Higher Polyvinyl Esters

Besides the methods described under vinyl acetate, the transvinylization of vinyl ether or vinyl acetate in the laboratory produces other vinyl esters. 

H2SO4 (vinyl acetate). An isolatable mercury complex is formed from the vinyl compound CH2=CH—O—R, the substrate R OH that is to be vinylized, and the Hg(OCOCH3)2. Under the influence of protons from the acetic acid, which is formed as an intermediate, the complex subsequently is destroyed by the reaction 

R and R can be acyl, aryl, or alkyl. The formation of acetate or diester is suppressed by low temperatures and optimal reaction times. In the vinylization of different types of reagent, the equilibrium is strongly directed toward one side of the reaction. The vinylization can only occur in the direction of vinyl ester vinyl aryl ether - vinyl alkyl ether. Poly(vinyl propionate) is also used as an adhesive. 

Poly(vinyl alcohol), (—CH2—CHOH—) , is produced by the deesterification or transesterification of poly(vinyl acetate) with methanol or, less often, with butanol. Methyl acetate and the valuable butyl acetate are useful solvents. Some methyl acetate is also saponified, and the acetic acid can be reconverted to vinyl acetate. 

During the transesterification, a highly viscous gel phase occurs at yields between 45% and 75%. To prevent the formation of this gel phase, it was proposed to work continuously in very dilute solutions, to work with poly(vinyl acetate) in hydrocarbon emulsions, or that kneaders or masticators should be used. One can avoid these difficulties with poly-(vinyl formiate), which is easily saponified in hot water. Monomeric vinyl formiate is, however, difficult to produce because of its great susceptibility to hydrolysis. In addition, the formic acid liberated during the saponification is very corrosive. 

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In 1950, Dahlquist et al. [82] reported the use of polyvinyl A -alkyl carbamates as PSA release materials. Since then, many other types of alkyl side chain polymers have been patented for use as release coatings, including copolymers based on higher alkyl acrylates or methaci ylates [83-86], polyvinyl esters of higher aliphatic fatty acids [87], higher alkyl vinyl esters or ethers and a maleic... 

Similar to caustic alkali, mineral acid is also effective in catalyzing the reaction. The use of acid, however, does not have any advantage and, often, partly water-insoluble PVA is obtained. Polyvinyl esters of higher fatty acids and aromatic esters were studied, but, from the viewpoint of fiber-making, no advantage in using esters other than acetate has been reported. The tacticity of polyvinyl esters and ethers is discussed in Section 4.3.1. 

Another very important property of plasticizers for PVC resins is the ability to act as a dispersing medium for polyvinyl chloride plastisols. The performance of the particular plasticizer in a plastisol application depends to a great extent on a property known as its viscosity stability. The stability of the plastisol to viscosity build up is the manifestation of the solvating effects of the plasticizer, and thus, those materials with higher solvating efficiency tend to display an increase in plastisol viscosity on standing. Figure 3 is the plot of the viscosity stability of PVC o-phthalate ester plastisol compositions and, in essence, compares the alcohol-derived plasticizers with that of the olefin-derived plasticizer. The data show that... 

Heat-setting resins cannot be plasticized by low molecular weight plasticizers. Polyvinyl acetals have been claimed for these products. American Cyanamid Co. has suggested polyvinyl acetals or butyrals in an amount of 10 to 25% of the resin for urea and melamine resins. For varnishes and adhesives, combinations of phenolic resins and polyvinyl formal are recommended. Polyvinyl acetals with higher alkyl radicals are suitable for cellulose esters and improve elasticity as well as resistance against water. 

DEHP levels in indoor air might be higher due to stow volatilization from plastic products (EPA 1981 Warns 1987). As noted in Section 6.2.1, Cadogan et al. (1994) reported that an indoor overall emission rate of 2.3x10 4 mg/second-m2 at 25 °C has been calculated for all phthalate plasticizers in products such as wall coverings, flooring, upholstery, and wire insulation. The air from rooms recently covered with polyvinyl chloride (PVC) tiles contained 0.15 0.26 mg/m3 (150,000 260,000 ng/m3) phthalate esters (EPA 1981). Indoor air levels in rooms with new flooring couldbe about 0.2 0.3 mg/m3 (Warns 1987). 

Ethylhexyl isodecyl phthalate (octyl iso-decyl phthalate) n, C8H17-OOCC6H4 COOC10H21. A mixed ester compatible with PVC, vinyl chloride-acetate copolymers, cellulose acetate-butyrates with higher butyrate contents, cellulose nitrate, and, in lower concentrations, with polyvinyl butyral. In vinyls, it is somewhat less volatile than dioctyl phthalate and has equivalent low-temperature properties. 

Copolymers of acrylonitrile and lower acrylates have also been used as thickeners. The proportion of the acrylate in the copolymer was 60-90% by weight the preferred acrylates were the methyl through butyl esters. These authors also tested an extensive list of known and novel thickeners as comparative examples. The latter included nitrile rubber and vinyl acetate-vinyl chloride, methyl methacrylate-butadiene-styrene (MBS), and acrylonitrile-butadiene-styrene (ABS) copolymers. The copolymers of this invention were claimed to provide better stability, higher viscosity, less stringing, and better impact strength than do the thickeners of the prior art. The claims of this patent do not cover the disclosed copolymers. Polyvinyl ethers are another class of cyanoacrylate thickeners which have been disclosed but not claimed. ... 

Epoxides are highly reactive compounds, especially at higher temperatures. They form dihydroxy derivatives with water, ethers with alcohols, esters with the carboxyl group of fatty adds, chloro-hydrins (a-chlorohydroxy compounds) with hydrochloric add and amino compounds with amines (Figure 3.43). Chlorinated hydroxy acids arise, for example, in polyvinyl chloride (PVC) by reaction of epoxidised soybean oil (used as a stabilizer of PVC) with hydrogen chloride (see Section 11.4.2.2.2). 

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