents of external packaging after packaging, printing and compounding.