Solution polymerization methacrylic acid

A nucleotide base-imprinted polymer membrane has been reported in which methacrylic acid was used as a functional monomer for the imprinting of an adenine derivative, 9-ethyladenine [41], A free-standing film was prepared by polymerizing a DMF solution containing methacrylic acid and ethylene glycol dimethacrylate on a silanized glass slide at 65-70 °C under nitrogen atmosphere. 

Figure 2.6 Control of the graft polymerization as determined with step height measurements of the brush dry tMckness. ETFE substrates were activated with EUV interference lithography. In most cases, the data points roughly follow a square root dependence on the exposure dose. The brush thickness was also influenced by (A) the pH of the graft solution (aqueous solution of methacrylic acid), (B) the viscosity of the solution (GMA in dioxane), controlled by addition of PEG, and (C) the addition of a RAFT agent to the monomer solution (GMA in methylethyl ketone). For details, see the text. Source Figure compiled from Neuhaus et al. [14] and Parquet et al. [15,16] with permission from Elsevier Ltd. and ACS.

Figure 3.4 shows a reactor used for the plasma graft-polymerization. The reactor diameter is 30 mm. and the length is 240 mm. A square polypropylene substrate membrane (Celanese. Celgard 2400.200 x 2000 X and 2500,400 x 4000 X, 6 X 6 cm) is placed in the reactor and is subjected to plasma treatment for 30 s in the presence of residual air under the pressure of 30 Pa. A low-temperature plasma is excited by a 13.56-MHz power source at less than 20 W to prevent the polypropylene substrate membrane from heat damage. Then an aqueous solution of methacrylic acid-2-hydroxyethyl and acrylic acid mixture (monomer concentration 5 wt%) is transferred from the monomer solution reservoir to the reactor. The reactor is immersed into a temperature-controlled bath where polymerization is carried out for 2 h at 50 to 70 C [32]. 

Monomeric methacrylic acid is soluble in benzene while poly(methacrylic acid) is not. This fact has led to a novel patented continuous slurry polymerization procedure [36]. A 5% benzene solution of methacrylic acid containing 1 % the weight of the monomer of benzoyl peroxide is heated at reflux until a haze due to polymer formation is observed. Then further solutions of initiator-containing monomer are added at a modest rate while the temperature is maintained at 82" C. At the same rate, the formed slurry overflows onto a filter. Over a 72-hr period 85-90% conversion of the utilized monomers was observed. The product was a free-flowing, dustless powder. 

Since the polymeric acids are somewhat weaker acids than the monomers, the pH of an aqueous solution of methacrylic acid, for example, increases on polymerization. For this reason, the study of Katchalsky and Blauer [38] recommends the use of buffers to maintain reasonable constancy of pH during polymerization. 

Special note A highly pure polymer is obtained from polymerization of an aqueous solution of methacrylic acid ester. Monomer has oral toxicity. LD50 = 2300mg/kg (mouse)... 

Poly(acrylic acid) and Poly(methacrylic acid). Poly(acryHc acid) (8) (PAA) may be prepared by polymerization of the monomer with conventional free-radical initiators using the monomer either undiluted (36) (with cross-linker for superadsorber appHcations) or in aqueous solution. Photochemical polymerization (sensitized by benzoin) of methyl acrylate in ethanol solution at —78° C provides a syndiotactic form (37) that can be hydrolyzed to syndiotactic PAA. From academic studies, alkaline hydrolysis of the methyl ester requires a lower time than acid hydrolysis of the polymeric ester, and can lead to oxidative degradation of the polymer (38). Po1y(meth acrylic acid) (PMAA) (9) is prepared only by the direct polymerization of the acid monomer it is not readily obtained by the hydrolysis of methyl methacrylate. 

Synthetic. The main types of elastomeric polymers commercially available in latex form from emulsion polymerization are butadiene—styrene, butadiene—acrylonitrile, and chloroprene (neoprene). There are also a number of specialty latices that contain polymers that are basically variations of the above polymers, eg, those to which a third monomer has been added to provide a polymer that performs a specific function. The most important of these are products that contain either a basic, eg, vinylpyridine, or an acidic monomer, eg, methacrylic acid. These latices are specifically designed for tire cord solutioning, papercoating, and carpet back-sizing. 

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. ... 

Dimethyl peroxide Diethyl peroxide Di-t-butyl-di-peroxyphthalate Difuroyl peroxide Dibenzoyl peroxide Dimeric ethylidene peroxide Dimeric acetone peroxide Dimeric cyclohexanone peroxide Diozonide of phorone Dimethyl ketone peroxide Ethyl hydroperoxide Ethylene ozonide Hydroxymethyl methyl peroxide Hydroxymethyl hydroperoxide 1-Hydroxyethyl ethyl peroxide 1 -Hydroperoxy-1 -acetoxycyclodecan-6-one Isopropyl percarbonate Isopropyl hydroperoxide Methyl ethyl ketone peroxide Methyl hydroperoxide Methyl ethyl peroxide Monoperoxy succinic acid Nonanoyl peroxide (75% hydrocarbon solution) 1-Naphthoyl peroxide Oxalic acid ester of t-butyl hydroperoxide Ozonide of maleic anhydride Phenylhydrazone hydroperoxide Polymeric butadiene peroxide Polymeric isoprene peroxide Polymeric dimethylbutadiene peroxide Polymeric peroxides of methacrylic acid esters and styrene... 

Abstract. Auto-accelerated polymerization is known to occur in viscous reaction media ("gel-effect") and also when the polymer precipitates as it forms. It is generally assumed that the cause of auto-acceleration is the arising of non-steady-state kinetics created by a diffusion controlled termination step. Recent work has shown that the polymerization of acrylic acid in bulk and in solution proceeds under steady or auto-accelered conditions irrespective of the precipitation of the polymer. On the other hand, a close correlation is established between auto-acceleration and the type of H-bonded molecular association involving acrylic acid in the system. On the basis of numerous data it is concluded that auto-acceleration is determined by the formation of an oriented monomer-polymer association complex which favors an ultra-fast propagation process. Similar conclusions are derived for the polymerization of methacrylic acid and acrylonitrile based on studies of polymerization kinetics in bulk and in solution and on evidence of molecular associations. In the case of acrylonitrile a dipole-dipole complex involving the nitrile groups is assumed to be responsible for the observed auto-acceleration. 

STRUCTURE AND SOLUTE SIZE EXCLUSION OF POLY(METHACRYLIC ACID)/POLY(A/-ISOPROPYL ACRYLAMIDE) INTERPENETRATING POLYMERIC NETWORKS... 

Structure and Solute Size Exclusion of Poly(methacrylic acid)/Poly(A -isopropyl acrylamide) Interpenetrating Polymeric Networks... 

The temperature-sensitive poly(A-isopropyl acrylamide) and pH-sensitive poly(methacrylic acid) were used as the two component networks in the IPN system. Since both A-isopropyl acrylamide (NIPAAm) (Fisher Scientific, Pittsburgh, PA) and methacrylic acid (MAA) (Aldrich, Milwaukee, Wl) react by the same polymerization mechanism, a sequential method was used to avoid the formation of a PNIPAAm/PMAA copolymer. A UV-initiated solution-polymerization technique offered a quick and convenient way to achieve the interpenetration of the networks. Polymer network I was prepared and purified before polymer network II was synthesized in the presence of network I. Figure I shows the typical IPN structure. 

Monomer and initiator must be soluble in the liquid and the solvent must have the desired chain-transfer characteristics, boiling point (above the temperature necessary to carry out the polymerization and low enough to allow for ready removal if the polymer is recovered by solvent evaporation). The presence of the solvent assists in heat removal and control (as it also does for suspension and emulsion polymerization systems). Polymer yield per reaction volume is lower than for bulk reactions. Also, solvent recovery and removal (from the polymer) is necessary. Many free radical and ionic polymerizations are carried out utilizing solution polymerization including water-soluble polymers prepared in aqueous solution (namely poly(acrylic acid), polyacrylamide, and poly(A-vinylpyrrolidinone). Polystyrene, poly(methyl methacrylate), poly(vinyl chloride), and polybutadiene are prepared from organic solution polymerizations. 

The heat of an emulsion polymerization is the same as that for the corresponding bulk or solution polymerization, since AH is essentially the enthalpy change of the propagation step. Thus, the heats of emulsion polymerization for acrylic acid, methyl acrylate, and methyl methacrylate are —67, —77, and —58 kJ mol-1, respectively [McCurdy and Laidler, 1964], in excellent agreement with the AH values for the corresponding homogeneous polymerizations (Table 3-14). 

Polymerization of Methacrylic Acid with Potassium Peroxodisulfate in Aqueous Solution... 

Polymerization reactions in aqueous medium can be carried out in homogeneous solution if the monomers and the polymers are soluble in water as in the case of acrylamide or methacrylic acid (see Examples 3-5,3-9, and 3-35). Since most of the monomers are only sparingly soluble in water, suspension or emulsion techniques have to be applied in these cases. 

Tewari and Srivastava published the results on interaction between atactic polyCvinyl acetate) and poly(acrylonitrile), and poly(methyl methacrylate) and poly(methacrylic acid). On the basis of viscometric measurements of DMF solutions of mixtures of the pair of polymers mentioned above, the authors concluded that for all the systems examined complex formation occurs. This observation explains the results published earlier by the authors about template polymerization of acrylonitrile, methacrylic acid, and methyl methacrylate carried out in the presence of poly(vinyl acetate). It was found that polymerization of acrylonitrile in DMF in the presence of atactic poly(vinyl acetate) (mol. weight 47,900) takes place much faster than without poly(vinyl acetate), especially, when concentration of the monomer is equimolar to the concentration of template repeat units. The overall energy of activation was found to be 55.76 kJ/mol for template polymerization and 77.01 kJ/mol for polymerization in the absence of the template. 

Suspension polymerization also is used When acrylic monomers or their mixtures with other monomers are polymerized while suspended (usually in aqueous system), the polymeric product is obtained m the form of small beads, sometimes called pearls or granules. Bead polymers are the basis of the production of molding powders and denture materials. Polymers derived from acrylic or methacrylic acid furnish exchange resins of the carboxylic acid type. Solutions in organic solvents furnish lacquers, coatings and cements, while water-soluble hydrolysates are used as thickeners, adhesives, and sizes. 

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