Vinyl esters polymerization

Poly(vinyl ester) Polymerization temp. ro Intrinsic viscosity, [)/] of derived poly(vinyl alcohol) (dl/gm) 1.2 Diol content, mol% in poly( vinyl alcohol)" Water soluble (%) Swelling index"... 

The published literature, particularly the patent literature, of vinyl ester polymerization is very extensive. No attempt will be made here to cover this field comprehensively. Rather, selected examples will be drawn from various sources which represent state-of-the-art methods for the preparation of these polymers from both a commercial and a laboratory point of view. 

A paper was given on applications of PVA , and a paper on history of vinyl ester polymerizations with Herrmann the inventor of PVA... 

Aqueous mineral acids react with BF to yield the hydrates of BF or the hydroxyfluoroboric acids, fluoroboric acid, or boric acid. Solution in aqueous alkali gives the soluble salts of the hydroxyfluoroboric acids, fluoroboric acids, or boric acid. Boron trifluoride, slightly soluble in many organic solvents including saturated hydrocarbons (qv), halogenated hydrocarbons, and aromatic compounds, easily polymerizes unsaturated compounds such as butylenes (qv), styrene (qv), or vinyl esters, as well as easily cleaved cycHc molecules such as tetrahydrofuran (see Furan derivatives). Other molecules containing electron-donating atoms such as O, S, N, P, etc, eg, alcohols, acids, amines, phosphines, and ethers, may dissolve BF to produce soluble adducts. 

Gandini and Rieumont26,119 have carried out an extensive examination of the polymerizability of several vinyl esters of furan carboxylic acids and of the causes of the autoinhibition which most of them display with free-radical initiation. The compounds studied were the vinyl esters of 2-furoic, 2-furylacetic, 2-furylpropionic, 2-furylacrylic and sorbic acid. All these derivatives, showed the same strong indifference towards radical polymerization. Only when treated with large doses (10—30%) of initiator did they give small yields of oligomers. The structure of all these products was carefully studied by spectroscopic and other techniques. Invariably, it was... 

The only other study of the polymerization of a furanic vinyl ester concerns allyl 2-furylacrylate120, but the conditions used were so violent (bulk at 200 °C with benzoyl peroxide) that no conclusions meaningful in the present context can be drawn. 

Tsuda156 reported the preparation of poly(vinyl 2-furylacrylate) by the reaction of 2-furylacrylyl chloride with poly(vinylalcohol) in NaOH-water-methyl ethyl ketone. Up to 80% of the hydroxyl groups were esterified. The interest of this technique is obvious here, considering that the vinyl ester of 2-furylacrylic acid does not polymerize119 A similar procedure was employed by Gandini and Rieumont26,1 9 for the synthesis of poly(vinyl 2-furoate) another product unobtainable via a standard polymerization process (see Section 1II-B-3). 

For less polar monomers, the most extensively studied homopolymerizations are vinyl esters (e.g. VAc), acrylate and methacrylate esters and S. Most of these studies have focused wholly on the polymerization kinetics and only a few have examined the mierostructures of the polymers formed. Most of the early rate data in this area should be treated with caution because of the difficulties associated in separating effects of solvent on p, k and initiation rate and efficiency. 

Acetaldehyde is formed during the degradation of PET. Vinyl ester endgroups formed during thermal degradation of PET liberate vinyl alcohol on transesterification with hydroxyethylterephthalate polymeric endgroups (Fig. 10.6). The vinyl alcohol tautomerizes to form acetaldehyde, which can affect the taste of foods in PET food contact applications.1... 

We make polyethylene resins using two basic types of chain growth reaction free radical polymerization and coordination catalysis. We use free radical polymerization to make low density polyethylene, ethylene-vinyl ester copolymers, and the ethylene-acrylic acid copolymer precursors for ethylene ionomers. We employ coordination catalysts to make high density polyethylene, linear low density polyethylene, and very low density polyethylene. 

Marvel, Dec, and Cooke [J. Am. Chem. Soc., 62 (3499), 1940] have used optical rotation measurements to study the kinetics of the polymerization of certain optically active vinyl esters. The change in rotation during the polymerization may be used to determine the reaction order and reaction rate constant. The specific rotation angle in dioxane solution is a linear combination of the contributions of the monomer and of the polymerized mer units. The optical rotation due to each mer unit in the polymer chain is independent of the chain length. The following values of the optical rotation were recorded as a function of time for the polymerization of d-s-butyl a-chloroacrylate... 

Detailed studies on the lipase-catalyzed polymerization of divinyl adipate and 1,4-butanediol were performed [41-44]. Bulk polymerization increased the reaction rate and molecular weight of the polymer however, the hydrolysis of the terminal vinyl ester significantly limited the formation of the polyester with high molecular weight. A mathematical model describing the kinetics of this polymerization was proposed, which effectively predicts the composition (terminal structure) of the polyester. 

End-functional polymers were also synthesized by lipase-catalyzed polymerization of DDL in the presence of vinyl esters [103,104]. The vinyl ester acted as terminator ( terminator method ). In using vinyl methacrylate (12.5 mol % or 15 mol % based on DDL) and lipase PF as terminator and catalyst, respectively, the quantitative introduction of methacryloyl group at the polymer terminal was achieved to give the methacryl-type macromonomer (Fig. 12). By the addition of divinyl sebacate, the telechelic polyester having a carboxylic acid group at both ends was obtained. 

Chung [34] concluded that the semiconducting properties of a metal species influence discoloration. In contrast to metals belonging to the insulator group, metals belonging to the semiconductor group promote yellowing, perhaps due to catalysis of the polymerization of vinyl esters. The formation of chromophores is enhanced when the metal has a variable valency with a reduction potential near to zero. 

The color of the polymer can also be affected by inappropriate reaction conditions in the polymerization process, such as temperature, residence time, deposits of degraded polymer or the presence of oxygen. Degradation of polyesters and the generation of chromophores are thermally effected [29b, 29c, 39], The mechanism of thermal decomposition is based on the pyrolysis of esters and the formation of unsaturated compounds, which can then polymerize into colored products. It can be assumed that the discoloration takes place via polymerization of the vinyl ester end groups or by further reaction of AA to polyene aldehydes. 

In fact, the first description of a polymeric vinyl ester dates back to 1912 when Klatte [1] managed to polymerise vinyl chloroacetate to obtain a solid resin. However, the potential of these materials was not seen at that time [2]. Additionally the polymerisation reaction faced severe practical problems leading to products... 

Monomers that copolymerize with thiocarbonyl fluoride include olefins, vinyl halides, vinyl esters, ally esters, acrylates, vinyl ethers, and vinyltrichloro-silane. Nonconjugated diolefins lead to crosslinked products. Conjugated dienes inhibit polymerization. 

There are two types of cure reactions of thermosetting resins step (e.g., epoxies, phenolics, urethanes) and chain (e.g., unsaturated polyesters, vinyl esters, acrilates) polymerizations. In the first type, the size of the polymer chain increases because of the linking of the oligomers (e.g., monomers, dimers, etc.) to themselves. Short chains can be linked to long ones in a condensation reaction. In the second case, the size of the polymer chain increases because of... 

An interesting exception reported by Rogovin and Tsaplina concerns vinyl acetate which when exposed to the influence of nitric esters, polymerizes very slowly. The ester radicals -N02, -ONC>2 and ions NO , ONO , do not seem to influence appreciably the rate of polymerization and the catalytic action of nitric esters is not produced by the presence of O—N02 groups. 

Fadner (42) reported preliminary results of electrically initiated polymerization experiments where liquid vinyl monomers are isolated from the electrodes. Liquid ethyl acrylate, for example, absorbed on a filter paper was polymerized in an alternating electric field. The filter paper was sandwiched between two layers of 1.5-mil Mylar film and placed between flat, parallel aluminum electrodes. Conversions of monomer to polymer ranged from 10 to 85% in the range between 20 and 240 sec at up to 25 kcps power. Acrylic acid and its ester polymerized most readily, others, such as styrene and vinyl chloride, resulted only in low yields in the same condition. 

Some Aspects of Vinyl Ester Emulsion Polymerization... 

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