Chemical structure of polyvinyl alcohol

Polyvinyl alcohol (PVOH, PVA, or PVAL) is a water-soluble synthetic polymer. Image File history File links Download high-resolution version (1150x960, 26 KB) Description: Chemical structure of Polyvinyl alcohol. ... Image File history File links Download high-resolution version (1150x960, 26 KB) Description: Chemical structure of Polyvinyl alcohol. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... It has been suggested that this article or section be merged with Solution. ... Synthetic polymers are often referred to as plastics, such as the well-known polyethylene and nylon. ...

Properties

Polyvinyl alcohol has excellent film forming, emulsifying, and adhesive properties. It is also resistant to oil, grease and solvent. It is odorless and nontoxic. It has high tensile strength, flexibility, as well as high oxygen and aroma barrier. However these properties are dependent on humidity, in other words, with higher humidity more water is absorbed. The water, which acts as a plasticiser, will then reduce its tensile strength, but increase its elongation and tear strength. An emulsion is a mixture of two immiscible substances. ... Dew drops adhering to a spider web Adhesion is the molecular attraction exerted between bodies in contact. ... For other uses, see Solvent (disambiguation). ... Humidity is the amount of water vapor in air. ...

PVA has a melting point of 230°C and 180–190°C for the fully hydrolysed and partially hydrolysed grades. It decomposes rapidly above 200°C as it can undergo pyrolysis at high temperatures. Simple sketch of pyrolysis chemistry Pyrolysis usually means the chemical decomposition of organic materials by heating in the absence of oxygen or any other reagents, except possibly steam. ...

PVA is an atactic material but exhibits crystallinity as the hydroxyl groups are small enough to fit into the lattice without disrupting it. In atactic macromolecules every substituent belonging to a repeating unit is placed randomly at either side of the backbone. ... For other uses, see Crystal (disambiguation). ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ...

Uses

Some uses of polyvinyl alcohol include:

1. Adhesive and thickener material in latex paints, paper coatings, hairsprays, shampoos and glues.
2. Carbon dioxide barrier in polyethylene terephthalate (PET) bottles.
3. Carotid phantoms for use as synthetic vessels in doppler flow testing.
4. Children's play putty or slime when combined with borax.
5. Feminine hygiene and adult incontinence products as a biodegradable plastic backing sheet.
6. As a mold release because materials such as epoxy do not stick to it.
7. As a water-soluble film useful for packaging.
8. As fiber reinforcement in concrete
9. As a surfactant for the formation of polymer encapsulated nanobeads
10. Used with polyvinyl acetate to make Elmer's glue
11. Used in eye drops and hard contact lens solution as a lubricant.
12. Used in protective chemical-resistant gloves

Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Polyethylene terephthalate (aka PET, PETE or the obsolete PETP or PET-P) is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination with glass fiber. ... This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... PuTTY is a free software SSH, Telnet, rlogin, and raw TCP client. ... Borax from Persian burah. ... Biodegradation is the decomposition of material by microorganisms. ... In chemistry, epoxy or polyepoxide is a thermosetting epoxide polymer that cures (polymerizes and crosslinks) when mixed with a catalyzing agent or hardener. Most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A. The first commercial attempts to prepare resins from epichlorohydrin occurred in 1927 in... A pair of contact lenses, positioned with the concave side facing upward. ...

Fishing

PVA is widely used in freshwater sport fishing. Small bags made from PVA are filled with dry- or oil-based bait and attached to the hook, or the baited hook is placed inside the bag and cast into the water. When the bag lands on the lake or river bottom it breaks down, leaving the hook bait surrounded by ground bait, pellets etc. This method helps attract fish to the hook bait, though it does result in dissolved plastic in the water.

Anglers also use string made of PVA for the purpose of making temporary attachments; for example holding in a coil a length of line that might otherwise tangle while the cast is made.

Production

There are over 22 producers worldwide with ~ 1 million tons on the open market in 2002. Larger producers include Kuraray (Japan) and Celanese (USA) but mainland China has installed a number of very large production facilities in the past decade.

Preparation

Unlike most vinyl polymers, PVA is not prepared by polymerization of the corresponding monomer. The monomer, vinyl alcohol, almost exclusively exists as the tautomeric form, acetaldehyde. PVA instead is prepared by partial or complete hydrolysis of polyvinyl acetate to remove acetate groups. Chemical structure of the vinyl functional group. ... In chemistry, a monomer (from Greek mono one and meros part) is a small molecule that may become chemically bonded to other monomers to form a polymer. ... Ethenol, also called vinyl alcohol, hydroxyethene or hydroxyethylene, is an alcohol with chemical formula C2H4O (H2C=CHOH) and CAS number 557-75-5. ... Tautomers are organic compounds that are interconvertible by a chemical reaction called tautomerization. ... R-phrases , , S-phrases , , , Flash point −39 °C Autoignition temperature 185 °C RTECS number AB1925000 Supplementary data page Structure and properties n, εr, etc. ... Hydrolysis is a chemical reaction or process in which a chemical compound reacts with water. ... Polyvinyl acetate formula Polyvinyl acetate or PVA is a rubbery synthetic polymer. ... An acetate, or ethanoate, is a salt or ester of acetic acid. ...

External links

• Chemical properties
• Listed as a plastic by the Society of the Plastics Industry
• "Slime" recipe
• Forming PVA layers in PET bottles