What is the molecular weight of PVA polymer and its characteristics?

What is the molecular weight of PVA polymer？In fact, molecular weight of PVA polymer is 44.053. In addition to the molecular weight of PVA polymer, you may also want to know its other chemical properties.

PVA (Polyvinyl alcohol) is made of vinyl acetate through polymerization and alcoholysis. It is a white, stable, non-toxic water-soluble polymer in the form of powder, flake or flocculent solid.

Solubility: Polyvinyl alcohol contains many alcohol groups, is polar, and can form hydrogen bonds with water, so it can be dissolved in polar water; it can also be dissolved in hot hydroxyl-containing solvents such as glycerol and phenol, but is insoluble in general organic solvents such as methanol, benzene, acetone, and gasoline. Polyvinyl alcohol powder can be dissolved in water.

Film-forming property: PVA aqueous solution is easy to form a film, and the film formed is colorless and transparent, has good mechanical strength, and has a smooth and non-sticky surface. The film can pass through water vapor, but the permeability of gases such as hydrogen, oxygen, and carbon dioxide is very low, and the external temperature change has little effect on the film. The molecular film has good light transmittance, high moisture permeability, no charge, no dust absorption, and good printability.

Adhesion: PVA aqueous solution can bond with porous materials such as fiber, wood, and paper, and has good adhesion.

Oil resistance and organic solvent resistance: At room temperature, the pH value of PVA aqueous solution is generally around 5-7, the viscosity is stable, and it is almost unaffected by weak acids, weak bases or organic solvents (esters, ketones, higher alcohols, hydrocarbons). It has extremely high oil resistance, but can be depolymerized and decomposed by peroxides such as H2O2.

PVA can be dissolved in polar solutions containing hydroxyl groups, such as glycerol, ethylene glycol, acetic acid, acetaldehyde, etc., but it is easy to gel and is insoluble in general non-polar organic solvents and inorganic acids such as H2SO4 and HCl.

Heat resistance (thermal stability): PVA softens when heated. When heated to 130-140°C, its properties hardly change, except that the color turns yellow. When heated for a long time at 160°C, the color becomes darker. At 200°C, the molecules are dehydrated and the water solubility decreases. At above 200°C, the molecules are dehydrated. At close to 300°C, it is completely decomposed into water, acetic acid, acetaldehyde and crotonaldehyde.

Storage stability: PVA is a low-viscosity polymer. Its aqueous solution is very stable at room temperature and will not deteriorate during storage.

Non-toxicity: Pure PVA is non-toxic and can be used as an adhesive for cosmetics and food packaging. It is completely harmless to contact with the skin.

All in all, the molecular weight of PVA polymer is 44.053. In addition, we also learned about the specific chemical properties such as solubility, film-forming properties, adhesion, oil resistance and organic solvent resistance, heat resistance, storage stability, and non-toxicity.