共查询到20条相似文献,搜索用时 11 毫秒
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J. M. Montorns J. A. Reina J. C. Ronda 《Journal of polymer science. Part A, Polymer chemistry》2005,43(23):5998-6006
A series of poly[ω‐(4′‐methoxy‐biphenyl‐4‐oxy)alkyl‐1‐glycidylether]s were synthesized by chemically modifying the corresponding poly(ω‐bromoalkyl‐1‐glycidylether)s with the sodium salt of 4‐hydroxy‐4′‐methoxybiphenyl. New high‐molecular‐weight side‐chain liquid‐crystalline polymers were obtained with excellent yields and almost quantitative degrees of modification. They were all insoluble in THF and other common solvents. Characterization by 13C NMR confirmed that all the polymers had the expected structure. The liquid crystalline behavior of the polymers was analyzed by DSC and polarized optical microscopy, and mesophase assignments were confirmed by X‐ray diffraction studies. Polymers that had alkyl spacers with n = 2 and 4 were smectic C, those that had spacers with n = 6 and 8 were nematic cybotactic, and those that had longer spacers (n = 10 and 12) were smectic C again. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5998–6006, 2005 相似文献
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J. Ramesh Babu G. Sinai-Zingde J. S. Riffle 《Journal of polymer science. Part A, Polymer chemistry》1993,31(7):1645-1651
This research has focused on the development of telechelic, aromatic amine functional, poly(dimethylsiloxane) oligomers without any aliphatic components in the polymer backbone. The intent is to produce flexible oligomers with enhanced thermal stability for incorporation into materials which will be processed at elevated temperatures. The poly(dimethylsiloxane)s have been synthesized using living polymerization of hexamethylcyclotrisiloxane with protected aniline derivatives as initiators and termination reagents for the reactions. Low molecular weight oligomers prepared using the living polymerization method can be easily converted to a range of higher, controlled molecular weight materials in redistribution reactions. A basic tetramethylammonium siloxanolate catalyst in conjunction with octamethylcyclotetrasiloxane has been used for the equilibration procedure. © 1993 John Wiley & Sons, Inc. 相似文献
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Sung-Kyu Kim Su-Dong Cho Deok-Heon Kweon Yong-Jin Yoon Jung-Ho Kim Jung-Nyoung Heo 《Journal of heterocyclic chemistry》1997,34(1):209-214
Alkylations of 4,5-dichloropyridazin-6-one (1) with dibromoalkanes 2 or 3 in the presence of potassium carbonate or tetrabutylammonium bromide/potassium hydroxide were investigated under restricted condition. Reactions of 1 with 2 or 3, except for 2b and 3b , in the presence of potassium carbonate or tetrabutylammonium bromide/potassium hydroxide gave only the N-alkylation products 3 and/or 4. Alkylation of 1 with 2b or 3b in the presence of potassium carbonate yielded the N-alkylation products 3b and/or 4b and the O-alkylation product 5 as the main product, whereas treatment of 1 with 2b or 3b in the presence of tetrabutylammonium bromide/potassium hydroxide afforded selectively the N-alkylation products 3b and/or 4b. 相似文献
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Florence Segui Xing‐Ping Qiu Françoise M. Winnik 《Journal of polymer science. Part A, Polymer chemistry》2008,46(1):314-326
Poly(N‐isopropylacrylamide)s (PNIPAMs) with cholesteryl or pyrenyl moieties at each chain end (CH‐PNIPAMs or Py‐PNIPAMs) were prepared via end‐group modification of α,ω‐dimercapto poly(N‐isopropylacrylamides), ranging in molecular weight from ~ 7000 to 45,000 g mol?1 with a polydispersity index of 1.10 or lower. The telechelic thiol functionalized PNIPAMs were obtained by aminolysis of α,ω‐di(isobutylthiocarbonylthio)‐poly(N‐isopropylacrylamide)s (iBu‐PNIPAMs) obtained by reversible addition‐fragmentation chain transfer (RAFT) polymerization of N‐isopropylacrylamide in the presence of the difunctional chain transfer agent, diethylene glycol di(2‐(1‐isobutyl)sulfanylthiocarbonylsulfanyl‐2‐methyl propionate) (DEGDIM). The self‐assembly of the polymers in water was assessed by fluorescence spectroscopy, using the intrinsic emission of Py‐PNIPAM or the emission of pyrene added as a probe in aqueous solutions of CH‐PNIPAM. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 314–326, 2008 相似文献
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Helmut Blum 《无机化学与普通化学杂志》1985,528(9):152-156
α,ω-Dihydroxyalkane-α,α-diphosphonic Acids by Desamination of ω-Aminoalkanediphosphonic Acids The title compounds represent a new group of complexing diphosphonic acids which are synthesized by desamination of ω-amino-α-hydroxyalkane-α,α-diphosphonic acids. In case of α,ω-dihydroxypropane-α,α-diphosphonic acid ( 1 ) a phosphonylated phostone is formed by dehydration. In contrast, the ω-phenyl drivative of ( 1 ) yields in a smooth reaction under the same conditions 2-hydroxy-5-phenyl-3-phosphono-1.2-oxaphosphol-3-en-2-oxide ( 6 ). 相似文献
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Alkylation of 4,5-dichloro-1-hydroxymethylpyridazin-6-one ( 1 ) with α,ω-dibromoalkanes 2 or ω-bromo-alkylpyridazin-6-ones 3 via a fragmentation of the retro-ene type under the two restricted conditions was investigated. 相似文献
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Martine Tessier Ernest Marechal 《Journal of polymer science. Part A, Polymer chemistry》1989,27(2):539-553
Several di-, tri- or multiblock poly(isobutylene-b-amide-11)s are prepared by reaction of α-mono or α,ω-dianhydride oligoisobutylenes with α-mono or α,ω-diamino oligoamides, in o-dichorobenzene at 140°C. They are characterized mainly by 1H- and 13C-NMR spectroscopy and GPC, using the trifluoroacetylation technique. Their thermal differential chromatograms are reported and analyzed. 相似文献
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S. Zhang Z. Hou K. E. Gonsalves 《Journal of polymer science. Part A, Polymer chemistry》1996,34(13):2737-2742
Various amounts of hydroxy terminated PDMS were linked into PLLA chains via in-situ ring opening polymerization at a very low content of SnOt2. The 1H and FTIR spectra provided evidence for the incorporation of the PDMS in the PLLA chains. The molecular weights, Tg, Tm, crystallinity and the heats of fusion decreased as the feed mole ratio of PDMS/LLA in the block copolymer increased. The molecular weight distribution broadened as the content of the PDMS increased, due the occurrence of two initiation and propagation mechanisms. Linking PDMS into the PLLA chains improved its thermal stability. © 1996 John Wiley & Sons, Inc. 相似文献
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Yung K. Kim George A. Grindahl John R. Greenwald Ogden R. Pierce 《Journal of heterocyclic chemistry》1974,11(4):563-568
The synthesis of 2-oxa and 2-thiaperfluoroglutaric acids and their corresponding ethyl esters, amides, nitriles, acid chlorides, and also 2-thiaperfluoroglutaric anhydride are described. These compounds were prepared as precursors to α,ω-ditriazinylperfluoroalkane derivatives containing a heteroatom in the perfluoroalkylene chain. The ditrazinylpropanes were prepared most satisfactorily from the diacid chlorides rather than the dinitriles. 相似文献
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Martin Proudmore Ji-Feng Ding Richard H. Mobbs Stephen G. Yeates Colin Price Colin Booth 《Journal of polymer science. Part A, Polymer chemistry》1995,33(10):1615-1625
Poly(hexafluoropropylene oxide), poly(HFPO), networks were prepared from functional polymers by end linking via urethane groups. The prepolymers were characterized by NMR spectroscopy and GPC. The networks were characterized by determination of the number of network chains from the shear modulus, and were snown to contain both trifunctional crosslinks and difunctional links. The properties of the networks were investigated by a range of techniques. Compared with fully-fluorinated networks formed via triazine cross-links, investigated previously, the urethane-linked networks were more readily prepared but were poorer elastomers, were less thermally stable, and were less resistant to swelling by common polar solvents. © 1995 John Wiley & Sons, Inc. 相似文献
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Yu-Chin Lai Richard Ozark Edmond T. Quinn 《Journal of polymer science. Part A, Polymer chemistry》1995,33(11):1773-1782
α,ω-Bis(4-hydroxybutyl) polydimethylsiloxane (molecular weight 1500 to 4500) can be pre-pared with well-controlled molecular weight through the reaction of 1,3-bis(4-hydroxybu-tyl)tetramethyl disiloxane and dimethoxydimethyl silane or diethoxydimethyl silane in the presence of a stoichiometric amount of water and hydrochloric acid. The molecular weight of these hydroxybutyl-terminated polysiloxanes can be determined fairly consistently by a titration method. These polysiloxanes are stable toward cyclization. © 1995 John Wiley & Sons, Inc. 相似文献