Polyvinyl acetate commercially available

Another commercially available blocky copolymer is partially hydrolyzed polyvinyl acetate commercially referred to as polyvinyl alcohol (PVA). The molecule contains short blocks of polyvinyl acetate (PVAc) which form the anchor chains to the hydrophobic surface leaving several loops and tails of PVA chains which are strongly hydrated to give an effective steric barrier ... 

Polyvinyl acetate was made commercially available in early 1930s. Poly ethers were developed by du Pont and produced on large scale in 1959. The poly carbonate were produced on large scale in 1960 by Bayer and General Electric. 

While unaffected by water, styrofoam is dissolved by many organic solvents and is unsuitable for high-temperature applications because its heat-distortion temperature is around 77°C. Molded styrofoam objects are produced commercially from expandable polystyrene beads, but this process does not appear attractive for laboratory applications because polyurethane foams are much easier to foam in place. However, extruded polystyrene foam is available in slabs and boards which may be sawed, carved, or sanded into desired shapes and may be cemented. It is generally undesirable to join expanded polystyrene parts with cements that contain solvents which will dissolve the plastic and thus cause collapse of the cellular structure. This excludes from use a large number of cements which contain volatile aromatic hydrocarbons, ketones, or esters. Some suitable cements are room-temperature-vulcanizing silicone rubber (see below) and solvent-free epoxy cements. When a strong bond is not necessary, polyvinyl-acetate emulsion (Elmer s Glue-All) will work. 

Saran (Dow polyvinylidene dichloride) is a tough, chemically resistant plastic available in a variety of forms that are useful in the laboratory. Saran pipe or tubing can easily be welded to itself or sealed to glass and is useful for handling corrosive solutions. Thin Saran film, available commercially as a packaging material, is useful for windows, support films, etc. Mylar (du Pont polyethylene terephthalate) film and other polyester films are also useful for these purposes. Mylar is chemically inert and has excellent electrical properties for electrical insulation and for use as a dielectric medium in capacitors. Much thinner than these are films that can be made in the laboratory by allowing a dilute ethylene dichloride solution of Formvar (polyvinyl acetal) to spread on a water surface and dry. 

Polyrmjl Ethers. A number of pol3rvinyl ether homologues are available in commercial quantities. The monomers are usually prepared by decomposition of the lower polyvinyl acetates or by direct vinylation of alcohols by acetylene... 

Useful polyvinyl acetate dispersions are milk-white, high-solids dispersions of vinyl acetate homopolymer in water. Such dispersions have excellent mechanical and chemical stability. Typical properties of a preferred polyvinyl acetate dispersion are given in the following table. Commercially available dispersions with similar characteristics are Monsanto s S-55L, Borden s Polyco 11755, Air Products Vynac XX-210, and Seydel Wooley s Seycorez C-79. 

PVA is a linear synthetic water soluble polymer with a pendant hydroxyl group (Fig. 8). Since the monomer, vinyl alcohol is not stable PVA is generally produced by the hydrolysis of polyvinyl acetate. The synthesis process is based on the partial replacement of ester groups in the vinyl acetate with hydroxyl groups and is done in the presence of anhydrous sodium methylate or aqueous sodium hydroxide. Commercial PVA grades are available with a high degree of hydrolysis. 

Polyvinyl alcohol is synthesized by the hydrolysis of polyvinyl acetate in a continuous process. Several grades are commercially available that differ with respect to the degree of polymerization and hydrolysis. Fully hydrolyzed samples are used primarily as warp sizes and partially hydrolyzed samples are used as adhesive components and polymerization aids [1]. 

Polyvinyl acetate has been available commercially in the United States since the 1930s. Growth was slow until the 1940s, when polyvinyl acetate emulsions were introduced. The volume of resin consumed has since grown from a negligible amount in 1945 to 1.7 billion pounds currently. 

PVC latex can be blended with polyvinyl acetate (PVAc), acrylonitrile butadiene rubber (NBR), and acrylic latex of comparable pH and surfactant systems. Since such blends are commercially available, this practice, at one time very popular with paint and coatings, has fallen off. 

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