Overview

Polyvinyl alcohol (commonly abbreviated PVA, PVAL or PVOH) is a synthetic polymer notable for its water solubility, film‑forming ability and chemical versatility. It is odorless, generally considered to have low toxicity for humans, and is used in many industrial, household and medical products. For further technical resources see more information.

Chemistry and production

PVA is produced by hydrolyzing polyvinyl acetate (PVAc), converting acetate groups to alcohol groups. The resulting polymer is a linear chain of repeating vinyl alcohol units. Two important variables—degree of hydrolysis (percentage of acetate groups removed) and molecular weight—determine solubility, crystallinity, melting behavior and mechanical strength. Partial hydrolysis yields materials with a balance of water resistance and solubility.

Properties

PVA is water‑soluble (depending on grade), forms clear flexible films, and adheres well to many substrates. It has good barrier properties to oxygen, is resistant to oils and greases, and can be crosslinked to improve water resistance. PVA is nonvolatile and relatively chemically stable under normal conditions; it degrades on strong heating or in harsh chemical environments.

Uses and examples

  • Textile sizing and finishing to improve thread strength during weaving.
  • Adhesives: white glues, paper and wood formulations, and glue sticks.
  • Water‑soluble packaging films for single‑dose detergents, agrochemical capsules and protective packaging.
  • Paper and board coatings to enhance surface strength and printability.
  • Pharmaceutical and medical uses: tablet coatings, suspending agents and components in eye lubricants and contact‑lens care solutions.
  • Specialty applications: 3D‑printing support materials, emulsion polymerization stabilizer and as a component in slime/craft products when crosslinked with borates.

History, safety and environmental notes

PVA was developed in the early 20th century and matured as an industrial polymer after methods to produce it from PVAc were established. It is generally regarded as having low acute toxicity, nonvolatile and nonirritant in many forms, but like all polymers it should be handled according to material safety guidance. PVA is biodegradable under certain conditions and by specific microorganisms, but its environmental fate depends on formulation, degree of hydrolysis and disposal pathway. Its water solubility makes wastewater treatment and formulation choices important in some applications.

Distinctions and notable facts

Although its precursor is polyvinyl acetate, PVA has very different properties because of the alcohol groups. Adjusting hydrolysis and molecular weight allows manufacturers to tailor solubility, strength and resistance to moisture. A well‑known consumer example of PVA use is water‑soluble film for single‑dose laundry and dishwasher products; a familiar classroom demonstration is the reversible crosslinking of PVA with borax to make slime.