Journal of Polymer Science Part A: Polymer Chemistry

Cover image for Vol. 43 Issue 23

1 December 2005

Volume 43, Issue 23

Pages 5723–6177

  1. Highlights

    1. Top of page
    2. Highlights
    3. Articles
    1. You have free access to this content
      Living polymerization of substituted acetylenes (pages 5723–5747)

      Martin G. Mayershofer and Oskar Nuyken

      Version of Record online: 11 OCT 2005 | DOI: 10.1002/pola.20993

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      Various initiating systems, that is, ill-de fined group 5 or 6 transition-metal halide-based complexes, well-defined Schrock-type or modified Grubbs–Hoveyda-type transition-metal alkylidenes, and rhodium(I)- based complexes induce the living polymerization of mono- or disubstit uted acetylenes or α,ω-diynes. Nevertheless, monomer–initiator combinations appropriate for the tailor-made synthesis of π-conjugated polymers have to be selected carefully. Therefore, initiating systems mediating the living polymerization of substituted acetylenes are presented, some insight into mechanistic advancements is given, and advantages as well as limitations of the different groups of initiators are briefly discussed.

    2. You have free access to this content
      Genesis of the CSIRO polymer group and the discovery and significance of nitroxide-mediated living radical polymerization (pages 5748–5764)

      David H. Solomon

      Version of Record online: 11 OCT 2005 | DOI: 10.1002/pola.21067

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      The background to the formation of the CSIRO polymer group is discussed. In particular, the challenges of working with high-conversion polymerization, as found in commercial systems, and the need to explain variations in polymer properties led to important advances in the theory of radical polymerization and control over both the initiation and termination steps. Studies on the fate of the macromonomer, formed in termination by disproportionation, led to an early form of addition/fragmentation now known as reversible addition–fragmentation chain transfer, whereas detailed studies on initiation pathways using nitroxide trapping led to nitroxide-mediated living radical polymerization. These studies contributed to the renaissance in free-radical polymerization studies.

  2. Articles

    1. Top of page
    2. Highlights
    3. Articles
    1. Synthesis and electrochemical and electroluminescent properties of N-phenylcarbazole-substituted poly(p-phenylenevinylene) (pages 5765–5773)

      Fushun Liang, Takashi Kurata, Hiroyuki Nishide and Junji Kido

      Version of Record online: 11 OCT 2005 | DOI: 10.1002/pola.21018

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      An N-phenylcarbazole-containing poly(p-phenylenevinylene) (Cz-PPV) was synthesized, and its optical, electrochemical, and electroluminescent properties were studied. The molecular structures of the key intermediates, the carbazole-containing boronic ester and dialdehydemonomer, were crystallographically characterized. A double-layer light-emitting diode (LED) device with the configuration of ITO/poly(3,4-ethylenedioxy-2,5-thiophene):poly(styrenesulfonic acid) (60 nm)/Cz-PPV (80 nm)/Ca/Al gave a low turn-on voltage at 3 V and a maximum brightness of 6600 cd/m2 at a bias of 8 V. The desired electroluminescence results demonstrated that the incorporation of hole-transporting functional groups into the PPVs was effective for enhancing the electroluminescent performance.

    2. Isothermal frontal polymerization: Confirmation of the mechanism and determination of factors affecting the front velocity, front shape, and propagation distance with comparison to mathematical modeling (pages 5774–5786)

      Lydia L. Lewis, Cynthia S. DeBisschop, John A. Pojman and Vladimir A. Volpert

      Version of Record online: 13 OCT 2005 | DOI: 10.1002/pola.21019

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      Isothermal frontal polymerization (IFP) is a directional polymerization that utilizes the Trommsdorff, or gel, effect to produce gradient materials for optical applications. Using the optical techniques of laser line deflection (Weiner's method) and shadowgraphy along with controls, we obtained definitive experimental evidence of IFP and were able to measure accurately and precisely the front position and front concentration profile as a function of time by monitoring IFP systems and controls of various initiator concentrations and cure temperatures. The experimental data were compared with theoretical predictions from a model using mass-diffusion and radical polymerization kinetics.

    3. Preparation and properties of high performance epoxy–silsesquioxane hybrid resins prepared using a maleimide–alkoxysilane compound as a modifier (pages 5787–5798)

      Ying-Ling Liu, Gung-Pei Chang, Chuan-Shao Wu and Yie-Shun Chiu

      Version of Record online: 14 OCT 2005 | DOI: 10.1002/pola.21057

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      A maleimide–alkoxysilane compound MSM was prepared and used as a modifier to epoxy resins. In situ curing of epoxy resins with MSM resulted in epoxy resins with good homogeneity. Only 5–10 wt % of MSM is enough to bring superior performance of high glass transition temperature (165 °C), good thermal stability above 360 °C, and high flame retardancy (LOI = 30) to bisphenol-A-based epoxy resins. [A color version of the adjacent figure can be viewed in the online issue, which is available at]

    4. Crosslinking study of mixtures of DGEBA and 1,3-dioxan-2-one catalyzed by lanthanide triflates (pages 5799–5813)

      Roser Cervellera, Xavier Ramis, Josep Maria Salla, Ana Mantecón and Angels Serra

      Version of Record online: 13 OCT 2005 | DOI: 10.1002/pola.21046

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      Diglycidylether of bisphenol A was copolymerized with different proportions of 1,3-dioxan-2-one in the presence of ytterbium and lanthanum triflates to obtain networks with carbonate groups in their chemical structure. By Fourier transform infrared in the attenuated-total-reflection different processes were detected and by differential scanning calorimetry the kinetics of the curing were studied. The mechanical and thermal characteristics of the materials were evaluated.

    5. Multifunctional, water-soluble, C60-pendant maleic anhydride copolymer (pages 5814–5822)

      Gabriela Aldea, Gabrielle C. Chitanu, Jacques Delaunay, Jean-Michel Nunzi, Bogdan C. Simionescu and Jack Cousseau

      Version of Record online: 13 OCT 2005 | DOI: 10.1002/pola.21064

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      Starting from the synthesis of a new methanofullerene derivative bearing an alcohol group, we report on the preparation of a water-soluble, fullerene-pendant copolymer. This multifunctional, C60-pendant maleic anhydride copolymer was characterized by conductometric titration, Fourier transform infrared and ultraviolet spectroscopy, thermogravimetric analysis, and cyclic voltammetry.

    6. Design, syntheses, and characterization of new thermoplastic polyureas based on 3,4-ethylenedioxythiophene (pages 5823–5830)

      Uma P. Ojha, C. Ramesh and Anil Kumar

      Version of Record online: 13 OCT 2005 | DOI: 10.1002/pola.21065

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      New thermoplastic polyureas labeled PUn (n = 2, 3, 4, 6, 7, 9, or 10), based on 3,4-ethylenedioxythiophene (EDOT) with flexible aliphatic spacers, were synthesized and characterized for the first time. A comparison of the thermal properties of these polyureas with the corresponding phenyl analogue indicated that EDOT was a viable heteroatomic analogue of the phenyl group to be inserted into the main-chain polyureas without hampering their thermal stability. The polyureas with spacer lengths greater than hexamethylene formed transparent gels in N-methylpyrrolidone, 1,1,2,2-tetrachloroethane, and dimethyl sulfoxide.

    7. Efficient route to well-characterized homo, block, and statistical polymers containing terpyridine in the side chain (pages 5831–5843)

      Raja Shunmugam and Gregory N. Tew

      Version of Record online: 13 OCT 2005 | DOI: 10.1002/pola.21102

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      Atom transfer radical polymerization yields homo, statistical, and block copolymers of the activated ester. These polymers can be converted, under mild conditions, to incorporate terpyridine ligands.

    8. Synthesis and self-catalyzed phase transfer reaction of novel methacrylate polymers (pages 5844–5854)

      Bekir Dizman and Lon J. Mathias

      Version of Record online: 13 OCT 2005 | DOI: 10.1002/pola.21008

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      A novel methacrylate monomer with two functional groups was synthesized from ethyl α-chloromethylacrylate and 5-chlorovaleric. Homopolymerization and copolymerization with methyl methacrylate were performed using photoinitiator Irgacure 651® and AIBN. The polymers were reacted with N,N-dimethyldodecylamine to obtain polymers with pendant quaternary ammonium moieties, which were employed in self-catalyzed phase transfer reactions with sodium phenoxide and 1-dodecanethiol to give either pendant phenyl ether or thiol ether groups. These reactions demonstrate capability of this monomer to allow polymer modification with a variety of reactive nucleophiles.

    9. Metal-cation-induced chiroptical switching for poly(phenylacetylene) bearing a macromolecular ionophore as a graft chain (pages 5855–5863)

      Issei Otsuka, Ryosuke Sakai, Toshifumi Satoh, Ryohei Kakuchi, Harumi Kaga and Toyoji Kakuchi

      Version of Record online: 13 OCT 2005 | DOI: 10.1002/pola.21090

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      A poly(phenylacetylene) bearing a polycarbohydrate ionophore as a graft chain (copolymer 4) was synthesized by the copolymerization of end-functionalized (1[RIGHTWARDS ARROW]6)-2,5-anhydro-3, 4-di-O-ethyl-D-glucitol with a 4-ethynylbenzoyl group (macromonomer 2) with phenylacetylene (3). Copolymer 4 showed a split-type circular dichroism (CD) in the long absorption region of the conjugated polymer backbone (280–500 nm), and the CD pattern varied in response to external stimuli, such as the solvents and temperature. This suggested that 4 had a predominantly one-handed helical conformation in the polyacetylene backbone. The CD pattern of 4 was completely inverted by the formation of a complex between the macromolecular ionophore units and the selected metal cations, that is, Ba2+, Pb2+, Sr2+, Na+, and Li+. This suggested that copolymer 4 underwent a helix–helix transition through the host–guest complexation with achiral inorganic metal cations.

    10. Radical polymerization behavior of trimethoxyvinylsilane (pages 5864–5871)

      Makiko Seno, Makoto Hasegawa, Tomohiro Hirano and Tsuneyuki Sato

      Version of Record online: 13 OCT 2005 | DOI: 10.1002/pola.21026

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      TMVS shows a high homopolymerizability in the bulk polymerization with DCPO. The polymerization in dioxane exhibits a conventional kinetic behavior at 120 °C: Rp = k[DCPO]0.6[TMVS]1.0. The polymerization system involves ESR-observable polymer radicals under the actual polymerization conditions. ESR-determined apparent rate constants of propagation and termination are 13 L/mol s and 3.1 × 104 L/mol s at 120 °C. The molecular weight of resulting poly(TMVS) is limited by the chain transfers to the monomer and dioxane as solvent. TMVS also shows a high reactivity in the copolymerization with VAc at 120 °C.

    11. New asymmetric vanadium catalyst for highly selective oxidative coupling polymerization (pages 5872–5878)

      Shigeki Habaue, Soichiro Murakami and Hideyuki Higashimura

      Version of Record online: 13 OCT 2005 | DOI: 10.1002/pola.21077

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      Novel oxovanadium(IV)–bisoxazoline catalysts, such as VOSO4–(R)-2,2′-isopropylidenebis(4-phenyl-2-oxazoline), for the asymmetric oxidative coupling polymerization of 2,3-dihydroxynaphthalene were developed. The enantioselectivity during the polymerization was estimated to be 80% enantiomeric excess (S), a value much higher than that observed for the polymerizations with the Cu(I)-based catalyst systems and the typical VO(IV) catalysts reported for the asymmetric oxidative coupling producing the 1,1′-bi-2-naphthol derivatives.

    12. Radical polymeric photoinitiators bearing side-chain camphorquinone moieties linked to the main chain through a flexible spacer (pages 5879–5888)

      Luigi Angiolini, Daniele Caretti, Stefano Rossetti, Elisabetta Salatelli and Marco Scoponi

      Version of Record online: 14 OCT 2005 | DOI: 10.1002/pola.21055

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      New polymeric photoinitiators, bearing the side-chain camphorquinone moiety spaced from the backbone by a long and flexible connection, have been prepared and tested in the photocuring of acrylic monomers upon irradation with visible light.

    13. Synthesis of core-shell structured carboxylated microparticles with a straightforward procedure and their evaluation as a polymer support (pages 5889–5898)

      Ann-Christine Albertsson, Geta David, Clara Strandberg, Doina Bilba and Carmen Paduraru

      Version of Record online: 11 OCT 2005 | DOI: 10.1002/pola.21022

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      Core-shell structured carboxylated microparticles with controlled characteristics (size, size distribution, and functionality) were obtained, and their ability to act as a polymer support for metal ion retention or as an additive in polymer stabilization was demonstrated. The synthesis was performed by grafting acrylic acid on preformed poly(trimethylolpropane trimethacrylate) beads containing residual insaturated bonds, both steps being carried out by simple precipitation polymerization.

    14. Synthesis and crosslinking reaction of poly(hydroxyurethane) bearing a secondary amine structure in the main chain (pages 5899–5905)

      Bungo Ochiai, Jun-ichi Nakayama, Masayuki Mashiko, Yoshiro Kaneko, Tomomi Nagasawa and Takeshi Endo

      Version of Record online: 17 OCT 2005 | DOI: 10.1002/pola.21078

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      The polyaddition of bifunctional five-membered cyclic carbonates and diethylenetriamine proceeded via the selective addition of the primary amine moiety to give poly(hydroxyurethane)s bearing a secondary amine structure. The resulting polymers could be crosslinked by reactions of the remaining secondary amine structure.

    15. Tetramethylguanidino-tris(2-aminoethyl)amine: A novel ligand for copper-based atom transfer radical polymerization (pages 5906–5922)

      A. S. Brar and Sukhdeep Kaur

      Version of Record online: 11 OCT 2005 | DOI: 10.1002/pola.21076

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      The atom transfer radical polymerization (ATRP) of methyl methacrylate, n-butyl acrylate, styrene, and acrylonitrile was conducted with CuBr/tetramethylguanidino-tris(2-aminoethyl)amine (TMG3-TREN) as the catalyst. A well-controlled polymerization was attained even at a low catalyst concentration. CuBr/TMG3-TREN was successfully used for the polymerization of methyl methacrylate and acrylonitrile, although it was less efficient for styrene. This catalyst behaved very similarly to CuBr/tris[2-(dimethylamino)ethyl]amine for the homopolymerization of n-butyl acrylate. End-group analysis of the homopolymers was determined by NMR spectroscopy. The isotactic parameters calculated with 13C{1H} NMR spectra for all the synthesized homopolymers indicated that the tacticity remained the same as for other ATRP catalysts.

    16. Thermally responsive complex polymer networks containing Fe3O4 nanoparticles: Composition/morphology/property relationship (pages 5923–5934)

      Chia-Lung Lin and Wen-Yen Chiu

      Version of Record online: 11 OCT 2005 | DOI: 10.1002/pola.21079

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      A stable ferrofluid containing Fe3O4 nanoparticles was synthesized via a coprecipitation method in the presence of a poly(acrylic acid) oligomer. By the adjustment of the pH value, the ferrofluid could remain stable in the polymerization system and then formed complex polymer networks with redox initiators. The effects of several variables, such as the molar ratio of methacrylic acid to N-isopropylacrylamide, the concentrations of the monomers and crosslinking agent, the addition of an ammonium solution, and the content of the ferrofluid, on the morphology, structure, polymerization rate, and thermal properties of the complex polymer networks were discussed. The swelling and thermoresponsive behaviors of the complex polymer networks were also studied, and the composition–morphology–property relationship was established.

    17. Copolymers of 2,5-bis[(4-methoxyphenyl) oxycarbonyl]styrene with n-butyl acrylate: Design, synthesis, and characterization (pages 5935–5943)

      Long-Cheng Gao, Qi-Wei Pan, Yi Yi, Xing-He Fan, Xiao-Fang Chen and Qi-Feng Zhou

      Version of Record online: 17 OCT 2005 | DOI: 10.1002/pola.21110

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      A series of rod–coil diblock copolymers, consisting of poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} as a rigid segment and poly(n-butyl acrylate) as a flexible part, were successfully prepared through two inverse procedures by atom transfer radical polymerization. The copolymers were characterized by 1H NMR and gel permeation chromatography and had high molecular weights and relatively narrow polydispersities (polydispersity index < 1.20). All the block copolymers synthesized had two distinct glass-transition temperatures according to differential scanning calorimetry. A polarizing optical microscopy investigation demonstrated the liquid crystallinity of the diblock copolymers. The self-assembly behaviors in dilute solutions was studied by transmission electron microscopy.

    18. Highly active copolymerization of ethylene with 10-undecen-1-ol using phenoxy-based zirconium/methylaluminoxane catalysts (pages 5944–5952)

      Xiaofan Zhang, Shangtao Chen, Huayi Li, Zhicheng Zhang, Yingying Lu, Chunhong Wu and Youliang Hu

      Version of Record online: 17 OCT 2005 | DOI: 10.1002/pola.21105

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      Activated with methylaluminoxane (MAO), three phenoxy-based zirconium complexes (ac) for the first time have been used for the copolymerization of ethylene with 10-undecen-1-ol. In comparison with the conventional metallocene, the phenoxy-based zirconium complexes exhibit much higher catalytic activities [>107 g of polymer (mol of catalyst)−1 h−1]. The incorporation of 10-undecen-1-ol into the copolymers and the properties of the copolymers are strongly affected by the catalyst structure. Complex c is the most favorable for preparing higher molecular weight functionalized polyethylene containing a higher content of hydroxyl groups. Studies on the polymerization conditions indicate that the incorporated commoner content in the copolymers mainly depends on the comonomer concentration in the feed. The catalytic activity is slightly affected by the Al(MAO)/Zr molar ratio but decreases greatly with an increase in the polymerization temperature.

    19. Synthesis of novel crosslinkable polymers by atom transfer radical polymerization of cardanyl acrylate (pages 5953–5961)

      Kattimuttathu I. Suresh and M. Jaikrishna

      Version of Record online: 19 OCT 2005 | DOI: 10.1002/pola.21088

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      In this article, we report the successful application of Atom Transfer Radical Polymerization (ATRP) for the synthesis of crosslinkable copolymers of methyl methacrylate and cardanyl acrylate, a monomer obtained from a renewable resource. The unsaturation in the side chain of cardanyl acrylate is unaffected during polymerization, which can be later crosslinked, as confirmed by 1H NMR and DMTA studies. Incorporation of nearly 10 mol % cardanyl acrylate in the copolymer was found to improve the thermal stability of poly methyl methacrylate by about 35 °C.

    20. Matrix-assisted laser desorption/ionization time-of-flight analysis of the copolymerization reaction of an expanding monomer with a diepoxide (pages 5962–5970)

      Matthew D. Miller, Andrew J. Holder, Jill R. Guthrie, Charles S. Pinzino, Cecil C. Chappelow and J. David Eick

      Version of Record online: 17 OCT 2005 | DOI: 10.1002/pola.21109

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      Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used for product analysis of the photoinitiated cationic polymerization reaction between an expanding monomer [1,5,7,11-tetraoxaspiro[5.5]undecane (TOSU)] and a diepoxide [bisphenol A diglycidyl ether (BADGE)]. Peaks were found corresponding to the copolymerization with masses up to 2901 Da. The results indicated that a new competing mechanism participated in the polymerization, which formed a cyclic carbonate byproduct, in addition to the presumed mechanism for six-membered TOSU polymerization.

    21. Flame-retardant epoxy resins with high glass-transition temperatures. II. Using a novel hexafunctional curing agent: 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-yl-tris(4-aminophenyl) methane (pages 5971–5986)

      Ching Hsuan Lin, Sheng Xiong Cai and Chun Hung Lin

      Version of Record online: 18 OCT 2005 | DOI: 10.1002/pola.21072

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      A novel phosphorus-containing triamine (dopo-ta) was synthesized from the nucleophilic addition of 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide and pararosaniline chloride with triethylamine as an acid receiver. dopo-ta served as a curing agent for diglycidyl ether of bisphenol A (DGEBA) and dicyclopentadiene epoxy (hp7200). The glass-transition temperatures of cured DGEBA/dopo-ta and hp7200/dopo-ta were 171 and 190 °C, respectively. The dielectric constants for DGEBA/dopo-ta and hp7200/dopo-ta were 2.91 and 2.82, respectively, implying that the dopo-ta curing systems exhibited low dielectric properties. The dopo-ta curing systems also exhibited high flame retardancy.

    22. Synthesis of poly(p-methoxyphenylacetylene) with the vanadium acetylacetonate-aluminum triethyl Ziegler–Natta catalyst system: Cyclotrimers/polymer ratio analysis (pages 5987–5997)

      J. Gonzalo Rodríguez, Antonio Lafuente and Rosa Martín-Villamil

      Version of Record online: 19 OCT 2005 | DOI: 10.1002/pola.21052

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      Poly(p-methoxyphenylacetylene) was obtained by reaction of p-methoxyphenylacetylene (MOPA) with the V(acac)3-AlEt3 homogeneous catalyst system. The crude product was always a mixture of 1,2,4- and 1,3,5-tris(p-methoxyphenyl)benzene and poly(MOPA) of low averaged molecular weight. The 1,2,4- and 1,3,5-cyclotrimers vs. poly(MOPA) ratio was analyzed. The poly(MOPA) obtained under different conditions, on the basis of the spectroscopic data, always shows a cis–transoidal stereo-regular structure. Molecular mass of poly(MOPA) was determined by vapor pressure osmometry, HPLC, and GPC techniques. The kinetic of the reaction has been also analyzed.

    23. Studies on the modification of poly(ω-bromoalkyl-1-glycidylether)s with 4′-methoxybiphenyl-4-oxy mesogenic groups (pages 5998–6006)

      J. M. Montornés, J. A. Reina and J. C. Ronda

      Version of Record online: 17 OCT 2005 | DOI: 10.1002/pola.21054

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      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 with quantitative degrees of modification. Polymers that had alkyl spacers with n = 2 and 4 were smectic C, those with n = 6 and 8 were nematic cybotactic, and those that had longer spacers (n = 10 and 12) were smectic C again.

    24. Oligo(p-phenyleneethynylene)-based coil–rod–coil triblock copolymer: Synthesis and controlled self-organization in solution (pages 6007–6019)

      Kun Li, Liang Guo, Ziqi Liang, Pappannan Thiyagarajan and Qing Wang

      Version of Record online: 18 OCT 2005 | DOI: 10.1002/pola.21041

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      A coil–rod–coil triblock copolymer, polystyrene–oligo(p-phenyleneethynylene)–polystyrene, has been prepared and characterized. This triblock copolymer exhibits unique solvatochromatic behaviors through the interplay of aggregation-induced π–π stacking and planarization of the conjugated backbone. It has been demonstrated that the use of the solvent composition to influence chain conformations and thus to manipulate the packing of the conjugated polymer blocks is important for achieving control in the assembly of conducting polymers and associated optical characteristics.

    25. Synthesis and characterization of novel aromatic poly(imide–benzoxazole) copolymers (pages 6020–6027)

      Steve Lien-Chung Hsu, Guo-Wei Luo, Hui-Tzu Chen and Shih-Wei Chuang

      Version of Record online: 18 OCT 2005 | DOI: 10.1002/pola.21093

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      A new route has been invented to prepare novel poly(imide–benzoxazole) copolymers through the reaction of a dianhydride, a diacid chloride, and a bis(o-diaminophenol) monomer in a two-step method. The poly(imide–benzoxazole) copolymers have high glass-transition temperatures, high thermal and thermooxidative stabilities, good chemical resistance, and low water absorption. They are suitable for use in electrical and electronic applications.

    26. The ligand effect in Ti-mediated living radical styrene polymerizations initiated by epoxide radical ring opening. 1. Alkoxide and bisketonate Ti complexes (pages 6028–6038)

      Alexandru D. Asandei and Isaac W. Moran

      Version of Record online: 18 OCT 2005 | DOI: 10.1002/pola.20972

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      Bisketonate and alkoxide Ti complexes were evaluated in the living radical polymerization (LRP) of styrene initiated by Ti-catalyzed epoxide radical ring opening and mediated by reversible termination with Ti(III). Although akoxides performed much better than bisketonates and provided LRP over a wide range of experimental conditions, the Mw/Mn could not be reduced below 1.4 and the initiator efficiency was only about 0.15. These results were rationalized in terms of a combination of decreased Ti oxophilicity and ligand exchange.

    27. The ligand effect in Ti-mediated living radical styrene polymerizations initiated by epoxide radical ring opening. 2. Scorpionate and half-sandwich LTiCl3 complexes (pages 6039–6047)

      Alexandru D. Asandei and Isaac W. Moran

      Version of Record online: 19 OCT 2005 | DOI: 10.1002/pola.20970

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      The ligand effect and the reaction conditions for the living radical polymerization of styrene initiated by epoxide radical ring opening was investigated in a series of piano-stool, Ti(IV) scorpionate, and half-sandwich metallocenes (LTiCl3; L = Tp, Cp*, Ind and Cp). On the basis of a combination of steric and electronic properties, the Ti ligands rank as Cp ≥ Ind ≫ Cp* ≫ Tp, with an optimum for epoxide/CpTiCl3/Zn = 1/2/4 at 70–90 °C.

    28. Thermosensitive gel formation of novel polypeptides containing a collagen-derived Pro-Hyp-Gly sequence and an elastin-derived Val-Pro-Gly-Val-Gly sequence (pages 6048–6056)

      Yasushi Morihara, Shin-Ichi Ogata, Masanobu Kamitakahara, Chikara Ohtsuki and Masao Tanihara

      Version of Record online: 18 OCT 2005 | DOI: 10.1002/pola.21097

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      Copolymers of (Pro-Hyp-Gly)10 and Val-Pro-Gly-Val-Gly showed an inverse phase transition in response to a rise in temperature. Furthermore, copolymers containing 82–86 mol % of Val-Pro-Gly-Val-Gly in composition showed reversible gel formation, suggesting that (Pro-Hyp-Gly)10 acts as a hydrated unit and Val-Pro-Gly-Val-Gly acts as a thermosensitive crosslinking point.

    29. Synthesis and characterization of multifunctional polymers via atom transfer radical polymerization of N-(ω′-alkylcarbazolyl) methacrylates initiated by Ru(II) polypyridyl chromophores (pages 6057–6072)

      Abdiaziz A. Farah and William J. Pietro

      Version of Record online: 18 OCT 2005 | DOI: 10.1002/pola.21027

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      Ru (II) complexes with radical initiating sites were employed in the presence of NiBr2(PPh3)2 as a catalyst for the atom transfer radical polymerization (ATRP) of functional (N-(ω′-alkylcarbazoly) methacrylates) to provide linear and three-dimensional metallopolymers with the metal chromophores at well-defined loci of the polymer chain. These polymers were characterized by gel permeation chromatography (GPC) in combination with low-angle laser light-scattering (LALLS), UV–vis, and emission spectroscopy to verify the multichromophoric nature of the polymer chain. The polymers thermal transitions and thermal stabilities were also investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).

    30. Synthesis of sequence-controlled copolymers from extremely polar and apolar monomers by living radical polymerization and their phase-separated structures (pages 6073–6083)

      Yuuki Inoue, Junji Watanabe, Madoka Takai, Shin-ichi Yusa and Kazuhiko Ishihara

      Version of Record online: 18 OCT 2005 | DOI: 10.1002/pola.21095

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      A series of copolymers with a controlled monomer unit sequence containing 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2,2,2-trifluoroethyl methacrylate (TFEMA) were synthesized by a reversible addition-fragmentation chain transfer (RAFT) living radical polymerization. The gradient copolymer, which has a continuous change in the monomer unit composition along the polymer chain, was synthesized as well as random and block copolymers. The thermal analysis and surface characterizations indicated the gradient sequence in the polymer chain would influence on the phase-separated structure in the bulk and surface structure. We believed the gradient sequence in the polymer chain could be a novel parameter for the biomaterials architecture.

    31. Molecular mobility of free-radical-functionalized carbon-nanotube/siloxane/poly(urea urethane) nanocomposites (pages 6084–6094)

      Han-Lang Wu, Yu-Ting Yang, Chen-Chi M. Ma and Hsu-Chiang Kuan

      Version of Record online: 18 OCT 2005 | DOI: 10.1002/pola.21121

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      Poly(urea urethane) (PUU) was end-capped with aminopropyltriethoxysilane (A-silane) or phenyltriethoxysilane (P-silane). A-silane-end-capped PUU was covalently bonded to functionalized MWNTs, whereas P-silane-end-capped PUU was noncovalently bonded to pristine MWNTs by a π–π interaction. Fourier transform infrared, Raman spectra, and thermogravimetric analysis confirmed the functionalization of MWNTs. The results showed that the optimal reaction time of the functionalization of MWNT was 8 h, and the organic content of the modified carbon nanotubes reached 35.22%.

    32. Thermoresponsive copolymers of methacrylic acid and poly(ethylene glycol) methyl ether methacrylate (pages 6095–6104)

      Janevieve A. Jones, Noel Novo, Kendra Flagler, Christina D. Pagnucco, Steve Carew, Charles Cheong, Xiang Z. Kong, Nicholas A. D. Burke and Harald D. H. Stöver

      Version of Record online: 17 OCT 2005 | DOI: 10.1002/pola.21099

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      Copolymers of methacrylic acid (MAA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) were prepared and their cloud points in aqueous solution were studied as a function of comonomer ratio, solution pH, and presence of hydrophobic comonomers. Under acidic conditions, the cloud point falls below 0 °C for copolymers with between 25% to 60% ether content, because of the formation of hydrophobic H-bonded ether–acid complexes. The cloud point also decreases with solution pH. For equivalent ether to acid ratios, the cloud point decreases with decreasing PEG chain length, because of the presence of a larger number of hydrophobic methyl and methacrylate groups. Similarly, the cloud point decreases upon incorporation of hydrophobic comonomers such as butyl, lauryl, or glycidyl methacrylates.

    33. Synthesis and characterization of carbon nanotube/polypyrrole core–shell nanocomposites via in situ inverse microemulsion (pages 6105–6115)

      Yijun Yu, Chu Ouyang, Yun Gao, Zhihuai Si, Wei Chen, Zhaoqun Wang and Gi Xue

      Version of Record online: 17 OCT 2005 | DOI: 10.1002/pola.21114

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      The general strategy for preparation of multiwalled carbon nanotube (MWNT)/polypyrrole (PPy) core–shell nanowires by in situ inverse microemulsion is illustrated.

    34. Star-shaped poly(L-lactide)s with variable numbers of hydroxyl groups at polyester arms chain-ends and directly attached to the star-shaped core—Controlled synthesis and characterization (pages 6116–6133)

      Tadeusz Biela, Andrzej Duda, Harald Pasch and Karsten Rode

      Version of Record online: 17 OCT 2005 | DOI: 10.1002/pola.21035

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      Star-shaped poly(L-lactide)s (PLA's) bearing variable numbers of secondary hydroxyl groups at linear arms chain-ends and primary hydroxyl groups directly attached to dipentaerithritol core (DPE) ((HO)6x DPE(PLA-OH)x, where x = 1 – 6) were prepared and then analyzed by means of size exclusion chromatography (SEC), 1H NMR spectroscopy, MALDI-TOF mass spectrometry, and by liquid chromatography at critical conditions (LC-CC). The latter measurements revealed that for (BnO)6x DPE(PLA-OH)x series the elution volumes increase monotonically with the increasing number of –PLA-OH arms in one macromolecule. Contrary to the polymers having the protected core hydroxyl groups, the elution volume for (HO)6x DPE(PLA-OH)x series decreases with the increasing number of -PLA-OH arms reaching a minimum value for 4-arm PLA and then slightly increases for 5- and 6-arm PLA.

    35. Synthesis and metathesis activity of ruthenium dimethylvinyl carbene complexes (pages 6134–6145)

      Stephen E. Lehman Jr., Kenneth B. Wagener and Shahab Akvan

      Version of Record online: 17 OCT 2005 | DOI: 10.1002/pola.20965

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      Two new dimethylvinyl carbene complexes, RuCl2 (SIMes) (PPh3)CHCHC(CH3)2 and RuCl2(SIMes)(3BP)2CHCHC(CH3)2, were synthesized from RuCl2(PCp3)2CHCHC(CH3)2. Acyclic diene metathesis (ADMET) polymerization of 1,9-decadiene with these catalysts was found to give results similar to those obtained with Schrock's molybdenum catalyst. These complexes are also catalysts for ring-opening metathesis polymerization (ROMP).

    36. Preparation, characterization, and thermal properties of alt-copoly[1,9-decaphenylpentasiloxanylene/1,3-bis(ethylene)permethyloligosiloxanylene]s (pages 6146–6152)

      Nam S. Lee, Thomas M. Gädda and William P. Weber

      Version of Record online: 17 OCT 2005 | DOI: 10.1002/pola.21043

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      alt-Copoly[1,9-decaphenylpentasiloxanylene/1,3-bis(ethylene) permethyloligosiloxanylene]s were synthesized by Pt-catalyzed hydrosilylation reactions of 1,9-divinyldecaphenylpentasiloxane with a series of oligodimethylsiloxanes. The copolymers were highly thermally stable by thermogravimetric analysis. The structures of the copolymers were verified by 1H, 13C, and 29Si NMR spectroscopy.

    37. Synthesis of poly(dimethylsiloxane)-containing diblock and triblock copolymers by the combination of anionic ring-opening polymerization of hexamethylcyclotrisiloxane and nitroxide-mediated radical polymerization of methyl acrylate, isoprene, and styrene (pages 6153–6165)

      Yozo Miura and Kazuki Miyake

      Version of Record online: 18 OCT 2005 | DOI: 10.1002/pola.21059

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      Lithiation of the 4-bromophenyl group-carrying TIPNO-based alkoxyamine and subsequent anionic ring-opening polymerization of D3 gave functional poly(D3). Nitroxide-mediated radical polymerization (NMRP) of methyl acrylate (MA), isoprene (IP), and styrene (St) from the functional poly(D3) gave poly(D3-b-MA), poly(D3-b-St), and poly(D3-b-IP) diblock copolymers with narrow polydispersities below 1.2. Moreover, poly(D3-b-MA-b-St) and poly(D3-b-IP-b-St) triblock copolymer were obtained via NMRP of St from the poly(D3-b-MA) and poly(D3-b-IP).

    38. Acyclic diene metathesis polymerization of 2,5-dialkyl-1,4-divinylbenzene with molybdenum or ruthenium catalysts: Factors affecting the precise synthesis of defect-free, high-molecular-weight trans-poly(p-phenylene vinylene)s (pages 6166–6177)

      Kotohiro Nomura, Yoshitaka Miyamoto, Hisao Morimoto and Yves Geerts

      Version of Record online: 18 OCT 2005 | DOI: 10.1002/pola.21104

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      The synthesis of structurally regular (all-trans), defect-free, high-molecular-weight poly(p-phenylene vinylene)s with both unimodal molecular weight distributions [degree of monomer repeating unit (DPn) = ca. 16–70 by 1H NMR, weight-average molecular weight/number-average molecular weight = 1.61 − 2.06)] and controlled polymer chain ends (as a vinyl group, [BOND]CH[DOUBLE BOND]CH2) was achieved by the acyclic diene metathesis polymerization of 2,5-dialkyl-1,4-divinylbenzene with Ru(CHPh)(Cl)2(IMesH2)(PCy3) or Ru(CH-2-OiPr-C6H4)(Cl)2(IMesH2) [IMesH2 = 1,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene] as a catalyst at 50 °C.