bluuebunny/crossref_metadata_2025_split huggingface dataset:
A lithium secondary battery using a thin film of polymer electrolyte as a separator
Authors: Ohta Tomoyuki , Takeoka Shinji , Tsuchida Eishun , Feng Han Yu , Fu Zheng Sheng , Wang Yun Pu 
Published: April 2003

AbstractIon‐conductive polymer which shows an ionic conductivity (σi) of 1.4 × 10−4S/cm at 25°C when mixed with LiClO4 (molar ratio in Li/OE = 0.05) was used as a separator of electrodes in a lithium secondary battery. The effect of high ionic conductivity on the performance of the battery was studied. The polymer structure was $$ \left[ {\rm H}\rlap{-} ({\rm CH}_2 {\rm CHR}\rlap{-} )_{\rm n} {\rm H},{\rm R} = - {\rm CH}_2 ({\rm OCH}_{\rm 2} {\rm CH}_{\rm 2} )_6 {\rm OCH}_3 \right],$$ and the cathode was comprised of poly(1,3,4‐thiadiazole disulfide), graphite powder and the polymer electrolyte. The cell [(−)Li/polymer electrolyte/graphite–poly(disulfide) (+)] had an open circuit voltage (Voc) of 3.25 V, a plateau voltage of 2.75 V, a discharge density (id) of 0.05 mA/cm2 with the cathode utilization of 63%, and achieved over several tens of cycles at 25°C.
Cellulose–polyacrylonitrile blends, 1: thermodynamic interaction parameters and phase diagram in dimethylacetamide–LiCl
Authors: Marsano Enrico , Tamagno Monica , Bianchi Estella , Terbojevich Maria , Cosani Alessandro 
Published: April 2003

AbstractThe phase diagram of ternary mixtures composed of cellulose, polyacrylonitrile and dimethylacetamide–7% LiCl was determined at room temperature. Homogeneous solutions were observed at low polymer concentrations. Two demixing areas were experimentally evidenced when the concentration increased: the first corresponds to an equilibrium between isotropic phases, while the second represents the coexistence of a cellulose mesophase with an isotropic phase. The diagram is discussed in terms of the interaction parameters, determined via light scattering.
Synthesis of a novel polysiloxane‐based polymer electrolyte and its ionic conductivity
Authors: Ni Jianlong , Lin Yunqing , Wang Fosong 
Published: April 2003

AbstractGraft copolymers were synthesized by means of hydrosilylation from poly[hydromethylsiloxane)‐co‐dimethylsiloxane)] and allylether of poly(ethylene oxide)‐co‐(propyleneoxide)] (poly(EO‐CO‐PO)). Network polymer electrolyte complexes were made from the graft copolymers and alkali metal salt by solvent‐casting from acetone and the tetraethyl orthosilicate crosslinking method. The influence of composition of the polyether side chains, and the species and concentration of inorganic salts on the ionic conductivity were investigated. The temperature dependence of the ionic conductivity of the network film was also studied. It is shown that the complexes of the network polymers with alkali metal salt exhibit a very high ionic conductivity of about 5 × 10−5 S/cm at 25°C and have the characteristic of a typical noncrystalline solid electrolyte.
Ionic conductors based on modified poly(p‐phenylene terephthalamide)
Authors: Foo Conrad , McBreen James , Xu Zhe‐Sheng , Okamoto Yoshiyuki 
Published: April 2003

AbstractIonic conductors based on N‐substituted oligo(ethylene oxide) poly(p‐phenylene terephthalamide) (PPTA) were investigated. Two different PPTAs (Mv = 12,000 and 3600) were grafted with tri(ethylene oxide) and hexa(ethylene oxide). These modified PPTAs were found to be soluble in organic solvents such as dimethyl acetamide and dimethyl sulfoxide and were miscible with various concentrations of oligo(ethylene oxide). The resulting blends formed complexes with lithium trifluoromethanesulfonate (LiSO3CF3). The thermal and ionic conductive properties of the blends were investigated. The conductivities of some of the blends were in the range of 0.5–5.0 × 10−5 S/cm at 25°C and 0.5–5.0 × 10−4 S/cm at 100°C. The profile of conductivity at various temperatures followed the Vogel–Tammann–Fulcher (VTF) plots and it suggested that the major ionic transport took place in the amorphous phase.
Photoresponse in ionic conductivity for poly[(ω‐hydroxy)oligo(oxyethylene) methacrylate‐co‐butyl methacrylate] doped with spiropyran derivative and LiClO4
Authors: Kubo N. , Yoshii T. , Kobayashi N. , Ikeda K. , Hirohashi R. 
Published: April 2003

AbstractPhotoresponse in ionic conductivity has been realized in the solid polymer electrolytes, consisting of poly[(ω‐hydroxy) oligo(oxyethylene) methacrylate] [P(MEO)OH] or poly[(MEO)OH‐co‐butyl methacrylate] (PBMA), spiropyran derivative (SP) and LiClO4. SP showed reversible isomerization upon photoirradiation in these films. The ionic conductivity in these films decreased upon ultraviolet light (UV) irradiation and subsequently increased upon visible light (Vis) irradiation. The interaction between photoisomerized merocyanine form (PMC form) and the hydroxyl group on the polymer side chain was confirmed by an IR shift assignable to OH stretching vibration. From DSC thermograms, the change of ionic conductivity was revealed to be considerably affected by this interaction and attributed to reversible photoisomerization of SP. Reversibility of ionic conductivity was improved in copolymer P[(MEO)OH‐co‐BMA] in comparison with that in P(MEO)OH.
A Raman study of ion solvation and association in polymer electrolytes
Authors: Torell Lena M. , Jacobsson Per , Petersen Greger 
Published: April 2003

AbstractIon–polymer and ion–ion interactions in polymer electrolytes have been investigated at different temperatures and pressures, and for different polymer molecular weights. Salt–polymer complexes of various triflate salts, M(CF3SO3)x (M = Li+, Na+, Ca2+, Cu2+ and Nd3+), in low molecular weight polyethers (PEO and PPO) have been studied using Raman and Brillouin scattering. It is found that anions coordinated to the OH end groups of the polyethers are more stable than cations forming crosslinks between oxygens of adjacent chains, which in turn are more stable than cations coordinated to single chains. We have observed that the number of ion pairs increases as the polymer molecular weight increases. Furthermore, the ion–ion interaction is strongly temperature‐dependent and shows widely different behavior in different systems. In the case of Li+‐, Na+‐ and Ca2+‐containing polyether complexes the ion association increases with increasing T. It is constant in Cu2+–triflate complexes, while it decreases for complexes containing trivalent Nd3+ cations. Pressure observations in LiCF3SO3–PPO complexes reveal increasing solubility and fewer ion pairs as pressure increases. It is shown that theories which consider volume changes in the salt dissociation process can qualitatively explain the effects of molecular weight, temperature and pressure using entropy considerations. The entropy effect includes contributions due to free‐volume dissimilarities between the solvated ions and the macromolecules, structural ordering induced via cationic crosslinking of adjacent chains and electrostriction. Comparing the spectroscopic data with conductivity data, it is found that differences in the “free” solvated ion concentration can account for differences in conductivity.
Softening behavior and conductivity in ionene polymer glasses
Authors: Rietz Ralf‐R. , Meyer Wolfgang H. 
Published: April 2003

AbstractIonene glasses are considered as being a new class of materials. Their properties have been investigated in detail by thermoanalytical, solid state NMR, and dielectric techniques. The segmental dynamics of these cationic polyelectrolytes, labeled in chosen positions, have been studied with solid state 2H‐NMR. Below the glass transition the quaternized ammonium groups in the polymer backbone are essentially static, due to strong Coulomb interactions. The glass transition in these materials is characterized by the softening of a network formed by the N+‐cations. However, both the low molecular weight counterions and the organic chain segments linking the ammonium groups are already mobile below Tg. The dynamics of the organic segments in the glassy state can be described as motion between fixed ends. Ionic conductivity in the glassy state is based on thermally activated anion transport. The influence of the flexibility of the organic chain segments and of the type of the anion on the conductivity are discussed. A simple analytic expression is proposed to describe the conductivity behavior in the low frequency limit.
NMR studies of ion mobility and association in polyether‐based polymer electrolytes
Authors: Greenbaum Steven G. 
Published: April 2003

AbstractThe results of several investigations of polyether‐based polymer electrolytes by nuclear magnetic resonance (NMR) spectroscopy conducted in the author's laboratory and by other groups are reviewed. For both 7Li and 23Na NMR, the onset of motional line‐narrowing occurs at about the glass transition temperature, illustrating the importance of polymer segmental motion to ion transport. Examples of the ability of NMR to probe cationanion interactions are discussed. These include chemical shift variations corresponding to different Li+ environments and nuclear quadrupole coupling and relaxation behavior as a probe of Na+ environment.
Paper form copper ion conductive solid electrolyte
Authors: Hara T. , Yasuda N. , Nagata M. , Kondo S. , Sotomura T. 
Published: April 2003

AbstractA paper form solid electrolyte (PFSE) with good conductivity and flexibility was developed. PFSE is made of an inorganic–organic composite consisting of a copper ion conductive solid electrolyte of Rb4Cu16I7Cl13 (SE) and a polymer binder embedded in a synthetic fibre network. A PFSE with styrene–butadiene based synthetic rubber (SB) was found to give the highest conductivity among the binding materials that we examined. The SB content was changed from 10 vol% to 90 vol% in the PFSE, and the electrical properties and the damp resistance of PFSE were evaluated. Electrical conductivity decreased slightly with an SB content below 70 vol% and abruptly above 70 vol%. The damp resistance of PFSE improved with the increase of the SB content and was superior to that of the raw powder. The PFSE with 65 vol% SB showed relatively high conductivity, 3 × 10−3 S/cm, which was sufficient for battery use, and good damp resistance.
Development and commercialization of ionic‐type photosensitive polyimides
Authors: Asano Masaya , Eguchi Masuichi , Kusano Kazutaka , Niwa Katsuhiro 
Published: April 2003

AbstractToray's ionic‐type photosensitive polyimide, “Photoneece”, is widely used as an interdielectric and as a protection layer for microelectronics, because of its properties, such as the removal of photoreactive groups at low temperature, excellent thermal, mechanical and electrical film properties and excellent adhesion to various substrates. Toray has developed a new type of “Photoneece”, UR‐5100, which is a low‐stress photosensitive polyimide. In addition to a low thermal expansion coefficient (25 ppm/°C), “Photoneece” UR‐5100 also features high resolution with an aspect ratio of more than 2.0 in 40 μm imaged film, and excellent mechanical properties in the cured film such as high elongation (>20%) and tensile strength (>200 MPa), even after 60 hr heat treatment at 350°C. “Photoneece” UR‐5100 can be applied in multichip modules (MCMs), hybrid circuits, ICs and LSIs. In this paper the characterization and processing of this “Photoneece” UR‐5100 are described.
Negative‐type photosensitive polyimide precursors developable with aqueous alkaline solutions
Authors: Kikkawa H. , Shoji F. , Tanaka J. , Kataoka F. , Satou H. 
Published: April 2003

AbstractNew photosensitive polyimide precursors developable with aqueous alkaline solutions were synthesized. Among diamine monomers having a photofunctional group, 2′‐(methacryloyloxy)ethyl 3,5‐diaminobenzoate yields high molecular weight polyamic acid. A photosensitive polymer composition consisting of Michler's ketone and a thermally stable peroxide, 3,3′,4,4′‐tetrakis(t‐butyldioxycarbonyl)benzophenone, results in a high photosensitivity of 200 J/m2. The photosensitive coating of the composition is soluble in aqueous alkaline solutions as well as in organic aprotic polar solvents, and both solvents can be used as developers. However, the resolution of patterns is quite different, especially in thick films. Solvent developers results in poor resolution, whereas aqueous alkaline developers give patterns of high aspect ratio even in thick films. This is probably due to the difference in the diffusion efficiency and swelling properties of the polymer compared to the developers.
Polyimides for electronics applications
Authors: Mukerji Prosanto K. , Demet George 
Published: April 2003

AbstractA variety of options exists for lithographically defining polyimides for microelectronics applications. The two investigated here, photosensitive polyimide and wet etching of low‐stress polyimides, offer lower cost, higher throughput solutions compared with dry etch processes. Via sizes of less than 25 μm and film thicknesses of greater than 14 μm are difficult to process using these techniques: however, for applications such as interlayer dielectrics for high‐density packaging or solder masks for flip chip die attachment, these limitations may not be insurmountable. Photosensitive polyimide can be patterned with fewer steps, but the overall quality of the film in terms of surface planarity and residual stress is not as good as wet etching of conventional polyimide.
Oxidation of a PPy‐modified tantalum electrode
Authors: Park Young‐Seo , Yamamoto Kimihisa , Takeoka Shinji , Ohta Tomoyuki , Tsuchida Eishun 
Published: April 2003

AbstractA tantalum electrode on which polypyrrole (PPy) had been previously formed by electropolymerization was galvanostatically electrolyzed in an aqueous solution of 0.01 wt% phosphoric acid. This process contains the irreversible oxidation of a PPy film, the decomposition of solvent, and the formation of Ta2O5 by the reaction of OH− coming through the PPy film, with Ta electrodes. A three layer‐structure (PPy/Ta2O5/Ta) was confirmed by electron spectroscopy for chemical analysis (ESCA). A PPy film containing CIO4− as dopant [PPy(CIO4−)] was significantly deteriorated in comparison with PPy(TsO−) at the electrolysis. Therefore, the (PPy(TsO−)/Ta2O5/Ta) system showed better electrical characteristics as a capacitor than the (PPy(CIO4−)/Ta2O5/Ta) system showed better electrical characteristics as a capacitor than the (PPy(ClO4−)/Ta2O5/Ta) system.
Antistatic applications of conducting polyaniline
Authors: Trivedi Dinesh Chandra , Dhawan Sundeep Kumar 
Published: April 2003

AbstractA method is described to impart flexibility and mechanical strength to conducting polyaniline by polymerizing aniline on fabrics and on cellulose papers. The study indicates that these conducting fabrics offer 16–18 dB of shielding effectiveness for the control of electromagnetic interference (EMI) up to a frequency of 103 MHz.
Radiation‐induced crosslinking and grafting of two polyphosphazene elastomers
Authors: Grune G. L. , Stannett V. T. , Chern R. T. , Harada J. 
Published: April 2003

AbstractThe radiation‐induced crosslinking and grafting of two aryloxy‐substituted elastomeric polyphosphazenes have been carried out by both gamma and electron beam irradiation. The classic Charlesby–Pinner [1] plus a simpler approach were used to determine the G(X) values for the crosslinked elastomeric polymers. The apparent G(X) value for the same polymer depended on whether the gamma‐ray or the E‐beam results were used. The presence of 8.5% repeat units with allylic groups in the side chain increased the G(X) value by an order of magnitude when the irradiation was performed under vacuum with the gamma source. The extent of acrylic acid grafting was also higher for the polymer containing the allylic group. Nearly all the grafted polyphosphazene films were insoluble in THF, a good solvent for the ungrafted samples.
Phase separation behavior of epoxy resin modified with crosslinked rubber
Authors: Kim Dae Su , Kim Sung Chul 
Published: April 2003

AbstractLow molecular weight liquid rubber (ATBN = amine terminated butadiene acrylonitrile copolymer or CTBN = carboxyl terminated butadiene acrylonitrile copolymer)–DGEBA (diglycidyl ether of bisphenol A) blends indicated upper critical solution temperature (UCST) behavior. The phase separation behavior of the neat and crosslinked rubber (ATBN, CTBN)–epoxy blends was analyzed by a laser light scattering experiment. Lauryl peroxide (LPO) was employed to crosslink the rubber during the initial annealing stage. The onset point of the phase separation in the crosslinked ATBN–epoxy system occurred later than in the case of the neat ATBN–epoxy system. However, the onset point of the phase separation process started earlier in the case of the crosslinked CTBN–epoxy system. The domain correlation length of the crosslinked rubber‐added system was smaller than that of the neat rubber‐added system.
Ethylene/propylene copolymers with vanadium‐based catalysts: Cocatalyst effect
Authors: Dall'Occo Tiziano , Galimberti Maurizio , Balbontin Giulio 
Published: April 2003

AbstractEthylene/propylene copolymers were obtained with vanadium‐based catalysts. Different aluminium alkyls were employed as cocatalyst: Al(C2H5)2Cl/promoter, Al(i‐C4H9)3, Al(n‐C6H13)3. and Al(n‐C8H17)3. The influence of the cocatalyst on the molecular weight, the molecular weight distribution and the microstructure of the copolymers was investigated through GPC, DSC, 13C–NMR analysis and fractionation.AIR3 afforded a polymerization activity that was much higher with respect to Al(C2H5)2Cl/nBPCC, but with the latter cocatalyst system copolymers were obtained with a more homogeneous distribution of the monomers and the absence of crystallinity. A comparison with ethylene/propylene copolymers obtained with a V(Acac)3/Al(C2H5)2Cl/promoter and with a high‐yield Ti‐based catalyst is also presented.
Ethylene–styrene thermoplastic copolymers prepared with supported Ziegler–Natta catalysts
Authors: Masson P. , Spitz R. , Pasquet V. 
Published: April 2003

AbstractThe magnesium chloride supported Ziegler–Natta catalysts are able to copolymerize ethylene and styrene in conditions of high activity. Different parameters, including catalyst type, monomer ratio, temperature and Lewis bases, allow variation of the activity and reactivity ratio. The incorporation of styrene in the copolymer remains always rather limited in moles. The products obtained contain less than 20% styrene in weight, and seem very similar in structure to linear low‐density polyethylenes (LLDPE) obtained with the same catalyst: the melting temperature is only about 5°C lower than that of pure polyethylene. The polymer can be fractionated by solvents in a similar manner to LLDPE, and contains a styrene‐enriched fraction, but homopolystyrene production has never been observed.
Copolymerization of propene‐nonconjugated dienes: Derivatization through hydroboration and epoxydation
Authors: Dassaud Jean Philippe , Guyot Alain , Spitz Roger 
Published: April 2003

AbstractCopolymerization of propylene and nonconjugated dienes such as 1–9 decadiene (α–ω symmetric) and 7‐methyl‐1,6 octadiene (asymmetric) is carried out in the presence of highly active isospecific catalysts for propene polymerization. The incorporation of the diene is random and does not affect the isospecificity of the catalytic system. For a low amount of diene, whatever its structure, an activation effect is observed. For the symmetric diene, the reactivity of the second double bond gives rise to crosslinking.Derivatization through hydroboration or epoxydation is carried out in suspension, using a toluenetetrahydrofuran solvent mixture that is able to swell the polypropylene and dissolve the reactants. After hydroboration the copolymer is transformed into hydroxylated polymer through oxidation in a phase transfer condition. The epoxydized copolymer shows excellent adhesive properties on anodized stainless steel.
Reactive blending of polypropylene/polyamide‐6 in the presence of tailor‐made succinic anhydride‐terminated oligopropene compatibilizers
Authors: Mülhaupt Rolf , Duschek Thomas , Rösch Joachim 
Published: April 2003

AbstractVarious anhydride‐terminated isotactic and atactic oligopropenes of number average molecular weights ranging between 1,000 and 10,000 g/mole, prepared by maleinating vinylidene‐terminated propene oligomers obtained with isospecific and nonstereospecific metallocene‐based Ziegler–Natta catalysts, have been evaluated as blend compatibilizers of polypropylene/polyamide‐6 (70 vol%/30 vol%) blends to study the role of blend compatibilizer molecular architecture. When added during processing, as shown by IR spectroscopic analysis, the anhydride‐terminated oligopropenes react with the amine‐terminated polyamide‐6 to yield polypropylene‐block‐polyamide‐6 in situ. Such block copolymers are efficient dispersing agents. While the polyamide dispersion in the polypropylene continuous phase is not affected by blend compatibilizer stereoregularities, both stiffness and yield stress as well as notched Charpy impact strength increase with increasing stereoregularities and molecular weights. With oligopropene molecular weights exceeding 1,150 g/mole, the average size of the dispersed polyamide microphases correlates with the volume fraction of the oligopropene‐block‐polyamide‐6 blend compatibilizer and the dicarboxylic acid anhydride/amine molar ratio.
Mechanical behavior and tensile fractography of compatible vinylchloride–vinylacetate–maleic acid terpolymer and nitrocellulose blends
Authors: Chattopadhyay Saumya , Banerjee Amar Nath 
Published: April 2003

AbstractVinylchloride–vinylacetate–maleic acid terpolymer (VMCH) and nitrocellulose (NC) were blended at 10% (W/V) concentration is cyclohexanone at different weight fractions. Compatible blends were obtained at all weight fractions. This paper reports the mechanical behavior of solvent cast blend films of VMCH and NC. The films were prepared by solution blending and subsequent casting on a mercury surface. Depending on the composition, the tensile behavior ranged from brittle to ductile. The effect of the blend ratio on the properties shows that within the Hookeian region the modulus and strength have a positive deviation from linearity, whereas the elongation has a negative deviation. The effect of the blend ratio on the ultimate properties of the materials shows a positive deviation in strength up to 63 wt% VMCH composition and a negative deviation in elongation and toughness. The tensile fractography of the pure VMCH and VMCH/NC blends shows the presence of peaks, foldings of fibrils along with cavities or voids, which indicate a ductile mode of failure with craze‐initiated fracture. Fractography of the pure NC Indicates a brittle mode of failure wit
h craze‐initiated fracturing.
Properties of tetra‐N‐glycidyl‐4,4′‐diamino diphenyl methane (TGDDM) cured thick films
Authors: Soni H. K. , Patel R. G. , Patel V. S. 
Published: April 2003

AbstractThick films of tetra‐N‐glycidyl epoxy resin of p,p′‐diaminodiphenyl methane (TGDDM) were prepared using p,p′‐diaminodiphenyl methane (DDM), p,p′‐diaminodiphenyl sulfone (DDS) and diethylene triamine (DETA) as curing agent with or without the epoxy fortifiers PGEHA and VCDRC (at 20 phr level). These thick films were used to evaluate various physical, mechanical, chemical resistant and dielectric properties.
Molecular composites in thermosets
Authors: Kwei T. K. , Levon Kalle , Tesoro Giuliana , Liu Frank , Mey‐Marom Abraham , Munukutla Surya 
Published: April 2003

AbstractThe synthesis of molecular composites where rigid polymer molecules are reinforcing elements in a thermoset bisimide matrix has been investigated. The approach has been designed to avoid phase separation by selecting systems where reaction of amine‐terminated rigid and semiflexible oligomers with maleimide unsaturation occurs prior to crosslinking of the thermoset. This objective has been met for some compositions. The concentration and molecular weight of the rigid oligomers have been varied. The structure of the reinforcing polymer, the reactivity of the maleimide and the conditions for composite synthesis are variables of critical importance, and further work must determine the promise and limitations of this approach.