Methacrylic acid acrylamide copolymerizations

The amount of polar monomer one would copolymerize with the alkyl acrylate monomer(s) very much depends on the type of polar monomer and the desired change in rheological properties one would like to achieve. Strong hydrogen bonding monomers, such as acrylic acid, methacrylic acid, acrylamide, or methacrylamide are typically used at levels of 12% or less of the total monomers. 

Imprinted polymers are frequently prepared by radical copolymerization of two of the most used cross-linkers ethylene dimethacrylate (EDMA) and trimethyl-olpropane trimethacrylate (TRIM) with one of the many functional monomers reported in literature (mainly methacrylic acid, acrylamide, 4-vinylpyridine, or tri-fluoromethacrylic acid, but also 2-hydroxyethylmethacrylate and A,A-diethyl-aminoethylmethacrylate (see this book. Chapter 7) The polymers obtained as bulk monoliths or dispersed microparticles have properties that are very suitable for liquid chromatographic applications. 

Styrene monomer was also copolymerized with a series of functional monomers by using a single-step dispersion copolymerization procedure carried out in ethanol as the dispersion medium by using azobisizobu-tyronitrile and polyvinylpyrollidone as the initiator and the stabilizer, respectively [84]. The comonomers were methyl methacrylate, hydroxyethyl acrylate, metha-crylic acid, acrylamide, allyltrietoxyl silane, vinyl poly-dimethylsiloxane, vinylsilacrown, and dimethylamino-... 

Ouchi et al. synthesized l,2-mono-0-isopropylidene-3-[3-(5-fluorouracil-l-yl)propionyl]-6-0-acryloyl-a-D-glucofuranose and copolymerized it with acrylamide [143], Ozaki et al. synthesized l-(meth)acryloyloxymethyl-5-fluorouracils and copolymerized with a number of comonomers, such as acrylic acid, methacrylic acid, methyl acrylate, and methyl methacrylate [144]. All the above mentioned polymer bound drugs possessed biological activity. 

M Suzuki and C. A. Wilkie, Graft copolymerization of methacrylic acid and acrylamide onto acrylonitrile-... 

Carboxyl groups may be introduced into block copolymers via direct polymerizations of free-acid monomers or protection—deprotection procedures. Block copolymers of styrene and nitrophenyl methacrylate (B-40) are used for the latter method, where the activated ester pendant is effectively converted into methacrylic acid or acrylamide under mild conditions.166 A homogeneous aqueous system with copper catalysts gives block copolymers with benzoate groups (B-41) via sequential block copolymerization of the two water-soluble monomers.247... 

Bulk addition multipolymerization kinetics occurs when two monomers are employed. Bulk free-radical homopolymerizations and copolymerizations that are implemented in REX include a) styrene-acrylonitrile, styrene-methyl methacrylate, styrene-acrylamide b) methyl methacrylate-acrylonitrile, ABS c) acrylate ester mixtures d) ethyl acrylate-methacrylic acid and mixtures with other monomers e) methyl methacrylate f) 8-caprolactone and, n-isopropylacrylamide-acrylic... 

Copolymerization was initiated with azobis(isobutyronitrile) (AIBN) with the following monomers acrylamide, allyl acrylamide, sodium acrylate, acrylonitrile, methacrylic acid and vinyl acetate. In all these cases, the partner monomer was more reactive and preferentially incorporated in the copolymer. Less-polar or nonpolar monomers, such as styrene and isobutene, failed altogether to copolymerize. 

This conclusion has been reached in the copolymerization of acrylic acid (AA) and methacrylic acid (MAA) with N-vinylpyrrolidone (34, 35) (a monomer noted for its thermal stability (36) and discussed in Chapter 9) and with acrylamide (37). The incorporation of the acid monomer in the copolymer decreases with increasing solution pH. The r values with MAA are particularly low at pH <5 because of hydrophobic associations of the methyl groups. Laser-Raman studies (38) have also indicated intramolecular association among the methyl groups of syndiotactic poly(methacrylic acid) (PMAA) in aqueous solution. The addition of NaCl, at a moderate pH, increases the amount of neutralized, weak acid monomer incorporated (Table III). A more gradual change is observed with pH in the MAA-AM combination than in the AA-AM pair because of the hydrophobic interactions cited. The relationships are nearly quantitative with the ionization of the acids as reflected by the pK of the monomer and polymer acid sequences. 

Different types of chemical initiators such as FAS-KPS, benzoyl peroxide, azo-bis-iso-butylnitrile, H O, ascorbic acid-KPS, ammonium persulphate, ceric ammonium persulphate, ceric ammonium nitrate, etc., can be used for the graft copolymerization of various vinyl monomers such as methylacrylate, methyl methacrylate, acrylic acid, methacrylic acid, ethyl methacrylate, vinyl acetate, acrylamide, etc., onto polysaccharides [38-40]. Figure 2.1 shows the proposed mechanism through which the grafting can be explained [39]. 

Most of the water-soluble monomers, such as the acrylic and methacrylic acids, are functional monomers and are covered in Section 6.2.3. In Table 6.1 the most water-soluble monomers are acrylamide, acrylonitrile, methyl acrylate and vinyl acetate. Acrylamide contains two reactive centres. The amide group undergoes the reactions characteristic to aliphatic amides. For this reason, acrylamide may be considered as a functional monomer. Copolymerization of acrylamide with other monomers is often done to incorporate hydrophilic centres in oleophylic polymers to promote adhesion and dye acceptance. The monomer is available either as a solid or as a 50% aqueous solution. The latter is the preferred form, since it eliminates handling of a solid. The monomer is a neurotoxin and exposure to skin or inhalation must be prevented. Acrylamide solution is stabilized with cupric ions. Cupric ion availability is pH dependent and the pH must be between 5.2 and 6. Storage temperature should be between 16 and 32 °C... 

Vinylbenzyl chloride (VBC Dow Chemical) represents a functional monomer with electrophilic sites which can be post-reacted after polymerization with nucleophiles such as amines, thiols, thioethers and thiourea [28]. The chloromethyl group may also be reacted before polymerization to form a new monomer, which can itself then be polymerized. VBC is typically copolymerized with monomers such as butadiene, styrene, acrylic or methacrylic acid, acrylonitrile, acrylamide and a variety of acrylate and methacrylate monomers [29] or it can be homopoly-merized to form functionalized particles [30]. Typical properties of vinylbenzyl chloride monomers include a homopolymer Tg of 82 °C, a boiling point of 229 °C (at 1 atm), a water solubility of 0.073 g dm , and Q and e values of 1.06 and —0.45, respectively. 

Copolymerization reactions are affected by solvents. One example that can be cited is an effect of addition of water or glacial acetic acid to a copolymerization mixture of methyl methacrylate with acrylamide in dimethyl sulfoxide or in chloroform. This caused changes in reactivity ratios. Changes in r values that result from changes in solvents in copolymerizations of styrene with methyl methacrylate is another example. The same is true for styrene acrylonitrile copolymeriza-tion. There are also some indications that the temperature may have some effect on the reactivity ratios/ at least in some cases. 

The use of acrylic acid not only led to a functionalization of nanoparticles, but also was important as a structure-directing monomer for the formation of nanocapsules. In this case, the hydrophilic groups of the acrylic acid [30] or methacrylic acid [31] resulted in the formation of a nanocapsule structure, instead of Janus-like or even separate nanoparticles. The copolymerization of the functional n-methylol acrylamide with vinyl acetate was found to follow (in batch miniemulsion) the Mayo-Lewis equation, despite huge differences in the solubility of the monomers in the aqueous continuous phase [32]. A functionality of fluori-nated particles could be easily introduced by copolymerizing fluoroalkylacrylates with protonated monomers, such as acrylic acid and methacryloxyethyltrimethyl ammonium chloride [33]. 

Much of the work reported in the academic literature is based upon microgels prepared from poly(NIPAM), but there are, however, a number of microgels that have been prepared from other monomers. These include methyl methacrylate with other copolymers such as ethylene glycol dimethacrylate (17,18), methyl methacrylate with p-divinylbenzene (19), and methyl methacrylate with methacrylic acid (20). Other microgel particles have been prepared from poly(allylamine hydrochloride) (21), vinylpyrrolidinone and acrylic acid (22), acrylamide and acrylamide with methacrylamidopropyltrimethylammonium chloride (23), and acrylamide copolymerized with 2-acrylamido-2-methylpropanesulfonic acid (24). 

Synthesis. Polyampholytes are most readily prepared by the direct statistical copolymerization of anionic and cationic monomers typically in aqueous media, via conventional free radical pol3unerization. Examples of such materials were first reported in the 1950s (240-244). Using this approach a wide range of copolymers and terpolymers, often with a neutral hydrophilic monomer such as acrylamide, have been reported. For example, early reports of statistical polyampholytes include the methacrylic acid-stat-2-(dimethylamino)ethyl methacrylate copolymers (245), from IZ and 2Z with 6Z and the iV,A(-diethylallylamine-stat-acrylic acid copolymers from IZ and 6Z (246). More recently, synthesis and properties of novel polyampholytic terpol5uners have been described (247-250). For example, the aqueous solution properties of novel ampholytic terpolymers of acrylamide, sodium 3-acrylamido-3-methylbutanoate 5Z and 3-(acrylamidopropyl)trimethylammonium chloride 8Z have been studied in detail (187). 

Macromolecular azo dyes which behave as photochromic polyelectrolytes have been reported where -aminoazobenzene dyes (VI and VII) are converted to the corresponding acrylamide and methacrylamide derivatives and are copolymerized with acrylic and methacrylic acids. 

Maleic anhydride has also been free-radical copolymerized with a number of other monomer pairs, such as allyl acetate-allyl chloride, vinyl chloride-diethyl fumarate, acrylamide-methacrylic acid, " " trimethylolpropane allyl ethers-methyl acrylate, " and styrene-acetyltriallyl citrate. " Systems of this type are very briefly reviewed. 

The term acrylic apphes to a family of copolymers of monomers that are polymerized by a chain growth mechanism. Most often, the mechanism of polymerization is by free radical initiation. Other mechanisms of polymerization, such as ionic and group transfer polymerization, are possible but will not be discussed in this publication. For a description of other polymerization mechanisms, polymer textbooks are available (5,6). Technically, acrylic monomers are derivatives of acrylic or methacrylic acid. These derivatives are nonfunctional esters (methyl methacrylate, butyl acrylate, etc.), amides (acrylamide), nitrile (acrylonitrile), and esters that contain functional groups (hydroxyethyl acrylate, glycidyl methacrylate, dimethylaminoethyl acrylate). Other monomers that are not acryhc derivatives are often included as components of acryhc resins because they are readily copolymerized with the acryhc derivatives. Styrene is often used in significant quantities in acryhc copolymers. 

Radical copolymerization is used in the manufacturing of random copolymers of acrylamide with vinyl monomers. Anionic copolymers are obtained by copolymerization of acrylamide with acrylic, methacrylic, maleic, fu-maric, styrenesulfonic, 2-acrylamide-2-methylpro-panesulfonic acids and its salts, etc., as well as by hydrolysis and sulfomethylation of polyacrylamide Cationic copolymers are obtained by copolymerization of acrylamide with jV-dialkylaminoalkyl acrylates and methacrylates, l,2-dimethyl-5-vinylpyridinum sulfate, etc. or by postreactions of polyacrylamide (the Mannich reaction and Hofmann degradation). Nonionic copolymers are obtained by copolymerization of acrylamide with acrylates, methacrylates, styrene derivatives, acrylonitrile, etc. Copolymerization methods are the same as the polymerization of acrylamide. 

DSEP direct soapless emulsion polymerization, SSEC seeded soapless emulsion copolymerization, DDC direct dispersion copolymerization, TDSC two-stage dispersion copolymerization, ATES Allyl trietoxysilane, VTES vinyl trietoxysilane, DMAEM dimethylaminoethyl-methacrylate, CMS chloromethylstyrene, GA glutaraldehyde, AAc Acrylic acid Aam Acrylamide HEMA 2-hydroxyethylmethacrylate. 

Monomers which can add to their own radicals are capable of copolymerizing with SO2 to give products of variable composition. These include styrene and ring-substituted styrenes (but not a-methylstyrene), vinyl acetate, vinyl bromide, vinyl chloride, and vinyl floride, acrylamide (but not N-substituted acrylamides) and allyl esters. Methyl methacrylate, acrylic acid, acrylates, and acrylonitrile do not copolymerize and in fact can be homopolymer-ized in SO2 as solvent. Dienes such as butadiene and 2-chloro-butadiene do copolymerize, and we will be concerned with the latter cortpound in this discussion. 

These superabsorbents are synthesized via free radical polymerization of acrylic acid or its salts in presence of a crosslinker (crosslinking copolymerization). Initiators are commonly used, water-soluble compounds (e.g., peroxodi-sulfates, redox systems). As crosslinking comonomers bis-methacrylates or N,hT-methylenebis-(acrylamide) are mostly applied. The copolymerization can be carried out in aqueous solution (see Example 5-11 or as dispersion of aqueous drops in a hydrocarbon (inverse emulsion polymerization, see Sect. 2.2.4.2). 

The first hydrophilic monoliths based on acrylamide chemistry were based on copolymerization of acrylic acid and (V,/V -methylene bis(acrylamide) in the presence of an aqueous buffer as porogen [66], Shortly after, the first hydrophobic capillary support for hydrophobic interaction chromatography was fabricated by the substitution of acrylic acid by butyl methacrylate, whereas the monomer... 

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