bluuebunny/crossref_metadata_2025_split huggingface dataset:
Model Supported Morphology Control of Electrospray Deposited Poly(vinylidene fluoride) Film
Authors: Rietveld Ivo B. , Kobayashi Kei , Yamada Hirofumi , Matsushige Kazumi 
Published: March 2007

AbstractPreparation of polymer films with electrospray deposition has been investigated. Morphologies of poly(vinylidene fluoride), prepared under a range of different conditions, have been imaged with AFM. To generalize the conditions under which a particular morphology appears, a model has been used. The model incorporates the parameters that determine droplet size and droplet evaporation in the electrospray deposition process. With the model, film morphology has been shown to depend on the droplet volume at impact, available surface area on the substrate and rate of solvent evaporation from the film. With this information, the model can predict the film morphology under many different spray conditions. This has been demonstrated by determining and predicting the conditions under which PVDF displays the smoothest films.
Fully Aliphatic Polyimides – Influence of Adamantane and Siloxane Moieties
Authors: Mathews Anu Stella , Kim Il , Ha Chang‐Sik 
Published: March 2007

AbstractSeries of fully aliphatic polyimides were prepared from cyclobutane‐ 1,2,3,4‐tetracarboxylic dianhydride and aliphatic diamines. The variations of the basic properties of these polyimides as a result of the incorporation of adamantyl and siloxane moieties are examined. The structure of the polyimides where confirmed by FT‐IR spectroscopy. It was found that polyimides with appropriate ratio of adamantane and siloxane groups showed excellent solubility, good thermal stability, high glass transition temperature, low dielectric constant and beneficial transparencies.
Synthesis of Polycarbonate‐Poly(methyl methacrylate) Copolymer via Sonochemical Polymerization of Methyl Methacrylate in Polycarbonate Solution
Authors: Choi Mikyung , Lee Kyunghee , Lee Juhyun , Kim Hyungsu 
Published: March 2007

AbstractMethyl methacrylate (MMA) was polymerized in the presence of polycarbonate (PC) by ultrasonic irradiation‐initiated polymerization. The resulting products consisted of mixtures of homopolymers of poly(methyl methacrylate) (PMMA), PC and PC‐PMMA copolymer because of the homopolymerization of MMA itself and copolymerization with macroradicals of PC. Formation of the PC‐PMMA copolymer was confirmed by FTIR analysis of the reaction products after a proper extraction of free PMMA from the mixture. In order to verify the effectiveness of the PC‐PMMA copolymer as a compatibilizer for PC/styrene‐co‐ acrylonitrile (SAN) blend, 5 phr of PC‐PMMA was added during melt mixing of PC/SAN in a batch mixer. It was found from the investigation of morphology and rheological properties that interphase of SAN and PC was fortified by numerous ligaments of PC‐PMMA copolymer, which resulted in increase of melt viscosity and storage modulus of the blend.
Synthesis of Diblock Codendrimers by Fusion of the Fréchet‐Type and the PAMAM Dendrons
Authors: Lee Jae Wook , Kim Jung Hwan , Han Seung Choul , Kim Woo Roi , Kim Byoung‐Ki , Kim Ji Hyeon , Huh Do‐Sung , Shin Won Suk , Jin Sung‐Ho 
Published: March 2007

AbstractSeveral diblock dendrimers were synthesized by fusion between the propargyl functionalized Fréchet‐type polyether and the azide functionalized Tomalia‐ type PAMAM dendrons. This was based on the click chemistry protocol, the copper‐catalyzed cycloaddition reaction between an alkyne and an azide. The diblock dendrimers were characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and mass spectra as well as GPC analysis.
Polystyrene Microgel Amphiphilies with Saccharide to Achieve a Fullerene‐Coating on a Hydrophilic Surface
Authors: Narumi Atsushi 
Published: March 2007

AbstractSynthesis of a polystyrene (PSt) microgel with glucose and maltohexaose, in which a good coating property was combined with an excellent hydrophilic property, is described. The glycoconjugated PSt microgel showed the ability to solubilize fullerene in aqueous solution, thus having a potential application to achieve the coating of a functional but incompatible compound, such as fullerene due to the lack of polarity, on the surface of various hydrophilic materials.
Template Polymerization of Multi‐Vinyl Monomer with Poly(2‐hydroxyethyl methacrylate) Backbone
Authors: Saito Reiko , Yokoi Kazuhiro , Iijima Yuki 
Published: March 2007

AbstractIn order to investigate the propagation of polymerization in the template with linear polymer chain, ATRP of methacryloyl type multi‐vinyl monomers of pol(2‐hydroxyethyl methacrylate) backbone with and without styryl groups on the chain ends was carried out. Change of hydrodynamic radii of products and conversion of vinyl group were analyzed by GPC and FT‐IR, respectively.When the multi‐vinyl monomer concentration was less than 0.3 wt%, gelation was completely hindered. The kinetic plots of polymerization of multi‐vinyl monomers with and without styryl group on the chain ends agreed well.
Design of Latent Accelerators for Thermally Latent (Poly)addition of Epoxide with Hemiacetal Ester
Authors: Endo Takeshi , Komatsu Hiroyuki , Ochiai Bungo , Hino Tetsuo 
Published: March 2007

AbstractThis article describes thermally latent addition of epoxides and hemiacetal esters using novel latent accelerators. As latent accelerators for the thermally‐controlled (poly)addition, we desinged schiff‐base zinc chloride complexes (ZnCl2/1R) and salen‐zinc complex (Zn/2). This latent reaction takes place via the reaction of epoxides and carboxylic acids produced from thermal dissociation of hemiacetal esters at moderate temperatures. Use of bifunctional monomers give the corresponding polyesters with side chains bearing acetal and hydroxyl group through the polymerization using the catalysts with tuned Lewis acidities. Zn/2 shows a sharper temperature dependence than ZnCl2/1H.
Temperature‐Responsive Surface Coatings Based on Poly(methylsilsesquioxane)‐hybrid Polymers
Authors: Kessler Daniel , Théato Patrick 
Published: March 2007

AbstractThe present paper presents a new method to build up temperature‐responsive surfaces. First a poly(silsesquioxane)‐block‐poly(N‐isopropyl‐acrylamide) (PMSSQ‐b‐PNIPAM) was successfully synthesized using RAFT polymerization. Spin‐coating or dip‐coating of PMSSQ‐b‐PNIPAM onto glass surfaces resulted in temperature‐responsive surfaces. Surface ATR FT‐IR measurements proofed the successful surface modification using PMSSQ‐b‐PNIPAM. IR fine structures of PNIPAM and PMSSQ could be assigned, respectively. In capillary rise experiments a change of the meniscus height measured at temperatures below or above LCST was observed, indicating a different wetting behavior. Thus, a simple spin‐ or dip‐coating step results in a clean and temperature‐responsive surface.
Enthalpy‐Entropy Compensation in Aggregation of Poly(styrene‐co‐sodium methacrylate) Ionomers in Aqueous Solution
Authors: Yu Jeong‐A , Oh Sung‐Hwa , Park Yu‐Ri , Kim Joon‐Seop 
Published: March 2007

AbstractSpectroscopic methods were employed to evaluate the thermodynamics of aggregates formation of P(S‐co‐MANa) in aqueous solution containing a trace of DMF(0.2 mol%) using pyrene as an optical probe. The mol %s of methacrylate unit in poly(styrene‐co‐sodium methacrylate)[P(S‐co‐MANa)] were 3.6, 5.0, 6.2 and 9.4. Measurements were made at a series of temperatures in the range 10–80 °C. Based on the temperature dependence of the critical aggregation concentration (CAC) and by the use of van't Hoff equation, thermodynamic parameters were calculated. At low temperature the aggregation is accomplished by a large positive entropy change and a small negative enthalpy changes. As the temperature increases, the magnitude of entropy change becomes smaller and the enthalpy change is more exothermic. Moreover, the changes in enthalpy and entropy compensate each other for all samples we have studied, and the compensation temperature was ∼320 K.
Soluble Asymmetric Perylene Derivatives for Organic Solar Cells
Authors: Do Jung Yun , Kim Bong Gun , Kwon Ji yun , Shin Won suk , Jin Sung‐Ho , Kim Young‐Inn 
Published: March 2007

AbstractOrganic acceptor material has been developed based on soluble perylene derivative for an organic solar cell. Asymmetric perylene derivatives with an imide and an imidazole group produce absorption spectra close to poly(3‐hexylthiophene) (P3HT) as a donor material. The frontier energy levels of the perylene derivatives can adjust to reasonable charge transmission within a blended polymer layer through the introduction of substituents such as alkoxy, nitro and alkoxycarbonyl group. The nitro group unlike the others leads to the exceeding decrement of the frontier energy levels, which would be unfavorable for efficient charge transfer. Cyclic voltammetry analysis is performed to determine the energy levels of the perylene derivatives.
31P Solid‐State NMR Characterization of Poly(vinylphosphate‐black‐styrene) for DMFC Membrane
Authors: Park Tae‐Joon , Kim Sang Hun , Li Guang Hua , Cho Chang Gi , Kim Yongae 
Published: March 2007

AbstractIn an attempt to develop direct methanol fuel cell (DMFC) membrane with low methanol permeability, we synthesized successfully poly(vinyl phosphate‐ b‐styrene) copolymers from poly(vinyl alcohol‐b‐styrene) by reaction with phosphorus oxychloride and subsequent hydrolysis. We obtained the ratio of the differently bound phosphorus by 31P Solid‐state NMR Spectroscopy because the majority of block copolymer is not soluble or does not make homogeneous solution in a NMR solvent. The total amount of acid groups as well as the ratio of singly and doubly bound phosphorus by 31P Solid‐state NMR and pH titration was slightly different due to the cross‐linked nature of the sample. Therefore, solid‐state NMR spectroscopy is the most powerful technique to characterize cross‐linked polymers like DMFC membrane.
DNA Dynamics under Turbulent Flow
Authors: Lim Sung Taek , Hong Cheng Hai , Choi Hyoung Jin 
Published: March 2007

AbstractUsing high molecular weight DNAs (λ‐and calf‐thymus (CT) DNAs), we investigated their flow characteristics under turbulence in a rotating disk geometry. By putting emphasis on the effect of CT‐DNA concentration, its turbulent drag reduction (DR) characteristics were compared with that of λ‐DNA based on both DR efficiency and mechanical degradation under turbulence. Addition of spermidine into the turbulent flow as a condensing agent showed abrupt change of the DR efficiency of λ‐DNA in a turbulent flow.
Surface Electronic Structures of Polythiophene Derivatives
Authors: Hao X. T. , Hosokai T. , Mitsuo N. , Kera S. , Sakamoto K. , Okudaira K. K. , Ueno N. 
Published: March 2007

AbstractWe report the surface electronic structures of polythiophene derivatives (including polythiophene, poly(3‐butylthiophene), poly (3‐hexylthiophene)(P3HT)) thin films observed by ultraviolet photoelectron spectroscopy and Penning ionization electron spectroscopy. He*‐impact‐surface‐modification was applied on the P3HT surface to control the distribution of the electron density.
Motional Coherency in Chain Dynamics of Glass‐Forming Polymers
Authors: Furuya Hidemine , Takemura Kazuhiro , Kanaya Toshiji 
Published: March 2007

AbstractMolecular dynamics (MD) simulations of 1,4‐polybutadiene in bulk amorphous state were performed. To investigate motional coherency the relaxation rates for the collective and self motions, the collective and self relaxation rates, were evaluated for the short and long time regimes of the normalized intermediate scattering functions. The scattering vector dependence of the collective relaxation rates estimated for both fast and slow processes indicated a minimum at scattering vector q = 1.3 Å−1, corresponding to the position of a peak in the static structure factor. The self relaxation rates increased monotonously with q. A phenomenon known as de Gennes narrowing was reproduced well in the simulation and found to be originated from the inter‐molecular correlation. The details of motional coherency and the distribution functions of relaxation time were evaluated.
Association–Dissociation Equilibrium of an Amphiphilic Polyelectrolyte in Aqueous Solution
Authors: Nojima Rika , Hashidzume Akihito , Sato Takahiro 
Published: March 2007

AbstractThe association–dissociation equilibrium in micellar solutions of an amphiphilic statistical copolymer was investigated by three different experimental techniques of sedimentation equilibrium, dynamic light scattering, and fluorescence. To analyze these experimental data, a novel method was proposed to determine the aggregation number, association constant, intermolecular interaction, and micellar structure. The application of this method to data from the three experimental techniques provided us consistent results characterizing the association–dissociation equilibrium in the present amphiphilic copolymer solutions.
New Biodegradable and Thermoresponsive Polymers Based on Amphiphilic Poly(asparagine) Derivatives
Authors: Watanabe Eiji , Tomoshige Naoki , Uyama Hiroshi 
Published: March 2007

AbstractNew biodegradable and thermoresponsive polymers based on amphiphilic poly(asparagine) derivatives have been developed. They showed a sol‐gel‐sol phase transition. In particular, not only a phase transition behavior but also a lower critical solution temperature (LCST) was observed in the polymers with N,N‐dimethylaminopropyl groups as the hydrophilic side chains. The LCST and a sol‐gel‐sol phase transition temperature could be precisely controlled by changing the composition ratio and kind of the hydrophobic and the hydrophilic groups of the side chains in the polymers. These polymers are expected to be applicable for controlled release of drugs, tissue engineering, and others.
Microwave‐Irradiated Copolymerization of Styrene and Butyl Acrylate
Authors: Jung Hyun Min , Yoo Youngjae , Kim Yong Seok , Lee Jae Heung 
Published: March 2007

AbstractThe emulsion copolymerization of butyl acrylate and styrene in microwave irradiated condition was investigated. The microwave irradiated condition afforded the enhanced conversion rate at high feeding contents of butyl acrylate monomer feeding and the relative increase of butyl acrylate composition in copolymer com pared with the conventional condition as an water bath heating. The reactivity ratio was calculated from Finemann‐Ross plot, and showed difference between two methods that increased reactivity ratio of butyl acrylate was obtained in microwave irradiated condition. The morphology of copolymer was observed by microscopy, then it was founded that the size of spherical polymer particles in microwave irradiated condition showed more regular than that in conventional heating condition.
Green Polymeric Blends and Composites from Renewable Resources
Authors: Yu Long , Petinakis Steven , Dean Katherine , Bilyk Alex , Wu Dongyang 
Published: March 2007

AbstractCurrently new blends and composites are extending the utilisation of polymers from renewable resources into new value‐added products. This paper briefly discusses the development in this area, and introduces our research, in particular the starch‐based nanocomposites, biodegradable polyester/starch blends and cellulose‐ reinforced PLA composites. It can be seen that hydrophilic character of natural polymers has contributed to the successful development of environmentally friendly composites, as most natural fibers and nanoclays are also hydrophilic in nature. On the other hand, hydrophobic property and moisture sensitivity of biodegradable polyesters are challenge to be reinforced by the natural materials.
Molecular Characterization of the Poly(3‐hydroxybutyrate) Depolymerase Gene from Penicillium funiculosum
Authors: Kasuya Ken‐ichi , Tezuka Yoko , Ishii Nariaki , Yamagata Yoko , Shiraki Mari , Saito Terumi , Hisano Tamao , Iwata Tadahisa , Doi Yoshiharu 
Published: March 2007

AbstractA cDNA encoding Penicillium funiculosum P(3HB) depolymerase (PhaZPfu) was cloned from a cDNA library. This cDNA contained a 1,020‐bp open reading frame (ORF) that encoded 339 amino acids. Edman degradation of PhaZPfu indicated that 20 amino acids from the N terminus function as a signal peptide. Homology analysis revealed that PhaZPfu lacks linker and substrate‐binding domains, both of which are observed in bacterial P(3HB) depolymerases. This may account for a weak binding affinity of PhaZPfu to the P(3HB) surface.
Design of Ion Conductive Polymers Based on Ionic Liquids
Authors: Ohno Hiroyuki 
Published: March 2007

AbstractSome ionic liquids have been polymerized after introducing vinyl groups on the component ions. Thus obtained polymerized ionic liquids showed relatively low glass transition temperature and moderate ionic conductivity attributable to unique characteristics of the ionic liquids. The properties of the polymers such as glass transition temperature, decomposition temperature, ionic conductivity, etc, have been further improved through the design of corresponding monomers. It is important to consider a task‐sharing between component monomers, such as providing conductive path and carrier ion source for the design of conductive polymers for specific ions.
Chiral Separation of Racemic Amino Acids through DNA‐Polydiallyldimethylammonium Polyion Complex Membranes
Authors: Yoshikawa Masakazu , Maruhashi Motokazu , Iwamoto Yuki , Ogata Naoya 
Published: March 2007

AbstractNovel polyion complex membrane was prepared from DNA‐Na and polydiallyldimethylammonium chloride (PDADMAC). The newly prepared DNA‐PDADMA polyion complex membrane showed a chiral separation ability, which was measured by using various racemic amino acids as model racemic mixtures. The membrane transported the L‐isomer of Trp or Phe in preference to the corresponding D‐isomer and permselectivities toward the L‐isomer were determined to be 1.26 for L‐Trp and 1.25 for L‐Phe, respectively. From adsorption experiments, it was revealed that the permselectivity was mainly governed by adsorption selectivity.
Modification of Performances of Various Membranes Using MWNTs as a Modifier
Authors: Choi Jae‐Hyun , Jegal Jonggeon , Kim Woo Nyon 
Published: March 2007

AbstractThe effect of multi‐walled carbon nanotubes (MWNTs) incorporated for the modification of membrane performances was studied. Two different types of membranes were prepared by using MWNTs: one was polysulfone (PSf) ultrafiltration (UF) membrane and the other was polyvinyl alcohol (PVA) pervaporation membrane. The PSf UF membranes with different contents of MWNTs were prepared by the conventional phase inversion process, and used for water‐treatment. On the other hand, the PVA membranes with different amount of MWNTs were prepared by the casting and drying method, and used for the pervaporation separation of water out of ethanol solution containing 10% of water. The two different types of membranes were then characterized with several analytical methods to figure out how the MWNTs were distributed through the membranes and affect on the properties of them: For the PSf membranes, the MWNTs mainly located on the surface of the membranes made them more hydrophilic and improved the selective permeation performances of the membranes. In the case of the PVA membranes, the MWNTs were distributed rather homogeneously through out the membranes, and affected on the micro‐morphology of the membranes, causing them to have different pervaporation performances.
On the Influence of Polymer Surface Layer Thickness on the Adhesion of Composite Assembly. Differences between Initial State and Thermal Ageing
Authors: Bénard Quentin , Fois Magali , Grisel Michel , Picard Céline 
Published: March 2007

AbstractNowadays the interest of surface preparation in order to manufacture lighter bonded assemblies is well recognized. However only few study dealing with ageing of bonded composite assembly is described in the literature. The present paper mainly aims to compare the influence of the polymer surface thickness of carbon/epoxy composites on the adhesion behaviour at the initial state and after thermo‐oxydative ageing. Conclusions show that contrary to the initial state, the reduction of the polymer surface layer thickness does not improve ageing behaviour. Indeed, the increase of polymer thickness provides a good protection of the degradation coming from micro/macro voids from the adhesive layer.
Control of Wavelength Dispersion of Birefringence by Miscible Polymer Blends
Authors: Kuboyama Keiichi , Kuroda Takayuki , Ougizawa Toshiaki 
Published: March 2007

AbstractWavelength dispersion of birefringence in a miscible polymer blend of a polynorbornene and poly(styrene‐co‐maleic anhydride) was investigated. By adjusting the blend composition, the drawing ratio and the drawing temperature, the wavelength dispersion was controlled and the wide band quarter‐wave film was obtained. From the results, the necessary conditions to control the dispersion for the wide‐band quarter‐wave film and wide‐band birefringence‐free material are discussed.
Novel Approach to Anti‐Fouling and Fouling‐Release Marine Coatings Based on Dual‐Functional Siloxanes
Authors: Choi Seok‐bong , Jepperson John , Jarabek Laura , Thomas Johnson , Chisholm Bret , Boudjouk Philip 
Published: March 2007

AbstractThe preparation, characterization, and bio‐testing of biocide incorporated silicone coatings for marine applications have been conducted. Derivatives of the biocide, Triclosan (5‐chloro‐2‐(2, 4‐dichlorophenoxy) phenol), were used to covalently attach the biocide moiety to a silicone backbone. The formulation process allowed for control of the resulting coating's mechanical properties as well as antifouling/fouling‐release performance in ocean site testing. The test results showed significantly reduce macro‐fouling with sustained fouling‐release characteristics for the coatings produced.
In vitro studies of steroid hormones in neurofibromatosis 1 tumors and schwann cells
Authors: Fishbein Lauren , Zhang Xuelian , Fisher Lori B. , Li Hua , Campbell‐Thompson Martha , Yachnis Anthony , Rubenstein Allan , Muir David , Wallace Margaret R. 
Published: March 2007

AbstractThe most common NF1 feature is the benign neurofibroma, which consists predominantly of Schwann cells. Dermal neurofibromas usually arise during puberty and increase in number throughout adulthood. Plexiform neurofibromas, associated with larger nerves, are often congenital and can be life threatening. Malignant peripheral nerve sheath tumors (MPNST) in NF1 are believed to arise from plexiforms in 5%–10% of patients. There are reports of increased potential for malignant transformation of plexiform tumors and increase in dermal neurofibromas, during pregnancy. These observations suggest that steroid hormones influence neurofibroma growth, and our work is the first to examine steroid hormone receptor expression and ligand‐mediated cell growth and survival in normal human Schwann cells and neurofibroma‐derived Schwann cell cultures. Immunohistochemistry and real‐time PCR showed that estrogen receptors (ERs), progesterone receptor (PR), and androgen receptor are differentially expressed in primary neurofibromas and in NF1 tumor‐derived Schwann cell cultures compared to normal Schwann cells. However, there is substantial heterogeneity, with no clear divisions based on tumor type or gender. The in vitro effects of steroid hormone receptor ligands on proliferation and apoptosis of early passage NF1 tumor‐derived Schwann cell cultures were compared to normal Schwann cell cultures. Some statistically significant changes in proliferation and apoptosis were found, also showing heterogeneity across groups and ligands. Overall, the changes are consistent with increased cell accumulation. Our data suggest that steroid hormones can directly influence neurofibroma initiation or progression by acting through their cognate receptor, but that these effects may only apply to a subset of tumors, in either gender. © 2007 Wiley‐Liss, Inc.