Styrene with acrylamide, copolymerization

Emulsifier-Free Emulsion Copolymerization of Styrene with Acrylamide and Its Derivatives... 

This paper deals with the copolymerization of styrene with acrylamide and its derivatives in emulsifier-free aqueous media. It is expected that the effects of acrylamides on the nucleation and stabilization of particles differ from those of ionic comonomers. The reaction mechanism, the characteristics of the latices prepared, and the effect of the properties of acrylamides on them are discussed. 

Figure 3. Copolymerization of glucosyloxyethyl methacrylate (GEMA) with other vinyl monomers. (Q) with acrylamide (AAm), (0) with styrene (St), ( ) with acrylonitrile (AN), and ( ) with methyl methacrylate (MMA).

In some but not so rare cases, however, reactivity of macromonomers was found to be apparently reduced by the nature of their polymer chains. For example, p-vinylbenzyl- or methacrylate-ended PEO macromonomers, 26 (m=l) or 27b, were found to copolymerize with styrene (as A) in tetrahydrofuran with increasing difficulty (l/rA is reduced to one half) with increasing chain length of the PEO [41]. Since we are concerned with polymer-polymer reactions, as shown in Fig. 3, the results suggest that any thermodynamically repulsive interaction, which is usually observed between different, incompatible polymer chains, in this case PEO and PSt chains, may retard their approach and hence the reaction between their end groups, polystyryl radical and p-vinylbenzyl or methacrylate group. Such an incompatibility effect was discussed in terms of the degree of interpenetration and the interaction parameters between unlike polymers to support the observed reduction in the macromonomers copolymerization reactivity [31,40]. Similar observations of reduction of the copolymerization reactivity of macromonomers have recently been reported for the PEO macromonomers, 27a (m=ll) with styrene in benzene [42], 27b with acrylamide in water [43], and for poly(L-lactide), 28, with dimethyl acrylamide or N-vinylpyr-rolidone in dioxane [44]. 

The synthetic path a of Fig. 153 makes it possible to obtain, by polyaddition, variously substituted polyenes (394, Fig. 154) starting from styrenic - or acrylic, mainly acrylamidic, monomers. In particular, the vinyl-P-aiylamino propiophenones are prepared from the corresponding Mannich base by amino group replacement and arc used in the synthesis of polymers 390 via copolymerization with styrene. Analogous derivatives are obtained by copolymerization with acrylamides. - " ... 

Hydrophobic regions can be one or two small, well-defined blocks of pendant hydrophobic moieties in an otherwise water-soluble polymer (2-4). An example is a water-soluble sulfonated BAB triblock copolymer where B is hydrophobic f-butylstyrene and A is vinyltoluene (2). However, hydro-phobic regions can also be less well-defined as well as more numerous in a polymer molecule than is the case for a triblock copolymer (5-22). For example, pendant alkyl esters appear to have been randomly incorporated in styrene-maleic anhydride (5) and vinyl benzyl ether-styrene-maleic anhydride (6-ii) copolymers. Also, alkyl polyoxyethylene acrylate monomers can be copolymerized with acrylamide to yield copolymers with pendant hydrophobic chains (12-15). More recently it was found (16-22) that small amounts of water-insoluble monomers that are solubilized by surfactants into aqueous solutions of a hydrophilic monomer produce copolymers with pendant hydrophobic chains, but the size, number, and nature of the hydro-phobic regions has not been determined. 

Other related co-monomers were also studied. These included 7V-(hydroxy-methyl)acrylamide (HMA), methacrylamide, and iV,A/-dimethylacrylamide. The copolymerization of styrene with HMA led to less water-soluble polymer in the serum than in the case of copolymers of acrylamide and styrene. This may be attributable to differences in the hydrophilic-hydrophobic properties of acrylamide and HMA. Some monodisperse latices were prepared from styrene-HMA-water systems by procedures similar to Procedure 12-2. At a ratio of HMA to styrene of 0.2 to 1.0 the reported particle diameter was 0.3 /im with good size uniformity. It was projected that even better uniformity would be obtained when the ratio of HMA to styrene is 0.09 to 1.0. Either potassium persulfate or Af,A -azobisisopropylamidine hydrochloride has been used as initiators with similar results. Latices were generally purified by repetitive centrifiigation-decantation-redispersion cycles. 

The latex copolymerization of styrene with A -methylacrylamide does not follow the three stage process observed with the other acrylamide derivatives. 

Natural protoporphyrins containing vinyl groups are suitable for polymerization. Fe(III) protoporphyrin-DC dimethylester has been copolymerized with styrene or methylmethacrylate in bulk or with acrylamide in methanol using radical initiators [130]. Increasing the porphyrin/styrene ratio decreases the molecular weight, indicating chain transfer. On the other side, the content of covalently incorporated porphyrin increases. 

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. 

It was reported by Barb in 1953 that solvents can affect the rates of copolymerization and the composition of the copolymer in copolymerizations of styrene with maleic anhydride [145]. Later, Klumperman also observed similar solvent effects [145]. This was reviewed by Coote and coworkers [145]. A number of complexation models were proposed to describe copolymerizations of styrene and maleic anhydride and styrene with acrylonitrile. There were explanations offered for deviation from the terminal model that assumes that radical reactivity only depends on the terminal unit of the growing chain. Thus, Harwood proposed the bootstrap model based upon the study of styrene copolymerized with MAA, acrylic acid, and acrylamide [146]. It was hypothesized that solvent does not modify the inherent reactivity of the growing radical, but affects the monomer partitioning such that the concentrations of the two monomers at the reactive site (and thus their ratio) differ from that in bulk. 

Styryl amylose amide (VAA) was prepared from maltopentose-substituted styrene (VM5A) by phosphorylase-catalyzed pol3unerization of glucose-1-phosphate (Glu-lP) (118) (Fig. 8). Subsequent radical copolymerization with acrylamide gave the corresponding graft copolymers.. 

In order to study the mchanism of micellar polymerization, they used a variety of initiators and inhibitors having different water solubilities. It was concluded that most of the time the radicals are produced in the water phase and have to enter the micelles before the polymerization can take place. The authors have studied three systems in the first, a hydrophobic acrylamido monomer swelling SDS micelles was copolymerized with acrylamide in the second, they used their styrenic cationic surfmer N16 and in the last, they used mixed micelles of N16 and a similar but nonpolymeriz-able surfactant B16. 

The production of such particles usually results fi-om the emulsion copolymerization of a hydrophobic monomer, such as styrene with a water-soluble monomer, such as acrylic acid. Differences in water solubility of the two monomers along with disparate reactivity ratios led to the preparation of particles having a core-shell structure with the hydro-phobic polymer in the core and the water-soluble polymer in the shell layer. It was also found that precipitation polymerization of alkyl(meth)acrylamide, such as N-isopropyl... 

The simplest monomer, ethylenesulfonic acid, is made by elimination from sodium hydroxyethyl sulfonate and polyphosphoric acid. Ethylenesulfonic acid is readily polymerized alone or can be incorporated as a copolymer using such monomers as acrylamide, aHyl acrylamide, sodium acrylate, acrylonitrile, methylacrylic acid, and vinyl acetate (222). Styrene and isobutene fail to copolymerize with ethylene sulfonic acid. 

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. 

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-... 

Acrylic textile fibers are primarily polymers of acrylonitrile. It is copolymerized with styrene and butadiene to make moldable plastics known as SA and ABS resins, respectively. Solutia and others electrolytically dimerize it to adiponitrile, a compound used to make a nylon intermediate. Reaction with water produces a chemical (acrylamide), which is an intermediate for the production of polyacrylamide used in water treatment and oil recovery. 

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. 

Emulsion polymerization was first employed during World War II for producing synthetic rubbers from 1,3-butadiene and styrene. This was the start of the synthetic rubber industry in the United States. It was a dramatic development because the Japanese naval forces threatened access to the southeast Asian natural-rubber (NR) sources, which were necessary for the war effort. Synthetic mbber has advanced significantly from the first days of balloon tires, which had a useful life of 5000 mi to present-day tires, which are good for 40,000 mi or more. Emulsion polymerization is presently the predominant process for the commercial polymerizations of vinyl acetate, chloroprene, various acrylate copolymerizations, and copolymerizations of butadiene with styrene and acrylonitrile. It is also used for methacrylates, vinyl chloride, acrylamide, and some fluorinated ethylenes. 

A very interesting modification of the system was examined by Ferguson and McLeod. The authors replaced poly(vinyl pyrrolidone) with copolymers vinyl pyrrolidone-styrene or vinyl pyrrolidone-acrylamide. It was found that the mechanism of polymerization is the same as in the presence of homopolymer (PVP). However, the rate of polymerization decreases rapidly when vinyl pyrrolidone concentration in copolymer decreases. The concentration of vinyl pyrrolidone residues was kept equimolar to the concentration of acrylic acid. It was stressed that structure of template and, in the case of copolymeric template, sequence distribution of units play an important role in template effect. 

Acrylonitrile resembles VC, a carcinogen, in structure. It is a flammable, explosive liquid (b.p. 77 C, V.P. 80 mm at 20°C). AN is a component of acrylic and modacrylic fibers produced by copolymerization with other monomers, e.g., with methyl acrylate, Me-methacrylate, vinyl acetate, VC and VDC. Other major uses of AN include copolymerizations with butadiene and styrene to produce ABS polymers, and with styrene to yield SAN resins which are used in the manufacture of plastics. Nitrile elastomers and latexes are also made with AN, as are a number of other chemicals, e.g. acrylamide and adiponitrile. Acrylonitrile is also used as a fumigant. 

N-(Hydroxymethyl)acrylamide (HMA, Tokyo Kasei Co.) was recrystallized from ethyl acetate. N,N-Dimethylacrylamide (DMA, Tokyo Kasei Co.) and styrene (St, Kashima Kagaku Yakuhin Co.) were distilled at 54°C/3.5 mmHg and 40°C/14.5 mmHg, respectively. In some copolymerizations cross-linking reagents were added to reduce the formation of water-soluble polymer. N -Methylenebisacrylamide (MBA, Nakarai Chemicals Co.) and N-allylacrylamide (AAA, Polysciences, Inc.) were used as received. Divinylbenzene (DVB, Tokyo Kasei Co.) was treated with 10 % sodium hydroxide and dried. Two kinds of initiators were used Potassium persulfate (KPS, Taisei Kagaku Co.) was recrystallized from water and azobis(isopropyl-... 

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