Journal of Polymer Science Part A: Polymer Chemistry

Cover image for Journal of Polymer Science Part A: Polymer Chemistry

15 January 2007

Volume 45, Issue 2

Pages 165–331

  1. Highlights

    1. Top of page
    2. Highlights
    3. Articles
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      Substituted polyacetylenes (pages 165–180)

      Toshio Masuda

      Article first published online: 5 DEC 2006 | DOI: 10.1002/pola.21782

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      This article reviews the chemistry of substituted polyacetylenes developed by our research group. The main features are as follows: A number of catalysts based on group 5, 6, and 9 transition metals (Nb, Ta, Mo, W, and Rh) have been developed, which include living polymerization catalysts. By using these catalysts, many new substituted polyacetylenes have been synthesized, whose molecular weights are very high (Mw = 104−106). Most of the polymers are soluble in many common solvents and stable enough in the air unlike polyacetylene. Some of these polymers exhibit interesting functions including high gas permeability and photoelectronic properties.

  2. Articles

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    2. Highlights
    3. Articles
    1. Novel, environmentally friendly crosslinking system of an epoxy using an amino acid: Tryptophan-cured diglycidyl ether of bisphenol A epoxy (pages 181–190)

      Yi Li, Fei Xiao and C. P. Wong

      Article first published online: 5 DEC 2006 | DOI: 10.1002/pola.21742

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      Tryptophan has been used as a novel, environmentally friendly curing agent to crosslink the diglycidyl ether of bisphenol A (DGEBA) epoxy resin. The optimum reaction ratio of DGEBA to tryptophan has been determined to be 3:1 with 1 wt % catalyst. In situ Fourier transform infrared spectra indicate a catalyst-initiated chain reaction mechanism. The mechanism is suitable for all zwitterion amino acid curing reactions with epoxy resins. The crosslinked structure exhibits a reasonably high glass-transition temperature and thermal stability. The application of this new class of ecofriendly epoxy-curing agents is an important step toward next-generation green electronics.

    2. Synthesis and characterization of poly(higher-α-olefin)s with a nickel(α-diimine)/methylaluminoxane catalyst system: Effect of chain running on the polymer properties (pages 191–210)

      Ummadisetty Subramanyam and Swaminathan Sivaram

      Article first published online: 5 DEC 2006 | DOI: 10.1002/pola.21783

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      Homopolymerization of octadecene-1 at different reaction conditions has been studied. Significant chain running can be seen at higher polymerization temperatures. Interestingly, insertion of octadecene-1 into a sterically hindered nickel-cation/carbon (secondary) bond is observed. The microstructure of the polymer was established using NMR spectroscopy. The effects of chain running on polymer melting, crystallization behavior, and dynamic mechanical thermal properties were studied using DSC and DMTA. The extent of chain running (i.e., 2,ω-, 1,ω-enchainments) decreases with an increase in the carbon number of α-olefins.

    3. Luminescent copolyethers containing isolated 1,4-distyrylbenzene derivatives backbone and 7-oxy-4-methylcoumarin side group: Synthesis and characterization (pages 211–221)

      Cheng-Jang Tsai, Kun-Ming Yeh and Yun Chen

      Article first published online: 4 DEC 2006 | DOI: 10.1002/pola.21792

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      Four new copoly(aryl ether)s (P1P4) were prepared by the Heck coupling reaction. In P2 and P4, the oxidation and reduction start from hole-transporting distyrylbenzene segments in backbone and electron-transporting 7-oxy-4-methylcoumarin (OMC) side groups, respectively. The OMC chromophore enhances electron affinity of P2 and P4 (LUMO: −3.43 eV and −3.41 eV) as compared with those of P1 and P2 (−2.47 eV and −2.48 eV). Electroluminescent devices of P1 and P2 exhibit green color, while those of P3 and P4 emit blue light. The OMC side groups effectively reduce turn-on electric field and enhance luminance efficiency of the EL devices due to increased electron affinity.

    4. Synthesis and properties of novel sulfonated polyimides containing binaphthyl groups as proton-exchange membranes for fuel cells (pages 222–231)

      Yuhan Li, Rizhe Jin, Zhen Wang, Zhiming Cui, Wei Xing and Lianxun Gao

      Article first published online: 5 DEC 2006 | DOI: 10.1002/pola.21778

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      Novel sulfonated copolyimides were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2′-bis(p-aminophenoxy)-1,1′-binaphthyl-6,6′-disulfonic acid, and common nonsulfonated diamine 4,4′-diaminodiphenyl ether. Their solubility behavior, proton conductivity, water uptake, and membrane stability were investigated. The copolyimide membranes displayed higher proton conductivity and excellent thermal stability.

    5. Deactivation reactions in the modeled 2,2,6,6-tetramethyl-1-piperidinyloxy-mediated free-radical polymerization of styrene: A comparative study with the 2,2,6,6-tetramethyl-1-piperidinyloxy/acrylonitrile system (pages 232–241)

      Andrzej Kaim

      Article first published online: 5 DEC 2006 | DOI: 10.1002/pola.21775

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      The structure of the most probable transition-state geometry for the radical disproportionation reaction of a 1-phenylpropyl radical and a 2,2,6,6-tetramethyl-1-piperidinyloxy radical optimized at the restricted Austin Model 1 level of theory is shown.

    6. Reversible addition-fragmentation chain transfer polymerization of methacrylates containing hole- or electron-transporting groups (pages 242–252)

      Ping Zhao, Qi-Dan Ling, Wei-Zhi Wang, Jie Ru, Sheng-Biao Li and Wei Huang

      Article first published online: 5 DEC 2006 | DOI: 10.1002/pola.21771

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      The controlled/living radical polymerization of 2-(N-carbazolyl)ethyl methacrylate and 4-(5-(4-tert-butylphenyl-1,3,4-oxadiazol-2-yl)phenyl) methacrylate via RAFT polymerization has been studied. Polymers with controlled molecular weights and narrow polydispersity were synthesized with cumyl dithiobenzoate as a chain transfer agent and AIBN as an initiator in a benzene solution. Good control of the polymerization was confirmed by the linear increase in the molecular weight with the conversion. The optical, thermal, and electrochemical properties of these pendant functional polymers containing carbazole and oxadiazole as charge-transporting groups have also been investigated.

    7. Controlled helical orientation of carbazole in amino acid derived poly(N-propargylamide)s (pages 253–261)

      Haichao Zhao, Fumio Sanda and Toshio Masuda

      Article first published online: 6 DEC 2006 | DOI: 10.1002/pola.21769

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      Novel L-alanine and L-glutamic acid based polyacetylene derivatives possessing carbazole in the side chains {poly[N-(9-carbazolyl)ethyloxycarbonyl-L-alanine N′-propargylamide] and poly[N-(9-carbazolyl)ethyloxycarbonyl-L-glutamic acid-γ-benzyl ester N′-propargylamide]} were prepared. Both poly[N-(9-carbazolyl)ethyloxycarbonyl-L-alanine N′-propargylamide] and poly[N-(9-carbazolyl)ethyloxycarbonyl-L-glutamic acid-γ-benzyl ester N′-propargylamide] took a helical conformation with a predominantly one-handed screw sense in the film state and in the given solvents. The conformation could be tuned by changes in the solvent composition and heat. The polymers exhibited redox activity based on carbazole.

    8. Synthesis and properties of novel poly(arylene ether)s and poly(arylene thioether)s based on a pyridazine biphenol or a phthalazine biphenol (pages 262–268)

      J. Xu, Y. Z. Meng, S. J. Wang and A. S. Hay

      Article first published online: 4 DEC 2006 | DOI: 10.1002/pola.21733

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      Novel biphenols were synthesized in high yields by the reaction of 4-mercaptophenol with chloropyridazine or chlorophthalazine compounds. Two series of high-molecular-weight poly(arylene ether)s were synthesized by a nucleophilic substitution reaction between these sulfur-containing biphenols and activated difluoro aromatic compounds. The polymers had glass-transition temperatures up to 240 °C and showed no weight loss in thermogravimetric analysis up to 390 °C.

    9. Polysulfone ionomers functionalized with benzoyl(difluoromethylenephosphonic acid) side chains for proton-conducting fuel-cell membranes (pages 269–283)

      Benoît Lafitte and Patric Jannasch

      Article first published online: 11 DEC 2006 | DOI: 10.1002/pola.21755

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      Novel polysulfones carrying benzoyl(difluoromethylenephosphonic acid) side chains were prepared and investigated for use as proton-conducting fuel-cell membranes. Membranes having 0.90 mmol of phosphonic acid unit/g of dry polymer took 6 wt % water at room temperature, and conductivities up to 5 mS cm−1 at 100 °C were recorded. The aryl[BOND]CF2 [BOND]PO3H2 chemical arrangement was, however, found to have limited thermal and hydrothermal stability.

    10. Multiblock copolymers of poly(2,5-benzophenone) and disulfonated poly(arylene ether sulfone) for proton-exchange membranes. I. Synthesis and characterization (pages 284–294)

      Hang Wang, Anand S. Badami, Abhishek Roy and James E. McGrath

      Article first published online: 6 DEC 2006 | DOI: 10.1002/pola.21837

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      A series of poly(2,5-benzophenone)-activated, telechelic aryl fluoride oligomers with different block molecular weights were successfully synthesized by the Ni(0)-catalyzed coupling of 2,5-dichlorobenzophenone and the end-capping agent 4-chloro-4′-fluorobenzophenone. These telechelic oligomers (hydrophobic) were then copolymerized with phenoxide-terminated, disulfonated poly(arylene ether sulfone)s (hydrophilic) by nucleophilic, aromatic substitution to form hydrophilic–hydrophobic multiblock copolymers. Two separate glass-transition temperatures were observed via differential scanning calorimetry in the transparent multiblock copolymer films when each block length was longer than 6000 g/mol. Tapping-mode atomic force microscopy also showed clear microphase separation between the hydrophilic and hydrophobic domains and the influence of the block length as it increased from 6000 to 10,000 g/mol.

    11. Third-generation amphiphilic conetworks. I. Synthesis and swelling behavior of poly(N,N-dimethyl acrylamide)/polydimethylsiloxane conetworks (pages 295–307)

      G. Erdodi and J. P. Kennedy

      Article first published online: 6 DEC 2006 | DOI: 10.1002/pola.21735

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      A strategy has been developed for the synthesis of novel grafts of poly(N,N-dimethyl acrylamide) main chains carrying polydimethylsiloxane branches fitted with terminal vinylsilyl groups. Subsequently, the vinylsilyl groups are crosslinked to bicontinuous, amphiphilic conetworks by hydrosilation with polyhydrosiloxanes. The synthesis is simple and efficient, and in situ casting/crosslinking leads to amphiphilic membranes with a combination of properties appropriate for biomaterial applications. The sketch shows an idealized microstructure of the amphiphilic membrane.

    12. Synthesis, characterization and properties of novel highly oxygen permeable amphiphilic membranes (pages 308–316)

      Radhakrishnan Karunakaran and Joseph P. Kennedy

      Article first published online: 6 DEC 2006 | DOI: 10.1002/pola.21757

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      Water-swollen bicontinuous membranes synthesized from hydrophilic poly(ethylene glycol) (PEG) and hydrophobic polydimethylsiloxane (PDMS) segments randomly crosslinked by novel pentamethylcyclopentasiloxane-based crosslinking/modifying agents (D5-R, where D5 = a pentamethylcyclopentasiloxane residue containing four H atoms, and R = TRIS, OFPE, or DEG groups) exhibit a combination of excellent properties, including optical clarity, outstanding oxygen permeability, water uptake and mechanical properties, rendering them suitable for extended wear soft contact lens applications.

    13. Aging of a donor conjugated polymer: Photochemical studies of the degradation of poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (pages 317–331)

      Sylvain Chambon, Agnès Rivaton, Jean-Luc Gardette, Muriel Firon and Laurence Lutsen

      Article first published online: 6 DEC 2006 | DOI: 10.1002/pola.21815

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      A two-step radical mechanism, involving first oxidation of the ether substituent and second oxidation of the double bonds, is shown to account for the modification of the chemical structure of poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO–PPV) induced by photoaging and thermal aging. In the light of our findings, singlet oxygen is not involved as the main intermediate in the degradation process. These reactions are responsible for the loss of conjugation of MDMO–PPV, chain scissions, and a decrease in the visible absorbance, which are anticipated to drastically shorten the lifetime of organic cells.

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