bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and luminescence characteristics of conjugated dendrimers with 2,4,6‐triaryl‐1,3,5‐triazine periphery
Authors: Kim Chae Kyu , Song Eun Seok , Kim Hyung Joo , Park Chiyoung , Kim Young Chul , Kim Jai Kyeong , Yu Jae Woong , Kim Chulhee 
Published: November 2005

AbstractWe have synthesized conjugated dendrimer with triazine peripheries, and their luminescence properties were investigated. The dendrimers consist of dendritic triazine wedges for electron transport, distyrylbenzene core as an emitting moiety, and t‐butyl peripheral groups for good processing properties. The dendrimers have LUMO values of about −2.7 eV possibly because of the triazine moiety with high electron affinity. Photoluminescence study indicates that energy transfer occurs from the triazine wedges to the stilbene bridge, and finally to the core chromophore units due to a cascade decrease of bandgap from the peripheral wedge to core moiety. Therefore, the emission wavelength was determined by the structure of the core unit. The energy transfer efficiency of distyrylbenzene‐cored dendrimers was about 75 and 55% for Trz‐1GD‐DSB and Trz‐2GD‐DSB, respectively. A preliminary electroluminescence property also was investigated. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 254–263, 2006
Improved EL efficiency of fluorene‐thieno[3,2‐b]thiophene‐based conjugated copolymers with hole‐transporting or electron‐transporting units in the main chain
Authors: Lim Eunhee , Jung Byung‐Jun , Shim Hong‐Ku 
Published: November 2005

AbstractNew electroluminescent polymers (poly(9,9′‐dioctylfluorene‐co‐thieno[3,2‐b]thiophene‐co‐benzo[2,3,5]thiadiazole) (P1) and poly(9,9′‐dioctylfluorene‐co‐thieno[3,2‐b]thiophene‐co‐benzo[2,3,5]thiadiazole‐co‐[4‐(2‐ethylhexyloxyl)phenyl]diphenylamine (P2)) possess hole‐transporting or electron‐transporting units or both in the main chains. Electron‐deficient benzothiadiazole and electron‐rich triphenylamine moieties were incorporated into the polymer backbone to improve the electron‐transporting and hole‐transporting characteristics, respectively. P1 and P2 show greater solubility than poly(9,9′‐dioctylfluorene‐co‐thieno[3,2‐b]thiophene (PFTT), without sacrificing their good thermal stability. Moreover, owing to the incorporation of the electron‐deficient benzothiadiazole unit, P1 and P2 exhibit remarkably lower LUMO levels than PFTT, and thus, it should facilitate the electron injection into the polymer layer from the cathode electrode. Consequently, because of the balance of charge mobility, LED devices based on P1 and P2 exhibit greater brightness and efficiency (up to 3000 cd/m2 and 1.35 cd/A) than devices that use the pristine PFTT. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 243–253, 2006
Formation of elastomeric network polymers from ambient heterogeneous hydrosilations of carboranylenesiloxane and branched siloxane monomers
Authors: Kolel‐Veetil Manoj K. , Keller Teddy M. 
Published: November 2005

AbstractThe Karstedt catalyst‐catalyzed ambient‐condition hydrosilation reactions in hexane of a monomeric vinyl‐containing carboranylenesiloxane, 1, and three‐branched siloxane crosslinker monomers were discovered to produce elastomeric network polymers at very rapid rates of formation. The flexible and transparent films of the saturated elastomeric network polymers were observed to possess low glass‐transition temperatures (below −35 °C). Similar hydrosilation reactions at two different reactant ratios involving a diethynyl‐containing carboranylenesiloxane, 2, and the siloxane crosslinkers produced partially hydrosilated and completely hydrosilated polymeric networked systems, which were transparent and elastomeric at room temperature. The glass‐transition temperatures of all the polymeric systems formulated from 2 were below 0 °C. The elastomeric polymeric networks from 1 and 2 were found to have degradation temperatures in the range of 500–550 °C. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 147–155, 2006
Acrylic polymer/silica hybrids prepared by emulsifier‐free emulsion polymerization and the sol–gel process
Authors: Tamai Toshiyuki , Watanabe Mitsuru 
Published: November 2005

AbstractAcrylic polymer/silica hybrids were prepared by emulsifier‐free emulsion polymerization and the sol–gel process. Acrylic polymer emulsions containing triethoxysilyl groups were synthesized by emulsifier‐free batch emulsion polymerization. The acrylic polymer/silica hybrid films prepared from the acrylic polymer emulsions and tetraethoxysilane (TEOS) were transparent and solvent‐resistant. Atomic force microscopy studies of the hybrid film surface suggested that the hybrid films did not contain large (e.g., micrometer‐size) silica particles, which could be formed because of the organic–inorganic phase separation. The SiOSi bond formed by the cocondensation of TEOS and the triethoxysilyl groups on the acrylic polymer increased the miscibility between the acrylic polymer component and the silica component in the hybrid films, in which the nanometer‐size silica domains (particles) were dispersed homogeneously in the acrylic polymer component. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 273–280, 2006
Anionic polymerization of 2,7‐di‐t‐butyldibenzofulvene: Synthesis, structure, and photophysical properties of the oligomers with a π‐stacked conformation
Authors: Yade Tohru , Nakano Tamaki 
Published: November 2005

Abstract2,7‐Di‐t‐butyldibenzofulvene (tBu2DBF), a bulky dibenzofulvene derivative, was polymerized using n‐butyllithium as initiator in tetrahydrofuran at −78 °C and in toluene at 0 °C. tBu2DBF afforded mainly oligomers up to trimer even at [monomer]0/[initiator]0 = 20 ([monomer]0 = 0.2 M) at −78 °C and 0 °C, indicating that this monomer is much less reactive than dibenzofulvene (DBF), its parent compound. The reaction at the same [monomer]0/[initiator]0 ratio at an elevated [monomer]0 gave a small amount of insoluble polymer. The oligomers indicated a hypochromic effect in the absorption spectra and only monomer emission in the fluorescent spectra. The conformation of the trimer and the dimer was examined by means of NOESY NMR spectra and semiempirical calculations. In the trimer conformation, the fluorene moieties of the central and the initiation‐side monomeric units were found to be closely stacked on top of each other, while the termination‐side monomeric unit appeared to be in a faster conformational dynamics compared with the other monomeric units. Although the dimer seemed to have a relatively flexible conformation, a π‐stacked structure appeared to be involved in the conformational dynamics to show hypochromicity. The results of this study suggest that the reported intramolecular excited dimer (excimer) formation of the poly‐ and oligo(DBF)s [J Am Chem Soc 2003, 125, 15474] is based on a slight, local conformational change upon photo absorption, leading to a closer π‐stacked alignment of two neighboring fluorene units than that in the ground state. Such a local conformational transition may be difficult for the tBu2DBF trimer because of steric repulsion of the t‐butyl groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 561–572, 2006
Synthesis and characterizations of well‐defined branched polymers with AB2 branches by combination of RAFT polymerization and ROP as well as ATRP
Authors: Luan Bin , Zhang Bao‐Qing , Pan Cai‐Yuan 
Published: November 2005

AbstractA well‐defined branched copolymer with PLLA‐b‐PS2 branches was prepared by combination of reversible addition‐fragmentation transfer (RAFT) polymerization, ring‐opening polymerization (ROP), and atom transfer radical polymerization (ATRP). The RAFT copolymerization of methyl acrylate (MA) and hydroxyethyl acrylate (HEA) yielded poly(MA‐co‐HEA), which was used as macro initiator in the successive ROP polymerization of LLA. After divergent reaction of poly(MA‐co‐HEA)‐g‐PLLAOH with divergent agent, the macro initiator, poly(MA‐co‐HEA)‐g‐PLLABr2 was formed in high conversion. The following ATRP of styrene (St) produced the target polymer, poly(MA‐co‐HEA)‐g‐(PLLA‐b‐PS2). The structures, molecular weight, and molecular weight distribution of the intermediates and the target polymers obtained from every step were confirmed by their 1H NMR and GPC measurements. DSC results show one T = 3 °C for the poly(MA‐co‐HEA), T = −5 °C, T= 122 °C, and T = 157 °C for the branched copolymers (poly(MA‐co‐HEA)‐g‐PLLA), and T = 51 °C, T = 116 °C, and T = 162 °C for poly(MA‐co‐HEA)‐g‐(PLLA‐b‐PS2). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 549–560, 2006
Singlewall carbon nanotubes covered with polystyrene nanoparticles by in‐situ miniemulsion polymerization
Authors: Ham Hyeong Taek , Choi Yeong Suk , Chee Mu Guen , Chung In Jae 
Published: November 2005

AbstractThis work is to make carbon nanotubes dispersible in both water and organic solvents without oxidation and cutting nanotube threads. Polystyrene‐singlewall carbon nanotube (PS‐SWNT) composites were prepared with three different methods: miniemulsion polymerization, conventional emulsion polymerization, and mixing SWNT with PS latex. The two factors, crosslinking and surface coverage of PS are important factors for the mechanical and electrical properties, including dispersion states of SWNT in various solvents. The PS‐SWNT composite prepared via a conventional emulsion polymerization showed SWNT bundles entirely covered with PS, whereas the PS‐SWNT composite prepared via a miniemulsion polymerization showed SWNT partially covered with crosslinked PS nanoparticles. The method of mixing SWNTs with PS latex did not show the well dispersed state of carbon nanotubes because PS was not crosslinked and was dissolved in a solvent, and nanotubes separated from PS precipitated. So the PS nanoparticle‐SWNT composite had lower electrical resistance, and higher mechanical strength than the other composites made by the latter two methods. As the amount of SWNT increases, the bare surface area of SWNT increases and the electrical conductivity increases in the composite made by the miniemulsion polymerization. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 573–584, 2006
Grafting of silica during the processing of silica‐filled SBR: Comparison between length and content of the silane
Authors: Ramier J. , Chazeau L. , Gauthier C. , Guy L. , Bouchereau M. N. 
Published: November 2005

AbstractThe treatment of nanoscopic silica grafted in the blend during the processing of silica‐filled styrene butadiene rubber was performed with silane, introduced at different concentrations, or at a constant concentration with a given length of alkyl chain. From swelling measurements in water and in solvent, the maximum silane content that can be grafted has been calculated as a function of the length of the silane alkyl chains as well as their efficiency to cover the silica surface. The found values are close to the values found in the literature for grafting in solution. Moreover, a direct correspondence between the length of the silane alkyl chains and their concentration has been deduced. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 143–152, 2006
Synthesis and characterization of polyaniline–polyamidoamine dendrimer blends
Authors: Chao C. M. , Wang G. P. , Wu K. H. , Chang T. C. 
Published: November 2005

AbstractA novel conductive blend of polyaniline (PANI) with polyamidoamine dendrimer (PAMAM (G 2.0)) was prepared by different blending procedure. The PANI‐PAMAM blended polymers were characterized by UV–vis, FTIR, and electron paramagnetic resonance (EPR) spectra. The effect of varying the blending procedure on structure and EPR properties of PANI‐PAMAM blended polymers was investigated. Varying the blending procedure and temperature has a direct effect on the structure and EPR parameters (ΔHPP, g factor, NS, T2, and A/B ratio). EPR spectroscopic studies suggested the presence of chemical interaction between PANI and PAMAM. Electron localization effects in PANI‐PAMAM blended polymers can therefore be studied using the technique of EPR. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1–8, 2006
Surface and interface morphology of polystyrene/poly(methyl methacrylate) thin‐film blends and bilayers
Authors: Li Yanxia , Yang Yuming , Yu Fusheng , Dong Lisong 
Published: November 2005

AbstractThe surface and interface morphologies of polystyrene (PS)/poly(methyl methacrylate) (PMMA) thin‐film blends and bilayers were investigated by means of atomic force microscopy (AFM) and X‐ray photoelectron spectroscopy. Spin‐coating a drop of a PS solution directly onto a PMMA bottom layer from a common solvent for both polymers yielded lateral domains that exhibited a well‐defined topographical structure. Two common solvents were used in this study. The structure of the films changed progressively as the concentration of the PS solution was varied. The formation of the blend morphology could be explained by the difference in the solubility of the two polymers in the solvent and the dewetting of PS‐rich domains from the PMMA‐rich phase. Films of the PS/PMMA blend and bilayer were annealed at temperatures above their glass‐transition temperatures for up to 70 h. All samples investigated with AFM were covered with PS droplets of various size distributions. Moreover, we investigated the evolution of the annealed PS/PMMA thin‐film blend and bilayer and gave a proper explanation for the formation of a relatively complicated interface inside a larger PS droplet. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 9–21, 2006
Compatibility characterization of poly(lactic acid)/poly(propylene carbonate) blends
Authors: Ma Xiaofei , Yu Jiugao , Wang Ning 
Published: November 2005

AbstractThe compatibility of poly(lactic acid) (PLA)/poly(propylene carbonate) (PPC) blends was investigated with Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile testing. The PLA/PPC blends were prepared over the whole composition range. FTIR spectroscopy revealed that there were several specific interactions between the chains of PLA and PPC: the interaction between CH and OC and CO···OC or CO···OC dipole–dipole interactions. Moreover, PLA and PPC were compatible. DSC indicated that PLA and PPC were partially miscible but compatible to some extent because of the similar chemical natures of the blend components. TGA showed that the compatibility of PLA and PPC enhanced the thermal stability of PPC in the blends. As calculated by the Horowitz–Metzger equation, the activation energy for decomposition (Et) of PPC in PLA/PPC (70/30) was 200.6 kJ/mol, whereas Et of pure PPC was only 56.0 kJ/mol. A study of the mechanical properties versus the composition and the strain versus the stress illustrated that there was good compatibility between PLA and PPC, and the phase inversion of the PLA/PPC system occurred between 70 and 60 wt % PLA in the PLA/PPC blends. The Pukanszky model gave credit to very strong interfacial adhesion between PLA and PPC. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 94–101, 2006
Modification of a hydrophilic linear polyurethane by crosslinking with a polydimethylsiloxane. Influence of the crosslink density and of the hydrophobic/hydrophilic balance on the water transport properties
Authors: Dolmaire N. , Méchin F. , Espuche E. , Pascault J. P. 
Published: November 2005

AbstractA hydrophilic thermoplastic polyurethane (TPU) was modified by reactive extrusion to obtain in a first step a grafted and soluble material and to finally form by a hydrolysis condensation process a weakly crosslinked network. Different isocyanates were used as grafting agents and a α,ω‐dihydroxypoly(dimethylsiloxane) (PDMS) was used to modify the hydrophilic/hydrophobic balance of the material and the chain length between the crosslinks. The influence of the isocyanate functionality and of the PDMS content were studied on the network formation and on the thermomechanical and water sorption properties. The networks properties were also compared with those of a TPU/PDMS blend. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 48–61, 2006
Thermal memory of poly(3‐hydroxybutyrate) using temperature‐modulated differential scanning calorimetry
Authors: Gunaratne L. M. W. K. , Shanks R. A. 
Published: November 2005

AbstractThe influence of thermal history on morphology, melting, and crystallization behavior of bacterial poly(3‐hydroxybutyrate) (PHB) has been investigated using temperature‐modulated DSC (TMDSC), wide‐angle X‐ray diffraction (WAXRD) and polarized optical microscopy (POM). Various thermal histories were imparted by crystallization with continuous and different modulated cooling programs that involved isoscan and cool–heat segments. The subsequent melting behavior revealed that PHB experienced secondary crystallization during heating and the extent of secondary crystallization varied with the cooling treatment. PHB crystallized under slow, continuous, and moderate cooling rates were found to exhibit double melting behavior due to melting of TMDSC scan‐induced secondary crystals. PHB underwent considerable secondary crystallization/annealing that took place under modulated cooling conditions. The overall melting behavior was interpreted in terms of recrystallization and/or annealing of crystals. Interestingly, the PHB analyzed by temperature modulation programs showed a broad exotherm before the melting peak in the nonreversing heat capacity curve and a multiple melting reversing curve, verifying that the melting–recrystallization and remelting process was operative. WAXRD and POM studies supported the correlations from DSC and TMDSC results. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 70–78, 2006
Quantum‐chemical approach to the solvatochromic transition in polysilane derivatives
Authors: Orimoto Yuuichi , Aoki Yuriko 
Published: November 2005

AbstractWe approached the solvatochromic transition observed in polysilane derivatives (poly[bis(4‐propoxybutyl)silylene] (PPBS)) from the standpoint of various quantum chemical treatments. It was found from conventional geometry optimizations at the levels of semiempirical and ab initio molecular orbital methods that a protonation to polysilane oligomers with side chain R = OCH3 results in the conformational change of Si‐backbone to a trans‐zigzag structure. Using the Elongation method, which was developed for efficient calculations of huge systems, it was demonstrated that a protonation could change the conformation of Si‐backbone to a trans‐zigzag structure over 10–14 Si atoms. In addition, ab initio calculations showed that the positive charge of a proton can delocalize into the Si‐backbone through a long side chain in PPBS. Positively charged polysilane oligomers provide a rotational barrier that prefers a trans‐zigzag structure, whereas neutral oligomers have a barrier that results to a random structure. This unique behavior of the charged polysilane oligomers should not be disregarded in understanding the mechanism of the solvatochromic transition in PPBS. In ab initio configuration interaction/Mφller‐Plesset through‐space/bond interaction analysis, it was found that such a unique behavior of the rotational barrier in polysilane oligomers could be explained by the effect of orbital delocalization through σ‐conjugation on the Si‐backbone. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 119–133, 2006
Enhanced morphological heterogeneity of PCL in the presence of PVC with isothermal supercritical CO2 treatment
Authors: Shieh Yeong‐Tarng , Yang Huang‐Shung 
Published: November 2005

AbstractThis report presents a continuing study of the morphological changes of polycaprolactone (PCL) with isothermal supercritical CO2 treatments at 304 atm and 35 °C in the presence of poly(vinyl chloride) (PVC). DSC and small‐angle X‐ray scattering (SAXS) data find that the CO2‐assisted melting of PCL at 304 atm and 35 °C recrystallized in the presence of PVC during depressurization of CO2 can result in a decreased thickness of crystal lamellar layers. Heterogeneity, with a size (21.7 nm for pure PCL) larger than the crystal layer thickness (8.2 nm for pure PCL) and the amorphous layer thickness (4.4 nm for pure PCL), is formed after the supercritical CO2 treatment. The size of this heterogeneity is found to enhance from 21.7 nm for pure PCL to 29.8 and 34.9 nm for the PCL samples containing 10 and 25 wt % PVC, respectively. These big heterogeneities in the PCL/PVC blends formed during CO2 depressurization might arise from the segregated PVC‐rich amorphous domains that are located between bundles of the lamellar stacks, possibly as a result of the molecular dragging on PCL during depressurization of the PCL‐interacted CO2. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 85–93, 2006
Deposition of Hydrocarbon Films by Means of Helium‐Ethylene Fed Glow Dielectric Barrier Discharges
Authors: Fanelli Fiorenza , Fracassi Francesco , d'Agostino Riccardo 
Published: November 2005

AbstractSummary: The present work provides a detailed study of helium‐ethylene dielectric barrier glow discharges. The effect of ethylene concentration, total gas flow rate, excitation frequency and applied voltage have been investigated in order to clarify both discharge operational mode, and coating composition. The discharge has been characterized by means of electrical measurements and optical emission spectroscopy, while the stable species contained in the gas effluent have been sampled and analyzed using gas chromatography with mass spectrometry detection to achieve indications on the reactive fragments generated inside the discharge. It has been observed that polyethylene‐like coatings can be obtained for a wide range of electrical conditions, and the deposition rates have been found to range between 20 and 80 nm · min−1.FT‐IR spectrum of a film deposited by Glow Dielectric Barrier Discharge, GDBD, using a helium‐ethylene containing feed ([C2H4] = 0.4%).magnified imageFT‐IR spectrum of a film deposited by Glow Dielectric Barrier Discharge, GDBD, using a helium‐ethylene containing feed ([C2H4] = 0.4%).
Protein Oxidation by Chronic Pulmonary Diseases in Children
Authors: Starosta V. , Griese M. 
Published: November 2005

AbstractThe oxidation of proteins may play an important role in the pathogenesis of chronic inflammatory lung diseases, and may contribute to lung damage. However, the extent of oxidation and the distribution among proteins are not known for most pediatric lung diseases. In this work, protein oxidation was assessed as protein carbonyls. Bronchoalveolar lavages (BAL) from children with chronic lung diseases were investigated by dot‐blot assay for content and for pattern of distribution of oxidized proteins by two‐dimensional (2D) electrophoresis and Western blotting. Significantly higher levels of protein oxidation than in healthy controls were determined in groups of patients with interstitial lung disease, gastro‐esophageal reflux disease, and pulmonary alveolar proteinosis. The proteins most sensitive to oxidation were serum albumin, surfactant protein A, and α1‐antitrypsin. Our data show increased oxidative stress in lungs of children with chronic pulmonary diseases, with significant interindividual variations. The extent of protein oxidation was proportional to the count of neutrophilic granulocytes in BAL fluid. These findings strongly support the concept that an abundance of reactive oxygen species produced during neutrophilic inflammation may be a deleterious factor, leading to pulmonary damage in these patients. Pediatr Pulmonol. © 2005 Wiley‐Liss, Inc.