DMSO solution radical polymerization

Poly-9-(f -methacryloyloxyethyl)adenine (polyMAOA, 25 a), poly-l-(fi-methacryloyl-oxyethyl)uracil (polyMAOU, 27 a), -thymine (poly-MAOT, 29 a), poly-9-(f -acryloyl-oxyethyl)adenine (polyAOA, 25b), poly-1 -(fi-acryloyloxyethyl)uracil (polyAOU, 27b) and -thymine (polyAOT, 29 b) were prepared by free-radical polymerization of their corresponding monomers26,27). PolyMAOA and polyAOA are soluble in DMSO, ethylene glycol and acidic aqueous solution (below pH 3), while the polymers having uracil and thymine moieties are soluble in DMSO, DMF and alkaline aqueous solution (above pH 10). 

Azo functions are well known to initiate free radical polymerization and have been used previously in polymeric initiators [6]. However, triazene functions are only rarely used in free radical polymerization [7], and not much is known about their thermal decomposition mechanism. The comparison of the thermal characterisitics of two model compounds, 3 and 4 (see Fig. 3), for AMP and TMP has shown that the azo fimction is much more thermally labile than the triazene group. The maximum of decomposition in bulk for 3 is at 135 °C and for 4 at 270 °C. Decomposition of 3 and 4 in DMSO solution at 80 °C followed by UV spectroscopy led to complete decomposition of 3 after 600 min whereas only about 5 % of the triazene functions are destroyed at this time. 

The reaction rate in the studied range (60-90°C) increases with temperature independently of the media. DAAH copolymerization with SO2 proceeds significantly easier in aqueous media - at lower temperatures and lesser concentrations of initiator, than in DMSO. The values of the total activation energy of DAAH copolymerization with SO2 in the water solution and DMSO, calculated from Arrenius equation, are 58,6 and 87,9 kJ/mol, respectively. It is known from reference data [9] that the values of activation energy of alternate copolymerization turn out to be lesser, than in the case of the most reactions of free-radical polymerization, effective activation energy of the latter being in the range 83,7-96,3 kJ/mol. 

The template polymerization of methacrylate monomers containing nucleic acid base was studied in the presence of the template polymer containing complementary nucleic acid bases. Four monomers N-P-methacryloylethyl derivatives of adenine (MAOA), thymine (MAOT), uracil (MAOU), and theophylline (MAOThe) were synthesized. Atactic polymers were obtained from these monomers by radical polymerization initiated by azobisiso butyronitrile (AIBN) in dimethylsulfox-ide (DMSO) solution and used as templates. 

Rutin is one of the most commonly found flavonol glycosides identified as vitamin P with quercetin and hesperidin. An oxidative polymerization of rutin using ML as catalyst was examined in a mixture of methanol and buffer to produce a flavonoid polymer [115]. Under selected conditions, the polymer with molecular weight of several thousands was obtained in good yields. The resulting polymer was readily soluble in water, DMF, and DMSO, although rutin monomer showed very low water solubility. UV measurement showed that the polymer had broad transition peaks around 255 and 350nm in water, which were red-shifted in an alkaline solution. ESR measurement showed the presence of a radical in the polymer. 

Acrylonitrile is one of the rare monomers that are polymerized in solution through a radical process. The solvent used is dimethylformamide (DMF) or dimethylsulfoxide (DMSO), and initiators are then azo compounds or organic peroxides. This technique is used only when the resulting concentrated polymer solution (collodion) serves for the production of textile fibers. 

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