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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 acetate used further for polyvinyl alcohol is manufactured by radical polymerization in methanol solution. Liquid polybutadienes are made by anionic or radical polymerization in hydrocarbon solutions. Butyl rubber (IIR) by low temperature cationic copolymerization of isobutylene with isoprene in ethylene or methylchloride solution.
Vinyl polymers are subject of several structural variations, which greatly expands the range of polymers and their applications. With the exception of polyethylene, vinyl polymers can arise from head-to-tail linking of monomers, head-to-head combined with tail-to-tail, or a mixture of those two patterns. Additionally the substituted carbon center in such polymers is stereogenic (a "chiral center")
For example, polyester chains grow by reaction of alcohol and carboxylic acid groups to form ester links with loss of water. However, there are exceptions; for example polyurethanes are step-growth polymers formed from isocyanate and alcohol bifunctional monomers) without loss of water or other volatile molecules, and are classified as addition ...
The term polyol is also attributed to other molecules containing hydroxyl groups. For instance, polyvinyl alcohol is (CH 2 CHOH) n with n hydroxyl groups where n can be in the thousands. Cellulose is a polymer with many hydroxyl groups, but it is not referred to as a polyol.
Some grades of polyvinyl alcohol and other water-soluble polymers can promote emulsion polymerization even though they do not typically form micelles and do not act as surfactants (for example, they do not lower surface tension). It is believed that growing polymer chains graft onto these water-soluble polymers, which stabilize the resulting ...
At room temperature, acetaldehyde (H 3 CC(O)H) is more stable than vinyl alcohol (H 2 C=CHOH) by 42.7 kJ/mol. [3] Vinyl alcohol gas isomerizes to the aldehyde with a half-life of 30 min at room temperature. [1] H 2 C=CHOH → H 3 CC(O)H The industrial synthesis of acetaldehyde (Wacker process) proceeds via the intermediacy of a vinyl alcohol ...
In polymer chemistry, suspension polymerization is a heterogeneous radical polymerization process that uses mechanical agitation to mix a monomer or mixture of monomers in a liquid phase, such as water, while the monomers polymerize, forming spheres of polymer. [2] The monomer droplets (size of the order 10-1000 μm) are suspended in the liquid ...
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