bluuebunny/crossref_metadata_2025_split huggingface dataset:
Composite polymer ionics: advanced electrolyte materials for thin‐film batteries
Authors: Scrosati Bruno , Croce Fausto 
Published: April 2003

AbstractIn recent years there has been a continuously growing interest in the development and characterization of polymeric materials having a fast ionic transport. If prepared in the form of thin films, these materials behave as very convenient electrolytic separators for the realization of advanced design, plastic‐like, electrochemical power sources. Various classes of these polymer ionics have been developed and today many choices are available for the realization of devices with different energy and power capabilities. In this paper we describe the properties of a class of composite polymer ionic conductors having improved mechanical and electrochemical properties and which appear particularly suitable for the realization of high‐energy, rechargeable lithium batteries.
Gel‐type solid polymer electrolytes for rechargeable film batteries
Authors: Kabata Toshiyuki , Fujii Toshishige , Kimura Okitoshi , Ohsawa Toshiyuki , Samura Tetsuya , Matsuda Yoshiharu , Watanabe Masayoshi 
Published: April 2003

AbstractGel‐type solid polymer electrolytes (SPE) which consisted of LiBF4 as the electrolyte, a mixture of propylene carbonate and 1,2‐dimethoxyethane as the solvents, and a mixture of ethoxypolyoxyethyleneacrylate and trimethylolpropanetriacrylate as the monomers, were prepared by photopolymerization. The composition range for the gelation and the SPE formation was defined. Relationships between the composition of the SPE, and the ionic conductivity and modulus were clarified. The ionic conductivity of the SPE film, the composition of which was 13 wt% monomer, 20 wt% LiBF4 and 67 wt% solvent, was 2.7 × 10‐3 S/cm, and the modulus was 103 dyn/cm2 at 25°C. When a polyaniline(PANI)/SPE interface was formed on polyaniline films by photopolymerization at the optimal composition, the redox behavior of PANI was almost equivalent to that in nonaqueous electrolyte solutions. The discharge capacity of a Li/SPE/PANI film rechargeable battery was 116 mAh/g‐PANI (based on the weight of PANI), almost the same as that of a Li/nonaqueous electrolyte solution/PANI cell.
Recent advances in photosensitive polyimides
Authors: Ahne Hellmut , Leuschner Rainer , Rubner Roland 
Published: April 2003

AbstractThe state of the art of photosensitive polyimides is reviewed with respect to the incorporation of photosensitivity into both polyimide precursors and soluble polyimides, for patterning in positive and negative modes. This paper emphasizes, in particular, the discussion of the performance of commercially available photosensitive polyimides with respect to their applications in electronics. The decisive properties, especially the patterning performance, and in the case of precursors the curing conditions, required to obtain full imidization, thermomechanical and electrical properties, solvent resistance and water uptake, as well as planarization of the commercially available materials, are compared with each other. An outlook presents the future demands on photosensitive polyimides.
Synthesis and mechanical properties of novel photosensitive polyimides
Authors: Khanna Dinesh N. 
Published: April 2003

AbstractThis paper surveys novel photoimageable polyimides (PHIMPI), with emphasis on synthesis. Details of the chemistry and synthesis techniques on PHIMPI are discussed. A number of associated issues such as swelling, storage stability, shrinkage, photospeed, solvent developability, moisture absorption, thermal expansion and mechanical properties are presented.Most of the photoimageable polyimides that are commercially suitable to date are negative‐acting, although recent developments in positive‐acting PHIMPI are included.
A mechanism for the electron beam lithography of solvent‐soluble photosensitive polyimides
Authors: Yamashita Takashi , Kudo Takafumi , Horie Kazuyuki 
Published: April 2003

AbstractSolvent‐soluble and intrinsically photosensitive polyimides were prepared, and their electron beam reaction was investigated. Negative tone patterns were formed by the electron beam irradiation of PI(BTDA/DEDPM) and PI(BEDA/DEDPM). The mechanism for the pattern formation of PI(BTDA/DEDPM) was determined from transient absorption measurements, changes in the molecular weights, and IR spectrum measurements to be crosslinking via hydrogen abstraction by the triplet excited state benzophenone moiety. For the case of PI(BEDA/DEDPM), the pattern was formed by insolubilization due to chemical change in the polymer. These reactions are found to be so inhomogeneous that insolubilization of the polymer occurs at an early stage of gelation.
Photosensitive polyimides for applications in electrical and optical interconnection technology
Authors: Chakravorty K. K. 
Published: April 2003

AbstractThe application of photosensitive polyimides in electrical and optical interconnection technology is discussed. Critical properties of two photosensitive polyimide formulations with significantly different structural chemistries have been compared. Polyamic ester based formulations such as Selectilux® HTR3 show significant distortions in the photopatterned features upon high‐temperature baking, which can be ascribed to anisotropic shrinkage. A BTDA‐alkylated diamine based preimidized formulation (Probimide®), on the other hand, shows a more uniform shrinkage of the photopatterned features. HTR3 films interacts strongly with metals such as copper, which adversely affect the photopatternability of these materials. Planarization behavior in multiple layer structures has also been investigated. We explored the viability of these materials for applications in optical interconnection. Probimide® materials exhibit low scattering losses and appear to be promising candidates for the development of a MCM‐compatible optical interconnection technology. We also describe here a novel technique for optical recording of refractive index patterns in Probimide® films.
Photoreactive fluorinated polyimide protected by a tetrahydropyranyl group (THP) based on photo‐induced acidolysis
Authors: Omote Toshihiko , Hayashi Syun'ichi , Ishii Kazuhisa , Naitoh Kazuhiko , Yamaoka Tsuguo 
Published: April 2003

AbstractA polyimide (6F‐THP) with a tetrahydropyranyl group (THP) in its side chain has been synthesized. The THP group exhibits a high acidolysis rate in this polymer's film. This rate was faster than that of a tertbutoxycarbonyl group (t‐BOC), which has been previously reported [1]. Furthermore, the deprotected fluorinated polyimide (6FDA‐AHHFP) became soluble in an aqueous base due to the presence of a hydroxyl group attached to the phenyl group of the diamine segment. The polyimide thus provides high performance as a photopolymer when used in conjunction with a photoacid generator after the post‐exposure baking process (PEB). The photoacid generators used in this study were p‐nitrobenzyl‐9,10‐dimethoxyanthoracene‐2‐sulfonate (NBAS) and diphenyliodonium‐9,10‐dimethoxyanthoracene‐2‐sulfonate (DIAS). The quantum yields of photodissociation and photoacid generation were also measured. The photoacid‐generating quantum yields closely corresponded to the photosensitivities of the photoreactive polyimide system. It was confirmed that the THP group was easily deprotected even in the 6F‐THP film with p‐toluenesulfonic acid as a model acid catalyst. The activation energy of the THP deprotection reaction was determined to be 12.8 kcal/mol (19.5 kcal/mol in the case of t‐BOC). The relationships between the THP deprotecting rate constant (kd) and acid molecular size and between kd and polyimide structure were further investigated.
Positive photosensitive polyimides with cyclobutane structure
Authors: Abe Toyohiko , Mishina Makoto , Kohto Noriaki 
Published: April 2003

AbstractA new family of positive photosensitive polyimide (PPI) systems composed of solvent soluble polyimides (Pls) with cyclobutane (CBDA) structures and diazonaphthoquinone compounds (DNQ) has been prepared. Heat and catalytic imidizations were carried out to obtain CBDA Pls; the former was better than the latter in controlling the molecular weight of the Pl. The OH groups in the Pls were easily acetylated during catalytic imidization, so COOH groups were selected as weak acidic groups in the Pls. The COOH groups were also effective in giving the Pls an alkaline solubility. Therefore, Pls having COOH groups were superior to those having OH groups for PPI systems. The photosensitive properties of various PPl systems containing COOH were found to vary with the fraction of COOH groups in the Pls, the content of DNQ in the systems, and the molecular weight of the Pls.
Photoreactive fluorinated polyimide protected by tetrahydropyranyl (THP) group based on chemical amplification: Acid generation in polyimide film and lithographic properties
Authors: Naitoh Kazuhiko , Ishii Kazuhisa , Yamaoka Tsuguo , Omote Toshihiko 
Published: April 2003

AbstractThe photochemistry of photoacid generator (PAG), diphenyliodonium 9,10‐dimethoxyanthracene‐2‐sulfonate (DIAS) and diphenyliodonium 8‐anilinonaphthalene‐1‐sulfonate (DIANS) was investigated in both alkalinesoluble polyimide (6FDA‐AHHFP) and novolak films. The quantum yields of photodissociation of DIAS and DIANS in both 6FDA‐AHHFP and novolak films. The quantum yields of photodissociation of DIAS and DIANS in both 6FDA‐AHHFP and novolak films were determined as 0.11, 0.21, 0.12 and 0.26, respectively. On the other hand, the quantum yields for acid generation from DIAS and DIANS in both of these films were 0.07, 0.18, 0.09 and 0.22, respectively, in the presence of an acid indicator. These results indicate that the values of the quantum yields of photodissociation and photoacid formation for DIAS and DIANS in 6FDA‐AHHFP film are lower than those in novolak film. In order to elucidate the lowering of the quantum yields in 6FDA‐AHHFP film, fluorescence quenchings of sodium 9,10‐dimethoxy‐anthracene‐2‐sulfonate and ammonium 8‐anilinonaphthalene‐1‐sulfonate by a model compound of polyimide was carried out in acetonitrile. The fluorescences of these two salts were efficiently quenched by the model compound with the diffusion‐controlled rate constant in acetonitrile, suggesting that a strong electron‐accepting capability of the imide carbonyl group may hinder the electron transfer process within PAG molecules in 6FDA‐AHHFP film. Although a polyimide (6F‐THP) protected by tetrahydropyranyl group is insoluble in aqueous base, 6F‐THP film containing PAG became soluble in a 2:1 mixture of 2.0 wt% tetramethylammonium hydroxide (TMAH) and methanol by exposure to 365 nm light and successive post‐exposure baking (PEB) at 120°C for 10 min. The sensitivity and contrast of 6F‐THP with DIANS after the PEB conditions mentioned above were 110 mJ/cm2 and 3.7, respectively. A high‐resolution pattern with a good profile was transferred into the 3 μm thickness of the 6F‐THP film.
Photosensitive polyimides consisting of simple mixtures of 4‐substituted diazonaphthoquinones and polyamic acids
Authors: Hayase Shuzi , Mikogami Yukihiro , Takano Kei , Nakano Yoshihiko , Hayase Rumiko 
Published: April 2003

AbstractPolyimide resists that can be developed with a basic aqueous solution were produced by simple mixtures of conventional polyamic acids and naphthoquinone diazides in which sulfonate groups are substituted at the 4‐position. The diazonaphthoquinones bearing electron‐withdrawing groups gave negative tone resists. On the other hand, those bearing electron‐donating groups gave positive tone resists. The difference in the resist behaviors depending on the photoactive structure was explained by crosslinking caused by photogenerated sulfonic acids. The thermal stability of polyimides prepared from the resists was almost the same as that of conventional polyimides.
New polyurethanes able to bind high amounts of heparin, suitable as biomedical compositions
Authors: Marconi W. , Magnone G. , Martinelli A. , Piozzi A. 
Published: April 2003

AbstractThe synthesis of new segmented polyurethanes containing different amounts of N,N‐diethylaminoethyl‐N′‐2,2 hydroxymethylpropionamide, and able to bind, after suitable quaternization, high amounts of heparin, is described. The quaternization is carried out on organic solutions of the polymers. Polymers have been characterized by spectroscopic techniques (transmission and reflectance IR and 1H and 13C NMR), molecular weight measurements and differential scanning calorimetry. The heparin content of the polymer films was determined by a colorimetric system, and its biological activity was evaluated in vitro by activated partial thromboplastin time (APTT) measurements. The distribution of heparin on the surface and in bulk of the heparinized films was evaluated by scanning electron microscopy (SEM) combined with X‐ray energy dispersive spectroscopy.
Antifoam effect of highly fluorinated polysiloxanes
Authors: Kobayashi Hideki , Owen Michael J. 
Published: April 2003

AbstractAqueous foaming solutions of permethylsiloxane surfactants and fluorocarbon surfactants are very resistant to antifoaming. Newly developed polysiloxane fluids having highly fluorinated chains showed very low surface tensions and were examined as antifoaming compounds to test against these two classes of surfactant systems. The fluorinated polysiloxanes evaluated were poly‐[(3,3,4,4,5,5,6,6,6 ‐ nonafluorohexyl)methylsiloxane] (PNFHMS), and 1H,1H,2H,2H‐perfluorodecyl‐terminated polydimethylsiloxane (Def‐DMS). Poly(dimethylsiloxane) (PDMS) was also studied as a standard siloxane polymer fluid for comparison. The antifoams composed of PNFHMS and Def‐DMS polymer fluids incorporated with silica showed effective antifoaming against the low surface tension aqueous solutions of representative permethylsiloxane and fluorocarbon surfactants.
Thermotropicity of fully aromatic polyesters based on 3,4′‐dicarboxydiphenyl ether
Authors: Carpaneto Luca , Marsano Enrico , Valenti Barbara , Costa Giovanna , Guenza Marina 
Published: April 2003

Abstract3,4′‐Substituted aromatic monomers, consisting of two phenylene units joined together by linking groups such as ketone or methylene, have recently been used for the preparation of quasi‐rigid fully aromatic thermotropic polymers, based on conformational isomerism, with accessible transition temperatures.In this work the polyester of 3,4′‐dicarboxydiphenyl ether and hydroquinone is considered: an Ullmann condensation has been carried out for the preparation of the asymmetric monomer, and low‐temperature solution polycondensation has been used to synthesize the polymer. Although a liquid crystalline behavior could be expected, the polyester melts to an isotropic phase. Several copolymers have been prepared, by partially substituting either the asymmetric monomer with terephthalic acid or hydroquinone with different diphenols. The attempt to decrease the stability of the crystalline phase did not lead to significant results. The appearance of the nematic phase in some samples has been attributed to an increased chain stiffness, expressed in terms of persistence length as derived from molecular dynamics (MD) simulations.
Polymeric photoinitiators based on side‐chain benzoin methyl ether and tertiary amine moieties for fast UV curable coatings
Authors: Angiolini Luigi , Caretti Daniele , Carlini Carlo , Lelli Nicola 
Published: April 2003

AbstractThe synthesis is reported of a new series of polymeric photoinitiators obtained by copolymerization of a‐methylolbenzoin methyl ether acrylate (MBA) with different N,N‐dialkylamino alkyl acrylates.The copolymers have been fully characterized and employed in the photoinitiated polymerization and crosslinking reactions of a standard acrylic formulation for clear curable coatings.The photoinitiation activity of the above systems has been measured by using microwave dielectrometry and differential photocalorimetry, and compared with that found for the corresponding low‐molecular‐weight models.The results clearly indicate that the copolymeric systems display a remarkable decrease of the induction period and an improved overall activity in the UV curing of the acrylic coatings.An interpretation of the experimental findings is also reported.
Synthesis of poly(1.4.‐benzamide) in solutions of randomly coiled polymers
Authors: Berger Werner , Kummerlöwe Claudia , Henze Andree 
Published: April 2003

AbstractThe polycondensation of p‐aminobenzoic acid by the use of triphenylphospine and hexachloroethane is described. One way to obtain a mixed solution of rigid rod and flexible coil polymers is the polycondensation of the rigid chains in a solution of a flexible polymer matrix. Results on matrix polycondensation of poly(p‐benzamide) in solutions of poly(methyl methacrylate), poly(methyl methacrylate‐co‐styrene), polystyrene and polyacrylonitrile are reported. It is shown that there exists an interrelation between the phase behavior of the mixed polymer solutions and the influence of the matrix polymer on the synthesis of poly(1.4.‐benzamide). The ternary phase diagrams of the rigid rod/flexible coil polymer solutions were determined.
Photochemical reactivities of photosensitive polymers containing chalcone derivatives
Authors: Akelah Ahmed , Selim A. , El‐Deen N. Salah 
Published: April 2003

AbstractMonomeric vinyl chalcone derivatives were prepared by the condensation reaction of p‐hydroxybenzaldehyde with acetophenone derivatives in the presence of sodium ethoxide as a base, followed by esterification of their hydroxy groups with methacryloyl chloride. The monomers, 4‐(methacryloyloxy)chalcone derivatives, have been polymerized by a free radical technique. Copolymers containing the chalcone groups with different ratios of p‐nitrophenylmethacrylate as photosensitizer group have also been prepared.The photosensitivities of the polymeric chalcone derivatives were investigated through their photochemical reaction on exposure to UV light, and by measuring the changes in their UV spectra before and after irradiation. The results obtained from the disappearance rates of the CC bonds indicate that the photoreactivities of the polymers are largely affected by the position of the substituent in the phenyl ring of the chalcone, the photosensitizer group ratio, and the irradiation time.
Polymerization of olefins in the presence of metal powders with homogeneous catalysts
Authors: Kaminsky Walter , Zielonka Holger 
Published: April 2003

AbstractHomogeneous catalysts based on metallocenes/methylaluminoxane are totally absorbed on surfaces of different metals. Because the methylaluminoxane is relatively stable against small molecules such as water covering metal surfaces, the aluminoxane can be fixed on powders without losing its activity. After treatment with the metallocene, active sites are only formed on the surface of the fillers. Upon injection of the olefins they are polymerized in the presence of the metals. Olefins such as ethene and propene, and cycloolefins or dienes, are used.
Chemical modification of neodymium high cis‐1,4 polybutadiene with styreneoxide
Authors: Hattori Iwakazu , Yasuda Kyouyuu , Sakakibara Mitsuhiko , Makino Kenya 
Published: April 2003

AbstractThe polymerization of 1,3‐butadiene (BD) was carried out in the presence of a catalyst composed of neodymium 2‐ethylhexanoate, triisobutyl aluminum, diisobutyl aluminum hydride (DIBAH), ethylaluminum sesquichloride and acetylacetone. The molecular weight of the BR could be controlled with DIBAH. The reactive polymer was then chemically modified with styreneoxide (STO). The STO content of BR increased with the decrease in the molecular weight of the BR. This polymer was modified by the STO at the chain terminal end. The physical properties of the vulcanizates with the modified BR were measured. The abrasion resistance and the tensile strength were found to be improved.
Synthesis and properties of super high molecular weight polyhexene‐1
Authors: Sukhova T. A. , Dyachkovskii F. S. 
Published: April 2003

AbstractTiCl4–alkylaluminium systems have been fixed on graphite and other inorganic supports and used in hexene‐1 polymerization. Kinetic studies show a decreasing polymerization rate from high initial values. High conversions (up to 99%) are reached, although retardation by a diffusion process is observed above 60%. The polymers have high molecular weights (up to 107) and high isotacticity (up to 98.5% from 13C NMR analysis). The effects of the nature of the components (carrier, alkylaluminium), and their concentration on the polymerization kinetics and the molecular structure of the polymer are discussed. The linear chain has one alkyl group (the alkylaluminium) and one unsaturation as the chain ends. Despite the high tacticity, the polymers are amorphous and rubber‐like.
Metal ion doped polymers as media for optical memories
Authors: Manivannan Gurusamy , Changkakoti Rupak , Lessard Roger A. 
Published: April 2003

AbstractPolymer materials are making an impact on optical storage technology to develop high information density and fast access type memories with a high read‐out efficiency. The principle and advantages of three‐dimensional (3‐D) data storage in the form of interference patterns (holograms) have been outlined. Three different information storage materials have been developed by doping metal ions such as Cr(VI) and Fe(III) in water‐soluble polymers, namely poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA), which need no further thermal or chemical treatment. Volume transmission holograms have been recorded in dichromated poly(vinyl alcohol) (DCPVA), ferric chloride doped poly(vinyl alcohol) (FePVA) and dichromated poly(acrylic acid) (DCPAA), with and without an electron donor (dimethyl formamide), and xanthene dyes (fluorescein, eosin Y and Rose Bengal). Different parameters influencing the holographic performance have been optimized to achieve a high real‐time diffraction efficiency (∼70%). An electron transfer process from the polymer matrix to Cr(VI)/Fe(III), leading to the photocrosslinking of the polymer in the form of an interference pattern, has been suggested as the mechanism of information storage (hologram recording) in these materials.
The effect of the bridge group on the thermal stability of nitro‐substituted aromatic polyamides
Authors: Oh Sang Yeol , Pearce Eli M. 
Published: April 2003

AbstractThe effect of introducing a bridge group into the diamine moiety on the thermal stability of aromatic polyamides substituted with nitro group in the diamine ring at the ortho position to the amide group was studied. Our present work showed that the bridge group, whether it was electron withdrawing or releasing, did not have a significant effect on the activity of the nitro group for the intramolecular cyclization reaction to poly(benzoxazole)s.
Calculation of heat transfer and uniformity of chemical amplification during post‐exposure bake
Authors: Ban Hiroshi , Sakai Tomoaki , Saito Kenichi 
Published: April 2003

AbstractHeat transfer in a resist‐coated silicon wafer using a bake process is theoretically evaluated by modeling the three‐dimensional diffusion process, focusing on the controllability of the lithographic performance of chemically amplified resists. Six models of various ambient conditions are used. The proximity gap between the hotplate and the wafer is found to have a dominant influence on the heat transfer process for the whole system. Because the atmosphere near the wafer acts as a thermal diffusion buffer layer, no temperature gradient occurs in the resist, even when it is subjected to convective heat transfer from the resist surface. Experimental results obtained by X‐ray lithography confirm the calculation results.