Vinyl acrylic ester copolymerization

Almost all synthetic binders are prepared by an emulsion polymerization process and are suppHed as latexes which consist of 48—52 wt % polymer dispersed in water (101). The largest-volume binder is styrene—butadiene copolymer [9003-55-8] (SBR) latex. Most SBRlatexes are carboxylated, ie, they contain copolymerized acidic monomers. Other latex binders are based on poly(vinyl acetate) [9003-20-7] and on polymers of acrylate esters. Poly(vinyl alcohol) is a water-soluble, synthetic biader which is prepared by the hydrolysis of poly(viayl acetate) (see Latex technology Vinyl polymers). 

Syntheses of Self-Sensitized Polymers by Cationic Copolymerizations. The cationic polymerizations of several vinyl ethers containing pendant ester groups such as cinnamic ester 12), methacrylic ester 16), acrylic ester (77), and crotonic ester 18) have been reported. Based on these reports, cationic copolymerizations of CEVE with photosensitizer monomers such as NPVE, NNVE, VNP and NPEVE were carried out using TFB as a catalyst in toluene at — 65 °C. Each copolymer was obtained with high yield except in the case of copolymerization of CEVE with VNP as summarized in Table I. 

Denka, Tokyo, Japan, Elastomer copolymerized from ethylene,vinyl acetate and acrylic esters. 

Acrylic acid - [ACRYLIC ACID AND DERIVATIVES] (Vol 1) - [ACRYLIC ACID ANDDERIVATTVES] (Vol 1) - [FEEDSTOCKS - COALCHEMICALS] (Vol 10) - [COATINGS] (Vol 6) - [PLANT SAFETY] (Vol 19) - [ACRYLONITRILE POLYMERS - SURVEY AND SAN (STYRENE-ACRYLONITRILECO-POLYMERS)] (Vol 1) -from acetic acid [ACETIC ACID AND DERIVATIVES - ACETIC ACID] (Vol 1) -acrylic ester comonomer [ACRYLIC ESTER POLYMERS - SURVEY] (Vol 1) -m acrylonitrile copolymers [ACRYLONITRILE POLYMERS - SURVEY AND SAN (STYRENE-ACRYLONITRILECO-POLYMERS)] (Vol 1) -cesium in prdn of [CESIUM AND CESIUM COMPOUNDS] (Vol 5) -dehydration of piSTILLATTON, AZEOTROPIC AND EXTRACTIVE] (Vol 8) -polymerization in SCFs [SUPERCRITICAL FLUIDS] (Vol 23) -from propylene [PROPYLENE] (Vol 20) -VP copolymerization [VINYL POLYMERS - N-VINYLAMIDEPOLYMERS] (Vol24)... 

Copolymerization. Vinyl chloride can be copolymerized with a variety of monomers. Vinyl acetate, the most important commercial comonomer, is used to reduce crystallinity, winch aids fusion and allows lower processing temperatures. Copolymers are used in flooring and coatings. This copolymer sometimes contains maleic add or vinyl alcohol (hydrolyzed from the poly(vinyl acetate ) to improve the coating s adhesion to other materials, including metals, Copolymers with vinylidene chloride are used as barrier films and coatings. Copolymers of vinyl chlonde with acrylic esters in latex from are used as film formers in paint, nonwoven fabric binders, adhesives, and coatings. Copolymers with olefins improve thermal stability and melt flow, but at some loss of heat-deflection temperature,... 

Catalysts of the Ziegler type have been used widely in the anionic polymerization of 1-olefins, diolefins, and a few polar monomers which can proceed by an anionic mechanism. Polar monomers normally deactivate the system and cannot be copolymerized with olefins. However, it has been found that the living chains from an anionic polymerization can be converted to free radicals in the presence of peroxides to form block polymers with vinyl and acrylic monomers. Vinylpyridines, acrylic esters, acrylonitrile, and styrene are converted to block polymers in good yield. Binary and ternary mixtures of 4-vinylpyridine, acrylonitrile, and styrene, are particularly effective. Peroxides are effective at temperatures well below those normally required for free radical polymerizations. A tentative mechanism for the reaction is given. 

Pure acrylonitrile may polymerize at room temperature to polyacrylonitrile (PAN), a compound that, unlike polyamides and polyesters, does not melt at elevated temperatures but only softens and finally discolors and decomposes. Nor is it soluble in inexpensive low-boiling organic solvents. Because fibers made from it resist the dyeing operations commonly used in the textile industry, the usual practice is to modify it by copolymerization with other monomers, for example, vinyl acetate, styrene, acrylic esters, acrylamide, or vinyl pyridine in amounts up to 15 percent of the total weight (beyond which the final product may not be termed an acrylic fiber). The choice of modifier depends on the characteristics that a given manufacturer considers important in a fiber, the availability and cost of the raw materials in the manufacturer s particular area of production, and the patent situation. 

Commercial acrolein is an intermediate in the manufacture of several products, in particular D,L-methionine, used as an additive in animal feeds. For the most part however it is directly oxidized to acrylic acid, without being separated and recovered as a pure material. The acid is mainly esterified to methyl and other acrylates, with the remainder being directly used for the manufacture of polymers. Acrylate esters are currently the final destination of most acrolein produced in the world. They readily form homopolymers and copolymerize with methacrylates, styrene, vinyl acetate and acrylonitrile to yield a range of prized products, characterized by excellent clarity, stability to UV light and aging, and good pigmentability. 

Most vinyl acetate is converted into polyvinyl acetate (PVA) which is used in the manufacture of dispersions for paints and binders and as a raw material for paints. It is also copolymerized with vinyl chloride and ethylene and to a lesser extent with acrylic esters. A substantial proportion of vinyl acetate is converted into polyvinyl alcohol by saponification or transesterification of polyvinyl acetate. The main applications for polyvinyl alcohol are either as raw material for adhesives or for fibres. It is also employed in textile finishing and paper glueing, and as a dispersion agent (protective colloid). The world production capacity of PVA was 4.35 Mt/a in 2005, of which 2.1 Mt were converted into polyvinyl alcohol. 

In general, acrylic ester monomers copolymerize readily with each other or with most other types of vinyl monomers by dee-radical processes. The relative ease of copolymerization for 1 1 mixtures of acrylate monomers with other common monomers is presented in Table 7. Values above 25 indicate that good copolymerization is expected Low values can often be offset by a suitable adjustment in the proportion of comonomers or in the method of their introduction into the polymerization reaction (86). 

The combination of durability and clarity and the ability to tailor molecules relatively easily to specific applications have made acrylic esters prime candidates for numerous and diverse applications. At normal temperatures the polyacrylates are soft polymers and therefore tend to find use in applications that require flexibility or extensibility. However, the ease of copolymerizing the softer acrylates with the harder methacrylates, styrene, acrylonitrile, and vinyl acetate, allows the manufacture of products that range from soft rubbers to hard nonfihn-formitig polymers. 

The high pressure polymerization of ethylene can be slightly modified for the copolymerization of ethylene with vinyl- and acrylic-type monomers such as vinyl acetate, vinyl chloride, acrylonitrile, or acrylic esters. Some of these copolymers of ethylene and vinyl acetate or maleic anhydride are already available and have found various applications in plastics, coatings, and adhesives. Copolymers of ethylene and vinyl chloride and of ethylene and acrylonitrile appear particularly interesting because of the low cost of monomers and the properties of the copolymers. Although their synthesis has been disclosed in a number of patents their larger scale production is still in a state of development. 

In practice, many commercial process employ a chain transfer agent to control molecular weight at a reduced level. Processes of commercial importance are the copolymerization of butadiene with styrene or acrylonitrile to produce synthetic rubber and the polymerization of acrylic esters, vinyl chloride, vinylidene, and vinyl acetate to produce latexes for adhesives and paints. 

The copolymerization of acrylic esters with 5%-15% acrylonitrile or 2-chloroethyl vinyl ether produces elastomers which are more heat and oxidation resistant than butadiene/acrylonitrile copolymers because of the absence of double bonds. For the same reasons, these materials are also suitable for the manufacture of gaskets and membranes for use with high-sulfur-content industrial oils (for example, crankshaft gaskets in the automobile industry). Since the side groups have poor resistance to hydrolysis, steam curing is not possible. Curing with amines can be subsequently carried out. 

Allyl esters, unsaturated polyesters, as well as some of what are known as vinyl or acrylic esters are cured by free radical addition polymerization. In the case of allyl esters, the monomers, themselves, are cross-linked. On the other hand, unsaturated polyesters are copolymerized with monomers such as styrene or methyl methacrylate. Since the unsaturated polyesters have many main-chain double bonds and the structure of a cross-linked network is fixed after quite low conversions, only a few double bonds actually react. These unconverted double bonds can then react later with atmospheric agents, and so produce poor weathering properties of the crosslinked networks. In addition, the polymerization produces many free chain ends that contribute nothing or even disadvantageously to the mechanical properties. The newly developed vinyl or acrylic esters avoid both of these problems in that the monomers capable of cross-linking only have unsaturated double bonds at the molecular ends (see also Section 26.4. S). 

The maleopimaric and acrylopimaric adducts, aftCT a three-step synthesis with ethylene glycol catalyzed by p-toluene sulphonic acid (pTS A), followed by epychlorydrine and by acrylic or methacrylic acid, led to the formation of vinyl-type ester monomers (Fig. 4.19), which wctc then submitted to radical copolymerization with styrene and tested as metal coatings [ 103]. A similar approach to coating materials was recently applied to prepare unsaturated polyester resins based on resin acid adducts, glycols and maleic anhydride [104, 105]. 

There are definite attractions for monomers that can be used without the aid of initiators. Such monomers are maleimides. The monomers based on vinyl acrylate are also capable of self initiation. The vinyl ester itself, however, is too volatile for practical use and its initiation of polymerization is slower than obtained with the traditional photoinitiators. When the acrylate group is replaced by crotonate, cinnamate, fumarate, or maleate chromophores, these monomers copolymerize readily with thiol and vinyl ether monomers and initiate free-radical polymerization upon direct excitation in the absence of any added photoinitiator. 

In some polymer families, copolymerization with more flexible comonomer units is very effective in producing the amount of flexibility desired. Major commercial examples are ethylene/propylene rubber, styrene/butadiene plastics and latex paint, vinyl chloride/ vinyl acetate plastics, vinyl acetate/acrylic ester latex paints, and methyl methacrylate/ acrylic ester plastics and latex paints. 

Maleic acid and phthalic acid are used as oligoester components together with bivalent alcohols (e.g., ethylene glycol, 1,4-butanediol) as co-condensation partners. Crosslinking is achieved by copolymerization of styrene, vinyl acetate, diallyl phthalate, acrylonitrile or acrylic ester. Cyclic structures impart a higher glass transition temperature. The aliphatic glycols in the... 

When copolymerized, the acrylic ester monomers typically randomly incorporate themselves into the polymer chains according to the percentage concentration of each monomer in the reactor initial charge. Alternatively, acrylic ester monomers can be copolymerized with styrene, methacrylic ester monomers, acrylonitrile, and vinyl acetate to produce commercially significant polymers. 

As can be seen in Table 1, the most common acrylic ester polymers have low Tg values and, therefore, soften films in which they are copolymerized with other vinylic monomers. This effect results in an internal plasticization of the pol5mier. That is, the plasticization effect from acrylic esters, unlike plasticizer additives which are not covalently bound, will not be removed via volatilization or extraction. 

Acrylic ester monomers are, in general, readily copolymerized with other acrylic and vinylic monomers. Table 7 presents data for the free-radical copolymerization of a variety of monomers 1 1 with acrylic ester monomers. These numbers are calculated through the use of reactivity ratios ... 

The polymerization of acrylic esters and acrylonitrile, isoprene, vinyl acetate, and butadiene have all been reviewed and reference is made to systems involving the copolymerization of these monomers. The review by Richards gives detailed attention to the copolymerization of butadiene with other monomers. 

Vinyl acetate and acrylate esters used as comonomers containing sufficient stabilizer to prevent the homopolymerization. The effect of the copolymerization with polar... 

The use of methaaylate ester monomers such as 2-sulfoethylmethacrylate, potassium-3-sulfopropylmethacrylate, or methacryloxyethyl trimethylammonium chloride is recently described (14). The adhesive prop es of these systems are significantly improved when a second water soluble monomer such as acrylic add or N-vinyl pytrolidone is copolymerized with the methacrylate ester monomer. 

Free-radical copolymerization of alkyl vinyl ethers has been carried out with the following typical monomers acrylic acid (bulk and emulsion) [39,40], acrylonitrile (emulsion) [26,27], acrylic esters (emulsion) [41], methyl methacrylate (bulk) [42], maleic anhydride (solution) [43], vinyl acetate (bulk and emulsion) [27,44,45], and vinyl chloride (emulsion) [26, 37,46]. The properties of these and other copolymers are described in a technical bulletin by General Aniline Film Corporation [38]. 

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