Fumarate-vinyl acetate copolymer

Copolymers of ethylene vinylacetate are the most commonly utilized fuel wax crystal modifiers. Other compounds such as vinyl acetate-fumarate copolymers, styrene-ester copolymers, diester-alphaolefin copolymers, as well as alkyl carbamate compounds are effective wax crystal modifiers. These compounds differ in both chemical structure and in the extent of performance provided. See FIGURES 6-7 and 6-8. 

Highly purified diallyl maleate and fumarate in an inert atmosphere, are said to polymerize very rapidly [118], However, trace impurities and atmospheric oxygen substantially reduce the polymerization rate under ordinary circumstances. Naturally with the double bond between the two carboxylate groups and the two allylic double bonds, crosslinking takes place at very low conversion. Even so, in copolymer systems such as in poly(vinyl acetate) emulsion copolymers, the cross-linking of a fumarate or maleate within the latex particles appears not to interfere significantly with film formation properties. As a matter of fact these monomers are incorporated in poly(vinyl acetate) latices used in adhesives and in water-based paints. 

In addition to homopolymers of varying molecular and particle structure, copolymers are also available commercially in which vinyl chloride is the principal monomer. Comonomers used eommercially include vinyl acetate, vinylidene chloride, propylene, acrylonitrile, vinyl isobutyl ether, and maleic, fumaric and acrylic esters. Of these the first three only are of importance to the plastics industry. The main function of introducing comonomer is to reduce the regularity of the polymer structure and thus lower the interchain forces. The polymers may therefore be proeessed at much lower temperatures and are useful in the manufacture of gramophone records and flooring compositions. 

Whilst vinyl acetate is reluctant to copolymerise it is in fact usually used today in copolymers. Two of particular interest to the plastics industry are ethylene-vinyl acetate (Chapter 11) and vinyl chloride-vinyl acetate copolymers (Chapter 12). In surface coatings internal plasticisation to bring the Tg to below ambient temperatures and thus facilitate film forming is achieved by the use of ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and dialkyl maleates and fumarates. 

Free-radical polymerization of a 1 1 mixture of dimethyl fumarate and vinyl acetate, resulting in a highly regular alternating copolymer, illustrates the importance of substitution on the properties of both the free radical and the olefinic substrate [139] ... 

Figure 8. Concentration of different radicals measured from ESR spectra during copolymerization of vinyl acetate (VAc) with maleic acid (MA) ana of VAc with fumaric acid (FA) at different molar concentrations of MA in the VAc-MA system and FA in the VAc-FA system, respectively. (VAc-) and (MA-) refer to monomer radicals and (VAc-MA-) and (VAc-MA-) to the copolymer radicals observed. [VAc] = 5.5 X 10 2M ...

Vinyls, finyl esters are usually used in waterborne coatings in the form of copolymer dispersions. Typical vinyl esters are vinyl acetate, vinyl propionate, vinyl laurate, and vinyl versatate. Acrylic, maleic, and fumaric acid esters are used as copolymers, finyl acetate is lower in cost compared to (meth) acrylic esters. Although vinyl acetate coatings are inferior to acrylics in both photochemical stability and resistance to hydrolysis, this does not prevent them from being used for exterior... 

Poly(vinyl acetate) latex is used in the production of water-based emulsion paints, adhesives, and textile and paper treatments. Emulsion paints are stable, dry quickly, and are relatively low cost. PVAC emulsion adhesives are used in labeling and packaging, and as the popular consumer white glue. Copolymers with dibutyl fumarate, vinyl stearate, 2-ethylhexyl acrylate, or ethyl acrylate are used to obtain compositions that are softer for emulsion use. As indicated above, a major use of poly(vinyl acetate) is in the production of poly(vinyl alcohol), which is itself the starting material for poly(viityl butyral) and poly(vinyl formal). 

Vinyl acetate polymers are extensively used in emulsion paints, as adhesives for textiles, paper, and wood, as a sizing material, and as a permanent starch. A number of commercial grades are available which differ in molecular weight and in the nature of comonomers (e.g., acrylate, maleate, fumarate) which are often used. Two vinyl acetate copolymers of particular interest to the plastics industry are EVA and vinyl chloride-vinyl acetate copolymers. 

A number of copolymers are known where vinyl acetate is the major component. In coatings, vinyl acetate is often used in copolymers with alkyl acrylates (line 2-ethylhexyl acrylate) or with esters of maleic or fumaric acids. Such copolymers typically contain 50-20% by weight of the comonomer and are usually formed by emulsion polymerization in batch processes. They are used extensively as vehicles for emulsion paints. 

On the other hand, the joint polymerization of a series of electron-accepting and electron-donating monomers leads to alternating copolymers, mostly as a mixture with the head-to-head cycloaddition products. Electron-accepting maleic anhydride, fumaric ester, sulfur dioxide, or carbon dioxide in combination with electron-donating butadiene, isobutylene, vinyl ether, and p-dioxene or vinyl acetate belong to this series. 

Copolymers. Vinyl chloride can be copolymerized, with vinyl acetate giving a polymer wi a lower softening point and better stability than pure PVC. The compositions can vary from 5 to 40 percent vinyl acetate content. This material has application in areas where PVC is too rigid and the use of plasticized PVC is unacceptable. Flooring is one application for these copolymers. Copolymers with about 10 percent vinylidene chloride and copolymers with 10 to 20 percent diethyl fumarate or diethyl maleate are also available. 

Water Insoluble Polymers. There are a number of polymeric substances reported to have functionality as defoamers. These include fatty acid modified alkyloid resins, copolymers of vinyl acetate and long-chain maleic and fumaric acid diesters, as well as polypropylene and butylene oxide polymers and addition products [19-21],... 

As mentioned previously, the Alfrey Priee Q and e values for vinyl acetate are 0.026 and —0.22, respectively [226]. Thus vinyl acetate is rather sluggish in its free-radical copolymerization, with most monomers, particularly olefinic monomers, bearing electron-donating subtitutents. The copolymerization reactivity ratios reflect the reluctance of vinyl acetate to enter into copolymerization with other monomers [270]. Nevertheless, vinyl acetate copolymers with a great many electron-rich as well as electron-poor olefins have been prepared. Especially significant from a commercial point of view are copolymers with ethylene, vinyl chloride, acrylates, methacrylates, fumarates, and maleates. Often, mixtures of three and more comonomers are used in these copolymerizations. 

Whereas homopolymerizations of maleic or fumaric add derivatives have not yet found technical interest, copolymers derived from MAH and various vinyl monomers are commercialized by several chemical companies. Such commerdal copolymers may be based on styrene (Scriptset or SMA), ethene (EMA, Malethamer, VINAC), isobutene (ISOBAM), butadiene (Maldene), vinyl alkyl ethers (Gantrez AN or Viscofres), and vinyl acetate (Lyfron, Benex, Amoco DriUing Aid 420,421, or Baroid X tend). 

As mentioned in the previous section, it is common practice to plasticize poly(vinyl acetate) intended for surface coatings by such materials as dibutyl phthalate, A limitation of external plasticizers of this kind is that they may eventually be lost by evaporation or by migration into the substrate, leaving an imperfect and brittle film. This limitation may be overcome by the use of copolymers and these are now widely used in surface coatings and other applications. Comonomers which may be employed for this purpose include alkyl (commonly 2-ethylhexyl) acrylates, fumarates and maleates. Typically, the copolymers contain 15—20% by weight of such comonomers. These... 

Not all the monomers listed in Table 1 react together satisfactorily thus vinyl acetate and styrene, ethylene and styrene, are examples of unfavourable pairs. Moreover, monomers without terminal unsaturation, e.g. the fumarates, and the related maleates, do not generally form homopolymers although readily forming copolymers with, for example, vinyl acetate. 

Figore9 ESR spectrum of 0.1% (w/w) fumarate-vinyl acetate copolymer, 2% dot-riacontane in dodecane (a) 23 °C, above the cloud point (b) 19 °C, just below the cloujd point (c) 15 °C... 

MA to obtain materials with pendent maleate or fumarate residues. It is also possible to transesterify a poly(ethylene-vinyl acetate) copolymer, using HgCl2 catalyst at Cotton materials have also been treated with... 

Monomers which are copolymerized with vinyl acetate include alkylacrylates, alkylma-leates, fumarates, and ethylene. The level of comonomers may vary from a few weight percent of the copolymer to as much as 70 weight percent. 

Vinyl resins - In the coatings industry, vinyl resins usually refer to either poly(vinyl chloride) (PVC) or poly(vinyl acetate) (PVAc) which is widely used in interior and exterior latex paints. Produced usually by emulsion polymerization, a PVAc homopolymer is too hard to allow its colloidal latex particles to coalesce well into a continuous film at ambient temperatures. Most PVAc emulsions used in the paint industry are copolymers with a plasticizing monomer such as dibutyl maleate, 2-ethyhexyl acrylate, n-butyl acrylate, dibutyl fumarate, isodecyl acrylate, or ethyl acrylate. By polymerizing under pressure, copolymers of vinyl acetate and ethylene are also produced for latex paints. External plasticizers such as dibutyl phthalate are used as well. All these methods not only soften the polymer to allow the latex particles to coalesce into a continuous film, but also impart the film flexiblity needed in exterior house paints. 

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