Journal of Polymer Science Part A: Polymer Chemistry

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

1 September 2003

Volume 41, Issue 17

Pages 2607–2742

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      Liquid-crystalline and light-emitting polyacetylenes (pages 2607–2629)

      Jacky W. Y. Lam and Ben Zhong Tang

      Version of Record online: 15 JUL 2003 | DOI: 10.1002/pola.10802

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      Rigid polymer backbones have often been considered to be detrimental to the packing of mesogenic pendants, and polyacetylenes have generally been regarded as unpromising materials for light-emitting applications. Our group, however, has succeeded in creating a series of liquid-crystalline polyacetylenes with rigid backbones and a variety of light-emitting polyacetylenes with luminescent chromophores. Here we demonstrate that the rigid polyacetylene skeleton can play a constructive role in guiding the alignments of mesogenic pendants and prove that polyacetylenes can be highly emissive with photoluminescence quantum yields of up to 98% and electroluminescence performances comparable or superior to those of the best blue-light-emitting polymers

  2. Articles

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    1. Synthesis and characterization of phenylethynyl-end-capped cooligomides from fluorinated dianhydrides 4,4′-(hexafluoroisopropylidene)dipthalic anhydride and 4,4′-(2,2,2-trifluoro-1-phenylethylidene)dipthalic anhydride and para- and meta-phenylene diamines and cooligomide blends with phenylethynyl-end-capped reactive diluents (pages 2630–2649)

      Hongbo Liu, C. D. Simone and D. A. Scola

      Version of Record online: 17 JUL 2003 | DOI: 10.1002/pola.10799

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      A series of phenylethynyl (PE)-end-capped cooligomides with number-average molecular weights (Mn) of 4000 and 7000 based on 4,4′-(hexafluoroisopropylidene)dipthalic anhydride (6FDA) and para- and meta-phenylene diamines containing 80/20 and 70/30 p/m molar ratios in the repeat unit were synthesized and characterized for their thermal and rheological properties. The cooligomides with Mn = 7000 exhibited high melt viscosities with respect to the cooligomides with Mn = 4000 at both 80/20 and 70/30 p/m molar ratios. A blend of the 3FDA cooligomide and reactive diluents containing 3FDA exhibited a much lower viscosity than a blend of the 6FDA cooligomide and a reactive diluent containing 6FDA.

    2. Blue-emitting poly[(m-phenylene vinylene)-alt-(o-phenylene vinylene)]s: The effect of regioregularity on the optical properties (pages 2650–2658)

      Liang Liao, Yi Pang, Liming Ding and Frank E. Karasz

      Version of Record online: 21 JUL 2003 | DOI: 10.1002/pola.10810

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      Blue-emitting poly[(m-phenylene vinylene)-alt-(o-phenylene vinylene)] (3) has been synthesized and characterized. The partial conjugation extension at o-phenylene allows minor color tuning of the electroluminescence (EL) emission of 3 to 463 and 475 nm in comparison with polymer 2 (EL emission at 445 and 462 nm).

    3. Monomer reactivity ratios and glass-transition temperatures of copolymers based on dimethyl amino ethyl methacrylate and two structural hydroxy-functional acrylate isomers (pages 2659–2666)

      L. Martín-Gomis, R. Cuervo-Rodriguez, M. C. Fernández-Monreal, E. L. Madruga and M. Fernández-García

      Version of Record online: 21 JUL 2003 | DOI: 10.1002/pola.10811

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      The differences in the values of the monomer reactivity ratios for 2-hydroxyethyl methacrylate (HEMA)–dimethyl amino ethyl methacrylate (DMAEMA) and ethyl α-hydroxymethyl acrylate (EHMA)–DMAEMA systems might have been due to electronic or steric contributions to the cross-propagation reactions of EHMA and HEMA, respectively.

    4. Ring-opening polymerization and block copolymerization of L-lactide with divalent samarocene complex (pages 2667–2675)

      Dongmei Cui, Tao Tang, Wuguo Bi, Jianhua Cheng, Wenqi Chen and Baotong Huang

      Version of Record online: 22 JUL 2003 | DOI: 10.1002/pola.10814

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      Divalent samarocene complex is highly active in the ring-opening polymerization of L-lactide (L-LA) with high conversion and high molecular weight under mild conditions. The polymerization showed some degree of living nature with minor racemization, and conformation of L-LA was retained. The successful synthesis of the block copolymer of caprolactone/L-LA was confirmed by NMR, differential scanning calorimetry, and atomic force microscopy.

    5. Thermotropic liquid-crystalline polymers containing five-membered heterocyclic groups. X. Relationships between structures of semirigid polyesters based on three disubstituted 2,5-diphenyl-1,3,4-thiadiazoles and thermotropic liquid-crystalline and optical properties (pages 2676–2687)

      Moriyuki Sato, Shinji Nakashima and Yuko Uemoto

      Version of Record online: 21 JUL 2003 | DOI: 10.1002/pola.10818

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      Thermotropic liquid-crystalline (LC) semirigid polyesters based on three terphenyl analogues of 1,3,4-thiadiazole (2,5-diphenyl-1,3,4-thiadiazole)s (DPTD) linking undecamethyleneoxy chain at different (4,4′-, 3,4′-, and 3,3′-) disubstituted positions were synthesized, and the relationships between polymer structures and LC and optical properties were investigated. The polymers composed of DPTD moiety having a more linear molecular structure and 1,4-phenylene unit or short aliphatic chain tended to exhibit a smectic phase. Peak maxima of ultraviolet–visible and photoluminescent spectra were shifted to lower wavelengths in the order of 4,4′-DPTD > 3,4′-DPTD > 3,3′-DPTD.

    6. Controlled/living polymerization of 2-(diethylamino)ethyl methacrylate and its block copolymer with tert-butyl methacrylate by atom transfer radical polymerization (pages 2688–2695)

      Leong-Huat Gan, Palaniswamy Ravi, Bao Wei Mao and Kam-Chiu Tam

      Version of Record online: 24 JUL 2003 | DOI: 10.1002/pola.10816

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      Very well controlled polymerization of 2-(diethylamino)ethyl methacrylate (DEAEMA) was achieved by atom transfer radical polymerization with the 1,1,4,7,10,10-hexamethyltriethylenetetramine/copper(I) chloride/p-toluenesulfonyl chloride system in methanol. Poly(DEAEMA) with a polydispersity index as low as 1.07 was obtained. Well-defined block copolymers of DEAEMA and tert-butyl methacrylate (tBMA) were successfully synthesized with equally good results by starting with either p(DEAEMA) or p(tBMA) as the macroinitiators. However, only the macroinitiators terminated with chlorine should be used.

    7. Characterization and properties of chemically modified Corchorus capsularis jute fiber via pulping and grafting: Infrared, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, biodegradation, and superabsorbency (pages 2696–2703)

      Prafulla K. Sahoo, Pradeep K. Rana, Nandalal Deb Sarkar, Anusmita Sahoo and Sarat K. Swain

      Version of Record online: 21 JUL 2003 | DOI: 10.1002/pola.10813

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      Chemical modification of Corchorus capsularis (JRC-321) jute fiber was carried out by pulping, bleaching, and grafting with acrylamide monomer. The above-prepared samples were characterized and analyzed by IR, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and X-ray diffraction. Evaluation of the superabsorbency and biodegradability of the samples revealed their potential uses as superabsorbents.

    8. Synthesis and properties of fluorosilicone with perfluorooctylundecyl side chains (pages 2704–2714)

      Y. Furukawa and T. Yoneda

      Version of Record online: 22 JUL 2003 | DOI: 10.1002/pola.10817

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      A series of fluorosilicone (FLS) homopolymers with 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoroundecylmethylsiloxane [[BOND]C8F17CH2CH2CH2(CH3)SiO[BOND]; HDFUSiO] and copolymers based on dimethylsiloxane [[BOND](CH3)2SiO[BOND], or I] were prepared by the hydrosilylation of 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoro-1-undecene (C8F17CH2CH[DOUBLE BOND]CH2) with poly(hydromethylsiloxane)s. The relationship between the HDFUSiO content and their thermal properties, refractive index, dielectric constant, and surface tension was investigated. FLSs with HDFUSiO and trichlorosilylethyl side chains (Cl3SiCH2CH2[BOND], or II) were also prepared so that their solid surface tension (surface free energy) could be measured. The surface free energy of these FLSs decreased with increasing Cl3SiCH2CH2[BOND] content, but the sliding angle of a water droplet and the contact-angle hysteresis adversely increased.

    9. Cationic polymerization of styrene on the surface of graphite expanded (pages 2715–2721)

      Wen-Ping Wang and Cai-Yuan Pan

      Version of Record online: 21 JUL 2003 | DOI: 10.1002/pola.10812

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      Cationic grafting polymerization of styrene initiated by the CO+ClOmath image group on the surface of expanded graphite (EG) made by graphite oxide was carried out for modifying the surface properties of graphite. The influence factors, such as polymerization time and temperature, on the polymerization including the grafting ratio and efficiency were investigated.

    10. Synthesis and characterization of poly(diethylsiloxane) and its copolymers with different diorganosiloxane units (pages 2722–2730)

      Lihua Liu, Shiyan Yang, Zhijie Zhang, Qian Wang and Zemin Xie

      Version of Record online: 21 JUL 2003 | DOI: 10.1002/pola.10822

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      Poly(diethylsiloxane) and its copolymers with two, three, or four kinds of R1R2SiO basic units were prepared via equilibrium polymerization of cyclosiloxanes with tetramethylammonium silanolate as the catalyst. Random microstructure was obtained from all the copolymers containing 50 mol % Et2SiO units content. Through differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) it showed that the presence of 2.5 mol % diphenylsiloxane units or 5.0 mol % methylphenysiloxane units content in the copolymer could disrupt the crystallinity, and led to noncrystalline copolymers with low glass-transition temperatures below −133 °C by DSC.

    11. Direct copolymerization of sulfonated poly(phthalazinone arylene ether)s for proton-exchange-membrane materials (pages 2731–2742)

      Yan Gao, Gilles P. Robertson, Michael D. Guiver, Xigao Jian, Serguei D. Mikhailenko, Keping Wang and Serge Kaliaguine

      Version of Record online: 22 JUL 2003 | DOI: 10.1002/pola.10820

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      Sulfonated poly(phthalazinone ether ketone) (SPPEK) and sulfonated poly(phthalazinone ether sulfone) (SPPES) were prepared by direct copolymerization of sulfonated monomers. Membrane films of SPPEKs and SPPESs cast from N,N-dimethylacetamide solutions were converted into acid form by treatment with 2 N sulfuric acid. An increase in sulfonic acid content in the copolymers resulted in increased glass-transition temperature (Tg) and enhanced membrane hydrophilicity. Proton conductivities of up to 10−2 S/cm were achieved for the copolymers. The conductivities increased with temperature, and were also less temperature dependent in comparison with postsulfonated products.