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Polyvinyl alcohol (PVOH, PVA, or PVAl) is a water-soluble synthetic polymer. It has the idealized formula [CH 2 CH(OH)] n . It is used in papermaking , textile warp sizing , as a thickener and emulsion stabilizer in polyvinyl acetate (PVAc) adhesive formulations, in a variety of coatings, and 3D printing .
Polyvinyl alcohol −[HOCHCH 2]−: Polyvinyl acetate is partially or completely hydrolysed to give polyvinyl alcohol. This reversible saponification and esterification reaction was a strong hint for Hermann Staudinger in the formulation of his theory of macromolecules. [12]
In recent years, EVA foam has seen popular use in cosplay communities, largely in part due to its ease to work with, durability, and comfort in comparison to traditional plastic-based costumes. [ 7 ] Flower-making foam is a thin sheet made of EVA, which is flexible, and is used by artists and craft makers to make artificial flowers.
Vinyl polymers are the most common type of plastic. Important examples can be distinguished by the R group in the monomer H 2 C=CHR: Polyethylene R = H; polypropylene from propylene, R = CH 3; Polystyrene is made from styrene, R = C 6 H 5; Polyvinyl chloride (PVC) is made from vinyl chloride, R= Cl; Polyvinyl acetate (PVAc) is made from vinyl ...
Ethylene vinyl alcohol (EVOH) is a formal copolymer of ethylene and vinyl alcohol.Because the latter monomer mainly exists as its tautomer acetaldehyde, the copolymer is prepared by polymerization of ethylene and vinyl acetate to give the ethylene vinyl acetate (EVA) copolymer followed by hydrolysis.
I think the inclusion of a boiling point and melting point is probably a bad idea without further explanation.JSR 13:09, 21 September 2012 (UTC). Melting point of PVA varies a lot depending on the level of Hydrolysis. The value of 228 C will refer to a fully-hydrolysed PVA (near 100% pure PolyVinyl Alcohol).
Formvar resin has a high softening point and strong electric insulation properties. It is also very flexible, water-insoluble, and resistant to abrasion. Formvar is also halogen free. Formvar resins are combustible and can cause dust explosions. For this reason exposure to heat, sparks, and flame should be avoided.
The worldwide production capacity of vinyl acetate was estimated at 6,969,000 tonnes/year in 2007, with most capacity concentrated in the United States (1,585,000 all in Texas), China (1,261,000), Japan (725,000) and Taiwan (650,000). [4]