Methacrylate esters, polymerization

Methacrylate double bond, 16 238 Methacrylate esters, polymerization of, 14 258... 

Acrylic and methacrylic esters polymerize by free-radical mechanism to atactic polymers. The sizes of the alcohol portions of the esters determine the Tg values of the resultant polymers. They also determine the solubility of the resultant polymers in hydrocarbon solvents and in oils. 

Solvents influence the rate of free-radical homopolymerization of acrylic acid and its copolymerization with other monomers. Hydrogen-bonding solvents slow down the reaction rates. Due to the electron-withdrawing nature of the ester groups, acrylic and methacrylic ester polymerize by anionic but not by cationic mechanisms. Lithium alkyls are very effective initiators of a-methyl methacrylate polymerization yielding stereospecific polymers.Isotactic poly(methyl methacrylate) forms in hydrocarbon solvents. Block copolymers of isotactic and syndiotactic poly(methyl methacrylate) form in solvents of medium polarity. Syndiotactic polymers form in polar solvents, like ethylene glycol dimethyl ether, or pyridine. This solvent influence is related to Lewis basicity in the following order ... 

The methacrylic ester polymerized rapidly in the presence of other UV active comonomers (Table V). The cured coating had good pencil hardness (>3H), high MEK rub resistance (>300 rubs), and good adhesion. 

Hydroxy-2-methylpropanenitrile is then reacted with methanol (or other alcohol) to yield methacrylate ester. Free-radical polymerization is initiated by peroxide or azo catalysts and produce poly(methyl methacrylate) resins having the following formula ... 

Table 8. Polymerization Data for Methacrylic Ester Monomers ...

Emulsion Polymerization. The principal markets for aqueous dispersion polymers made by emulsion polymerization of methacrylic esters are the paint (qv), paper (qv), textile, floor poHsh, and leather (qv) industries where they are used principally as coatings or binders. Copolymers of methyl methacrylate with either ethyl acrylate or butyl acrylate are most common. 

The cationic ring opening polymerization of oxolane (THF) or of N-substituted aziridines can be initiated by oxocarbenium salts [42]. The methacrylic ester unsaturation is insensitive to cationic sites, and polyoxolanes (poly-THF) macromonomers are obtained in good yields. 

The furfuryl esters of acrylic and methacrylic acid polymerize via a free-radical mechanism without apparent retardation problems arising from the presence of the furan ring. Early reports on these systems described hard insoluble polymers formed in bulk polymerizations and the cross-linking ability of as little as 2% of furfuryl acrylate in the solution polymerization of methylacrylate121. ... 

Values of kjkli for polymerizations of EM A and BMA and higher methacrylate esters have been determined.11 lIl>1V7 l5i The extent of disproportionation increases with the size of the ester alkyl group. 

The chemistry is dependent on the particular substituents. Oxygen analogs of 31, ot-alkoxyacylates (32), do not inhibit polymerization but readily polymerize and copolyrnerize with reactivity ratios similar to methacrylate esters.191"194... 

The major applications of catalytic chain transfer are in molecular weight control and in synthesis of macromonomcrs based on methacrylate esters. However, they have also been shown effective in polymerizations and copolymerizations of MAA, MAM, MAN, AMS, S and some other monomers. 

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. 

Chain ends formed with monosubstituted monomers, other than S, appear resistant to photolysis and polymerizations of MA and VAc do not show living characteristics. Most polymerizations involve methacrylate esters or S,... 

Stable carbon-centered radicals, in particular, substituted diphenylmethyl and triphenylmethyl radicals, couple reversibly with propagating radicals (Scheme 9.11). With, the carbon-centered radical-mediated polymerization systems described to dale, the propagating radical should be tertiary (e.g. methacrylate ester) to give reasonable rates of activation. 

The most important side reactions are disproportionation between the cobalt(ll) complex and the propagating species and/or -elimination of an alkcnc from the cobalt(III) intermediate. Both pathways appear unimportant in the case of acrylate ester polymerizations mediated by ConTMP but are of major importance with methacrylate esters and S. This chemistry, while precluding living polymerization, has led to the development of cobalt complexes for use in catalytic chain transfer (Section 6.2.5). 

ATRP has also been used to synthesize maeromononicrs subsequently used to make graft copolymers by conventional radical polymerization. Thus, low molecular weight PBA formed by ATRP was converted in near quantitative yield to the methacrylate ester (351) or the corresponding acrylate ester.612... 

The polymerization of methacrylic esters, by lithium-organic initiators, carried out in toluene at low temperature, yields some stereocontrol46147 >. 

Preparation and Reactions of S-b-MM. As mentioned in the introduction, we were interested in block copolymers of styrene and alkali metal methacrylates with overall molecular weights of about 20,000 and methacrylate contents on the order of 10 mol%. The preparation of such copolymers by the usual anionic techniques is not feasible. An alternative is to prepare block copolymers of styrene and methacrylic esters by sequential anionic polymerization, followed by a post-polymerization reaction to produce the desired block copolymers. The obvious first choice of methacrylic esters is methyl methacrylate. It is inexpensive, readily available, and its block copolymers with styrene are well-known. In fact, Brown and White have reported the preparation and hydrolyses of a series of S-b-MM copolymers of varying MM content using p-toluenesulfonic acid (TsOH) (6). The resulting methacrylic acid copolymers were easily converted to their sodium carboxylates by neutralization with sodium hydroxide. 

Dispersion devices, ozone, 17 801-802 Dispersion force, 12 4 Dispersion-free solvent extraction, 10 766 Dispersion hardening, 13 501, 502, 527 of refractory metal alloys, 13 528 Dispersion polymerization, 24 156-157 of acrylamide polymers, 1 323 of methacrylic ester polymers, 16 289 Dispersion processing of FEP polymer, 18 314... 

Grafting from method, 7 652-653 Grafting onto method, 7 654 Grafting process, 73 537 Grafting through method, 7 653 Graft polymerization. See also Graft copolymerization ABS, 7 419, 421 acrylic ester monomers, 7 386 of methacrylic ester polymers, 76 289-290... 

Living organisms, fermentation by, 11 1-2 Living polymerization, 23 728 of acrylic ester monomers, 1 386 of methacrylic ester polymers, 16 291 Living polymers, 24 705 Living ring-opening metathesis... 

See a/so Methacrylic ester monomers Methacrylic ester polymers Methacrylic monomers acute toxicity of, 16 260t exposure to, 16 261 for 193-nm resists, 15 178-179 physical properties of, 16 227-235t, 278t polymerization of, 14 259 Methacrylates... 

See also Methacrylate monomers polymerization data for, 16 279t Methacrylic ester polymers, 16 271-298. See also Methacrylate monomers Methacrylic esters analytical test methods and specifications for, 16 291-293 bulk polymerization of, 16 281-282 chemical properties of, 16 276-277 electrical properties of, 16 276 emulsion polymerization of, 16 285-288 glass transition temperature of, 16 273-274... 

Nonaqueous dispersion (NAD) polymerization, 20 82 of methacrylic ester polymers, 16 289 Nonaqueous media, separations in, 21 654r-656... 

Radical grafting, 10 206 Radical-induced decompositions, 14 280 of dialkyl peroxydicarbonates, 14 289 Radical ozone reactions, 17 774 Radical polymerization, 22 40. See also Free-radical polymerization controlling, 14 297 of methacrylic ester polymers, 16 279-290... 

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