Poly(vinyl alcohol) (PVA) is a remarkable water-soluble and environmentally-friendly plastic that has been gaining increasing attention in recent years. As human society has entered the era of polymers, plastic products have become ubiquitous, bringing great convenience to our lives. However, the non-biodegradable nature of most plastics has also led to severe "white pollution" and environmental harm. PVA stands out as a unique plastic material that can dissolve in water, forming a flocculent structure that ultimately degrades completely, making it an effective solution to reduce environmental pollution.

Chemical Structure and Solubility of PVA

PVA is a white, stable, and non-toxic water-soluble polymer. It has a main carbon-carbon chain backbone, with a large number of hydrophilic hydroxyl (-OH) groups attached to the carbon atoms. Chemically, PVA can be considered a polyhydric alcohol, allowing it to undergo various reactions common to polyols, such as etherification, esterification, and acetal formation.

PVA is typically produced by the alcoholysis (hydrolysis) of polyvinyl acetate (PVAc), resulting in a head-to-tail structure that facilitates the formation of intermolecular and intramolecular hydrogen bonds. These hydrogen bonds contribute to PVA's water solubility, as the hydroxyl groups can interact with water molecules. However, the highly regular chemical structure of PVA also creates strong intermolecular and intramolecular hydrogen bonds, which can hinder its solubility to some extent. The presence of residual acetate groups, on the other hand, increases the spatial hindrance between PVA molecules, allowing water molecules to more easily access and dissolve the polymer.

The solubility of high polymers is influenced by various factors, including the chemical structure, molecular weight, and the interaction between the polymer and solvent.

Biodegradability of PVA

PVA is the only vinyl polymer that can be utilized as a carbon and energy source by bacteria, making it a highly biodegradable material. Under the action of bacteria and enzymes, up to 75% of PVA can be degraded within 46 days. This unique property positions PVA as an essential green material for sustainable development strategies, bridging the gap between traditional plastics and rubbers.

Applications of PVA

• Textile industry

In the textile industry, PVA plays a crucial role as a sizing agent and finishing treatment, improving the stiffness, elasticity, and water resistance of fabrics.

• Paper industry

In the paper industry, PVA is widely used as a binder for pigments, enhancing the brightness, gloss, and printability of various paper grades.

• Pharmaceutical and cosmetic industries

Beyond these traditional applications, PVA has also found use in the pharmaceutical and cosmetic industries, owing to its non-toxic and biocompatible nature. The polymer can be employed in the formulation of drug delivery systems, as well as in personal care products.

As a testament to its versatility and environmental friendliness, PVA has gained increasing attention as a biodegradable and sustainable alternative to traditional petroleum-based polymers. This growing interest in PVA's eco-friendly properties further highlights its potential to contribute to a more sustainable future.