Journal of Polymer Science Part A: Polymer Chemistry

Cover image for Vol. 42 Issue 20

15 October 2004

Volume 42, Issue 20

Pages 5031–5300

  1. Highlights

    1. Top of page
    2. Highlights
    3. Articles
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      Advanced solid-state nuclear magnetic resonance for polymer science (pages 5031–5044)

      Hans Wolfgang Spiess

      Version of Record online: 3 SEP 2004 | DOI: 10.1002/pola.20365

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      Double-quantum nuclear magnetic resonance (NMR) spectroscopy in the solid state provides unique information on the key elements of supramolecular systems: hydrogen bonds, π stacks, attachment to surfaces, and shape control. Atomic resolution is obtained even in noncrystalline materials. Moreover, solid-state NMR provides unique information on the molecular and collective dynamics of polymers. The development of these methods largely benefited from the close analogy between NMR spectroscopy and X-ray and neutron scattering.

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      Synthesis and characterization of poly(L-lactic acid)–poly(ε-caprolactone) multiblock copolymers by melt polycondensation (pages 5045–5053)

      Cuiqing Teng, Kai Yang, Ping Ji and Muhuo Yu

      Version of Record online: 3 SEP 2004 | DOI: 10.1002/pola.20412

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      As shown in the 13C NMR spectrum, the carbon atoms that from PLLA units are of similar chemical shifts from the PLLA homopolymer, and PLLA and PCL are copolymerized by the reaction between [BOND]NCO groups at the end of PCL and [BOND]OH (or [BOND]COOH) groups at the end of PLLA.

  2. Articles

    1. Top of page
    2. Highlights
    3. Articles
    1. Synthesis and characterization of novel thermoresponsive-co-biodegradable hydrogels composed of N-isopropylacrylamide, poly(L-lactic acid), and dextran (pages 5054–5066)

      Xiao Huang, Bishwa Ranjan Nayak and Tao Lu Lowe

      Version of Record online: 3 SEP 2004 | DOI: 10.1002/pola.20327

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      Multifunctional hydrogels with both thermoresponsive and biodegradable properties were designed, synthesized, and characterized. The hydrogels were copolymeric networks composed of N-isopropylacrylamide as a thermoresponsive component, poly(L-lactic acid) as a hydrolytically degradable and hydrophobic component, and dextran as an enzymatically degradable and hydrophilic component. Due to their multifunctional properties, the designed hydrogels show great potential for biomedical applications, including drug delivery and tissue engineering.

    2. Synthesis of core-shell poly(divinylbenzene) microspheres via reversible addition fragmentation chain transfer graft polymerization of styrene (pages 5067–5076)

      Leonie Barner, Chao'En Li, Xiaojuan Hao, Martina H. Stenzel, Christopher Barner-Kowollik and Thomas P. Davis

      Version of Record online: 7 SEP 2004 | DOI: 10.1002/pola.20328

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      Styrene has been grafted from crosslinked poly(divinylbenzene) core microspheres by both reversible addition fragmentation chain transfer (RAFT) polymerization and conventional free radical polymerization. The core microspheres were prepared by precipitation polymerization. Crosslinked poly(DVB) core microspheres containing double bonds on the particle surface can be used directly to graft polymers from the surface by RAFT without prior modification of the core microspheres. The RAFT process was also used to synthesize core poly(DVB) RAFT microspheres that contain residual RAFT end groups on the surface and within the particle. Styrene was subsequently grafted from the surface of these core poly(DVB) RAFT microspheres. The generated microspheres were characterized by 1H-NMR spectroscopy, focused ion beam (FIB) milling, Coulter particle sizing, and size exclusion chromatography.

    3. Synthesis of functional polymers—Vinylidene fluoride based fluorinated copolymers and terpolymers bearing bromoaromatic side-group (pages 5077–5097)

      R. Souzy, B. Ameduri and B. Boutevin

      Version of Record online: 7 SEP 2004 | DOI: 10.1002/pola.20324

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      The radical copolymerization and the terpolymerization of [trifluorovinyl)oxy]bromo benzene (FVOBB) with various fluoroalkenes [(vinylidene fluoride (VDF), hexafluoropropene (HFP), perfluoromethyl vinyl ether (PMVE), and chlorotrifluroroethylene (CTFE)] were investigated. The physico-chemical properties are presented and discussed.

    4. Synthesis of rod copolyaramids with short flexible spacers (pages 5098–5112)

      Julie Boivin and Josée Brisson

      Version of Record online: 3 SEP 2004 | DOI: 10.1002/pola.20329

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      Regular rigid-flexible copolymers composed of aramid segments and aliphatic chains formed of 5 to 10 CH2 groups were synthesized using a two-stage procedure involving the Yamasaki–Higashi phosphorylation conditions. Molecular weights and polydispersities were estimated from viscosity and size exclusion chromatography of allylated derivatives, and are in the 2500 to 8600 g mol−1 range. Polydispersity indices ranged from 1.6 to 4.7. Mv and Mw are comparable for all copolyaramids, which indicates that addition of short aliphatic chains had a negligible effect on Mark–Houwink parameters.

    5. Cationic copolymerization behavior of cyclic ether monomers with norbornene-containing cyclic carbonate or spiro–orthoether structure (pages 5113–5120)

      Tetsuo Hino, Naoto Inoue and Takeshi Endo

      Version of Record online: 7 SEP 2004 | DOI: 10.1002/pola.20341

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      Cationic ring-opening copolymerizations of various cyclic ether compounds with volume expanding monomers bearing norbornene backbones [N-SOC and N-CC] were carried out in the presence of a thermally latent initiator. In the comparison between copolymerizations of “bifunctional epoxides and monofunctional oxetanes” with N-SOC and with N-CC, it was found that N-CC served as a more useful volume controllable comonomer than N-SOC.

    6. Ethylene/1-pentene copolymers synthesized using the metaloxycarbene complex catalyst system [(CO)5W=C(Me)OZr(Cp)2Cl]/MAO (pages 5121–5133)

      Nyambeni Luruli, Valérie Grumel, Robert Brüll, Aletta du Toit, Harald Pasch, Albert J. van Reenen and Helgard G. Raubenheimer

      Version of Record online: 9 SEP 2004 | DOI: 10.1002/pola.20314

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      A metaloxycarbene complex of zirconium activated with methylaluminoxane (MAO) copolymerizes ethylene with 1-pentene. The copolymers (analyzed using 13C-NMR, DSC, CRYSTAF, and SEC-FTIR) have broad molecular weight distributions. The short chain branching distribution (SCBD) in the copolymers is interpretable in terms of different amounts of branching in the high and low molecular weight fractions.

    7. Synthesis and characterization of N-substituted hyperbranched polyureas (pages 5134–5145)

      Ashootosh V. Ambade and Anil Kumar

      Version of Record online: 7 SEP 2004 | DOI: 10.1002/pola.20295

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      N,N′-disubstituted hyperbranched polyureas with methyl, benzyl, and allyl substituents were synthesized starting from AB2 monomers based on 3,5-diamino benzoic acid. This approach opens up a possible synthetic route wherein different functional substituents can be used to generate a library of internally functionalized hyperbranched polymers.

    8. Synthesis of functionalized amine oligomers by free-radical telomerization of methyl methacrylate with a peculiar telogen: 2-Aminoethanethiol hydrochloride (pages 5146–5160)

      Cyrille Boyer, Cédric Loubat, Jean Jacques Robin and Bernard Boutevin

      Version of Record online: 7 SEP 2004 | DOI: 10.1002/pola.20303

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      Amine functionalized telomers were synthesized from methyl methacrylate and 2-aminoethane thiol in a radical way. The telogen agent presents a peculiar behavior because secondary reactions were observed other than telomerization. Specific experimental conditions were applied in order to protect the amine function and to lead successfully and exclusively to primary amine terminated oligomers. The role of the acido–basic equilibrium between the amine form and its hydrochloride derivative form was highlighted. Finally, monofunctionalized oligomers with molecular weights from 2000 g/mol to 15,000 g/mol were synthesized and characterized.

    9. Controlled polymerizations of 2-(dialkylamino)ethyl methacrylates and their block copolymers in protic solvents at ambient temperature via ATRP (pages 5161–5169)

      Baowei Mao, Leong-Huat Gan, Yik-Yuen Gan, Xiaoshi Li, Palaniswamy Ravi and Kam-Chiu Tam

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/pola.20228

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      Controlled/“living” polymerizations of 2-(diethylamino)ethyl methacrylate(DEAEMA) and 2-(dimethylamino)ethyl methacrylate(DMAEMA) via ATRP were achieved using the p-toluenesulfonyl chloride(p-TsCl)/CuCl catalyst system in solvent mixtures of methanol and water at ambient temperature. The rate enhancements due to increasing water content were clearly demonstrated for the polymerization of DMAEMA. Successful block copolymerization using macroinitiators of DEAEMA and DMAEMA suggests that the chain ends of the macroinitiaors are almost fully chlorine-functionalized.

    10. Initiator efficiency of 2,2′-azobis(isobutyronitrile) in bulk dodecyl acrylate free-radical polymerizations over a wide conversion and molecular weight range (pages 5170–5179)

      Nathalie Charton, Achim Feldermann, Alexander Theis, Martina H. Stenzel, Thomas P. Davis and Christopher Barner-Kowollik

      Version of Record online: 9 SEP 2004 | DOI: 10.1002/pola.20322

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      The initiator efficiency, f, of 2,2′-azobis(isobutyronitrile) (AIBN) in dodecyl acrylate (DA) bulk free radical polymerizations has been determined over a wide range of monomer conversion in high molecular weight regimes at 60 °C. The initiator efficiency at low monomer conversions is relatively low (f = 0.13) and decreases with increasing monomer to polymer conversions. The evolution of f with monomer conversion (in high molecular weight regimes), x, at 60 °C can be summarized by the following functionality f60 °C (x) = 0.13 − 0.22 · x + 0.25 · x2 (for x ≤ 0.4). The ratio of the initiator efficiency and the average termination rate coefficient, 〈kt〉, (f/〈kt〉) has been determined at various molecular weights. The (f/〈kt〉) data may be indicative of a chain length dependent termination rate coefficient decreasing with (average) chain length, 〈i〉, proportional to 〈i−0.2.

    11. Free-radical polymerization of dioxolane and dioxane derivatives: Effect of fluorine substituents on the ring opening polymerization (pages 5180–5188)

      Weihong Liu, František Mikeš, Yinzhong Guo, Yasuhiro Koike and Yoshi Okamoto

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/pola.20309

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      Partially fluorinated and perfluorinated dioxolane and dioxane derivatives have been prepared to investigate the effect of fluorine substituents on their free-radical polymerization products. We found that the ring opening contents of the resulting polymers are in the following order: 2-methylene-1,3-dioxolane (II) > 2-difluoromethylene-1,3-dioxolane (I); 2-difluoromethylene-4-methyl-1,3-dioxolane (III) > perfluoro-2-methylene-4-methyl-1,3-dioxolane (IV); 2-methylene-1,3-dioxane (V) > 2-difluoromethylene-1,3-dioxane (VI) > perfluoro 2-methylene-1,3-dioxane (VII). The reaction mechanism of the ring opening and the vinyl addition polymerizations of these partially fluorinated and perfluorinated dioxolane and dioxane derivatives is discussed.

    12. Microstructure and properties of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA)-p-phenylene diamine (PDA) polyimide/poly(vinylsilsesquioxane) hybrid nanocomposite films (pages 5189–5199)

      Mohammad A. Wahab, Il Kim and Chang-Sik Ha

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/pola.20312

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      Hybrid nanocomposite films of poly(vinylsilsesquioxane) (PVSSQ) and polyimide (PI) (PI/PVSSQ) were prepared via sol–gel process from triethyoxyvinylsilane (VSSQ) and thermal imidization from 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA)-p-phenylene diamine (PDA) polyamic acid (BPDA-PDA PAA). Microstructure, interfacial interaction, and properties of the hybrid films were strongly dependent on the composition of PVSSQ.

    13. Polymers derived from N-isopropylacrylamide and azobenzene-containing acrylamides: Photoresponsive affinity to water (pages 5200–5214)

      Haruhisa Akiyama and Nobuyuki Tamaoki

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/pola.20307

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      N-Isopropylacryamide (NIPAM) was copolymerized by free-radical polymerization with N-[2-(4-phenylazophenoxy)ethyl]acrylamide derivatives. The polymers are soluble in cold water and possess lower critical solution temperatures (LCSTs). The value of the LCST rose a few degrees upon UV irradiation and dropped upon irradiation with visible light, reversibly, in processes that correspond to the isomerization of the azobenzene units. The structure of the substituent on the azobenzene unit affects both the transition temperature and the hydrophobicity. A change in photoinduced wettability for water was observed to occur on a prepared film at a temperature different from the LCST measured in water.

    14. Novel thermotropic liquid crystalline-cum-photocrosslinkable polyvanillylidene alkyl/arylphosphate esters (pages 5215–5226)

      P. Sakthivel and P. Kannan

      Version of Record online: 9 SEP 2004 | DOI: 10.1002/pola.20350

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      A new class of linear unsaturated polyphosphate esters based on divanillylidene cyclohexanone possessing liquid crystalline-cum-photocrosslinkable properties have been synthesized from 2,6-bis[n-hydroxyalkyloxy(vanillylidene)]cyclohexanone [n = 6,8,10] with various alkyl/aryl phosphorodichloridates in chloroform at ambient temperature. The resultant polymers were characterized by intrinsic viscosity, FT-IR, 1H, 13C, and 31P-NMR spectroscopy. All the polymers showed anisotropic behavior under hot stage optical polarized microscope (HOPM). The liquid crystalline textures of the polymers became more transparent with increasing spacer length. The Tg, Tm, and Ti of the polymers decreased with increasing flexible methylene chain. The photocrosslinking property of the polymer was investigated by UV light/UV spectroscopy; the crosslinking proceeds via 2π-2π cycloaddition reactions of the divanillylidene exocyclic double bond of the polymer backbone. The pendant alkyloxy containing polymers show faster crosslinking than the pendant phenyloxy containing polymers.

    15. Antimicrobial activity on the copolymers of 2,4-dichlorophenyl methacrylate with methyl methacrylate: Synthesis and characterization (pages 5227–5234)

      Milan V. Patel, Samir A. Patel, Arabinda Ray and Rajni M. Patel

      Version of Record online: 9 SEP 2004 | DOI: 10.1002/pola.20348

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      Copolymers of monomers 2,4-dichlorophenyl methacrylate (2,4-DMA) with methyl methacrylate (MMA) were synthesized with different monomer feed ratios using toluene as a solvent and 2,2′-azobisisobutyronitrile (AIBN) as an initiator at 70 °C. (See the reaction scheme, right.) The copolymers were characterized by IR-spectroscopy. Copolymers composition was determined by UV-spectroscopy. The monomer reactivity ratios were determined by applying the conventional linearization method of Fineman–Ross. Gel permeation chromatography (GPC) was employed to determine molecular weights and polydispersity indexes. The thermal properties have been investigated using thermogravimetric analysis (TGA). The antimicrobial activity of these polymers against bacteria, fungi, and yeast were investigated.

    16. Selectivity in anionic and cationic ring-opening polymerizations of tetramethyl-1-(3′-trifluoromethylphenyl)-1-phenylcyclotrisiloxane and tetramethyl-1-[3′,5′-bis(trifluoromethyl)phenyl]-1-phenylcyclotrisiloxane (pages 5235–5243)

      Thomas M. Gädda, Allison K. Nelson and William P. Weber

      Version of Record online: 9 SEP 2004 | DOI: 10.1002/pola.20349

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      Regioselective anionic attack by propagating silanolate anions on the aryl substituted silicon of I, followed by ring opening, leads to a polysiloxane with regular microstructure.

    17. Polyelectrolyte complexes. VII. Complex nanoparticles based on poly(sodium 2-acrylamido-2-methylpropanesulfonate) tailored by the titrant addition rate (pages 5244–5252)

      Ecaterina Stela Dragan and Simona Schwarz

      Version of Record online: 9 SEP 2004 | DOI: 10.1002/pola.20388

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      Complex nanoparticles with different characteristics, z-averaged particle sizes (Rh), polydispersity indices, and colloidal stabilities were tailored by the addition rate of the titrant, a less investigated factor in the synthesis of interpolyelectrolyte complexes. Poly(sodium 2-acrylamido-2-methylpropanesulfonate) (NaPAMPS) and two polycations bearing positive charges in the backbone, poly(diallyldimethylammonium chloride) (PDADMAC) and a polycation containing 95 mol % N,N-dimethyl-2-hydroxypropyleneammonium chloride units (PCA5), were used for this purpose. The complex nanoparticle characteristics and storage stability were monitored via optical density at 500 nm and dynamic light scattering. Nanoparticles with Rh values of 100–250 nm resulted from the same polyion pair and the same polyion concentrations when the addition rate of the titrant, either the polyanion or polycation, varied within the range of 0.1–1.5 mL/mL of the starting polyion × h.

    18. Transition from microemulsion to emulsion polymerization: Mechanism and final properties (pages 5253–5261)

      Kevin D. Hermanson and Eric W. Kaler

      Version of Record online: 9 SEP 2004 | DOI: 10.1002/pola.20340

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      Microemulsion and emulsion polymerization can have some similarities in starting conditions and polymerization mechanisms, but the resulting latexes are unalike. Here we show that polymerizations can be formulated that display the characteristics often separately associated with microemulsion or emulsion polymerization. Kinetic modeling and particle size measurements show that emulsion polymerizations with initial concentrations close to the microemulsion-emulsion phase boundary demonstrate relatively fast consumption of monomer droplets and produce smaller particles. None of the emulsion polymerizations examined demonstrate the classical Smith–Ewart emulsion polymerization kinetics but instead have a long period of particle nucleation that subsides only after monomer droplets disappear.

    19. Side-chain cholesteric liquid-crystalline elastomers derived from smectic crosslinking units: Synthesis and phase behavior (pages 5262–5270)

      Jian-She Hu, Bao-Yan Zhang, Yan Guan and Xiao-Zhi He

      Version of Record online: 9 SEP 2004 | DOI: 10.1002/pola.20390

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      Side-chain cholesteric liquid crystalline elastomers derived from smectic crosslinking units were synthesized. The influence of the content of the crosslinking unit on phase behavior of the elastomers is discussed. Elastomers containing less than 17 mol % of the crosslinking units showed reversible phase transition, wide mesophase temperature ranges, and high thermal stability. Experimental results demonstrated that the Tg, Ti, and ΔT decreased with an increase in the concentration of the crosslinking unit.

    20. Synthesis and vesicular polymerization of novel counter-ion polymerizable/crosslinkable surfactants (pages 5271–5283)

      Geeta Kheter Paul, S. S. Indi and S. Ramakrishnan

      Version of Record online: 9 SEP 2004 | DOI: 10.1002/pola.20392

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      Two novel two-tail surfactants, DDVB and DDDB, with polymerizable (or crosslinkable) counterions, were synthesized. These surfactants formed vesicles, which upon polymerization led to the fixation of vesicular aggregates, probably in a manner wherein the polymer chains (or network) encased the surfactant bilayer by electrostatic interactions. The kinetics of polymerization of both the homo and mixed vesicles prepared from these surfactants were followed by UV–vis spectroscopy and the formation of the polymer was further confirmed by 1H NMR and IR spectroscopy. The role of crosslink density on the stability of these polymerized vesicles was investigated with lysis experiments.

    21. Double metal cyanide complex based on Zn3[Co(CN)6]2 as highly active catalyst for copolymerization of carbon dioxide and cyclohexene oxide (pages 5284–5291)

      Shang Chen, Guo-Rong Qi, Zheng-Jiang Hua and Hong-Qiang Yan

      Version of Record online: 9 SEP 2004 | DOI: 10.1002/pola.20334

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      Double metal cyanide complexes based on Zn3[Co(CN)6]2 were prepared in the presence of different complexing agents and were used in the copolymerization of carbon dioxide and cyclohexene oxide. The FTIR and 1H NMR spectra of the products confirmed the formation of a nearly alternative copolymer. Compared with zinc carboxylate, zinc phenoxide, and so forth, these catalysts demonstrated great enhancement of catalytic activity. Their highest turnover number and turnover frequency reached 3300 and 1650 h−1, respectively, at 90 °C. The molar fraction of CO2 (FCO2) for the copolymers was about 0.44–0.47, and it varied slightly with different catalysts at a temperature of 90 °C and a pressure of 3.8 MPa. The FCO2 of the copolymer can reach 0.40 even at 0.6 MPa, and it changed slightly above 3.8 MPa.

    22. Synthesis and comparison of CF3 versus CH3 substituted perfluorocyclobutyl (PFCB) networks for optical applications (pages 5292–5300)

      Jianyong Jin, Chris M. Topping, Shengrong Chen, John Ballato, Stephen H. Foulger and Dennis W. Smith Jr.

      Version of Record online: 9 SEP 2004 | DOI: 10.1002/pola.20342

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      The new monomer, 1,1,1-tris(4-trifluorovinyloxyphenyl)-2,2,2-trifluoroethane (5), was prepared and represents the CF3 analogue of an established CH3 substituted monomer (6). Monomer 5 polymerizes by free-radical mediated thermal cyclodimerization to produce a crosslinked perfluorocyclobutyl (PFCB) polymer. Compared to monomer 6, fluorinated analogue 5 exhibits increased thermal and oxidative stability and thus may be better suited for optical applications.