bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application and Modification of Cyclometalated Ruthenium(II) Complex [Ru(o‐C6H4‐2‐C5H4N)‐ (MeCN)4]PF6 for Atom Transfer Radical Polymerization
Authors: Camacho Francisco Diaz , Morales Salvador Lopez , Le Lagadec Ronan , Alexandrova Larissa 
Published: November 2006

AbstractPolymerizations of n‐butyl acrylate (BA), methyl methacrylate (MMA) and styrene (St) were promoted by the Ru(II) cyclometalated complex with labile MeCN ligand in the presence of Al(OiPr)3. The polymerization proceeds via radical mechanism and requires the loss of MeCN ligand. The poor control over the polymerizations can be explained in terms of the traditional ATRP scheme. However, the controllability may be significantly improved by addition of reducing SnCl2. Mechanism of the process is proposed.
Synthesis and Electrorheological Characterization of Polyaniline/Barium Titanate Hybrid Suspension
Authors: Fang Fei Fei , Kim Ji Hye , Choi Hyoung Jin 
Published: November 2006

AbstractAs organic/inorganic composites having attracted much attention due to their heterogeneous physical properties, conducting polyaniline (PANI) and barium titanate (BaTiO3) which possesses large electronic resistance and excellent dielectric strength, were utilized to synthesize PANI/BaTiO3 hybrid which is applicable for an electrorheological (ER) material via ‘in‐situ’ oxidative polymerization. Physical properties of the obtained PANI/BaTiO3 composites were characterized via Fourier‐transform infrared spectra (FT‐IR), thermogravimetry analysis (TGA), and scanning electron microscopy (SEM). The ER behaviors were investigated via a rotational rheometer, and their shear stresses were fitted using our previously proposed rheological equation of state.
Reinforcement of Biodegradable Poly(DL‐lactic acid) Material by Equal‐Channel Angular Extrusion
Authors: Cui Hongxiang , Zhang Lianhong , Gong Jianguo , Ma Yuchun , Ying Wang 
Published: November 2006

AbstractThe purpose of this study was to reinforce biodegradable poly(DL‐lactic acid) (PDLLA) material using a new method, equal‐channel angular extrusion (ECAE). Different processing parameters, including the number of extrusion passes and the process temperature, were investigated to analyze their effect on the PDLLA properties. Experimental results indicate that the mechanical strength of PDLLA increased with the number of extrusion passes. The extrusion temperature also affected the mechanical strength of the PDLLA. After two ECAE passes, the bending strength of PDLLA increased from 83.3 to 178.7 MPa. The bending fracture mode for PDLLA changed from brittle failure for initial specimens to ductile fracture after ECAE processing. SEM micrographs showed that the longitudinal split surfaces of PDLLA are of a fibrillar structure. Taken together, the results suggest that ECAE might represent a useful approach for the preparation of reinforced PDLLA.
A “ladder” Morphology in an ABC Triblock Copolymer
Authors: Kaneko Takeshi , Suda Kazuya , Satoh Kotaro , Kamigaito Masami , Kato Toshinori , Ono Tomohiro , Nakamura Eiji , Nishi Toshio , Jinnai Hiroshi 
Published: November 2006

AbstractABC triblock copolymers are known to exhibit a wide variety of unique types of morphologies compared to AB diblock copolymers. In the present study, poly(styrene‐block‐(ethylene‐alt‐propylene)‐block‐(methyl methacrylate)) (SEPM) triblock copolymers were synthesized and their morphologies were extensively studied by transmission electron microtomography (TEMT). In the SEPM triblock copolymer, two kinds of morphologies coexist: One was the well‐known knitting morphology, and the other was a novel morphology called the “ladder morphology”. The ladder morphology was a major morphology in the SEPM copolymer, the stability of which was discussed in terms of the interfacial area and the solubility parameters between the three components.
Magnetic Alignment of Rhodamine B Intercalated in Synthetic Mica
Authors: Kimura Tsunehisa , Uemura Taichi , Kimura Takumasa , Takagi Shinsuke , Inoue Haruo 
Published: November 2006

AbstractRhodamine B was intercalated in interlayer spaces of Somasif Me‐100, a synthetic mica, and the obtained rhodamine B/Somasif hybrid was suspended in a UV‐curable resin precursor. Then, the suspension was subjected to an applied rotating magnetic field to align the hybrid particles, followed by solidification of the medium by UV irradiation to fix the alignment. The hybrid particles were aligned so that the Somasif layer lay perpendicular to the axis of rotation of the applied rotating magnetic field. UV/vis measurement indicated that the transition moment of xanthene ring of rhodamine B lay inclined to the layer of Somasif.
Study of the Impact Resistance of Physically and Dynamically Vulcanized Mixtures of PP/EPDM
Authors: Murillo Edwin A. , López Betty L. 
Published: November 2006

AbstractPhysically and dynamically vulcanized (TPV) mixtures of polypropylene (PP) and ethylene propylene diene terpolymer (EPDM) are prepared by extrusion in order to improve the impact resistance of PP. To enhance the chemical compatibility and provide better interaction between the PP and EPDM in the physical mixtures, both polymers are modified with maleic anhydride (MAH) in solution using xylene as solvent and dicumyl peroxide (DCP) as initiator. The qualitative and quantitative determination of the degree of grafting is study by Fourier Transform Infrared Spectroscopy (FTIR) and varying the amount of DCP and/or amount of MAH in order to determine the optimum amounts to obtain the highest degree of grafting. The effect of the relation of PP/EPDM, the amount of reinforcement filler and mix rate are studied for modified polymer mixtures (PP‐g‐MAH/EPDM‐g‐MAH). For the TPV of PP/EPDM the effects of amount and triallylisocyanurate (TAC) as coupling agent in presence of different amounts of DCP are studied. The physical mixtures of modified polymers prepared with a PP/EPDM ratio of 80/20 and the TPVs blends prepared with a PP/EPDM ratio of 70/30 and containing 15% filler at 60 rpm show the highest impact resistance. The impact resistance, melt flow index and hardness of the different mixtures are measured to determine their possible applications to prepare front panels and bumpers for automobiles by injection molding.
Pre‐Averaged Sampling On the Entanglement Kinetics for Polymer Dynamics
Authors: Horio Kazushi , Masubuchi Yuichi 
Published: November 2006

AbstractA new model for entangled polymer dynamics based on pre‐averaged sampling of the entanglement structure is proposed. Although it has been reported that sliplink simulations are powerful and promising to predict entangled polymer dynamics, it is still unpractical to calculate polymers with many entanglements. In the present study, a possible approach to achieve fast calculation is proposed by pre‐averaged sampling of entanglement structure with skipping detail kinetics of entanglements dominated by chain ends in conventional sliplink models. To achieve time development of the chain conformation and entanglement structure, i) number of entanglement per chain and number of monomers for each segment are randomly obtained from the equilibrium distribution proposed by Schieber [J. Chem. Phys. 2003, 118, 5162] and ii) the renewed entanglement structure is mechanically equilibrated. The established power‐laws on molecular weight dependence of chain dimension, the longest relaxation time and self‐diffusion coefficient were reasonably reproduced. Comparison on linear viscoelastic response is also discussed.
Characterization of PVA and Chitosan/PVA Blends Prepared from Aqueous Solutions of Various Na2SO4 Concentrations
Authors: Drambei Petronela , Nakano Yumiko , Bin Yuezhen , Okuno Tsumuko , Matsuo Masaru 
Published: November 2006

AbstractUniplaner orientation of a particular crystal plane along the surface of a film was investigated for poly (vinyl alcohol) (PVA) film prepared by a coagulation bath with concentrated aqueous solution containing 100 ∼ 300g of Na2SO4 against 1 ℓ of water. The orientation distribution functions of the three crystallographic principal axes of the dried films were obtained by the X‐ray diffraction technique. The same treatment was carried out for the films prepared by stretching biaxially of the fresh gel and then by drying the resultant fresh gel. The very high preferential orientation of the crystal chain axes and amorphous chain segments could be realized by the biaxially elongation. Accordingly, the techniques were applied to the biaxially stretching of chitosan and PVA blend films with high Young's modulus. The planer orientation of the chain axes of chitosan and PVA crystallites could be confirmed. The morphology of the film surface was estimated by measurements of contact angle and electron spectroscopy for chemical analysis. The results suggested that the admixture of chitosan decreases wet ability of the specimen and this tendency was slightly enhanced by the biaxially elongation.
(Supercritical) Ammonia for Recycling of Thermoset Polymers
Authors: Mormann Werner , Frank Petra 
Published: November 2006

AbstractChemical recycling of thermosetting bisphenol‐A‐polycyanurate, triphenylisocyanurate and of N‐phenylmaleimide (pPMI) as well as 4,4′‐methylenbis‐ (4‐N‐phenylmaleimide) (pBMI) has been studied. Polycyanurate thermosets undergo ammonolytic degradation to the level of oligomeric soluble products already at room temperature, complete degradation to bisphenol‐A and melamine, however requires supercritical conditions (160 °C) and longer reaction times. Polyimides prepared by free radical polymerisation after ammonolysis at 160 °C give the corresponding amines and linear polymers with unsubstituted imide and diamide units. SEC of the polymer analogous (with respect to the carbon chain) reaction products and of linear pPMI shows that the polymers have a polymodal molar mass distribution with a high molar mass and an oligomeric fraction.
Nucleation and Crystallization of PLDA‐b‐PE and PLLA‐b‐PE Diblock Copolymers
Authors: Müller Alejandro J. , Castillo Reina V. , Hillmyer Marc 
Published: November 2006

AbstractThe nucleation and crystallization of two types of strongly segregated poly(lactide)‐block‐polyethylene diblock copolymers with an approximate 50/50 composition has been investigated. One material contains an amorphous PLDA block (PLDA‐b‐PE) and the other contains a semicrystalline PLLA block (PLLA‐b‐PE). The overall isothermal crystallization rate of the PLLA block was slowed down as compared to homo‐PLLA by the covalently bonded PE chains that were molten at the PLLA crystallization temperatures. This crystallization rate depression of the PLLA block produces a coincident crystallization process when PLLA‐b‐PE is cooled down from the melt at rates larger than 2 °C/min. The overall crystallization rate of the PE block is faster when it is covalently bonded to previously crystallized PLLA than when it is attached to a rubbery PDLA block, this results from a nucleation effect of PLLA on the PE block. Polarized Light Optical Microscopy (PLOM) confirmed the confined nature of the crystallization process within lamellar microdomains for both diblock copolymers, since neither PLLA nor PE are capable of breaking out and spherulites can not be formed.
Relaxation Processes in Polymer Surface Layers
Authors: Myasnikova Liubov , Blashenkov Nicolai , Boiko Yurii , Ivan'kova Elena , Kalachev Alexei , Lebedev Dmitrii , Marikhin Vycheslav , Radovanova Elena 
Published: November 2006

AbstractA recently built and patented device Nanoluminograph is used for the investigation of the relaxation processes in the surface layers of HDPE films, produced at various conditions. The work of the device is based on the phenomenon of radiothermoluminescence. The use of high‐frequency low‐power, low‐temperature plasma as an ionizing source, and a reduction of the consumed energy down to several orders of magnitude (as compared to that used in similar devices) provides excitation of a surface layer as thin as 100–200 nm. The high sensitivity of the device enables one to reduce the excitation time to 1–2 seconds for obtaining a sufficient intensity of glow curves even from ultrathin layers 20–30 nm thick. All of that minimizes the modifying plasma action on the samples under investigation and provides well reproducible and reliable data. It is found that the intensity, number and positions of peaks on the glow curves are strongly influenced by the preparation conditions of polymer films. The complicated profile of glow curve peaks allows one to assume the overlapping of multiple relaxation processes. Decomposing and fitting peak profiles with the help of a PEAKFIT computer program result in revealing at least 4 relaxation transitions in the temperature region from 109 to 213 K. The temperatures and activation energies of relaxation transitions in surface layers appeared to be lower than those inferred from the DSC data for the bulk polymer. The activation energies of trap depletion upon heating are calculated. The nature of traps is discussed in terms of molecular conformations, morphology and structural defects, as well as the attribution of the observed relaxation transitions to defreezing mobility of different kinetic units.
Polymorphism in Nylon‐11: Characterization using HTWAXS and HTFTIR
Authors: Nair Smitha S. , Ramesh C. , Tashiro K. 
Published: November 2006

AbstractNylon‐11 was crystallized into different crystalline phases by appropriate methods. The α phase was obtained by precipitating nylon‐11 in 1,4‐butanediol. The melt crystallized sample at 175 °C gave pseudohexagonal phase. The γ phase was obtained by casting nylon‐11 in trifluroacetic acid (TFA). The change in the structure was monitored in situ by high temperature wide‐angle X‐ray scattering (HTWAXS) and high temperature Fourier transform infrared spectroscopy (HTFTIR). The studies have shown that nylon‐11 is one of the few nylons that exhibit extensive degree of polymorphism. HTFTIR studies revealed, apart from the conformational differences between various phases of nylon‐11, some information on the formation of γ phase.
A High Performance Flocculating Agent and Viscosifiers Based On Cationic Guar Gum
Authors: Singh R. P. , Pal Sagar , Mal D. 
Published: November 2006

AbstractThe anionic, cationic and nonionic polymeric flocculants endowed with several distinguished characteristics are being increasingly applied for the treatment of industrial effluents, municipal and wastewater. For the treatment of highly negatively charged particle suspensions, cationic flocculants are more efficient. A new route to guar gum derivatives bearing cationic groups has been developed. A series of cationic guar gums (Cat GG) have been developed by incorporating a cationic moiety N‐ (3‐ Chloro‐2‐ hydroxypropyl) trimethyl ammonium chloride (CHPTAC) onto the backbone of guar gum in presence of NaOH. The various grades of cationic guar gum have been characterized by elemental analysis, FTIR spectroscopy and intrinsic viscosity measurement. The flocculation characteristics of these cationic guar gums have been evaluated in silica suspension by jar test. It has been found that among the various grades of cationic guar gums, the one with longer CHPTAC chains shows better performance. The flocculation characteristics of this best performing cationic guar are compared with those of various commercially available flocculants in silica suspension. Their rheological investigations have also been undertaken.
Controlled Release of Model Drug from Biodegradable Segmented Polyurethane Ureas: Morphological and Structural Features
Authors: Reddy Thatiparti Thimma , Hadano Michiko , Takahara Atsushi 
Published: November 2006

AbstractSegmented polyurethane ureas (SPUUs), which are being used in implant devices, were evaluated as drug delivery matrices using theophylline as a model drug without much sacrificing the mechanical properties of films after drug doping. SPUUs were synthesized from aliphatic diisocyanate (lysine methyl ester diisocyante (LDI)), poly(caprolactone) diol with molecular weights 530, 1250 and 2000 and 1,4‐butanediamine. Three series of segmented SPUUs were prepared with various soft segment lengths and were characterized by Fourier transform infrared spectroscopy, dynamic viscoelastic measurements and tensile testing. A single tanδ peak was observed in dynamic viscoelastic measurements, which revealed phase mixing of hard and soft segments. Low elongation at break was observed in case of PCL 2000 based SPUUs, may be due to partial cystallization of PCL segment. The degradation of SPUUs in alkaline solution and in vitro drug release of theophylline in pH 7.4 buffer were also investigated. The drug release behavior from these films were analyzed by the exponent relation Mt/M∞ = ktn, where k and n are constants and Mt/M∞ is the fraction of drug released until time, t. The constant n was found to be close to 0.5 in all samples, which suggests the release of drug from these polymers can be explained by the Fickian diffusion model.
Thermally‐Induced Phase Transitions in the Uniaxially‐Oriented δ Form of Syndiotactic Polystyrene
Authors: Gowd E. Bhoje , Shibayama Naoya , Tashiro Kohji 
Published: November 2006

AbstractThe empty δ (δe) form of uniaxially‐oriented syndiotactic polystyrene (sPS) samples were obtained by extracting the solvent molecules from the δ form of sPS and solvent complex in acetone and methanol. Temperature dependence of the X‐ray fiber diagrams starting from the uniaxially‐oriented δe and δ form has been measured successfully at various temperatures for the first time. The transition behavior was traced clearly by separating the equatorial and layer line reflections. The δe form transformed to the γ form via an intermediate form. The intermediate form is speculated to take disordered structure due to the empty cavities present in the δe form. Calorimetric studies showed an endotherm followed by an exotherm during this phase transition, which is consistant with such a speculation. On the other hand the δ form transformed to the γ form directly without passing through the intermediate form or δe form. During the δ to γ phase transition the solvent molecules evaporate through the columnar structure in a broad range of temperature, allowing the transition to occur smoothly.
Structural Study on Water‐induced Phase Transitions of Poly(ethylene imine) as Viewed from the Simultaneous Measurements of Wide‐Angle X‐ray Diffractions and DSC Thermograms
Authors: Hashida Tomoko , Tashiro Kohji 
Published: November 2006

AbstractThermal behavior of poly(ethylene imine) [PEI] has been studied using simultaneous WAXD/DSC measurement system. PEI exhibits water‐induced and thermally‐induced phase transitions among four kinds of crystalline hydrates: anhydrate (EI/water = 1/0), hemihydrate (1/0.5), sesquihydrate (1/1.5), and dihydrate (1/2). The chain conformation changes from a double helix in the anhydrate to a planar zigzag form in the three hydrates. The anhydrate melts at 60 °C while the hydrates melt differently in the temperature region of 70–110 °C. By means of the simultaneous WAXD/DSC measurements, complex DSC thermograms of PEI hydrates were characterized on the basis of X‐ray diffractions obtained concurrently.
Structural Study of Phase Transition Behavior of Uniaxially‐Oriented Ethylene‐Tetrafluoroethylene Alternating Copolymer
Authors: Phongtamrug Suttinun , Tashiro Kohji , Funaki Atsushi , Arai Kiyotaka , Aida Shigeru 
Published: November 2006

AbstractCrystal modifications and phase transition behavior have been investigated for the uniaxially‐oriented ethylene‐tetrafluoroethylene alternating copolymer samples of equimolar content by the temperature‐dependent X‐ray diffraction and Raman spectral measurements. The X‐ray fiber diagram measured for the sample drawn at 0 °C has been found to be quite different from that drawn above 100 °C or the normal orthorhombic‐type sample. The new X‐ray diagram is characterized by the sharpness of the reflections and the positional shift from the horizontal lines, indicating the tilting phenomenon of the crystallites. This sample was found to transform into the hexagonal phase in the temperature region around 110 °C with keeping the tilting phenomenon. The molecular motion of the more or less conformationally disordered chains was enhanced above this transition region as seen from the increase in the half‐width of trans bands and the intensity increment of gauche bands in the Raman spectra.
Confirmation of Disorder α Form of Poly(L‐lactic acid) by the X‐ray Fiber Pattern and Polarized IR/Raman Spectra Measured for Uniaxially‐Oriented Samples
Authors: Zhang Jianming , Tashiro Kohji , Domb Abraham J. , Tsuji Hideto 
Published: November 2006

AbstractIn the present research, we report for the first time the X‐ray fiber pattern and polarized IR/Raman spectra taken for the uniaxially oriented disorder α form of PLLA, which can confirm the existence of the disorder PLLA α form (α′‐form) and provide some new insight on the structural difference between the order and disorder α forms.
The Control of Thermal and Radiation Stability of Polypropylene Containing Calcium Carbonate Nanoparticles
Authors: Zaharescu Traian , Jipa Silviu , Kappel Wilhelm , Supaphol Pitt 
Published: November 2006

AbstractThermal and γ radiation stability of iPP containing CaCO3 nanoparticles were investigated by oxygen uptake procedure at 190 °C. The loading of iPP matrix was maximum 25% (w/w). The behavior on thermal oxidation was investigated for two formulations of iPP compounds differing by the surface characteristics of nanoparticles (i.e. uncoated and stearic acid‐coated filler). Three irradiation doses (5, 15 and 25 kGy) were applied. The efficient protection of stabilizers that are present in the as‐prepared formulations was emphasized by proper values of the kinetic parameters obtained for oxidation. The contribution of CaCO3 nanoparticles to the oxidative process of iPP is discussed.
Relationships among symptoms, bother, and treatment satisfaction in overactive bladder patients
Authors: Michel Martin C. , Oelke Matthias , Goepel Mark , Beck Elmar , Burkart Martin 
Published: November 2006

AbstractAimsWe have studied the association between various symptoms, bother, and patient treatment satisfaction in overactive bladder (OAB).MethodsEpisodes of urgency, incontinence, daytime frequency and nocturia and responses to the patient perception of bladder condition scale, the urgency perception scale, and visual analog scales of limitations in daily life and of treatment satisfaction were evaluated in 3,824 OAB patients at baseline and during 9 months treatment with tolterodine ER (4 mg q.d.) in an open‐label, observational study. Relationships amongst number of symptoms/ 24 hr and scales were explored. Treatment satisfaction was correlated with improvements in symptoms and scales.ResultsAt baseline, the number of episodes of the four OAB symptoms correlated only poorly with each other and with the two bother‐related scales, while the two scales assessing bother correlated much stronger with each other. Factor analysis identified four components which described “bother,” “incontinence,” “urgency/frequency,” and “nocturia” and in combination explained 81.9% of the total variance. The component “bother” had the strongest individual effect accounting for 42.1% of the total variance. While improvements of symptoms and bother were seen with tolterodine treatment, patient treatment satisfaction correlated strongest with improvements of the two bother‐related scales.ConclusionsWe conclude that the counting of episodes of OAB symptoms only insufficiently describes the afflicted patients. Patient bother is the strongest individual component but only poorly explained by episodes of the four symptoms defining OAB. Alterations of bother may better reflect patient‐relevant outcomes in OAB treatment than alterations in the number of symptom episodes. Neurourol. Urodynam. 26:190–195, 2007. © 2006 Wiley‐Liss, Inc.