bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical properties of a novel fluorene‐based thermally stable conjugated polymer containing pyridine and unsymmetric carbazole groups
Authors: Liaw Der‐Jang , Wang Kun‐Li , Kang En‐Tang , Pujari Sidharam Pundlik , Chen Min‐Hung , Huang Ying‐Chi , Tao Bo‐Cheng , Lee Kueir‐Rarn , Lai Juin‐Yih 
Published: January 2009

AbstractA new diiodo monomer containing heterocyclic pyridine and carbazole groups was synthesized via Chichibabin reaction and used in the preparation of a conjugated polymer via Suzuki coupling approach. The conjugated polymer was highly soluble in common organic solvents such as NMP, THF, dichloromethane, chloroform, toluene, xylene, and benzene at room temperature. The polymer had high glass transition temperature at 191 °C and Td10 at 434 °C in nitrogen atmosphere. The pristine polymer exhibited the UV–vis maximum absorption at 355 nm and shifted to 420 nm after protonation. The emission of the polymer in THF solution changed from the blue region with maximum peak at 400 nm to the yellow region with maximum peak at 540 nm after protonated by HCl, and the intensity of emission depended on the concentration of acid. The polymer also showed electrochromic behavior under applied voltage. The emission color of the polymer film changed from blue (435 nm) to yellow (570 nm) when 2.5 V bias voltage was applied. The polymer also exhibited write‐once and read‐many‐times (WORM) polymer memory effect with tristable states. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 991–1002, 2009
Synthesis and photovoltaic properties of poly(p‐phenylenevinylene) derivatives containing oxadiazole
Authors: Wen Shanpeng , Pei Jianing , Zhou Yinhua , Xue Lili , Xu Bin , Li Yaowen , Tian Wenjing 
Published: January 2009

AbstractA novel poly(p‐phenylenevinylene) PPV‐based copolymer (3C‐OXD‐PPV) with electron‐deficient oxadiazole segments as the side chain has been successfully synthesized through the Gilch polymerization. The obtained copolymer is soluble in common organic solvents such as chloroform, tetrahydronfuran, and 1,1,2,2‐tetrachloroethane. The copolymer was characterized by 1H NMR, elemental analysis and GPC. TGA measurement of the copolymer shows it has good thermal stability with decomposition temperature higher than 350 °C. The absorption, electrochemical properties of the 3C‐OXD‐PPV were investigated and also compared with the properties of MEH‐PPV. The HOMO and LUMO levels of 3C‐OXD‐PPV were estimated from the electrochemical cyclic voltammograms. Bulk‐heterojunction PVCs were fabricated by using 3C‐OXD‐PPV blended PCBM as an active layer. The PCE of the PVC is 1.60% under 100 mW cm−2 AM 1.5 illumination, which indicates that 3C‐OXD‐PPV is a potential candidate for the application of polymer PVC. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1003–1012, 2009
Perfluorocarbon‐loaded shell crosslinked knedel‐like nanoparticles: Lessons regarding polymer mobility and self‐assembly
Authors: Nyström Andreas M. , Bartels Jeremy W. , Du Wenjun , Wooley Karen L. 
Published: January 2009

AbstractReversible addition‐fragmentation chain transfer polymerization was employed to synthesize a set of copolymers of styrene (PS) and 2,3,4,5,6‐pentafluorostyrene (PPFS), as well as block copolymers with tert‐butyl acrylate (PtBA)‐b‐PS‐co‐PPFS, with control over molecular weight and polydispersity. It was found that the copolymerization of styrene and PFS allowed for the preparation of gradient copolymers with opposite levels of monomer consumption, depending on the feed ratio. Conversion to amphiphilic block copolymers, PAA‐b‐(PS‐co‐PPFS), by removing the protecting groups was followed by fitting with monomethoxy poly(ethylene glycol) chains. Solution‐state assembly and intramicellar crosslinking afforded shell crosslinked knedel‐like (SCK) block copolymer nanoparticles. These fluorinated nanoparticles (ca. 20 nm diameters) were studied as potential magnetic resonance imaging (MRI) contrast agents based on the 19F‐nuclei; however, it was found that packaging of the hydrophobic fluorinated polymers into the core domain restricted the mobility of the chains and prohibited 19F NMR spectroscopy when the particles were dispersed in water without an organic cosolvent. Packing of perflouro‐15‐crown‐5‐ether (PFCE) into the polymer micelle was demonstrated with good uptake efficiency; however, it was necessary to swell the core with a good solvent (DMSO) to increase the mobility and observe the 19F NMR signal of the PFCE. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1023–1037, 2009
Synthesis and characterization of sulfonated‐fluorinated, hydrophilic‐hydrophobic multiblock copolymers for proton exchange membranes
Authors: Yu Xiang , Roy Abhishek , Dunn Stuart , Badami Anand S. , Yang Juan , Good Alec S. , McGrath James E. 
Published: January 2009

AbstractHydrophilic/hydrophobic block copolymers as proton exchange membranes (PEMs) has become an emerging area of research in recent years. These copolymers were obtained through moderate temperature (∼ 100 °C) coupling reactions, which minimize the ether‐ether interchanges between hydrophobic and hydrophilic telechelic oligomers via a nucleophilic aromatic substitution mechanism. The hydrophilic blocks were based on the nucleophilic step polymerization of 3,3′‐disulfonated, 4,4′‐dichlorodiphenyl sulfone with an excess 4,4′‐biphenol to afford phenoxide endgroups. The hydrophobic (fluorinated) blocks were largely based on decafluoro biphenyl (excess) and various bisphenols. The copolymers were obtained in high molecular weights and were solvent cast into tough membranes, which had nanophase separated hydrophilic and hydrophobic regions. The performance and structure‐property relationships of these materials were studied and compared to random copolymer systems. NMR results supported that the multiblock sequence had been achieved. They displayed superior proton conductivity, due to the ionic proton conducting channels formed through the self‐assembly of the sulfonated blocks. The nano‐phase separated morphologies of the copolymer membranes were studied and confirmed by atomic force microscopy. Through control of a variety of parameters, including ion exchange capacity and sequence lengths, performances as high, or even higher than those of the state‐of‐the‐art PEM, Nafion, were achieved. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1038–1051, 2009
Ruthenium‐incorporated, metathesis‐active polyacetylene
Authors: Sherwood Danielle E. Schuehler , Williams Joseph E. , Sponsler Michael B. 
Published: January 2009

AbstractTwo olefin metathesis methods have been developed for the preparation of metal‐incorporated polyacetylene (MIPA) with high levels of covalently attached ruthenium complex. Treatment of freshly prepared, porous polyacetylene (PA) formed by polymerization of acetylene by the metathesis catalyst (H2IMes)RuCl2(CHPh)(3‐bromopyridine)2 (G2B) with additional G2B resulted in the incorporation of the ruthenium complex into the solid polymer in levels up to 75% by mass, giving two‐step MIPA (MIPA2). Alternatively, single‐step MIPA (MIPA1) samples with similar levels (up to 79% by mass) of ruthenium incorporation were obtained by polymerization of acetylene with highly concentrated solutions of G2B, and the resulting materials formed fine suspensions in CH2Cl2. A variety of experiments confirmed that both the methods give materials with ruthenium covalently attached to PA chains. Shiny, tough MIPA films were obtained by pressing the black powders obtained by either method. Some MIPA properties were dependent on the amount of metal incorporation, but even samples with high incorporation levels mimicked untreated PA in many respects. MIPA1, but not MIPA2, was made electrically conductive by doping with iodine. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1061–1072, 2009
Thermally degradable maleimides for reworkable adhesives
Authors: Zhang Xinnan , Chen Gang‐Chi , Collins Andrew , Jacobson Solomon , Morganelli Paul , Dar Yadunandan L. , Musa Osama M. 
Published: January 2009

AbstractNew thermosetting materials were developed for reworkable adhesive applications by introducing acetal ester groups as thermally degradable linkages into maleimide compounds. The synthesis of compounds containing maleimide functionality and acetal ester linkages was conducted by a one‐step neat reaction from commercially available materials. The polymerization process and thermal degradation of the synthesized materials were studied. It was found that the acetal ester linkage degraded rapidly above 225 °C, and introduction of this linkage into the adhesive formulation led to improved reworkability of adhesively bonded substrates. A mechanism for reworkability was proposed based on the insight provided by experimental and modeling work. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1073–1084, 2009
Relevance of a prereaction for the in situ NMP of styrene using the C‐Phenyl‐N‐tert‐butylnitrone/2,2′‐azobis(isobutyronitrile) pair
Authors: Sciannamea Valérie , Catala Jean‐Marie , Jerome Robert , Jérôme Christine , Detrembleur Christophe 
Published: January 2009

AbstractIn this article, we compare two routes for carrying out in situ nitroxide‐mediated polymerization of styrene using the C‐phenyl‐N‐tert‐butylnitrone (PBN)/2,2′‐azobis(isobutyronitrile) (AIBN) pair to identify the best one for an optimal control. One route consists in adding PBN to the radical polymerization of styrene, while the other approach deals with a prereaction between the nitrone and the free radical initiator prior to the addition of the monomer and the polymerization. The combination of ESR and kinetics studies allowed demonstrating that when the polymerization of styrene is initiated by AIBN in the presence of enough PBN at 110 °C, fast decomposition of AIBN is responsible for the accumulation of dead polymer chains at the early stages of the polymerization, in combination with controlled polystyrene chains. On the other hand, PBN acts as a terminating agent at 70 °C with the formation of a polystyrene end‐capped by an alkoxyamine, which is not labile at this temperature but that can be reactivated and chain‐extended by increasing the temperature. Finally, the radical polymerization of styrene is better controlled when the nitrone/initiator pair is prereacted at 85 °C for 4 h in toluene before styrene is added and polymerized at 110 °C. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1085–1097, 2009
Core‐shell nanoparticles with hyperbranched poly(arylene‐oxindole) interiors
Authors: Kowalczuk Agnieszka , Vandendriessche Annelies , Trzebicka Barbara , Mendrek Barbara , Szeluga Urszula , Cholewiński Grzegorz , Smet Mario , Dworak Andrzej , Dehaen Wim 
Published: January 2009

AbstractCore‐shell type star polymers composed of poly(tert‐butyl acrylate) (poly(t‐BuA)) arms and 100% hyperbranched poly(arylene‐oxindole) interiors were synthesized via the “core‐first” method. Atom transfer radical polymerization of t‐BuA initiated by 2‐bromopropionyl terminal groups of the hyperbranched core was applied for the synthesis of the stars. The resultant star structures were characterized by gel permeation chromatography with triple detection. Polymers of molar masses Mn up to 1.68 × 105 g/mol were obtained. The obtained star polymers compared with the linear counterparts of the same molar mass have a much more compact structure in solution. The intrinsic viscosities of the stars are also significantly lower than their linear counterparts. Light scattering experiments were performed to provide information about the size of these macromolecules in solution. Preliminary characterization of the thermal properties of these novel materials is also reported. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1120–1135, 2009
A new route to acrylate oils: Crosslinking and properties of acrylate triglycerides from high oleic sunflower oil
Authors: de Espinosa L. Montero , Ronda J. C. , Galià M. , Cádiz V. 
Published: January 2009

AbstractTriglycerides with acrylate functionality were prepared from a new route that involves the singlet oxygen photooxygenation of high oleic sunflower oil and further reduction of the resulting hydroperoxide derivatives to a mixture of secondary allylic alcohols. These unsaturated alcohols can be further reduced to saturated alcohols. These two new hydroxyl‐containing triglycerides were functionalized as acrylate esters and radically crosslinked in presence of different amounts of pentaerythritol tetraacrylate. The crosslinking reactions were followed by FTIR spectroscopy and the thermal properties of the final materials were evaluated. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1159–1167, 2009
Controlled synthesis of trifluoropropylmethylsiloxane–dimethylsiloxane gradient copolymers by anionic ROP of cyclotrisiloxanes
Authors: Cypryk Marek , Delczyk BogumiŁa , Juhari Azhar , Koynov Kaloian 
Published: January 2009

AbstractKinetics of the anionic ring opening copolymerization of 2,4,6‐tris(3,3,3‐trifluoropropyl)‐2,4,6‐trimethylcyclotrisiloxane (F3) with hexamethylcyclotrisiloxane (D3) was studied in THF using BuLi as the initiator. The apparent reactivity ratios were estimated by computer simulation to r = 0.10 ± 0.02, r = 51.8 ± 5.5, which were used to predict the copolymer composition. As a result of so much different reactivities, simultaneous copolymerization leads to copolymers of blocky structure containing a narrow intermediate fragment with gradient distribution of siloxane units. Polymers having more uniform distribution of the trifluoropropyl groups along the chain were obtained by the semibatch process, adding F3 to the polymerization of less reactive D3. The resulted copolymers were characterized by SEC chromatography, 29Si NMR, DSC, DMA, and SAXS. Thermal and mechanical properties of the copolymers obtained by simultaneous copolymerization were similar to those of block copolymers. Only the copolymers obtained by semibatch method showed properties typical for gradient copolymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1204–1216, 2009
Butylene copolyesters based on aldaric and terephthalic acids. Synthesis and characterization
Authors: Zamora Francisca , Hakkou Khalid , Alla Abdelillah , Rivas Manuel , De Ilarduya Antxón Martínez , Muñoz‐Guerra Sebastián , Galbis Juan A. 
Published: January 2009

AbstractThe synthesis, characterization, and some properties of new copolyesters analogous to poly(butylene terephthalate) (PBT), based on L‐arabinaric and galactaric acids, are described. These copolyesters were obtained by polycondensation reaction in the melt of mixtures of methyl 2,3,4‐tri‐O‐methyl‐L‐arabinarate or methyl 2,3,4,5‐tetra‐O‐methyl‐galactarate and dimethyl terephthalate with 1,4‐butanediol. Their weight‐average molecular weights ranged between 10,000 and 34,000, with polydispersities ranging from 1.4 to 2.2. The composition of all the copolymers was analyzed by NMR, and was found to have a statistical microstructure. All these copolyesters were thermally stable, with degradation temperatures well above 300 °C. The melting temperature and crystallinity decreased in both series, and the glass transition temperature increased and decreased respectively, for the PBTGa and PBTAr series with increasing amounts of aldaric units in the copolyester chain. Only PBT‐derived copolyesters containing a maximum of 30% aldaric units showed discrete scattering characteristic of crystalline material. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1168–1177, 2009
Spontaneous formation of narrowly‐distributed self‐assembly from polyamidoamine dendron‐poly(L‐lysine) block copolymers through helix‐coil transition of poly(L‐lysine) block
Authors: Harada Atsushi , Nakanishi Kenichi , Ichimura Shinichi , Kojima Chie , Kono Kenji 
Published: January 2009

AbstractThe self‐assembly of head‐tail type block copolymers composed of polyamidoamine dendron head block and poly(L‐lysine) (PLL) tail block was studied using a light scattering technique and transmission electron microscopy. A PLL tail block in a head‐tail type block copolymer exhibits a coil‐to‐helix transition as a result of the change in solvent quality from water to methanol. When the PLL tail block takes a helical conformation in high methanol content, the resulting head‐tail type block copolymer has a defined three‐dimensional structure like that of a protein molecule. Self‐assemblies of such block copolymers having a totally fixed molecular shape spontaneously form polymersome‐like self‐assemblies with an extremely narrow size distribution through converging to a thermodynamically stable assembling state. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1217–1223, 2009
Secretome‐based proteomics reveals sulindac‐modulated proteins released from colon cancer cells
Authors: Ji Hong , Greening David W. , Kapp Eugene A. , Moritz Robert L. , Simpson Richard J. 
Published: January 2009

AbstractAlthough experiments in rodents and human population‐based studies have demonstrated the efficacy of nonsteroidal anti‐inflammatory drugs (NSAIDs) such as sulindac in colorectal cancer (CRC) prevention, a detailed knowledge of the underlying mechanism of action of this drug is limited. To better understand the chemopreventitive effects of sulindac, especially early sulindac‐induced apoptotic events, we used the CRC cell line LIM1215 as an experimental model, focusing on proteins secreted into the LIM1215 culture medium – i.e., the secretome. This subproteome comprises both soluble‐secreted proteins and exosomes (30–100 nm diameter membrane vesicles released by several cell types). Selected secretome proteins whose expression levels were dysregulated by 1 mM sulindac treatment over 16 h were analyzed using 2‐D DIGE, cytokine array, Western blotting, and MS. Overall, 150 secreted proteins were identified, many of which are implicated in molecular and cellular functions such as cell proliferation, differentiation, adhesion, invasion, angiogenesis, metastasis, and apoptosis. Our secretome‐based proteomic studies have identified several secreted modulators of sulindac‐induced apoptosis action (e.g., Mac‐2 binding protein, Alix, 14‐3‐3 isoforms, profilin‐1, calumenin/Cab45 precursors, and the angiogenic/tumor growth factors interleukin 8 (IL‐8) and growth related oncogene (GRO‐α)) that are likely to improve our understanding of the chemopreventitive action of this NSAID in CRC.
Proteomic profiling of yeast‐ and hyphal‐specific responses ofCandida albicansto the antifungal agent, HWY‐289
Authors: Kim Ki‐Young , Shin Yu‐Kyong , Kang Kap‐Chul , Yoo Jong‐Shin , Kim Jung‐Ho , Paik Young‐Ki 
Published: January 2009

AbstractVirulence ofCandida albicansis attributable to its unique dimorphic transition from nonpathogenic yeast cells to pathogenic hyphal cells. We previously discovered a novel antifungal agent, known as HWY‐289. To characterize the mechanism underlying HWY‐289 antifungal activity, we performed 2‐DE to identify proteins that were differentially expressed during yeast‐to‐hyphal transition and in response to HWY‐289. Twenty‐four differentially expressed protein spots were identified in HWY‐289‐treated yeast. Most differentially expressed proteins were involved in carbohydrate‐derived energy metabolism, cellular detoxification, and antioxidant defenses. Two proteins were involved in cell cycle regulation and DNA processing, and both were downregulated by HWY‐289, suggesting that this agent might promote cell death by weakening cellular defense systems. HWY‐289 inhibited yeast‐to‐hyphal transition in a dose‐dependent manner. 2‐DE analysis of hyphae uncovered several proteins that were induced during yeast‐to‐hyphal transition. Of these, aconitase and phosphatidylinositol transfer protein were downregulated by HWY‐289, suggesting that they mediate the antifungal effects of HWY‐289. Finally, RT‐PCR analysis revealed that HWY‐289 induced expression of three RAS‐related genes (CcCST20,CaHST7, andCaCPH1) in yeast cells, but suppressed their expression in hyphae. Thus, the antifungal action of HWY‐289 may be attributable to its ability to disrupt prohyphal RAS signaling.
Air Gaps, Size Effect, and Corner‐Turning in Ambient LX‐17
Authors: Souers P. Clark , Hernandez Andrew , Cabacungan Chris , Garza Raul , Lauderbach Lisa , Liao Sen‐Ben , Vitello Peter 
Published: January 2009

AbstractVarious measurements under ambient conditions are presented for LX‐17. The size (diameter) effect has been measured with copper and Lucite confinement, where the failure radii are 4.0 and 6.5 mm, respectively. The air well corner‐turning has been measured with an LX‐07 booster, and the dead‐zone results are comparable to the previous TATB‐boosted work. Four double cylinders have been fired, and dead zones appear in all cases. The steel‐backed samples are faster than the Lucite‐backed samples by 0.6 μs. Bare LX‐07 and LX‐17 charges of 12.7 mm radius were fired with air gaps. Long acceptor regions were used to truly determine if detonation occurred or not. The LX‐07 booster crossed a 10 mm gap with a slight time delay. Steady‐state LX‐17 crossed a 3.5 mm gap but failed to cross a 4.0 mm gap. LX‐17 charge with a 12.7 mm radius run after the booster crossed a 1.5 mm gap but failed to cross a 2.5 mm gap. Timing delays were measured where the detonation crossed the gaps. The Tarantula model is introduced as embedded in reactive flow JWL++and Linked Cheetah V4, mostly at 4 zones mm−1. Tarantula has four pressure regions: off, initiation, failure, and detonation. The physical basis of the input parameters is considered.
Room temperature growth of semipolar AlN (1$ \bar 1 $02) films on ZnO (1$ \bar 1 $02) substrates by pulsed laser deposition
Authors: Ueno Kohei , Kobayashi Atsushi , Ohta Jitsuo , Fujioka Hiroshi , Amanai Hidetaka , Nagao Satoru , Horie Hideyoshi 
Published: January 2009

AbstractSemipolar AlN $(1 \bar 102) $ films have been prepared on ZnO $(1 \bar 102) $ substrates by employing room temperature (RT) grown AlN layers using pulsed laser deposition. The use of the RT‐AlN layer suppresses the interfacial reactions between AlN and ZnO and makes it possible to take full advantage of the nearly lattice matched wurtzite substrates. The FWHM values of XRCs of semipolar AlN $(1 \bar 102) $ films were 1180 arcsec and 1620 arcsec for symmetric $1 \bar 102 $ diffraction and in‐plane $11\bar 20 $ diffraction, respectively. These results indicate that the use of the RT‐AlN layers and the ZnO substrates would be quite attractive for fabrication of high efficiency UV light emitting devices. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)