Journal of Polymer Science Part A: Polymer Chemistry

Cover image for Vol. 42 Issue 23

1 December 2004

Volume 42, Issue 23

Pages 5847–6173

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      Development of amorphous copolyesters based on 1,4-cyclohexanedimethanol (pages 5847–5852)

      S. Richard Turner

      Article first published online: 12 OCT 2004 | DOI: 10.1002/pola.20460

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      The development of three commercially successful families of amorphous copolyesters based on 1,4-cyclohexanedimethanol (CHDM) was made possible by discoveries resulting from fundamental structure–property polyester research in the 1950s and 1960s at Tennessee Eastman Co., a division of Eastman Kodak Co. One of the copolyester families is based on poly(ethylene terephthalate) modified with CHDM. The second family is based on poly(1,4-cyclohexylenedimethylene terephthalate) (PCT) modified with ethylene glycol, and the third family is based on PCT modified with isophthalic acid.

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    1. Synthesis and luminescence of yellow/orange-emitting poly[tris(2,5-dihexyloxy-1,4-phenylenevinylene)- alt-(1,3-phenylenevinylene)]s (pages 5853–5862)

      Liang Liao, Yi Pang, Liming Ding, Frank E. Karasz, Philip R. Smith and Michael A. Meador

      Article first published online: 12 OCT 2004 | DOI: 10.1002/pola.20425

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      Soluble poly(phenylene vinylene) derivatives of equal conjugation length were synthesized and characterized. One polymer of chromophore B exhibited an electroluminescence efficiency of 0.25%, which was about 10 times higher than that of another polymer of chromophore A. This demonstrated the large effect of the substitution on an m-phenylene ring.

    2. The role of diphenyl iodonium salt (DPI) in three-component photoinitiator systems containing methylene blue (MB) and an electron donor (pages 5863–5871)

      Dongkwan Kim and Alec Scranton

      Article first published online: 12 OCT 2004 | DOI: 10.1002/pola.20426

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      To characterize the role of diphenyl iodonium salt (DPI) in three-component photoinitiator systems containing methylene blue (MB) as the photosensitizer, a systematic series of electron donors was used. Comparison of the photopolymerization rates of each two-component initiator system (containing the photosensitizer and amine) to those of the corresponding three-component system (with the addition of diphenyliodonium chloride) allowed information regarding the role of the DPI to be obtained. It was concluded that the DPI enhances the photopolymerization kinetics in two ways: (1) it consumes an inactive MB neutral radical and produces an active phenyl radical thereby regenerating the original methylene blue, and (2) it reduces the recombination reaction of MB neutral radical and amine radical/cation.

    3. Synthesis of π-conjugated poly(dithiafulvene) by cycloaddition polymerization of aldothioketene from a bis(1,2,3-thiadiazole) monomer (pages 5872–5876)

      Kensuke Naka, Adriana Gelover-Santiago and Yoshiki Chujo

      Article first published online: 13 OCT 2004 | DOI: 10.1002/pola.20442

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      A π-conjugated poly(dithiafulvene) (2) was obtained by cycloaddition polymerization of aldothioketene with its alkynethiol tautomer derived from 1,4-bis(1,2,3-thiadiazolyl)benzene (1). To a mixure of 1 and DMSO/ethanol (5/1, v/v), KOH was added. After stirring the mixture overnight, piperidine was added to quench terminal thioketenes. Then the reaction mixture was poured into water to obtain the product. The structure of the polymer was supported by the 1H NMR and 13C NMR spectra. The number-average degree of polymerization (DP) of 2 was 8, estimated from the 1H NMR analysis. Optical properties and electrochemical analysis of 2 were also studied.

    4. Dendrimers as scaffolds for multifunctional reversible addition–fragmentation chain transfer agents: Syntheses and polymerization (pages 5877–5890)

      Xiaojuan Hao, Camilla Nilsson, Martin Jesberger, Martina H. Stenzel, Eva Malmström, Thomas P. Davis, Emma Östmark and Christopher Barner-Kowollik

      Article first published online: 13 OCT 2004 | DOI: 10.1002/pola.20434

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      The synthesis and characterization of novel first- and second-generation true dendritic reversible addition–fragmentation chain transfer (RAFT) agents carrying 6 or 12 pendant 3-benzylsulfanylthiocarbonylsulfanylpropionic acid RAFT end groups with Z-group architecture based on 1,1,1-hydroxyphenyl ethane and trimethylolpropane cores are described in detail. The multifunctional dendritic RAFT agents have been used to prepare star polymers of poly(butyl acrylate) (PBA) and polystyrene (PS) of narrow polydispersities (1.4 < polydispersity index < 1.1 for PBA and 1.5 < polydispersity index < 1.3 for PS) via bulk free-radical polymerization at 60 °C. The star-shaped structure of the generated polymers has been confirmed through the cleavage of the pendant arms off the core of the star-shaped polymeric materials.

    5. Synthesis and properties of the [2.2]paracyclophane-containing conjugated polymer with benzothiadiazole as an electron acceptor (pages 5891–5899)

      Yasuhiro Morisaki, Tamao Ishida, Hiroyuki Tanaka and Yoshiki Chujo

      Article first published online: 13 OCT 2004 | DOI: 10.1002/pola.20443

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      A novel donor–acceptor type conjugated polymer based on PPE with [2.2]paracyclophane and benzothiadiazole units in the main chain was synthesized by the Sonogashira coupling reaction. The obtained polymer was quite soluble in common organic solvents, and the transparent and uniform thin film of the polymer was obtained easily by casting or spin-coating from a toluene solution. The polymer showed an extension of π-delocalization via the through-space with π-π stacking according to the UV–visible (UV–vis) absorption spectra in comparison with that of the model compound. The polymer exhibited orange photoluminescence in solution (fluorescence quantum efficiency = 0.13) and in the solid state.

    6. Luminescent copoly(aryl ether)s with new electron-transporting bis(3-(trifluoromethyl)phenyl)-1,3,4-oxadiazole or bis(3-(trifluoromethyl)phenyl)-4-(4-hexyloxyphenyl)-4H-1,2,4-triazole segments (pages 5900–5910)

      Shinn-Horng Chen and Yun Chen

      Article first published online: 13 OCT 2004 | DOI: 10.1002/pola.20427

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      Four novel copoly(aryl ether)s (P1P4) consisting of alternate isolated electron- and hole-transporting fluorophores have been synthesized and characterized. The emissions of P1P4are dominated by the hole-transporting fluorophores with longer emissive wavelengths around 442–453 nm via efficient excitation energy transfer. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of P1P4 are −5.15, −5.18, −5.30, −5.27, −3.39, −3.49, −3.36, and −3.48 eV, respectively. Incorporation of two trifluoromethyl groups in 2,5-diphenyl-1,3,4-oxadiazole moiety greatly lowers its LUMO level from −2.45 to −3.39 eV.

    7. Synthesis and characterization of cellulose derivatives prepared in NaOH/urea aqueous solutions (pages 5911–5920)

      Jinping Zhou, Lina Zhang, Qinghai Deng and Xiaojun Wu

      Article first published online: 15 OCT 2004 | DOI: 10.1002/pola.20431

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      Water-soluble hydroxypropyl cellulose (HPC) and methylcellulose (MC) were successfully synthesized from cellulose in 6 wt % NaOH / 4 wt % urea aqueous solution at room temperature. The relative reactivity of hydroxyl groups at C-2 position of cellulose was slightly higher than those at C-3 and C-6 positions. The low limits for the MS and DS values of water-soluble HPC were 1.03 and 0.85, respectively. The MC sample exhibited a normal phase separation rather than a sol-gel transition in an aqueous solution because of the uniform distribution of substituents along the chain, and its precipitation temperature was determined to be 67 °C.

    8. Preparation and characterization of hyperbranched polyaspartimides from bismaleimides and triamines (pages 5921–5928)

      Ying-Ling Liu, Shr-Hau Tsai, Chuan-Shao Wu and Ru-Jong Jeng

      Article first published online: 15 OCT 2004 | DOI: 10.1002/pola.20448

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      Hyperbranched polyaspartimides were successfully prepared from bismaleimides and triamines through the Michael addition reaction. Degrees of branching ranging from 0.51 to 0.69 were found with the polyaspartimides, ensuring their hyperbranched structure. The polymers also showed good solubility in common solvents, high glass-transition temperatures of 256 °C, and excellent thermal stability above 370 °C.

    9. γ-Irradiation of ultrahigh-molecular-weight polyethylene: Electron paramagnetic resonance and nuclear magnetic resonance spectroscopy and imaging studies of the mechanism of subsurface oxidation (pages 5929–5941)

      Todd M. Alam, Mathew Celina, John P. Collier, Barbara H. Currier, John H. Currier, Simon K. Jackson, Dean O. Kuethe and Graham S. Timmins

      Article first published online: 15 OCT 2004 | DOI: 10.1002/pola.20415

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      Aging of irradiated UHMWPE causes subsurface oxidation leading to failure, yet its mechanisms remain unclear. Aging of γ irradiated UHMWPE bars was studied by EPR and NMR imaging, and by microtoming and FTIR microscopy. A band of low radical intensity just beneath the outer peroxyl radical layer became apparent. The area of maximal oxidation and mechanical disruption, measured after 3 years, was at the interface between the zone of exterior peroxyl radical and the zone of low radical intensity. We present a mechanism involving the intermediacy of sterically strained reactive dialkylperoxides at this interface to explain subsurface oxidation.

    10. Tetrafunctional initiators for cationic polymerization of olefins (pages 5942–5953)

      Stacy J. Taylor and Robson F. Storey

      Article first published online: 19 OCT 2004 | DOI: 10.1002/pola.20393

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      3,3′,5,5′-Tetrakis(2-chloro-2-propyl)biphenyl (biphenyl tetracumyl chloride, BPTCC) and 1,3-bis[3,5-bis(2-chloro-2-propyl)phenoxy]propane (diphenoxypropane tetracumyl chloride, DPPTCC) were synthesized as initiators for quasiliving cationic polymerization of isobutylene (IB). In the synthesis of BPTCC, tetrafunctionality was achieved via the coupling of dimethyl 5-bromoisophthalate (DMBI) using nickel dibromide bis(triphenylphosphine) and zinc in the presence of a base; in the synthesis of DPPTCC, two equivalents of dimethyl 5-hydroxyisophthalate were linked via reaction with 1,3-dibromopropane in the presence of potassium carbonate. Both initiators were used to initiate the polymerization of IB under quasiliving cationic polymerization conditions. PIB initiated from BPTCC revealed a chain end/molecule value (as determined by 1H-NMR) of 3.85, verifying the nearly exclusive production of 4-arm polyisobutylene (PIB). GPC analysis revealed a narrow peak representing the target four-arm PIB, with a slight shoulder at high elution volumes (low molecular weights). GPC analysis of the PIB initiated by DPPTCC revealed multimodal distributions, suggesting the formation of two-, three-, and four-arm star polymers during the polymerization. This behavior was attributed to Friedel–Crafts alkylation of the initiator core after the addition of one IB unit, which was activated by the electron-donating oxytrimethyleneoxy linking moiety.

    11. Preparation and properties of novel benzoxazine and polybenzoxazine with maleimide groups (pages 5954–5963)

      Ying-Ling Liu, Juin-Meng Yu and Ching-I Chou

      Article first published online: 15 OCT 2004 | DOI: 10.1002/pola.20428

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      A benzoxazine compound with a maleimide group (HPM-Ba) was prepared from N-(4-hydroxyphenyl)maleimide, formaldehyde, and aniline. HPM-Ba showed a melting point of 52–55 °C and good solubility in common organic solvents. A two-stage process of thermal polymerization arising from the polymerization of maleimide groups and the ring-opening reaction of benzoxazine groups, respectively, was observed with HPM-Ba. Fusible polymaleimides with a Tg of around 100 °C could be obtained by thermally polymerizing HPM-Ba at 130 °C. Further polymerizing the polymaleimides at 240 °C resulted in a completely cured resin showing a Tg at 204 °C. Good thermal stability and self-extinguishing behavior was observed with the cured polybenzoxazine resins.

    12. Polymers based on benzyl methacrylate: Synthesis via atom transfer radical polymerization, characterization, and thermal stabilities (pages 5964–5973)

      Kadir Demirelli, Mehmet Coskun and Esin Kaya

      Article first published online: 15 OCT 2004 | DOI: 10.1002/pola.20447

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      Copolymerization and homopolymerization of benzyl methacrylate (BMA) and ethyl methacrylate (EMA) by the atom transfer radical polymerization method (ATRP) were performed at 90 °C. ATRP of BMA was also carried out at 80, 100, and 110 °C. When ATRP conditions, in view of temperature, was changed from 80 to 110 °C, an increasing at carbonyl stretch in a lacton ring with five-member is observed. It may be suggested that lactone ring forms by means of removing benzyl bromide at chain end. The number of average molecular weight (Mn) and polydispersities decreased with temperature. When BMA units increased in the copolymer system, the Mn values and polydispersities decreased (1.63 < Mw/Mn < 1.13). Each polymer blend prepared in this study shows single transition, which can be attributed to poly(BMA) and poly(EMA) to give the compatibility blends. An inner shift of single Tg's for poly(BMA):poly(EMA) blends indicated good compatibility of both polymers.

    13. Stereoselective polymerization of rac-lactide with a bulky aluminum/Schiff base complex (pages 5974–5982)

      Zhaohui Tang, Xuesi Chen, Yongkun Yang, Xuan Pang, Jingru Sun, Xuefei Zhang and Xiabin Jing

      Article first published online: 19 OCT 2004 | DOI: 10.1002/pola.20429

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      An aluminum-Schiff base initiator was prepared and employed for the stereoselective ring-opening polymerization of rac-lactide. The initiator polymerized rac-lactide to crystalline polymer that was characterized by 1H NMR, WAXD, ESI-MS, and GPC. The kinetics of the polymerization was of first order in both monomer and initiator, and besides, there was linear relationship between the rac-LA conversion and Mn of poly(rac-LA)s with narrow molecular distribution. These features manifested that the polymerization was well controlled. The high Tm (196–201°C) and isotacticity of the poly(rac-LA) indicated that complex 2 was highly stereoselective initiator for the ROP of rac-lactide.

    14. Facile synthesis and crosslinking reaction of trifunctional five-membered cyclic carbonate and dithiocarbonate (pages 5983–5989)

      Akane Suzuki, Daisuke Nagai, Bungo Ochiai and Takeshi Endo

      Article first published online: 19 OCT 2004 | DOI: 10.1002/pola.20436

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      The trifunctional five-membered cyclic carbonate 2 and dithiocarbonate 3 were synthesized by the reaction of trifunctional epoxide 1 with carbon dioxide and carbon disulfide. The crosslinking reaction of 2 and 3 with amines gave poly9hydroxyurethanes)s and poly(thioester–thiourethane)s quantitatively. The thermal property of the obtained crosslinked polymers is also discussed.

    15. Novel positive-working and aqueous-base-developable photosensitive poly(imide benzoxazole) precursor (pages 5990–5998)

      Steve Lien-Chung Hsu, Hui-Tzu Chen and Shih-Jung Tsai

      Article first published online: 19 OCT 2004 | DOI: 10.1002/pola.20438

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      A novel positive-working and aqueous-base-developable photosensitive poly(imide benzoxazole) precursor based on a poly(amic acid hydroxyamide) was synthesized. The photosensitive polyimide precursor, containing 25 wt % diazonaphthoquinone photoactive compound, showed a sensitivity of 256 mJ/cm2 and a contrast of 1.14 with a 0.6 wt % tetramethylammonium hydroxide developer. A pattern with a resolution of 5 μm was obtained.

    16. Solid-state amidization and imidization reactions in vapor-deposited poly(amic acid) (pages 5999–6010)

      Mitchell Anthamatten, Stephan A. Letts, Katherine Day, Robert C. Cook, Anthony P. Gies, Tracy P. Hamilton and William K. Nonidez

      Article first published online: 20 OCT 2004 | DOI: 10.1002/pola.20446

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      The condensation polymerization of 4,4′-oxydianiline with pyromellitic dianhydride forming poly(amic acid) and the subsequent imidization yielding polyimides were investigated for films prepared with vapor-deposition polymerization techniques. The as-deposited films were studied using Fourier-transform infrared spectroscopy, thermal analysis, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Vapor-deposited poly(amic acid) material had a number-average molecular weight of about 1500 Da. Between 100–130 °C, these chains underwent an additional condensation reaction and formed slightly higher molecular weight oligomers. Experiments indicate that reaction kinetics depend on the reaction conversion as well as the processing conditions used to deposit the films.

    17. Grafting of poly(ε-caprolactone) onto maghemite nanoparticles (pages 6011–6020)

      C. Flesch, C. Delaite, P. Dumas, E. Bourgeat-Lami and E. Duguet

      Article first published online: 20 OCT 2004 | DOI: 10.1002/pola.20449

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      Condensation between silane functionalized poly(ε-caprolactone) chains and surface hydroxyls of maghemite nanoparticles is reported for the first time. This strategy provides magnetic, biodegradable, and biocompatible nanoparticles with a relative high polymer surface coverage, up to 3 μmol · m−2, that could be used for therapeutic applications.

    18. Macromonomer synthesis using α-(2-methyl-2-phenylpropyl)acrylates as addition–fragmentation chain-transfer agents expelling the cumyl radical (pages 6021–6030)

      Eriko Sato, Per B. Zetterlund and Bunichiro Yamada

      Article first published online: 21 OCT 2004 | DOI: 10.1002/pola.20332

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      The use of α-(2-methyl-2-phenylpropyl)acrylates (RS-2) as addition–fragmentation chain-transfer agents was carefully examined within the specific context of efficient macromonomer synthesis. Polystyrene and poly(ethyl methacrylate) macromonomers of appropriate molecular weights were successfully prepared with a high efficiency of unsaturated-end-group introduction and without significant retardation. The efficiency was significantly lower for poly(cyclohexyl acrylate) macromonomers, and marked retardation was observed. The influence of the cumyl group as the substituent of the RS-2 adduct radical was discussed in comparison with the 2-carbomethoxy-2-propyl group.

    19. Thermal analysis of 1,4-di[n′-(quinolyl)]buta-1,3-diynes, structure, and topo-oligomerization: Polymerization of 3-ethynylquinoline with the triethyl aluminum/vanadium 2,4-pentanedionate catalyst system (pages 6031–6040)

      J. G. Rodríguez, A. Lafuente and C. De Los Ríos

      Article first published online: 21 OCT 2004 | DOI: 10.1002/pola.20441

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      Conjugated 1,4-bis(n′-quinolyl)-1,3-butadiynes were obtained through the oxidative dimerization of the corresponding n′-ethynylquinolines catalyzed by cuprous chloride. Differential scanning calorimetry analysis of the 1,4-bis[n′-(quinolyl)]buta-1,3-diyne molecules produced evidence of a syn–anti rotational equilibrium around the 1,3-diyne axis and an irreversible transformation into a thermopolymer. The topo-oligomerization of 1,4-bis[3′-(quinolyl)]buta-1,3-diyne, which took place by irradiation with sunlight, was investigated with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The polymerization of 3-ethynylquinoline was carried out with the AlEt3/V(acac)3 system to produce a mixture of 1,2,4- and 1,3,5-tris(3′-quinolyl)benzene cyclotrimers and a trans–cisoid polyene structure.

    20. 3,6-linked 9-alkyl-9H-carbazole main-chain polymers: Preparation and properties (pages 6041–6051)

      Ahmed Iraqi and Isao Wataru

      Article first published online: 21 OCT 2004 | DOI: 10.1002/pola.20420

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      Poly(9-alkyl-9H-carbazole-3,6-diyl)s were prepared with palladium catalyzed cross-coupling reactions involving 3-halo-6-halomagnesio-9-alkyl-9H-carbazoles, generated in situ from their corresponding 3,6-dihalogeno-derivatives. The effects of the nature of halogen substituents on the polymerization reaction as well as the steric bulk of their alkyl substituents were investigated. The fluorescence quantum yields of these materials in solution and their thermal and electrochemical properties are also reported.

    21. New results on the influence of the nature of the nucleophile in the stereospecific modification of poly(vinyl chloride) (pages 6052–6060)

      Gerardo Martínez and José Luis Millán

      Article first published online: 21 OCT 2004 | DOI: 10.1002/pola.20454

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      The nucleophilic substitution reactions on poly(vinyl chloride) (PVC) with potassium 4-acetamidothiophenolate, potassium 2-naphthalenethiolate, and sodium 2-mercaptobenzothiazolate (NaMBT) have been carried out in a cyclohexanone solution. Because of the steric hindrance and moderate reactivity of NaMBT, the stereoselective nature of the reaction is enhanced. This circumstance and the fact that the nucleophile bulkiness and interaction effects provide an enhancement of the molecular microstructure-based mechanisms, provokes the Tg to vary with the degree of substitution, in all cases, in a similar way to the ratio between the extent to which mmr and rrmr structures intervene in the substitution reaction.

    22. Conjugated and partially conjugated 2,5-diphenylthiophene-containing light-emitting copolymers in polymeric light-emitting diode (PLED) device fabrications (pages 6061–6070)

      Sheng-Han Wu, Jar-Hung Chen, Chi-Hsien Shen, Chia-Chen Hsu and Raymond Chien-Chao Tsiang

      Article first published online: 21 OCT 2004 | DOI: 10.1002/pola.20444

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      New light-emitting copolymers comprising either alternate 2,5-diphenylthiophene and vinylene (fully conjugated) or alternate 2,5-diphenylthiophene and aliphatic ether segments (partially conjugated) were synthesized. Both copolymers emitted a sky bluish fluorescence in dilute solution (10−2 mg/mL). The latter copolymer had better solubility and provided enhanced photophysical properties for the fabricated polymeric light-emitting diode (PLED) device: At 15 V, the maximum current and brightness were 110 mA/cm2 and 4289 cd/m2, respectively, and the electroluminescence efficiency remained constant at approximate 4.9 cd/A in a voltage range of 8 to 14 V.

    23. Novel cyclohexyl-substituted salicylaldiminato–nickel(II) complex as a catalyst for ethylene homopolymerization and copolymerization (pages 6071–6080)

      Junquan Sun, Yuhua Shan, Yongjin Xu, Yonggang Cui, H. Schumann and M. Hummert

      Article first published online: 21 OCT 2004 | DOI: 10.1002/pola.20458

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      [O-(3-C6H11)(5-CH3)C6H2CH[DOUBLE BOND]N-2,6-C6H3iPr2]Ni(PPh3)(Ph) has been synthesized and characterized with 1H NMR and X-ray structure analysis. In the presence of phosphine scavengers, it is an active catalyst for ethylene polymerization and copolymerization with the polar monomers tert-butyl-10-undecenoate, methyl-10-undecenoate, and 4-penten-1-ol under mild conditions.

    24. Preparation and characterization of core–shell polymer particles with protonizable shells prepared by oxyanionic polymerization (pages 6081–6088)

      Lan Jin, Yonghui Deng, Jianhua Hu and Changchun Wang

      Article first published online: 22 OCT 2004 | DOI: 10.1002/pola.20453

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      A series of PS/PVAc crosslinked particles were prepared by soap-free emulsion polymerization firstly, and then base on these crosslinked polymer particles, three series of monodispersed core-shell particles with pH-sensitive poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) shell, were synthesized by oxyanionic polymerization. Because the PDMAEMA chain could be protonized at low pH, these core-shell particles could absorb negative charged magnetite particles, and at higher pH, the magnetite particles could be released again; this process is reversible.

    25. Poly(ether imide)s derived from phthalazinone-containing dianhydrides (pages 6089–6097)

      Jin Yan Wang, Gong Xiong Liao, Cheng Liu and Xi Gao Jian

      Article first published online: 22 OCT 2004 | DOI: 10.1002/pola.20364

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      A new unsymmetrical aromatic dianhydride containing a phthalazinone moiety and its poly(ether imide)s with five commercial diamines were synthesized. The structure of the novel dianhydride was confirmed with Fourier transform infrared and NMR spectroscopy. Some properties of these poly(ether imide)s were also measured.

    26. Sequential synthesis of multiblock copolymers by atom transfer radical and cationic polymerization (pages 6098–6108)

      Luděk Toman, Miroslav Janata, Jiří Spěváček, Petr Vlček, Petra Látalová, Bohumil Masař and Antonín Sikora

      Article first published online: 22 OCT 2004 | DOI: 10.1002/pola.20369

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      Multiblock copolymers of methyl methacrylate (MMA), styrene (S), and isobutylene (IB) were synthesized through a combination of atom transfer radical polymerization (ATRP) and cationic polymerization. First, the poly(S-b-MMA-b-S) triblock copolymer was prepared by ATRP, and then IB was polymerized cationically with the triblock macroinitiator in conjunction with BCl3. This produced a poly(IB-b-S-b-MMA-b-S-b-IB) pentablock copolymer.

    27. Synthesis and properties of processable conducting copolymers from N-ethylaniline with aniline (pages 6109–6124)

      Xin-Gui Li, Hai-Jun Zhou and Mei-Rong Huang

      Article first published online: 22 OCT 2004 | DOI: 10.1002/pola.20437

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      Copolymers were synthesized through the oxidative polymerization of N-ethylaniline (EA) and aniline (AN). The polymerization characteristics, molecular structure, and properties of the copolymers were systematically studied through changes in the comonomer ratio, polymerization temperature, oxidant, oxidant/monomer ratio, and acid medium. The polymers exhibited good solubility, interesting solvatochromism, and variable electrical conductivity. The conductivity of the HCl-doped copolymers increased monotonically with decreasing EA content and showed a percolation transition between EA concentrations of 20 and 30 mol %. The copolymers also had excellent film formability and flexibility together with high mechanical and oxygen-enriching properties.

    28. Ionic and excited species in irradiated poly(dimethylsiloxane) doped with pyrene (pages 6125–6133)

      M. Szadkowska-Nicze and J. Mayer

      Article first published online: 22 OCT 2004 | DOI: 10.1002/pola.20450

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      The influence of temperature on the fate of pyrene (Py) radical ions and Py excited states in irradiated polydimethylsiloxane (PDMS) doped with Py is described. At 77 K, the Py excited states are generated via tunnelling charge transfer. In Tg temperature range (152–153 K) the Py radical ions start to decay taking part in recombination process leading to the Py monomer and excimer fluorescence and phosphorescence. The wavelength selected radiothermoluminescence (WS RTL) observed at ∼395nm, ∼475nm, and ∼600nm help us to identify the Tg range (152–153 K). The mechanisms involved in these phenomena are discussed.

    29. Synthesis and characterization of polyaryleneetherketone triphenylphosphine oxides incorporating cycloaliphatic/cage hydrocarbon structural units (pages 6134–6142)

      Thuy D. Dang, Matthew J. Dalton, N. Venkatasubramanian, Joel A. Johnson, Clifford A. Cerbus and William A. Feld

      Article first published online: 25 OCT 2004 | DOI: 10.1002/pola.20457

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      New high temperature polyaryleneetherketone triphenylphosphine oxides incorporating trans-1,4-cyclohexane, 4,9-diamantane, and 1,3-adamantane structural units were synthesized by the base-promoted polymerization reaction between 4,4′-difluorotriphenylphosphine oxide and the novel dihydroxy monomers trans-1,4-bis(4-hydroxybenzoyl)cyclohexane, 1,3-bis(4-hydroxybenzoyl)adamantane, and 4,9-bis(4-hydroxybenzoyl)diamantane. The polymers, which could be processed into tough, freestanding films from organic solvents, exhibited high Tg's in the range of 192–239 °C, as well as thermooxidative stabilities in the range of 445–490 °C.

    30. Poly(ethyleneimine)/arginine–glycine–aspartic acid conjugates prepared with N-succinimidyl 3-(2-pyridyldithio)propionate: An investigation of peptide coupling and conjugate stability (pages 6143–6156)

      Jiang Bai, Başak Açan, Aziz Ghahary, Bruce Ritchie, Vishwa Somayaji and Hasan Uludağ

      Article first published online: 25 OCT 2004 | DOI: 10.1002/pola.20472

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      Disulfide-linked conjugates of poly(ethylene imine) (PEI) and peptides containing arginine, glycine, and aspartic acid are readily cleaved in the presence of thiol compounds, but not in the absence of thiols. The cleavage rate is inversely related to the degree of peptide substitution on PEI and positively correlated to the pH of the medium, but it is not influenced by the ionic strength of the medium.

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      Asymmetric polymerization of N-1-naphthylmaleimide with (R,R)-N, N′-bis(3,5-di-tert-butylsalicylidene)-1, 2-cyclohexanediaminatocobalt (II) (pages 6157–6162)

      Yong-Kyung Lee, Shinya Kitamura, Kenjiro Onimura, Hiromori Tsutsumi and Tsutomu Oishi

      Article first published online: 25 OCT 2004 | DOI: 10.1002/pola.20445

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      Asymmetric polymerizations of N-1-naphthylmaleimide (1-NMI) with (R,R)-N,N′-bis(3,5-di-tert-butylsalicylidene)-1, 2-cyclohexanediaminatocobalt (II) (DBCCo), and 2,2′-azobisisobutyronitrile (AIBN) were performed under several conditions to obtain chiral poly(1-NMI) having the maximum [α]D of +36.5°. The degree of asymmetric induction to the main chain decreased with enhancement of the molecular weight of polymer. The conformation of poly(1-NMI) obtained in toluene may be different from that in THF-pyridine.

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      Polypropylene/montmorillonite nanocomposites and intumescent, flame-retardant montmorillonite synergism in polypropylene nanocomposites (pages 6163–6173)

      Yong Tang, Yuan Hu, Baoguang Li, Lei Liu, Zhengzhou Wang, Zuyao Chen and Weicheng Fan

      Article first published online: 25 OCT 2004 | DOI: 10.1002/pola.20432

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      Polypropylene/montmorillonite (MMT) nanocomposites were prepared by a novel method, with pristine MMT with a surfactant. This study showed that the present of maleic acid modified polypropylene and the ratio of the surfactant to MMT had an influence on the dispersion of MMT in the hybrids. A density functional theory and a self-consistent field were used to illuminate the results. We studied the synergy between MMT and an intumescent flame retardant (IFR) and found that there was a optimal ratio of MMT to IFR. In addition, the mechanisms of melt intercalation and synergism between MMT and IFR were examined.

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