Acrylic copolymers carboxylic acid containing

Carboxylic acid groups may deactivate ATRP initiators however, carboxylic acid-containing monomers can be polymerized via ATRP by carefully adjusting the solution pH [69]. Matyjaszewski et al. reported the controlled copolymerization of DMAEMA with methyl methacrylate, methyl acrylate, and styrene yielding pH-responsive amphiphilic block copolymers [70]. Aqueous RAFT... 

By employing anionic techniques, alkyl methacrylate containing block copolymer systems have been synthesized with controlled compositions, predictable molecular weights and narrow molecular weight distributions. Subsequent hydrolysis of the ester functionality to the metal carboxylate or carboxylic acid can be achieved either by potassium superoxide or the acid catalyzed hydrolysis of t-butyl methacrylate blocks. The presence of acid and ion groups has a profound effect on the solution and bulk mechanical behavior of the derived systems. The synthesis and characterization of various substituted styrene and all-acrylic block copolymer precursors with alkyl methacrylates will be discussed. 

Hydrolysis of amide groups to carboxylate is a major cause of instability in acrylamide-based polymers, especially at alkaline pH and high temperatures. The performance of oil-recovery polymers may be adversely affected by excessive hydrolysis, which can promote precipitation from sea water solution. This work has studied the effects of the sodium salts of acrylic acid and AMPS, 2-acrylamido-2-methylpropanesulfonic acid, as comonomers, on the rate of hydrolysis of polyacrylamides in alkaline solution at high temperatures. Copolymers were prepared containing from 0-53 mole % of the anionic comonomers, and hydrolyzed in aqueous solution at pH 8.5 at 90°C, 108°C and 120°C. The extent of hydrolysis was measured by a conductometric method, analyzing for the total carboxylate content. 

As a design to develop a polyvinyl-type poly(sodium carboxylate), acrylate copolymers containing hydroxyl or carbonyl groups which are susceptible to the enzymatic reaction, were prepared. It is presumed that the copolymer is first cleaved at a hydroxyl or carbonyl group as in the case of PVA, then the resultant acrylate oligomer is further assimilated by the microbes. The biodegradation of oligomeric acrylic acid (11), in fact, occurs as shown in Table I. 

Ionomers of practical interest have been prepared by two synthetic routes (a) copolymerization of a low level of functionalized monomer with an olefinically unsaturated monomer or (b) direct functionalization of a preformed polymer. Typically, carboxyl containing ionomers are obtained by direct copolymerization of acrylic or methacrylic acid with ethylene, styrene and similar comonomers by free radical copoly-merization. Rees (22) has described the preparation of a number of such copolymers. The resulting copolymer is generally available as the free acid which can be neutralized to the degree desired with metal hydroxides, acetates and similar salts. Recently, Weiss et al.(23-26) have described the preparation of sulfonated ionomers by copolymerization of sodium styrene sulfonate with butadiene or styrene. 

Isomerization has been studied in polymers containing aromatic azo-groups. For example, Eisenbach has investigated isomerization of azo-groups in poly(ethyl acrylate) and found the process to be very dependent on the cross-linking density. Photoinduced reversible pH changes in poly(carboxylic acid)-azo dye complexes were found to be very dependent upon the composition of the copolymer. Cis-trans isomerization of azobenzene has been used as a tool to... 

Among the carboxylic acid and anhydride functional monomers that have been employed in the synthesis of these thickener polymers are acrylic acid, methacrylic acid, itaconic acid, citraconic acid, maleic acid, fumaric acid, crotonic acid, maleic anhydride, and citraconic anhydride. The copolymers containing maleic and citraconic anhydride monomers are either hydrolyzed or partially esterified to obtain the required carboxyl functionality. Among these carboxylic monomers, maleic anhydride and particularly methacrylic acid are most frequently favored. Carboxylic homopolymers, where they can be formed, might be considered the simplest examples of ASTs were it not for the fact that they are not copolymers as defined, and some are water soluble in their un-ionized states. Examples of carboxylic homopolymers are the un-ionized free-radical-polymerized atactic forms of polyacrylic acid (i) and polymethacrylic acid (2), which are both readily soluble in water. 

Ill) Epoxy functionalities are not essential for grafting. For a graft copolymer made by the reaction of epoxy with carboxyl functionalities, the presence of epoxy functionalities is essential. Since this approach requires carbon-carbon bond formation, ester linkages are not necessary. Therefore epoxy functionalities can be capped with phenol or benzoic acid, etc., or bisphenol-A terminated epoxy resin can be prepared followed by grafting with acid containing monomers, and resultant epoxy-g-acrylic copolymer can be prepared. 

Neutralization of ethylene copolymers containing up to 5%-10% acrylic or methacrylic acid copolymer with a metal salt such as the acetate or oxide of zinc, magnesium, and barium yields products referred to as ionomers. (Commercial products may contain univalent as well as divalent metal salts.) lonomers are marked by Du Pont under the trade name Surlyn. These have interesting properties compared with the nonionized copolymer. Introduction of ions causes disordering of the semicrystalline structure, which makes the polymer transparent. lonomers act like reversibly cross-linked thermoplastics as a result of microphase separation between ionic metal carboxylate and nonpolar hydrocarbon segments. The... 

Special post-functionalizable copolymers have also been used to derive acid ionomers by hydrolysis, thus avoiding the difficulties of copolymerizing ionic and nonionic monomers. To this end there are many examples where carboxylic acid polymers are formed by hydrolyzing copolymers containing acrylate esters, acrylonitrile, or maleic anhydride. As described later, a sulfonic acid ionomer, Nafion, is formed by hydrolysis of tetrafluoroethylene copolymerized with a sulfonyl fluoride. 

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