Journal of Polymer Science Part A: Polymer Chemistry

Cover image for Vol. 47 Issue 21

1 November 2009

Volume 47, Issue 21

Pages 5565–5927

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      Recent advancement on polybenzoxazine—A newly developed high performance thermoset (pages 5565–5576)

      Yusuf Yagci, Baris Kiskan and Narendra Nath Ghosh

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/pola.23597

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      Polybenzoxazine is a newly developed addition polymerized phenolic system, having a wide range of interesting features and the capability to overcome several shortcomings of conventional novolac and resole type phenolic resins. Though benzoxazine-based materials possess several advantages, preparation of polybenzoxazine with good mechanical property and processibility is still a major challenge. In this article, we have discussed about the recent development of benzoxazine chemistry. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

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    1. New efficient reaction media for SET-LRP produced from binary mixtures of organic solvents and H2O (pages 5577–5590)

      Nga H. Nguyen, Brad M. Rosen, Xuan Jiang, Sven Fleischmann and Virgil Percec

      Version of Record online: 10 SEP 2009 | DOI: 10.1002/pola.23665

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      SET-LRP of MA in a library of solvents with different equilibrium constants for disproportionation of Cu(I)X such as DMSO, DMF, DMAC, EC, PC, EtOH, MeOH, methoxyethanol, NMP, acetone and in their binary mixtures with H2O is reported. The apparent rate constant of the polymerization exhibits a linear increase with the addition of H2O, consistent with higher equilibrium constants for disproportionation generated by addition of H2O. Furthermore, the rate constant of polymerization could be correlated with the Dimroth-Reichardt solvent polarity parameter (shown above). This is consistent with the single-electron transfer mechanism proposed for SET-LRP that involves a polar transition state. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    2. Cooperative and synergistic solvent effects in SET-LRP of MA (pages 5591–5605)

      Xuan Jiang, Sven Fleischmann, Nga H. Nguyen, Brad M. Rosen and Virgil Percec

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/pola.23689

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      SET-LRP of MA in binary mixtures of DMSO, DMAC, DMF, and ethyl acetate with acetone, ethylene carbonate, and methanol are reported. As with binary mixtures of organic solvents and water the apparent rate constant of propagation scales linearly with polarity of the medium for most ranges of composition. However, at higher volume fractions of ethylene carbonate or methanol deviations are observed indicating that the kinetics and control of SET-LRP is cooperatively and synergistically controlled by a variety of parameters including solvent polarity, degree of disproportionation, and the ability of the solvent to stabilize Cu(0) and control its particle size. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    3. The disproportionation of Cu(I)X mediated by ligand and solvent into Cu(0) and Cu(II)X2 and its implications for SET-LRP (pages 5606–5628)

      Brad M. Rosen, Xuan Jiang, Christopher J. Wilson, Nga H. Nguyen, Michael J. Monteiro and Virgil Percec

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/pola.23690

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      Disproportionation of Cu(I)X is the major step in SET-LRP. UV–vis experiments reveal that disproportionation is dependent on solvent composition and concentration of ligand. Exemplified by DMSO, disproportionation can be up to four-orders of magnitude greater than the value reported from electrochemistry experiments. UV–vis and DLS demonstrate that some solvents including DMSO stabilize colloidal Cu(0), while others facilitate agglomeration. Ligand concentration and solvent composition determine particle size distribution. Therefore, the kinetics of SET-LRP are cooperatively and synergistically determined by solvent polarity, the extent of disproportionation in the solvent/ligand mixture, and its ability to stabilize colloidal Cu(0) and control its size distribution. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    4. The effect of ligand on the rate of propagation of Cu(0)-wire catalyzed SET-LRP of MA in DMSO at 25 °C (pages 5629–5638)

      Nga H. Nguyen, Xuan Jiang, Sven Fleischmann, Brad M. Rosen and Virgil Percec

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/pola.23691

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      The effect of initial ligand concentration on the apparent rate constant of propagation of SET-LRP of MA in DMSO at 25 °C is examined using various lengths of Cu(0) wire as catalyst. The response of the rate of SET-LRP to initial ligand concentration is complex and is likely determined by a competition of ligand-dependent extent of disproportionation as well as the role of ligand concentration in the surface mediated activation process. Results suggest that a minimum concentration of ligand is needed to achieve both acceptable reaction rate and reaction control, and therefore, ligand concentration must be considered in designing experimental conditions for SET-LRP. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    5. Redox initiated cationic polymerization: Reduction of diaryliodonium salts by 9-BBN (pages 5639–5651)

      James V. Crivello

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/pola.23605

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      Diaryliodonium salts undergo facile reduction by the dialkylborane, 9-BBN. The combination of these two reagents constitutes a redox couple that can be employed as a convenient and versatile initiator system for the cationic polymerizations of styrenic monomers, vinyl ethers and the ring-opening polymerizations of epoxides, oxetanes and 1,3,5-trioxane. Studies of the effects of variations in the structure and concentrations of the diaryliodonium salt and 9-BBN on the polymerizations of various monomers were carried out. A mechanism for the redox cationic initiation of the polymerizations was proposed.

    6. Postfunctionalization of poly(propargyl methacrylate) using copper catalyzed 1,3-dipolar Huisgen cycloaddition: An easy route to electro-optic materials (pages 5652–5660)

      Annabelle Scarpaci, Clement Cabanetos, Errol Blart, Véronique Montembault, Laurent Fontaine, Vincent Rodriguez and Fabrice Odobel

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/pola.23606

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      Electro-optic polymers were prepared by clicking two different azido-functionalized moieties on an acetylated polymer using copper-catalyzed Huisgen 1,3-dipolar cycloaddition. The bulky adamantyl units raise the glass transition temperature of the polymers and enhance the poling efficiency compared with conventional methacrylate Disperse Red One-containing polymers. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    7. Thermally stable red electroluminescent hybrid polymers derived from functionalized silsesquioxane and 4,7-bis(3-ethylhexyl-2-thienyl)-2,1,3-benzothiadiazole (pages 5661–5670)

      Yang Xiao, Xuehong Lu, Li-Wei Tan, K.S. Ong and Chaobin He

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/pola.23608

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      Hyperbranched hybrid conjugated polymer P1 was prepared via FeCl3-oxiditive polymerization of 4,7-bis(3-ethylhexyl-2-thienyl)-2,1,3-benzothiadiazole and octa(3-ethylhexyl-2-thienyl-phenyl)POSS. Compared to linear polymer PM, P1 shows much higher PL quantum efficiency in condensed state with improved thermal stability. While the electroluminescent spectra of both P1 (in red) and PM (in green) show λmax at 660 nm, P1 exhibits a much narrower EL spectrum and higher electroluminescence (∼500%) compared with PM at same voltage, film thickness, and device figure. The maximum current efficiency of P1 is more than seven times of that of PM. The turn-on voltage of P1 is lower than that of PM. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    8. Synthesis, structure, and property of well-defined polymethylene-based diblock copolymers by a combination of living polymerization of ylides and atom transfer radical polymerization (pages 5671–5681)

      Jian-Zhuang Chen, Qiao-Ling Zhao, Li-Ping Shi, Jin Huang, Guang-Yu Li, Shu-Yuan Zhang and Zhi Ma

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/pola.23609

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      A combination of living polymerization of ylides and atom transfer radical polymerization (ATRP) was used successfully in the design and synthesis of well-defined polymethylene-b-poly(methyl methacrylate) (PM-b-PMMA) and polymethylene-b-poly(n-butyl acrylate) (PM-b-n-BuA). The precipitated PM-b-PMMA micelles formed in toluene were characterized by atomic force microscopy (AFM). The scanning electron microscopy (SEM) images showed that the compatibilization of LDPE /PMMA blend was improved greatly by the incorporation of PM-b-PMMA. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    9. Polyethersulfone-epoxy terminated materials as thermosetting resins for microelectronic devices (pages 5682–5689)

      Emilio Scamporrino, Placido Mineo, Andrea Scamporrino, Sandro Dattilo, Daniele Vitalini and Rossana Alicata

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/pola.23611

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      SEM image of a cross-section of assembled chip-on-chip device. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    10. Structure–property relationship of octa-substituted POSS in thermal and mechanical reinforcements of conventional polymers (pages 5690–5697)

      Kazuo Tanaka, Shigehiro Adachi and Yoshiki Chujo

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23612

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      We report the structure–property relationships between the POSS fillers and thermomechanical properties of the polymer composites using several conventional polymers. It was shown that the longer alkyl chains and unsaturated bonds at the side chains in POSS are favorable to improve thermal stability and elasticity of polymer matrices. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    11. Novel anionic polyaddition of 2-trifluoromethylacrylate by double Michael reaction with ethyl cyanoacetate (pages 5698–5708)

      Youhei Umino, Hiroshi Nozaki, Hiroshi Hamana and Tadashi Narita

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23613

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      Novel fluorinated polymer synthesis with anionic polyaddition by double Michael addition reaction of 2-trifluoromethylacrylate derivatives with ethyl cyanoacetate (ECA) was proposed. Novel anionic polyaddition of 1,4-phenylene bis(2-trifluoromethylacrylate) [CH2=C(CF3)COOC6H4OCOC (CF3)=CH2] (PBFA) with ECA afforded the polymer of 1.2 × 104 as the highest molecular weight. A polymer of 2.8 × 104 as a molecular weight was obtained by the reaction of isolated polymer with PBFA in the presence of sodium ethoxide. The reaction mechanism that the proton abstraction from ECA followed by the addition of 2-trifluoromethylacrylate was proposed. The polyaddition reaction of acetylacetone with PBFA was also examined to give the polymer of 7.6 × 103.

    12. A non-PFT (polymerization filling technique) approach to poly(ethylene-co-norbornene)/MWNTs nanocomposites by in situ copolymerization with scandium half-sandwich catalyst (pages 5709–5719)

      Andrea Ravasio, Laura Boggioni, Incoronata Tritto, Cristina D'arrigo, Angelo Perico, Julia Hitzbleck and Jun Okuda

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23614

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      Well deaggregated MWNTs coated with P(E-co-N) were prepared in situ by the scandium half-sandwich precatalyst [Sc(η5-C5Me4SiMe3)(η1-CH2SiMe3)2(THF)] activated by [Ph3C][B(C6F5)4]. Small amounts of AliBu3 prevent catalyst poisoning and allow tuning of N content, microstructure, and the material properties of the copolymer.

    13. Influences of steric bulkiness in hydrotris(pyrazolyl)borate ligands on ethylene polymerization reaction (pages 5720–5727)

      Masaaki Nabika, Seiki Kiuchi, Tatsuya Miyatake and Kiyoshi Fujisawa

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23616

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      Manganese(II) complexes with hydrotris(pyrazolyl)borate ligands have been examined on their catalytic performance in ethylene polymerization and ethylene/1-hexene copolymerization. The activities of [Mn(TpPh,Me)(Cl)(NCMe)] (1) and [Mn(TpAd,i-Pr)(Cl)] (2) activated by Al(i-Bu)3/[Ph3C][B(C6F5)4] for ethylene polymerization go up to 326 and 11 kg mol (cat−1) h−1, respectively. In particular, for ethylene/1-hexene copolymerization, complex 1 gives high-molecular-weight poly(ethylene-co-1-hexene)s with the highest Mw of 439,000 in manganese(II) olefin polymerization catalyst systems.

    14. Effect of an anionic monomer on the pickering emulsion polymerization stabilized by titania hydrosol (pages 5728–5736)

      Xiaomei Song, Guannan Yin, Yongliang Zhao, Haitao Wang and Qiangguo Du

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23617

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      The article presents the synthesis of polystyrene (PS)/titania nanocomposite particles with well-defined core-shell structure obtained from a photocatalytic Pickering emulsion polymerization. A self-made anatase titania hydrosol modified by an anionic monomer sodium styrene sulfonate (NaSS) is used as a stabilizer and photocatalyst. The effect of NaSS content on the emulsion stability and the morphology of the final composite spheres are studied extensively. Colloidal particles have the diameter of around 120 nm and the titania content of the composite spheres is up to about 20 wt %. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    15. Development of reactive phosphonated methacrylates (pages 5737–5746)

      Seda Edizer, Gorkem Sahin and Duygu Avci

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23618

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      Five phosphonated-methacrylate monomers (15) were successfully synthesized from (i) reactions of two o-hydroxyaryl phosphonates with methacryloyl chloride, (ii) two stepwise reactions of α-(chloromethyl)acryloyl chloride (CMAC) with a phosphonated alcohol followed by an acid, and (iii) reaction of CMAC with two moles of phosphonated alcohol. The synthesized monomers showed high reactivity during homo- and copolymerizations to give polymers with pendant phosphonate groups. The maximum rate of polymerizations decreased in the following order: Bis-GMA∼3 > 1 > 4 > 5. It is possible to increase reactivity of CMAC-based monomers by changing the substituents, aromatic substituents being more reactive than aliphatic ones. The homopolymers and copolymers produced char on burning indicating their potential as flame-retardant materials.

    16. Synthesis of polyester having pendent hydroxyl groups via regioselective dehydration polycondensations of dicarboxylic acids and diols by low temperature polycondensation (pages 5747–5759)

      Yosuke Shibata and Akinori Takasu

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23619

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      In this article, we describe the one-step synthesis of polyesters having pendent hydroxyl groups by Lewis acid-catalyzed, regioselective, dehydration polycondensations of diols (glycerol and sorbitol) and dicarboxylic acids [tartaric acid (TA) and malic acid (MA)] containing pendent hydroxyl groups, using low-temperature polycondensation technique. Direct polycondensations of TA or MA and 1,9-nonanediol catalyzed by scandium trifluoromethanesulfonate [Sc(OTf)3] successfully yielded linear polyesters having hydroxyl functionality (Mn = ca. 1.0 × 104). Poly(nonamethylene L-malate) showed significant higher biodegradability, compared with poly(nonamethylene L-tartrate) or poly(nonamethylene succinate). Furthermore, direct polycondensations of TA and diethylene glycol (DEG) or triethylene glycol (TEG) successfully produced water-soluble polyesters having hydroxyl groups. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    17. Fatty acid derived phosphorus-containing polyesters via acyclic diene metathesis polymerization (pages 5760–5771)

      Lucas Montero De Espinosa, Juan C. Ronda, Marina Galià, Virginia Cádiz and Michael A.R. Meier

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23620

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      The acyclic diene metathesis (ADMET) polymerization of a phosphorus-containing α,ω-diene prepared with a plant oil derived building block is reported. Different ruthenium based metathesis catalysts and conditions were tested to optimize the ADMET polymerization of this new monomer. Undecylenyl undecenoate was used as comonomer to obtain polyesters with different phosphorus contents and to increase the renewable part of the final polymers. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    18. Naphthalene-based poly(arylene ether ketone) copolymers containing sulfobutyl pendant groups for proton exchange membranes (pages 5772–5783)

      Ke Shao, Jing Zhu, Chengji Zhao, Xianfeng Li, Zhiming Cui, Yang Zhang, Hongtao Li, Dan Xu, Gang Zhang, Tiezhu Fu, Jing Wu, Hui Na and Wei Xing

      Version of Record online: 8 SEP 2009 | DOI: 10.1002/pola.23621

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      A new monomer 1,5-bis(4-fluorobenzoyl)-2,6-dimethoxylnaphthalene (DMNF) was prepared and further polymerized to form naphthalene-based poly(arylene ether ketone) copolymers containing methoxy groups (MNPAEKs). The side-chain-type sulfonated naphthalene-based poly(arylene ether ketone) copolymers (SNPAEKs) were obtained by demethylation and sulfobutylation. The IEC (0.99–1.82 mequiv/g) of the SNPAEKs can be readily controlled and the SNPAEK-xx membranes exhibited low methanol permeability, lower water swelling, and high proton conductivity and could be the promising materials as alternative to Nafion membrane for DMFC applications.

    19. Strong activation of MgCl2-supported Ziegler-Natta catalysts by treatments with BCl3: Evidence and application of the “cluster” model of active sites (pages 5784–5791)

      David Ribour, Vincent Monteil and Roger Spitz

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23622

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      Heterogeneous Ziegler-Natta precatalysts were modified by treatments with boron compounds such as BCl3 before their use in the polymerization of propylene. Performed on previously “detitanated” or unmodified precatalysts, the treatment leads to a strong increase of productivity without drastic modifications of polypropylenes properties (tacticity, molecular weight distribution). In addition, this new simple and versatile activation process of Ziegler-Natta catalysts can be rationalized by the formation of heteronuclear B-Ti clusters and seems to confirm the hypothesis of a “cluster” organization of active sites at the catalyst surface. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    20. Enzymatic ring-opening polymerization of ε-caprolactone by Yarrowia lipolytica lipase in ionic liquids (pages 5792–5805)

      Karla A. Barrera-Rivera, Ángel Marcos-Fernández, Ricardo Vera-Graziano and Antonio Martínez-Richa

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23623

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      Catalytic site of lipase is known to be a serine-residue. The key step is the reaction of lactone with lipase involving the ring opening of the lactone to give an enzyme intermediate. The initiation is a nucleophilic attack of water, contained in the enzyme, onto the acyl carbon of the intermediate to produce the shortest propagating species. Lipase catalyzed ring-opening polymerizations in ionic liquids proceeded with markedly enhanced activity. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    21. Porous polyurethanes synthesized within high internal phase emulsions (pages 5806–5814)

      Dganit David and Michael S. Silverstein

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23624

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      Highly porous polyurethanes were successfully synthesized within high internal phase emulsions (HIPE) using a step-growth polymerization reaction. The isocyanate reacted with a poly(ε-caprolactone) triol to produce polyurethane and with the water in the HIPE to produced urea and CO2 bubbles. The polymer walls separating the CO2 bubbles had a porous, emulsion-templated structure. Polymerization with an excess of isocyanate yielded significant enhancements in the urea and CO2 contents and produced an increase in wall modulus that was over 20-fold. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    22. Methacrylated dendrimers in thiol-methacrylate networks and the effect of conversion on the thermoset properties (pages 5815–5826)

      Camilla Nilsson, Eva Malmström, Mats Johansson and Stacy M. Trey

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23625

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      This article describes the synthesis of methacrylate functional polyester dendrimers of generation 1 through 4 by the divergent approach, by functionalization of the hydroxyl groups by methacrylic anhydride in the last step. These materials are further investigated once incorporated into photo-cured methacrylate-thiolene-based networks and compared with the properties of allyl ether-thiolene networks previously reported by the authors. The large extent of methacrylate homopolymerization allows for tuning the amount of residual thiol in the film for use in further chemistries, with less residual thiol as the dendrimer functionality increases in the film. Through comparison of two different thiols in the thiol-methacrylate films, the thermal properties can be tuned by the character of the thiol monomer. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    23. Sulfonated poly(ether sulfone)s with binaphthyl units as proton exchange membranes for fuel cell application (pages 5827–5834)

      Kazuya Matsumoto, Taijiro Nakagawa, Tomoya Higashihara and Mitsuru Ueda

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23627

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      Sulfonated poly(ether sulfone)s containing binaphthyl units (BNSHs) were successfully prepared for fuel cell applications. BNSH-100 (IEC = 3.19 mequiv/g) showed excellent proton conductivity, which was comparable to or even higher than that of Nafion 117, over a range of 30–50% RH at 80 °C. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    24. Synthesis of hyperbranched poly(ether nitrile)s by one-step polycondensation of an AB2 monomer (pages 5835–5844)

      Mitsutoshi Jikei, Hideaki Itoh, Norihiro Yoshida, Yosuke Inai, Teruaki Hayakawa and Masa-Aki Kakimoto

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23629

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      Hyperbranched poly(ether nitrile)s were prepared from a novel AB2 type monomer via nucleophilic aromatic substitution. Soluble and low-viscous hyperbranched polymers with molecular weights upto 233,600 (Mw) were isolated. 1H NMR and GPC data indicated that the weight average molecular weight increased after the number average molecular weight reached plateau region. The ether exchange reaction and cyclization occurred during the polymerization would affect the unique polymerization behavior. The resulting polymers showed a good solubility in organic solvents similar to other hyperbranched aromatic polymers. The hydroxy-terminated polymer was even soluble in basic water.

    25. Association phenomena of the ferrocenylsiloxane polyamide in solution (pages 5845–5852)

      Maria Cazacu, Carmen Racles, Anton Airinei, Mihaela Alexandru and Angelica Vlad

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23630

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      A segmented ferrocene-siloxane polyamide has been investigated by tensiometry, viscometry, and UV–vis spectrophotometry in solution at different concentrations and temperatures. Sharp changes in the dependences of the measured characteristics suggest a self-organization of the polymer occurring in dimethylformamide at critical concentrations or temperatures. Micelles or micellar aggregates are formed as emphasized by dynamic light scattering and scanning electron microscopy. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    26. Degradable polymer networks and star polymers based on mixtures of two cleavable dimethacrylate crosslinkers: Synthesis, characterization, and degradation (pages 5853–5870)

      Efrosyni Themistou and Costas S. Patrickios

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23631

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      Polymer networks and star polymers of methyl methacrylate (MMA, white color) bearing a hydrolyzable (gray color) and a thermolyzable (black color) dimethacrylate crosslinkers were synthesized by group transfer polymerization. All randomly crosslinked polymer networks and star polymers based on mixtures of these two cleavable under different conditions crosslinkers gave THF-soluble final products when applying sequential thermolysis and hydrolysis, in this order. When subjected to sequential hydrolysis and thermolysis, only the star polymers containing a thermolyzable crosslinker content equal to or higher than 50% resulted in THF-soluble final products.

    27. Low temperature polymerization of novel, monotropic liquid crystalline benzoxazines (pages 5871–5881)

      Pedro Velez-Herrera and Hatsuo Ishida

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23632

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      Liquid crystalline benzoxazine resins have been developed for the first time. The resins exhibit nematic liquid crystalline phase only during the cooling process, corresponding to monotropic liquid crystalline behavior. Polymerization of benzoxazine groups occurs at much lower temperature than ordinary benzoxazine resins without an added initiator or catalyt despite their good purity. This phenomenon is observed above the liquid crystalline transitions. The resultant polybenzoxazines do not exhibit liquid crystalline structure due to the interference of the hydrogen bonding. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    28. Preparation of three-dimensional poly(dimethylsiloxane) (PDMS) with movable cross-linking (pages 5882–5890)

      Kazuya Miki, Yasunari Inamoto, Shuka Inoue, Takahiro Uno, Takahito Itoh and Masataka Kubo

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23633

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      A pentamethylcyclotrisiloxane moiety was introduced into cyclic polystyrene (cPSt) and cyclic PDMS (cPDMS) to obtain noncovalent cross-linking agents, D3-cPSt and D3-cPDMS, respectively. Anionic ring-opening polymerization of octamethylcyclotetrasiloxane (D4) in nitrobenzene was carried out in the presence of D3-cPSt to obtain a cloudy white PDMS gel as a precipitation. On the other hand, bulk copolymerization of D3-cPDMS with D4 proceeded in a homogeneous state to give a colorless transparent PDMS gel in high yield.

    29. Grafting of polymer matrix to exfoliated montmorillonite nanoplatelets in nanocomposite film cast from soap-free emulsion polymerized latex and its fortified mechanical properties (pages 5891–5897)

      Keng-Jen Lin, Ting Hsiang Weng, Chia-Hsin Lee and King-Fu Lin

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23634

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      The P(MA-co-MMA) nanocomposite film with 1 wt % exfoliated MMT nanoplatelets that have been grafted by P(MA-co-MMA) matrix has unusual higher strain, higher strain recovery ratio after creep, and higher modulus and strength compared to neat P(MA-co-MMA). [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

    30. Synthesis of high-molecular-weight aliphatic–aromatic copolyesters from poly(ethylene-co-1,6-hexene terephthalate) and poly(L-lactic acid) by chain extension (pages 5898–5907)

      Wen-Da Li, Jian-Bing Zeng, Yi-Dong Li, Xiu-Li Wang and Yu-Zhong Wang

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23635

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      A series of aliphatic–aromatic multiblock copolyesters consisting of poly(ethylene-co-1,6-hexene terephthalate) (PEHT) and poly(L-lactic acid) (PLLA) were synthesized successfully by chain-extension reaction of dihydroxyl terminated PEHT-OH prepolymer with dihydroxyl terminated PLLA-OH prepolymer using toluene-2,4-diisoyanate as a chain extender. This synthetic method has been proved to be very efficient for the synthesis of high-molecular-weight copolyesters (say, higher than Mw = 3 × 105 g/mol). PEHT and PLLA segments had good miscibility and the resulting novel aromatic– aliphatic copolyesters are expected to find a potential application in the area of biodegradable polymer materials.

    31. Synthesis and characterization of 9,10-diphenylanthracene-based blue light emitting materials (pages 5908–5916)

      Sul Ong Kim, Hyun Cheol Jung, Min-Jung Lee, Chen Jun, Yun-Hi Kim and Soon-Ki Kwon

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23636

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      A new series of conjugated polymers having diphenylanthracene vinylene biphenylene and diphenylanthracene vinylene terphenylene in the main chain and fluorene pendant group, were synthesized by nickel catalized Yamamoto coupling and palladium catalized Suzuki coupling. The polymers showed blue emission (λmax = 461 for PFPA and λmax = 455 nm for PFPAME) in PL spectra. The double-layered device with an ITO/PEDOT/PFPAME/LiF/Al structure has a turn-on voltage of about 5.8 V, maximum brightness of 152 cd/m2 and an electroluminescent efficiency of 0.143 lm/W.

  3. Rapid Communications

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      Controlled preparation of poly(ethylene glycol) and poly(L-lactide) block copolymers in the presence of a monomer activator (pages 5917–5922)

      Sang Hyo Lee, Jae Min Oh, Jin Soo Son, Jung Won Lee, Byung Soo Kim, Gilson Khang, Dong Keun Han, Jae Ho Kim, Hai Bang Lee and Moon Suk Kim

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23638

      Thumbnail image of graphical abstract

      Polymerization of L-lactide by PEG as an initiator was performed in the presence of CF3SO3H as monomer activator. The hydroxyl end group of PEG attacked the carbonyl carbon of protonated LA rather than the PLLA carbonyl carbon, even though CF3SO3H can interact with the carbonyl carbon of both LA and PLLA. PEG and PLLA block copolymers successfully prepared by using activated monomer mechanism in the presence of CF3SO3H.

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      Asymmetric anionic polymerization of 7-cyano-7-ethoxycarbonyl-1,4-benzoquinone methide (pages 5923–5927)

      Noboru Nakagaki, Takahiro Uno, Masataka Kubo and Takahito Itoh

      Version of Record online: 28 SEP 2009 | DOI: 10.1002/pola.23654

      Thumbnail image of graphical abstract

      An optically active polymer having configurational chirality in the main chain was synthesized from a prochiral monomer, 7-cyano-7-ethoxycarbonyl-1,4-benzoquinone methide (1), by asymmetric anionic polymerization using various chiral anionic initiators. The effects of the chiral ligand and solvent polarity on the specific rotations of the resulting polymers were investigated. The polymerization of 1 using iPrPhOLi/(−)-PhBox complex initiator in a mixture solution of dichloromethane/toluene ratio of 30/70 (in vol %) at −78 °C afforded an optically active polymer with a large positive specific rotation ([α]435 = +90.4°).

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