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Acetylene Monomers (acetylene + monomer)
Selected AbstractsCatalytic Polymerizations of Hydrophobic, Substituted, Acetylene Monomers in an Aqueous Medium by Using a Monomer/Hydroxypropyl- , -cyclodextrin Inclusion ComplexMACROMOLECULAR RAPID COMMUNICATIONS, Issue 2 2009Lei Ding Abstract Ten hydrophobic, substituted, acetylene monomers were examined as to their abilities to form an inclusion complex with hydroxypropyl- , -cyclodextrin (HPCD). Only the monomers with suitable substitutents were found to form the monomer/HPCD complex, which was identified by NMR, FTIR, and UV-vis spectroscopy. Polymerizations of the monomers were successfully carried out in aqueous solution by using the prepared monomer/HPCD inclusion complex and by using a water-soluble Rh-based catalyst, [Rh(cod)2BF4] or [Rh(nbd)(H2O)OTs]. Such polymerizations provided high-yield (>90%) polymers with a cis content of approximately 100%. The as-prepared polymers could take an ordered helical conformation, just like their counterparts obtained in organic solvents. [source] Degradable star polymers with high "click" functionalityJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2009James T. Wiltshire Abstract Degradable polyester-based star polymers with a high level of functionality in the arms were synthesized via the "arms first" approach using an acetylene-functional block copolymer macroinitiator. This was achieved by using 2-hydroxyethyl 2,-methyl-2,-bromopropionate to initiate the ring-opening polymerization (ROP) of caprolactone monomer followed by an atom transfer radical polymerization (ATRP) of a protected acetylene monomer, (trimethylsilyl)propargyl methacrylate. The hydroxyl end-group of the resulting block copolymer macroinitiator was subsequently crosslinked under ROP conditions using a bislactone monomer, 4,4,-bioxepanyl-7,7,-dione, to generate a degradable core crosslinked star (CCS) polymer with protected acetylene groups in the corona. The trimethylsilyl-protecting groups were removed to generate a CCS polymer with an average of 1850 pendent acetylene groups located in the outer block segment of the arms. The increased functionality of this CCS polymer was demonstrated by attaching azide-functionalized linear polystyrene via a copper (I)-catalyzed cycloaddition reaction between the azide and acetylene groups. This resulted in a CCS polymer with "brush-like" arm structures, the grafted segment of which could be liberated via hydrolysis of the polyester star structure to generate molecular brushes. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1485,1498, 2009 [source] Synthesis and chiroptical properties of optically active poly(ethynylcarbazole) derivatives: Substituent effect on the helix formationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2007Fumio Sanda Abstract Novel chiral acetylene monomers containing carbazole, 2-ethynyl-9-[(S)-2-methylbutoxycarbonyl]carbazole (1), 3-ethynyl-9-[(S)-2-methylbutoxycarbonyl]carbazole (2), 2-ethynyl-9-[(S)-2-methylbutyl]carbazole (3), and 2-ethynyl-9-[(S)-4-methylhexyl]carbazole (4) were synthesized and polymerized with [(nbd)RhCl]2Et3N. The corresponding polyacetylenes with number-average molecular weights ranging from 68,700 to 310,000 were obtained in good yields. Poly(1) exhibited a large specific rotation and an intense Cotton effect in toluene, indicating that it formed a helix with predominantly one-handed screw sense, while the other three polymers showed no evidence for taking a helical structure. Poly(1) largely decreased the CD intensity upon heating from ,10 to 60 °C. Poly(1) showed a Cotton effect in film state in a manner similar to solution state. No chiral amplification was observed in the copolymerization of 1 with achiral 2-ethynyl-9- tert -butoxycarbonylcarbazole (5). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4450,4458, 2007 [source] Catalytic Polymerizations of Hydrophobic, Substituted, Acetylene Monomers in an Aqueous Medium by Using a Monomer/Hydroxypropyl- , -cyclodextrin Inclusion ComplexMACROMOLECULAR RAPID COMMUNICATIONS, Issue 2 2009Lei Ding Abstract Ten hydrophobic, substituted, acetylene monomers were examined as to their abilities to form an inclusion complex with hydroxypropyl- , -cyclodextrin (HPCD). Only the monomers with suitable substitutents were found to form the monomer/HPCD complex, which was identified by NMR, FTIR, and UV-vis spectroscopy. Polymerizations of the monomers were successfully carried out in aqueous solution by using the prepared monomer/HPCD inclusion complex and by using a water-soluble Rh-based catalyst, [Rh(cod)2BF4] or [Rh(nbd)(H2O)OTs]. Such polymerizations provided high-yield (>90%) polymers with a cis content of approximately 100%. The as-prepared polymers could take an ordered helical conformation, just like their counterparts obtained in organic solvents. [source] | ||||||||||