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New Monomer (new + monomer)
Selected AbstractsPolymer electrolyte membranes for high-temperature fuel cells based on aromatic polyethers bearing pyridine unitsPOLYMER INTERNATIONAL, Issue 11 2009Joannis K Kallitsis Abstract This review is focused on the design and synthesis of new high-temperature polymer electrolytes based on aromatic polyethers bearing polar pyridine moieties in the main chain. Such materials are designed to be used in polymer electrolyte fuel cells operating at temperatures higher than 100 °C. New monomers and polymers have been synthesized and characterized within this field in respect of their suitability for this specific application. Copolymers with optimized structures in order to combine excellent film-forming properties with high mechanical, thermal and oxidative stability and controlled acid uptake have been synthesized which, after doping with phosphoric acid, result in ionically conducting membranes. Such materials have been studied in respect of their conductivity under various conditions and used for the construction of membrane-electrode assemblies (MEAs) which are used for fuel cells operating at temperatures up to 180 °C. New and improved, in terms of oxidative stability and mechanical properties in the doped state, polymeric membranes have been synthesized and used effectively for MEA construction and single-cell testing. Copyright © 2009 Society of Chemical Industry [source] Macroporous monolithic chiral stationary phases for capillary electrochromatography: New chiral monomer derived from cinchona alkaloid with enhanced enantioselectivityELECTROPHORESIS, Issue 17 2003Michael Lämmerhofer Abstract A new chiral monomer derived from cinchona alkaloid, namely O -9-(tert -butylcarbamoyl)-11-[2-(methacryloyloxy)ethylthio]-10,11-dihydroquinine 1, was employed for the preparation of enantioselective monolithic capillary columns by an in situ copolymerization with 2-hydroxyethyl methacrylate 2 (HEMA), ethylene dimethacrylate 3 (EDMA) in the presence of cyclohexanol and 1-dodecanol as porogens (UV or thermal initiation of azobisisobutyronitrile (AIBN) as radical initiator). The porous properties and the electrochromatographic behavior of the new chiral monoliths were comparatively evaluated with previously described analogs obtained from O -9-[2-(methacryloyloxy)ethylcarbamoyl]-10,11-dihydroquinidine 4 as chiral monomer. Despite close structural and physicochemical similarities of the both chiral monomers, the pore distribution profiles of the resulting monoliths were shifted typically towards larger pore diameters with the new monomer 1. Once more, it was confirmed that a low cross-linking (10 wt% related to total monomers) and a pore diameter of about 1 ,m in the dry state provides the best electrochromatographic efficiency as a result of lower resistance to mass transfer (smaller C-term contribution to peak broadening) and more homogeneous flow profile (smaller A-term). Most importantly, as expected the new poly(1 - co -HEMA- co -EDMA) monoliths showed enhanced enantioselectivities and in addition faster separations as compared to poly(4 - co -HEMA- co -EDMA) analogs, which represents a significant improvement. Further, the elution order was reversed owing to the pseudoenantiomeric behavior of quinine- and quinidine-derived monomers. Fluorescence-labeled 9-fluorenylmethoxycarbonyl (FMOC), dansyl (DNS), 7-dimethylaminosulfonyl-1,3,2-benzoxadiazol-4-yl (DBD), carbazole-9-carbonyl (CC) amino acids could be separated with resolution values between 2 and 4 (with efficiencies typically between 100,000 and 200,000 plates/m) and fluorescence detection (variable wavelength fluorescence detector in-line with UV) yielding routinely a gain in detection sensitivities up to two orders of magnitude without specific optimization of the conditions with regards to fluorescence efficiency. [source] Thermally curable benzoxazine monomer with a photodimerizable coumarin groupJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2007Baris Kiskan Abstract A new monomer, 4-methyl-9- p -tolyl-9,10-dihydrochromeno[8,7-e][1,3]oxazin-2(8H)-one, possessing both benzoxazine and coumarin rings in its structure was synthesized by the reaction of 4-methyl-7-hydroxycoumarin, paraformaldehyde, and p -toluidine in methanol at 40 °C and characterized with spectral analysis. Upon photolysis around 300 nm, this monomer underwent dimerization via the [2,s+2,s] cycloaddition reaction. Photodimerization reactions were investigated with UV and 1H NMR spectroscopy measurements. The thermal ring-opening reaction of the benzoxazine ring was demonstrated with differential scanning calorimetry measurements. The thermal behavior of the cured product was also investigated with thermogravimetric analysis. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1670,1676, 2007 [source] Use of a new methacrylic monomer, 4,4,-di(2-hydroxy-3-methacryloyloxypropoxy)benzophenone, in the synthesis of porous microspheresJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 24 2006Beata Podko, cielna Abstract A new aromatic, tetrafunctional methacrylate monomer, 4,4,-di(2-hydroxy-3-methacryloyloxypropoxy)benzophenone, and its application to the synthesis of porous microspheres are presented. This new monomer was copolymerized with divinylbenzene in the presence of pore-forming diluents. The properties of the obtained highly crosslinked microspheres were investigated as column packing for high-performance liquid chromatography. Their porous structures in both dry and wet states were studied and compared with those of poly(divinylbenzene) and the less crosslinked copolymer of 2,3-epoxypropyl methacrylate and divinylbenzene. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 7014,7026, 2006 [source] Synthesis of poly(aryl ether ketone)s containing diphenyl moieties by electrophilic Friedel,Crafts solution polycondensationPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2009Mingzhong Cai Abstract A new monomer, 4,4,-bis(4-phenoxybenzoyl)diphenyl (BPOBDP), was prepared by Friedel,Crafts reaction of 4-bromobenzoyl chloride and diphenyl, followed by condensation with potassium phenoxide. Novel poly(ether ketone ketone) (PEKK)/poly(ether ketone diphenyl ketone ether ketone ketone) (PEKDKEKK) copolymers were synthesized by electrophilic Friedel,Crafts solution copolycondensation of isophthaloyl chloride (IPC) with a mixture of diphenyl ether (DPE) and BPOBDP, in the presence of anhydrous aluminum chloride and N -methyl-pyrrolidone (NMP) in 1,2-dichloroethane (DCE). The copolymers obtained were characterized by various analytical techniques such as FT-IR, DSC, TGA, and wide-angle X-ray diffraction (WAXD). The results showed that the resulting copolymers exhibited excellent thermal stability due to the existence of diphenyl moieties in the main chain. The glass transition temperatures are above 152°C, the melting temperatures are above 276°C, and the temperatures at a 5% weight loss are above 548°C in nitrogen. The copolymers with 50,70,mol% BPOBDP had tensile strengths of 101.5,102.7,MPa, Young's moduli of 3.23,3.41,GPa, and elongations at break of 12,17%. All these copolymers were semicrystalline and insoluble in organic solvents. Copyright © 2008 John Wiley & Sons, Ltd. [source] PNA synthesis using a novel Boc/acyl protecting group strategyJOURNAL OF PEPTIDE SCIENCE, Issue 8 2001Thomas Kofoed Abstract The synthesis of novel Boc/acyl protected monomers for the synthesis of peptide nucleic acid (PNA) is described. The oligomerization protocol using these new monomers has been optimized with regard to coupling reagents. The use of base-labile acyl protecting groups at the exocyclic amines of the heterocyclic bases (isobutyryl for guanine and benzoyl for adenine and cytosine) and a PAM-linked solid support offers an attractive alternative to the present procedures used in PNA synthesis. This strategy has been applied for the synthesis of a test 17mer PNA on both control pore glass (CPG) and a polystyrene MBHA support and was used in the preparation of PNA,DNA chimeras. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd. [source] Facile syntheses of 4-vinyl-1,2,3-triazole monomers by click azide/acetylene couplingJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2008Kenichi Takizawa Abstract Synthetic strategies for the preparation of a new family of vinyl monomers, 4-vinyl-1,2,3-triazoles, have been developed. These monomers are noteworthy as they combine the stability and aromaticity of styrenics with the polarity of vinylpyridines and the structural versatility of acrylate/methacrylate derivatives. To enable the wide adoption of these unique monomers, new methodologies for their synthesis have been elaborated which rely on Cu-catalyzed azide/acetylene cycloaddition reactions,"click chemistry",as the key step, with the vinyl substituent being formed by either elimination or Wittig-type reactions. In addition, one-pot "click" reactions have been developed from alkyl halides, which allow for monomer synthesis without isolation of the intermediate organic azides. The high yield and facile nature of these procedures has allowed a library of new monomers including the parent compound, 1- H -4-vinyl-1,2,3-triazole, to be prepared on large scales. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2897,2912, 2008 [source] Synthesis and cationic photopolymerization of epoxy-functional siloxane monomers and oligomersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2003Myoungsouk Jang Abstract A series of difunctional silicon-containing monomers were prepared with a novel method consisting of the monohydrosilation of an ,,,-difunctional SiH-terminated siloxane with a vinyl-functional epoxide or oxetane followed by the dehydrodimerization of the resulting SiH-functional intermediate. This method used simple, readily available starting materials and could be conducted as a streamlined one-pot, two-step synthesis. This novel method was also applied to the synthesis of several epoxy,silicone oligomers. The reactivities of these new monomers and oligomers were examined with Fourier transform real-time infrared spectroscopy and optical pyrometry. Those monomers containing epoxycyclohexyl groups displayed excellent reactivity in cationic ring-opening polymerization in the presence of lipophilic onium salt photoinitiators. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3056,3073, 2003 [source] | ||||||||||