bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct copolymerization of sulfonated poly(phthalazinone arylene ether)s for proton‐exchange‐membrane materials
Authors: Gao Yan , Robertson Gilles P. , Guiver Michael D. , Jian Xigao , Mikhailenko Serguei D. , Wang Keping , Kaliaguine Serge 
Published: July 2003

AbstractSulfonated poly(phthalazinone ether ketone) (SPPEK) copolymers and sulfonated poly(phthalazinone ether sulfone) (SPPES) copolymers containing pendant sodium sulfonate groups were prepared by direct copolymerization. The reaction of disodium 3,3′‐disulfonate‐4,4′‐difluorobenzophenone (SDFB‐Na), 4,4′‐difluorobenzophenone (DFB), and 4‐(4‐hydroxyphenyl)‐1(2H)‐phthalazinone (DHPZ) at 170 °C in N‐methyl‐2‐pyrrolidione containing anhydrous potassium carbonate gave SPPEKs. SPPESs were similarly obtained with 3,3′‐disulfonate‐4,4′‐difluorophenyl sulfone, 4‐fluorophenyl sulfone (DFS), and DHPZ as monomers. The sulfonic acid groups, being on deactivated positions of the polymer backbone, were expected to be hydrolytically more stable than postsulfonated polymers. Fourier transform infrared and 1H NMR were used to characterize the structures and degrees of sulfonation of the sulfonated polymers. Membrane films of SPPEKs with SDFB‐Na/DFB molar feed ratios of up to 60/40 and SPPESs with sulfonated 4‐fluorophenyl sulfone/DFS molar feed ratios of up to 50/50 were cast from N,N‐dimethylacetamide polymer solutions. Membrane films in acid form were then obtained by the treatment of the sodium‐form membrane films in 2 N sulfuric acid at room temperature. An increase in the number of sulfonate groups in the copolymers resulted in an increased glass‐transition temperature and enhanced membrane hydrophilicity. The sodium‐form copolymers were thermally more stable than their acid forms. The proton conductivities of the acid‐form copolymers with sulfonated monomer/unsulfonated monomer molar feed ratios of 0.5 and 0.6 were higher than 10−2 S/cm and increased with temperature; they were less temperature‐dependent than those of the postsulfonated products. SPPESH‐50 showed higher conductivity than the corresponding postsulfonated poly(phthalazinone ether sulfone). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2731–2742, 2003
Synthesis and characterization of poly(diethylsiloxane) and its copolymers with different diorganosiloxane units
Authors: Liu Lihua , Yang Shiyan , Zhang Zhijie , Wang Qian , Xie Zemin 
Published: July 2003

AbstractPoly(diethylsiloxane) and its copolymers with various kinds of R1R2SiO (R1 = R2 = methyl or phenyl, or R1 = methyl and R2 = phenyl) units have been prepared by the equilibrium polymerization of cyclosiloxanes. All the polymers have been characterized by 1H and 29Si NMR, gel permeation chromatography, differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) measurements. The results indicate that a random distribution of different units has been obtained in the structures of copolymers containing 50 mol % diethylsiloxane units content. DSC and DMA show that the presence of 2.5 mol % diphenylsiloxane units or 5.0 mol % methylphenylsiloxane units in the copolymer can disrupt the crystallinity and lead to noncrystalline copolymers with low glass‐transition temperatures (ranging from −133 to −137 °C according to DSC). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2722–2730, 2003
Methane plasma polymerization by low‐temperature cascade arc discharge for enhanced adhesion of primer to thermoplastic olefins
Authors: Lin Yung‐Sen , Yasuda Hirotsugu K. 
Published: July 2003

AbstractImprovement of primer adhesion to thermoplastic olefins (TPOs) by methane plasma polymerization with a low‐temperature cascade arc discharge was investigated. Methane plasma with a low‐temperature cascade arc plasma torch can be used for improving the primer adhesion to TPOs. Tape‐adhesion tests (ASTM 3359‐92a method) demonstrated this improvement, with a rating of 0 for untreated TPOs and 5 for methane plasma‐polymerized TPOs at certain plasma conditions even for aging at 60 °C and 80% relative humidity for 5 days. The adhesion to primer for the soft, flexible TPOs (ETA‐3041c and ETA‐3101) was easily enhanced. The adhesion to primer for the hard and brittle TPOs (ETA‐3183) needs to optimize the plasma conditions to pass the dry‐ and wet‐adhesion test with methane plasmas. To relate the surface characteristics of methane plasma‐polymerized TPOs to adhesion performance with primer, the wettability and polarity of TPOs were evaluated by the contact‐angle measurements of primer and deionized water to TPOs. TPO surface morphology was evaluated with scanning electron microscopy. The surface composition was characterized with electron spectroscopy for chemical analysis. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2004–2021, 2003
Spherulite morphology studies of N‐alkyl chitosan films cast from formic acid solutions
Authors: Dong Yanming , Sakurai Kensuke , Wu Yusong , Kondo Yukie 
Published: July 2003

AbstractThe films of N‐ethyl chitosan were prepared via the solution‐casting technique with formic acid as a solvent. The solutions with different concentrations (35 and 40 wt %) were prepared previously from dilute solution (1 wt %) via evaporating process. The crystalline morphology of these films was investigated by means of polarized optical microscopy and scanning electron microscopy. Normal spherulites with a low growth rate formed in the casting films. The different morphologies of spherulite appeared in the films cast from the solutions with different concentrations. After further crystallizing for a few days, the spherulites were decorated by thousands of needlelike extended‐chain crystals, which had a typical size of ∼50 μm (length) × 2∼5 μm (width) × 1∼2 μm (height) in the central part of the spherulite, but a typical size of ∼5 μm (lenght)× 1∼2 μm (width) × 1∼2 μm (height) in the fringe part of the spherulite. The real concentration for crystallization was determined to be 65–82 wt%. Thus, the crystallization actually appeared in supersaturated solution. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2033–2038, 2003
Determination of the rheological behavior of epoxy–amine thermosets by dynamic mechanical analysis: Isothermal methods versus nonisothermal methods
Authors: Cuevas J. M. , Laza J. M. , Correa M. , Vilas J. L. , Rodríguez M. , León L. M. 
Published: July 2003

AbstractThe reticulation process of an epoxy resin using an amine as a cure agent was studied at different temperatures and concentrations of the cure agent with dynamic mechanical thermal analysis. The study was performed under both isothermal and nonisothermal conditions, and a temperature–time–transformation diagram was obtained. The measurements from the two modes gave similar results, although the nonisothermal mode required fewer experiments. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1965–1977, 2003
Characterization of the interaction of poly(ethylene oxide) with nanosize fumed silica: Surface effects on crystallization
Authors: Ding Jiang , Maitra Prithwiraj , Wunder Stephanie L. 
Published: July 2003

AbstractPoly(ethylene oxide) (PEO) of 4600 molar mass (PEO‐4600) was crystallized from methanol in the presence of hydrophilic fumed silicas (A380, A200, and OX50) with nominal surface areas of 380, 200, and 50 m2/g and a hydrophobic fumed silica (R812s) modified with methyl groups. The composites were characterized by thermogravimetric analysis and differential scanning calorimetry. The inhibition of crystallization and the tendency for chain reorganization after melting were in the order of A380 > A200 > OX50 > R812s, respectively, that is, both were least for the hydrophobic silica and increased with increasing specific surface area for the hydrophilic silica. The interaction of PEO with the silica increased in the melt state as compared with the solution‐cast samples, resulting in enhanced suppression of crystallization. The following took place at a high silica content: (1) crystallization occurred at crystallization temperatures [Tc < Tc (bulk)], suggesting that the silica inhibited crystallization; (2) crystallites with melt temperatures [Tm < Tm (bulk)] were observed, indictive of smaller and/or less perfect crystals; and (3) melt entropies [ΔSm (surface) < ΔSm (bulk)] suggested that the interaction of surface silanols, SisOH, with PEO decreased both the melt entropy and crystallite size/perfection. Crystallinity was observed in solution‐cast composites when there were greater than ∼0.03 PEO molecules/nm2 for native and ∼0.01 PEO molecules/nm2 for methylated fumed silica, similar to reported plateau equilibrium adsorption values from methanol. These results were consistent with a model in which PEO interacted more strongly with native fumed silica as compared with hydrophobically modified silica because of hydrogen bonding of the ether oxygens of PEO with the acidic silanols, preventing chain mobility and crystallization. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1978–1993, 2003
Block copolymer modified novolac epoxy resin
Authors: Guo Qipeng , Dean Jennifer M. , Grubbs Robert B. , Bates Frank S. 
Published: July 2003

AbstractThe phase behavior of uncured and cured mixtures containing stoichiometric amounts of Epon164 novolac epoxy resin and 4,4′‐methylenedianiline combined with a nearly symmetric poly(methyl acrylate‐co‐glycidyl methacrylate‐b‐polyisoprene) diblock copolymer was investigated with small‐angle X‐ray scattering and transmission electron microscopy. A series of morphologies were documented as a function of the copolymer concentration, which ranged from pure diblock to 2.5 wt % in the thermoset resin. Ordered lamellae bordered a wide multiphase region followed by disordered wormlike micelles that transformed continuously into vesicles at the lowest compositions. The thermal curing of this pentafunctional epoxy system to complete conversion had little impact on the phase behavior of the mixtures, and this was consistent with previous experiments with difunctional epoxy and the same hardening agent. However, changing the epoxy component led to gross changes in the phase behavior that were interpreted with the concept of a wet‐to‐dry brush transition. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1994–2003, 2003
Effect of surface‐grafted ionic groups on the performance of cellulose‐fiber‐reinforced thermoplastic composites
Authors: Cai Xiaolin , Riedl Bernard , Ait‐Kadi A. 
Published: July 2003

AbstractThe influence of the surface chemistry of the cellulose fiber and polymer matrix on the mechanical and thermal dynamic mechanical properties of cellulose‐fiber‐reinforced polymer composites was investigated. The cellulose fiber was treated either with a coupling agent or with a coupling‐agent treatment followed by the introduction of quaternary ammonium groups onto the fiber surface, whereas the polymer matrix, with opposite polar groups such as polystyrene incorporated with sulfonated polystyrene and poly(ethylene‐co‐methacrylic acid), was compounded with the fiber. The grafting of the fiber surface was investigated with Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. Experimental results showed that an obvious improvement in the mechanical strength could be achieved for composites with an ionic interface between the fiber and the polymer matrix because of the adhesion enhancement of the fiber and the matrix. The improved adhesion could be ascribed to the grafted ionic groups at the cellulose‐fiber surface. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2022–2032, 2003
Characterization of polyethylene with partially random chlorine substitution
Authors: Stephens C. H. , Yang H. , Islam M. , Chum S. P. , Rowan S. J. , Hiltner A. , Baer E. 
Published: July 2003

AbstractA series of chlorine‐containing polymers were prepared by ring‐opening metathesis polymerization (ROMP) followed by hydrogenation. This synthesis route was chosen specifically so that chain microstructures would be obtained that resembled copolymers of ethylene and vinyl chloride. The chlorine content was varied by the copolymerization of 5‐chlorocyclooctene and cyclooctene. Differential scanning calorimetry, light microscopy, tapping‐mode atomic force microscopy, wide‐angle X‐ray diffraction (WAXD), and density were employed to characterize the polymers. The copolymers had certain restrictions on the length of the methylene sequence between substituted carbons, however, ROMP copolymerization introduced enough variation in the methylene sequence length that model copolymers with the equivalent of 14 mol % vinyl chloride or less closely resembled random copolymers of ethylene and vinyl chloride. These materials organized as spherulites and exhibited the orthorhombic crystal form. Constraints on the placement of chlorine atoms strongly affected the crystallization of polymers with more than the equivalent of 14 mol % vinyl chloride. More regular chlorine substitution along the polyethylene chain translated into better ordered crystal structures with sharp melting peaks. The granular morphology of these materials at ambient temperature was interpreted as fringed micellar crystals. The WAXD patterns provided definitive evidence that chains in the fringed micelle took the hexagonal crystal form. The lower density hexagonal form facilitated the crystallization of short ethylene sequences and accommodated chlorine atoms more easily than the orthorhombic form. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2062–2070, 2003
Solidlike transition of melt‐intercalated biodegradable polymer/clay nanocomposites
Authors: Lim Sung T. , Lee Chung H. , Choi Hyoung J. , Jhon Myung S. 
Published: July 2003

AbstractSynthetic biodegradable aliphatic polyester (BAP) intercalated into organoclay was prepared by melt compounding, and its solidlike characteristics were investigated via several rheological test modes: steady shear rotation, oscillation, and creep testing. Structural investigations with X‐ray diffraction and transmission electron spectroscopy were also performed for a better understanding of the characteristic rheological behaviors. The creep, recovery, and stress modulus exhibited a solidlike transition of BAP/clay nanocomposites that depended on the clay content. An increase in the zero shear rate viscosity and a shifting of the crossover point (storage modulus vs loss modulus) to a lower frequency were also observed with increasing clay contents. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2052–2061, 2003
Electrical and mechanical behavior of filled elastomers. I. The effect of strain
Authors: Yamaguchi K. , Busfield J. J. C. , Thomas A. G. 
Published: July 2003

AbstractElectrical and mechanical property tests have been used to examine the changes in the carbon black network structure that occur in a filled elastomer at large strains in tension and compression. These changes have been examined both in materials that have no previous loading history and in test pieces that have been subjected to a specific known prestrain. When a previously unstrained, filled elastomer specimen is stretched to moderate extensions, the electrical resistivity increases. This is ascribed to the breakdown of the carbon black network structure. At higher tensile extensions, the resistivity decreases. This reduction in the electrical resistivity is attributed to the alignment of the shaped carbon black aggregates under strain. During unloading, the resistivity behavior is different from that during loading, with the final unloaded electrical resistivity being significantly higher than that measured in the unstrained elastomer. This dramatic change in the electrical properties after unloading is in marked contrast to the relatively modest changes observed in the mechanical behavior. After the first cycle, the electrical behavior becomes much more reversible, and this indicates that the bulk of the damage experienced by the carbon black network is developed during the first cycle. After unloading from a large strain, the electrical anisotropy is small, whereas the mechanical anisotropy is more marked. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2079–2089, 2003
Depth profile analysis of polyimide film treated by potassium hydroxide
Authors: Okumura H. , Takahagi T. , Nagai N. , Shingubara S. 
Published: July 2003

AbstractThe structural change in the depth direction of a polyimide (UPILEX‐S) film treated in alkaline solution, which was a representative surface treatment used to form a seed layer for plating and to improve the adhesive strength, was analyzed by means of micro Fourier transform infrared attenuated total reflection (FTIR‐ATR) line analysis with gradient shaving preparation. The polyimide film was treated with KOH. The imide ring opened through the alkaline treatment, and the amide structure and carboxylic acid salt were formed. The attainment depth of this structural change was almost proportional to the treatment time, and it reached about 8 μm after a 30‐min treatment. The degree of structural change through the alkaline treatment was almost constant after it reached a considerably degraded stage, and the chemically changed region penetrated into the inner part of the film from the surface. An intermediate layer before the final degraded stage appeared in the treated layer, and its thickness increased with the treatment time. The region that was changed chemically by the alkaline treatment progressed to the inner part simultaneously and continuously as the treatment time increased. The combined use of gradient shaving preparation and micro FTIR‐ATR line analysis was found to be extremely effective for the depth profiling of organic materials. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2071–2078, 2003
Specific reversible melting of polymers
Authors: Androsch R. , Wunderlich B. 
Published: July 2003

AbstractTemperature‐modulated differential scanning calorimetry can detect a certain amount of reversible latent heat in flexible macromolecules. In short, one can identify a reversible melting in such polymers earlier thought to exhibit only fully irreversible crystallization and melting. Details of the reversible melting of isotactic polypropylene and ethylene‐1‐octene copolymers of low and medium densities have newly been measured and linked to the crystallization, annealing, or melting temperature. It is possible to assign the experimental reversibility of melting to specific crystal fractions that ultimately melt irreversibly at higher temperatures; that is, it is suggested that reversible melting mainly occurs only between the temperatures of their formation and their zero‐entropy‐production melting temperature, at which they change to a melt of the same degree of metastability. This is supported by the almost complete absence of reversibility below the temperature of crystal formation and the observation of a distinct relationship between the amount of irreversibly by annealing reorganized material and reversibility in the case of isotactic polypropylene. A given crystal fraction, characterized by its formation temperature and zero‐entropy‐production melting temperature, has a specific reversibility of the melt‐to‐crystal transition, which is represented by the ratio of the reversible latent heat to the total enthalpy change when the crystal fraction of interest ultimately melts. This specific reversibility is, for ethylene‐1‐octene copolymers, at least 25% at temperatures in the primary crystallization range, and this indicates that the reversible contribution to the total of the melting processes is much larger than expected from simple calculations by the excess apparent reversible heat capacity being referred to the heat of fusion of the polymer, as is commonly done. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2039–2051, 2003
In vivo preservation of steroid specificity in CWR22 xenografts having a mutated androgen receptor
Authors: Shao Tsang C. , Li Huiling , Eid Wael , Ittmann Michael , Unni Emmanual , Cunningham Glenn R. 
Published: July 2003

AbstractBackgroundIn vitro studies of CWR22 tumor cells lack steroid specificity. We sought to determine if CWR22 xenografts also lack steroid specificity.MethodsWe injected castrated nude mice with CWR22 tumor cells (6 × 106 cells) and implanted Alzet osmotic pumps that delivered approximately 1 mg steroid/kg body weight/day.ResultsSerum PSA levels were detectable in intact mice and castrated mice treated with testosterone (T), but not in those treated with estradiol (E2), progesterone (P), or flutamide (F). T maintained mean tumor weight similar to that in intact mice (P = NS). We observed no tumors in castrated mice or mice treated with E2, P, or F, and tumor histology was consistent with weights.ConclusionsThe mutation of the androgen receptor (H874Y) that occurs in the CWR22 xenograft model of human prostate cancer does not significantly affect in vivo steroid specificity for E2, P, or F. Prostate 57: 1–7, 2003. © 2003 Wiley‐Liss, Inc.
Possibility of re‐screening intervals of more than one year in men with PSA levels of 4.0 ng/ml or less
Authors: Ito Kazuto , Yamamoto Takumi , Ohi Masaru , Takechi Hiroyuki , Kurokawa Kohei , Suzuki Kazuhiro , Yamanaka Hidetoshi 
Published: July 2003

AbstractBACKGROUNDThe optimal re‐screening interval is one of the most important issues to evaluate the effectiveness of screening for prostate cancer.METHODSBetween 1992 and 2000, 7,026 men aged 50–78 with baseline PSA levels of 4.0 ng/ml or lower underwent screening for prostate cancer twice or more. The risk of developing prostate cancer relative to elapsed years and baseline PSA levels were investigated.RESULTSProstate cancer was detected in a total of 127 cases (1.8%). The detection rate of prostate cancer was high between 1.6% and 5.5% at 1 year after baseline PSA measurements in men with baseline PSA levels of 2.1–4.0 ng/ml. In men with baseline PSA levels of 1.1– 2.0 ng/ml, the detection rate increased from 0.06% to 1.02% with passed years. The proportion of stage ≥T3 was high at 63% in prostate cancer cases detected between 3 and 4 years after baseline PSA levels being 1.1–2.0 ng/ml. In men with baseline PSA levels of 1.0 or lower, the cumulative detection rate of prostate cancer was low at 0.01% within 3 years, however, the detection rate increased to 0.34% after 5 or more years from baseline PSA measurements.CONCLUSIONSThe re‐screening interval was recommended to be 1, 1–2, and 3–5 years for men with baseline PSA levels of 2.1–4.0 ng/ml, 1.1–2.0 ng/ml, and 1.0 ng/ml or lower, respectively. Prostate 57: 8–13, 2003. © 2003 Wiley‐Liss, Inc.