Methacrylic acid, photopolymerization

The published results concerning polymerization of acrylic acid or methacrylic acid in the presence of polyCethylene oxide) in water are controversial. Ferguson and Shah found that PEG with sufficiently high molecular weight increases the polymerization rate, while Kabanov at al found that in the presence of high molecular weight PEG the rate of polymerization of acrylic and methacrylic acids is lower than in blank reaction. Our results show that in the case of methacrylic acid photopolymerization in the presence of PEG of mol. weight 20,000, the rate of the reaction increases. This differences can be explained by the conditions of polymerization as well as methods used to follow the process different in both studies. 

Not only does the temperature/viscosity of media affect O another possible way that O increases in a system with the same reagents was observed in Ref. 16. Photopolymerization of acrylamide initiated by IRG2959 (Scheme 12.1) was studied in the aqueous solution in the presence of poly(methacrylic acid) (PMA). It was found that PMA forms a cluster around the IRG2959 at pH < 6.9 and that the cluster holds the RP in proximity. As a result, O increases, and the rate of photopolymerization decreases. ... 

Highly crosslinked networks synthesized by photopolymerization of dimethacrylated sebacic acid were degraded in a phosphate saline solution, and the poly(methacrylic acid) degradation product, purified from sebacic acid, was characterized by MALDl-TOE. ... 

Acrylic acids and methacrylic acids are mostly applied to polymerize monomers. However, esters of their acids are generally used. Monofunctional monomers are basic monomers for photopolymerization and are used for dilution because of low viscosity. Bifunctional monomers induce crosslinking and hard coating. Polymerization of 1,4-butanediol diacrylate (BDDA) is shown below ... 

The dispersed phase was injected through a 35 pm hole drilled in the acetate sheet. The formulation for the MIP synthesis, containing the template [(J, S)-propranolol], the monomer (methacrylic acid, MAA), the crosslinker (trimethylolpropane trimethacrylate, TRIM), the photoinitiator (2,2-dimethoxy-2-phenylacetophenone, DMPAP) and a porogenic solvent (acetonitrile), was emulsified at the T-junction with a mineral oil (heavy white) and then photopolymerized by UV irradiation in the spiral-like channel. The resulting MIP particles were compared with those obtained with a conventional batch process. The continuous microsystem-assisted process led to near-monodisperse particles (CV <2%), whereas the conventional process gave particles having a broad range of sizes (CV >10%). The same conclusion holds for... 

LB coatings have been used as photoresists. In the area of ultrathin (single molecule) photoresists, spin-coated polymers tend to lack the consistency in structure and thickness necessary for these applications. However, preformed polymer LB films or polymerized monomeric LB films are extremely uniform, and can be used in these apphcations. Photo-cross-linking of poly(p-phenylene) and photopolymerization of ft>-tricosenoic acid and methacrylic acid LB films have been investigated (20,21). Etching resulted in patterns that had resolutions of ca 60 nm. (see Lithographic Resists)... 

Vinyl ester resins are related to UPRs. They consist of a styrene monomer and the addition products of epoxy resins with methacrylic acid. The vinyl esters are usually cured using a peroxide initiator at elevated temperature [62] or at ambient temperature using a peroxide initiator with a cobalt promoter. Vinyl ester resin can also be photopolymerized [63]. Photocurable vinyl ester systems with methacrylic acid/phenyl glycidyl ether addition product as a diluent were used with ( )-camphorquinone photoinitiator and N,N,3,5-tetramethylaniline photoreducer [64]. The effect of the monomethacrylate... 

Synthesis. Functionalized monomers (and oligomers) of sebacic acid (SA-Me2) and 1,6 -bis(/ -carboxyphenoxy)hexane (CPH-Me2) were synthesized and subsequently photopolymerized as illustrated in Figure 1. First, the dicarboxylic acid was converted to an anhydride by heating at reflux in methacrylic anhydride for several hours. The dimethacrylated anhydride monomer was subsequently isolated and purified by dissolving in methylene chloride and precipitation with hexane. Infrared spectroscopy (IR), nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis results indicated that both acid groups were converted to the anhydride, and the double bond of the methacrylate group was clearly evident. 

Polymeric phospholipids based on dioctadecyldimethylammonium methacrylate were formed by photopolymerization to give polymer-encased vesicles which retained phase behavior. The polymerized vesicles were more stable than non-polymerized vesicles, and permeability experiments showed that vesicles polymerized above the phase transition temperature have lower permeability than the nonpolymerized ones [447-449]. Kono et al. [450,451] employed a polypeptide based on lysine, 2 aminoisobutyric acid and leucine as the sensitive polymer. In the latter reference the polypeptide adhered to the vesicular lipid bilayer membrane at high pH by assuming an amphiphilic helical conformation, while at low pH the structure was disturbed resulting in release of the encapsulated substances. 

A more conventional mechanism appears to be operative in the photopolymerization of ethyl acrylate [178] and methyl methacrylate [179] in aqueous solution, sensitized by fluorescein and Erythrosin, respectively. Ascorbic acid is the reducing agent in both cases and it is observed that the reaction does not proceed in the absence of buffer, usually phosphate buffer pH 6. Polymer formation starts after an induction period but its dependence on light intensity and ascorbic acid concentration has not been determined. The rate of photopolymerization is proportional to the monomer concentration and to the square root of the light intensity, dye, and ascorbic acid concentration. The authors report the order with respect to the monomer as 3/2. However, from our analysis of the data for fluorescein, which are more... 

However, no independent evidence is presented for the existence of this complex. In our view a simpler explanation for the lack of reaction in unbuffered solution is that the nondissociated form of ascorbic acid is a chain terminator. At the typical concentrations employed, 1-10 mM, more than 90% of ascorbic acid (pK = 4.1) is not dissociated when dissolved in pure water. At pH 6.0 only 1% is present as the protonated form. Furthermore, in their study of the photopolymerization of methyl methacrylate initiated by acriflavine-ascorbic acid, Lenka and Mohanty [180] report the rate of polymerization reaches a maximum when the ascorbic acid concentration is approximately 10 mM. The decrease in polymerization rate at higher concentrations suggests ascorbic acid participates in chain transfer and/or termination reactions. 

Byme et al. [124] have shown the possibility of creating imprinted polymer ordered micropattems, of a variety of shapes and dimensions, on polymer and silicon substrates using iniferters and photopolymerization. They applied this approach to the recognition of D-glucose using copolymer networks containing poly(ethylene glycol) and functional monomers such as acrylic acid, 2-hydro-xyethyl methacrylate, and acrylamide. 

A novel attempt was made to realize different IPN architectures in a composite system of cellulose/poly(AT-vinyl pyrrolidone-co-glycidyl methacrylate) (CELL/P(VP-co-GMA)) [73]. The copolymer-rich compositions (4-19 wt % CELL) were synthesized successfully via photopolymerization in the gel state of cellulose impregnated with a monomer mixture of VP and GMA, resulting in the development of a semi-IPN-like organization (Fig. 5a) within the copolymerized bulks. An additional treatment of the as-polymerized composites ([O]-series) with 50% formic acid or 3% sodium hydrox-... 

All acrylate- and methacrylate-based membranes were synthesized by photopolymerization on top of the polyHEMA interlayer. The resulting FETs showed in the absence of an ionophore a cation response of 36-54 mV/decade and therefore we concluded that residual anionic groups must be present. Titration of the ACE monomer with KOH solution indicated the presence of 7.5 x Id5 eq. acid.g"1 ACE monomer. As shown in Table 2 the ACE was chemically modified by reaction of the hydroxyl group. In this way acetyl, pentanoyl, and hydroxy... 

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