bluuebunny/crossref_metadata_2025_split huggingface dataset:
Propylene polymerization using combined syndio‐ and isospecific metallocene catalysts supported on silica/MAO
Authors: Marques Maria De Fátima Vieira , Conte Anunciata 
Published: November 2005

AbstractSyndiotactic and isotactic polypropylene were produced using the metallocene compounds Ph2C(Flu)(Cp)ZrCl2 and SiMe2(2‐Me,4‐Ph‐Ind)2ZrCl2 in homogeneous system and supported on silica/MAO. These catalysts were evaluated either isolated or as a binary system. In the latter case, the iso‐ and syndiospecific metallocene complexes were immobilized together during the preparation of the supported catalyst. In a further experimental set, the syndio‐ and isospecific isolated heterogeneous catalysts were mixed at the moment of propylene polymerization. The polypropylenes obtained were evaluated using differential scanning calorimetry. The catalytic activities were also investigated. At all the studied polymerization temperatures, the results showed that the binary catalyst produced polypropylenes with lower melting temperatures in comparison with those obtained when the mixture of isolated supported syndio‐ and isospecific catalysts was employed. Moreover, the activation energies for the polymerization of all catalysts systems were calculated, resulting in a lower value for the binary system when compared to that employing the catalyst mixture and to both the isolated supported metallocene catalysts. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 628–637, 2006
Charge storage behavior of isotropic and biaxially‐oriented polypropylene films containing α‐ and β‐nucleating agents
Authors: Behrendt Nico , Mohmeyer Nils , Hillenbrand Joachim , Klaiber Martin , Zhang Xiaoqing , Sessler Gerhard M. , Schmidt Hans‐Werner , Altstädt Volker 
Published: November 2005

AbstractA study on the influence of the crystal modification (α and β) of isotactic polypropylene (i‐PP) films on the resulting electret properties is presented. Two commercial nucleating agents, sodium 2,2′‐methylene‐bis(4,6‐di‐tert‐butylphenyl)‐phosphate (NA11) and N,N′‐dicyclo‐hexyl‐2,6‐naphthalene‐dicarbox‐amide (NU100), were employed in this investigation. Isothermal charge decay was measured at 90°C. In hot pressed isotropic polypropylene films, no significant differences in the charge storage properties were observed for α‐ and β‐nucleated specimens. In addition, the article presents the influence of the nucleating agents at different concentrations on the PP‐film morphology of biaxially stretched films with respect to electret features. It was possible to prepare elongated cavities with the virtually insoluble NA11 additive during stretching, even at concentrations below 0.3 wt %. These films displayed slightly improved electret properties in comparison to stretched neat PP films due to generated cavities acting as barriers for the drift of charges. Various draw ratios were also studied for i‐PP films with 0.15 wt % NA11. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 650–658, 2006
Preparation of spherical nanocomposites consisting of silica core and polyacrylate shell by emulsion polymerization
Authors: Mizutani Tsutomu , Arai Koji , Miyamoto Masatoshi , Kimura Yoshiharu 
Published: November 2005

AbstractNanocomposite particles consisting of silica (inorganic core) and polyacrylate (organic shell) were prepared in a form of emulsion by a new and simple method—the emulsion polymerization of acrylic monomers in the presence of silica sol. The key technique of the present emulsion polymerization, which made the formation of the nanocomposites successful, is the usage of nonionic surfactant above its cloud point. The morphology of the composite was investigated by DLS, AFM, and TEM, which clearly showed formation of the core‐shell‐type particles. A transparent film was prepared by casting the emulsion, which showed high resistibility against organic solvents. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 659–669, 2006
Melting, nonisothermal crystallization behavior and morphology of polypropylene/random ethylene—propylene copolymer blends
Authors: Wang Dong , Gao Jungang 
Published: November 2005

AbstractThe melting, nonisothermal crystallization behavior and morphology of blends of polypropylene (PP) with random ethylene–propylene copolymer (PP‐R) were studied by differential scanning calorimetry, polarized optical microscopy, scanning electron microscopy, and X‐ray diffraction. The results showed that PP and PP‐R were very miscible and cocrystallizable. Modified Avrami analysis was used to analyze the nonisothermal crystallization kinetics of the blends. The values of the Avrami exponent indicated that the crystallization nucleation of the blends was heterogeneous, the growth of the spherulites was tridimensional, and the crystallization mechanism of PP was not affected by PP‐R. The crystallization activation energy was estimated using the Kissinger method. An interesting result was obtained with the modified Avrami analysis and the Kissinger method, whose conclusions were in good agreement. The addition of a minor PP‐R phase favored an increase in the overall crystallization rate of PP. Maximum enhancing effect wass found to occur with a PP‐R content of 20 wt %. The relationship between the composition and the morphology of the blends is discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 670–678, 2006
Surface modification of polyimide films by argon plasma for copper metallization on microelectronic flex substrates
Authors: Lin Yung‐Sen , Liu Huang‐Ming , Chen Hsuan‐Ta 
Published: November 2005

AbstractSurface modification of polyimide films such as Kapton E(N) and Upilex S by argon plasma was investigated because of the enhanced adhesive strength with sputtered copper. Peel tests demonstrated this improvement, with a peel strength of 0.7 and 1.2 g/mm for unmodified Kapton E(N) and Upilex S, respectively, and 110.3 and 98 g/mm for argon plasma–modified Kapton E(N) and Upilex S, respectively, in certain plasma conditions. This study showed that the enhanced adhesive strength of polyimide films with sputtered copper by argon plasma was strongly affected by the surface characteristics such as surface morphology and surface energy of polyimide films. Atomic force microscopy and the sessile drop method indicated that the surface roughness and surface energy of the polyimide films were greatly increased by argon plasma, resulting in highly increased peel strength of the polyimide films with sputtered copper. It was observed in electron spectroscopy for chemical analysis (ESCA) that the increased surface energy of the polyimide films from argon plasma was a result of more of the surface being composed of O and N and of the increased number of CO, CO, and CN chemical bonds. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 744–755, 2006
Structural and mechanical characterization of poly(ether ether ketone) (PEEK) and sulfonated PEEK films: Effects of thermal history, sulfonation, and preparation conditions
Authors: Reyna‐Valencia A. , Kaliaguine S. , Bousmina M. 
Published: November 2005

AbstractIn this work, virgin and sulfonated poly(ether ether ketone) films (PEEK and SPEEK, respectively) have been studied by dynamic mechanical analysis, modulated differential scanning calorimetry, wide‐angle X‐ray diffraction, birefringence, and optical microscopy. The properties of the unmodified polymer have been addressed to assess the original morphological characteristics and the changes induced by sulfonation. In general, the introduction of ionic groups in the polymer backbone alters dramatically the intrinsic properties of the parent material. The particular thermomechanical response exhibited by PEEK and SPEEK samples, characterized by a hysteresis loop, can be explained by the reversible and irreversible relaxation–orientation of the microstructure, even in the sub‐Tg region. The results showed that the preparation conditions largely determine the nonequilibrium morphological features of both compression‐molded PEEK films and solvent‐cast SPEEK membranes. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 756–774, 2006
Characterization of PVC cable insulation materials and products obtained after removal of additives
Authors: Beneš M. , Plaček V. , Matuschek G. , Kettrup A. , Györyová K. , Balek V. 
Published: November 2005

AbstractOrganic solvents cyclohexane, dichloromethane, hexane, and tetrahydrofuran were tested to separate the dioctylphthalate (DOP) as plasticizer from the poly(vinyl chloride) (PVC)‐based materials. It was found that the efficiency of ultrasound‐enhanced hexane extraction of the DOP from PVC is 70% and the efficiency of the separation of the DOP and other compounds from the PVC by dissolution in THF followed by subsequent precipitation was 98–99%. Differential scanning calorimetry (DSC) and thermogravimetry (TG) were used to characterize the thermal behavior of PVC materials before and after extraction of plasticizers. It was found that during heating in the range 20–800°C the total mass loss measured for the nontreated, extracted, and precipitated PVC samples was 71.6, 66.6, and 97%, respectively. In the temperature range 200–340°C, the release of DOP, HCl, and CO2 was observed by simultaneous thermogravimetry (TG)/FTIR. The effect of plasticizers on thermal behavior of PVC‐based insulation material was characterized by DSC in the range −40–140°C. It was found that, concerning the PVC cable insulation material before treatment, the value of the glass transition temperature (Tg) was 1.4°C, whereas for the PVC sample extracted by hexane, the value of Tg was 39.5°C and for the PVC dissolved in THF and subsequently precipitated, the value of Tg was 80.4°C. Moreover, the PVC samples after extraction of plasticizers, fillers, and other agents were tested to characterize their thermal degradation. The TG and FTIR results of chemically nontreated, extracted, and precipitated samples were compared. The release of DOP, HCl, CO2, and benzene was studied during thermal degradation of the samples by FTIR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 788–795, 2006
Resins with the ability to bind copper and uranyl ions
Authors: Rivas Bernabé L. , Pereira Eduardo , Jara Miguel , Esparza Carolina 
Published: November 2005

AbstractCrosslinked poly(1‐vinyl imidazole‐co‐acrylic acid) and crosslinked poly(1‐vinylmidazole‐co‐2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) were synthesized by radical polymerization and characterized by elemental analysis and FTIR spectroscopy. The polymerization yields were 79 and 99%, respectively. The metal ion binding properties for copper(II) and uranium(VI) were studied under noncompetitive and competitive conditions by Batch equilibrium procedure. The resin crosslinked poly(1‐vinyl imidazole‐co‐acrylic acid) showed a higher dependence on pH than crosslinked poly(1‐vinylmidazole‐co‐2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid). The retention of uranyl ions for the latter resin was close to 100% at pH 5.0. The higher maximum retention capacity was close to 0.8 mmol/g dry resin at pH 5.0. Regeneration of the resin was possible by treatment with basic eluent. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 706–711, 2006
Further investigation of polyaminoamide‐epichlorohydrin/stearic anhydride compatibilizer system for wood‐polyethylene composites
Authors: Geng Y. , Li K. , Simonsen J. 
Published: November 2005

AbstractThe combination of a polyaminoamide‐epichlorohydrin (PAE) resin (a paper wet strength agent) and stearic anhydride was recently reported as an effective compatibilizer system for wood‐polyethylene composites. Further investigation of this new compatibilizer system revealed that the pH value of a PAE solution, dosages of PAE and stearic anhydride, and the weight ratio of PAE to stearic anhydride had significant impacts on the compatibilization effects of the compatibilizer system. Adjusting the pH value of the PAE solution from 5.0 to 10.4 increased the strength of the resulting wood‐polyethylene composites. The highest strength of the resulting wood‐polyethylene composites was obtained at 3 wt % PAE and 3 wt % stearic anhydride. At 4 wt % or 6 wt % of a compatibilizer, this PAE‐stearic anhydride system was superior to maleic anhydride‐grafted polyethylene (MAPE), one of the most effective compatibilizers, in terms of enhancing the strength of the resulting wood‐polyethylene composites. Fourier transform infrared spectroscopy (FTIR) analysis revealed that PAE and stearic anhydride formed covalent bonding with wood flour. The compatibilization mechanisms of this PAE‐stearic anhydride compatibilizer system were investigated in detail. Water‐resistance tests indicated that the PAE‐stearic anhydride compatibilizer system increased the water‐resistance of the resulting composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 712–718, 2006
Synthesis and characterization of poly(N‐methyl aniline) doped with sulphonic acids: Their application as humidity sensors
Authors: Kulkarni Milind V. , Viswanath Annamraju Kasi , Khanna P. K. 
Published: November 2005

AbstractSingle step chemical polymerization of N‐methyl aniline was carried out by using ammonium persulphate as an oxidizing agent. The conducting emeraldine salt phase of the polymers using camphor sulfonic acid and p‐toluene sulfonic acid as dopants was made by a direct process. The polymers were characterized by UV‐vis and FTIR spectroscopy, scanning electron microscopy, TGA, and conductivity measurements. The synthesized polymers were found to have very good physicochemical properties and good electrical conductivity. Conductivity measurements have shown “thermal activated behavior.” The change in resistance with respect to % relative humidity (RH) was observed, when pressed pellets of the polymer were exposed to the broad range of humidity (ranging between 20 and 100% RH). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 812–820, 2006
Carbon‐13 NMR, GPC, and DSC study on a propylene‐1‐butene copolymer fractionated by temperature rising elution fractionation
Authors: Zhang Yudong 
Published: November 2005

AbstractA random copolymer of propylene with small amounts of 1‐butene comonomer, synthesized with a Ziegler–Natta catalyst, was fractionated by temperature rising elution fractionation (TREF) to systemically investigate the fraction samples' molecular microstructure, as well as their relationship to the melting and crystallization behavior. First, TREF was employed to fractionate the sample, and then crystallization analysis fractionation (Crystaf) was used to check the effect of the TREF experiment. In the characterization of the molecular microstructure, carbon‐13 NMR spectroscopy (13C NMR) and gel permeation chromatography (GPC) experiments gave the following results: the fraction samples have relatively uniform molecular microstructure; with an increase in elution temperature, the 1‐butene content in the fraction samples decreases, but the molecular weight (Mn) and number average sequence length of propylene (n̄P) increase. In the study on melting and crystallization behavior, differential scanning calorimetry (DSC) experimental results show that the melting temperature increasingly decreases with an increase in 1‐butene content; however, dependence of the melting temperature on molecular weight becomes weaker and weaker with an increase in the number average molecular weight in the range of number average molecular weight below 1.82 × 105 g/mol. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 845–851, 2006
Micro‐structure and characteristics of highly oriented polyoxymethylene obtained by press and biaxial drawing
Authors: Takasa Kenji , Miyashita Norikazu , Takeda Kunihiko 
Published: November 2005

AbstractThe physical structure of oriented polyoxymethylene (POM) drawn in two steps by press drawing and subsequent simultaneous biaxial drawing was studied. The degree of crystallinity, the orientation, and the tensile modulus depending on draw ratio were analyzed. By the press drawing method, the draw ratio reached 6.0, the tensile modulus was 4.5 GPa, and the degree of crystallinity decreased from 70% to 65%. By the two‐step drawing of press drawing followed by subsequent simultaneous biaxial drawing, the tensile modulus reached 11 GPa when the draw ratio was 14 times, and the degree of crystallinity increased from 71% to 76–80%, but it did not depend on the draw ratio, and showed effectively a constant value (average 77%). The physical structural properties, such as the degree of crystallinity, the orientation of the crystal, and the lamella structure, were analyzed by SEM, X‐ray diffraction, and other methods. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 835–844, 2006
Preparation and curing kinetics of bisphenol A type novolac epoxy resins
Authors: Liu Yanfang , Zhang Chen , Du Zhongjie , Li Hangquan 
Published: November 2005

AbstractA bisphenol A type novolac resin (Bis‐ANR) was synthesized from bisphenol A and formaldehyde; the resulting novolac was epoxidized to generate a bisphenol A type novolac epoxy resin (Bis‐ANER). The chemical structures of Bis‐ANR and Bis‐ANER were confirmed by 1H‐NMR spectroscopy and IR spectroscopy; the molecular weights and molecular weight distributions were determined by gel permeation chromatography. In addition, the curing process of Bis‐ANER with 4,4′‐diaminodiphenyl sulfone was studied in both dynamic and isothermal modes with differential scanning calorimetry. The dynamic curing kinetic analysis was evaluated with both the Kissinger and Flynn–Wall–Ozawa methods, and the curing activation energy values were obtained. The isothermal curing reaction exhibited autocatalytic behavior, and the curing kinetics were described with the Kamal kinetics model, which accounted for both the autocatalytic and diffusion‐control effects. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 858–868, 2006
Synthesis and Biological Activity of Novel Acyclic Versions of NeplanocinA
Authors: Wu Ying , Hong Joon Hee 
Published: November 2005

AbstractNovel acyclic Neplanocin A analogues were designed and synthesized. The coupling of the alkyl bromide 6 with nucleosidic bases (T, U, 5‐FU, 5‐IU, C, A) and desilylation afforded a series of novel acyclic nucleosides. The synthesized compounds 13–18 were evaluated for their antiviral and antitumor activity.
The Topical Protective Effect of Soybean‐Germ Oil against UVB‐Induced Cutaneous Erythema: an in vivo Evaluation
Authors: Bonina Francesco , Puglia Carmelo , Avogadro Milvio , Baranelli Enzo , Cravotto Giancarlo 
Published: November 2005

AbstractThe preparation and detailed composition of an oil newly extracted from pure soy germ (not less than 96 % hypocotyle) are presented. Experiments in vivo showed that soybean‐germ oil (SGO) possesses a remarkable protective activity against UVB‐induced skin inflammation, exceeding that of tocopherol acetate by a factor of 2. These results suggest that SGO might have interesting therapeutic and cosmetic applications in the management of skin diseases initiated, sustained, or exacerbated by an over production of free radicals.
Synthesis and Antiviral Evaluation of Novel Exomethylene Acyclic Nucleosides and Phosphonic Acid Nucleosides
Authors: Kim Aihong , Hong Joon Hee 
Published: November 2005

AbstractThis paper describes a very simple synthesis route of novel acyclic nucleosides and phosphonic acid nucleosides. The condensation of the mesylates 6 and 17 with the natural nucleosidic bases (A, C, U, T) under nucleophilic substitution (K2CO3, 18‐Crown‐6, DMF) and deprotection afforded the target nucleosides (11, 12, 13, 14) and phosphonic acid nucleosides (22, 23, 24, 25). In addition, these compounds were evaluated for their antiviral properties against various viruses. Uracil derivative 24 shows significant anti‐HCMV activity (EC50 = 10.24 μM).
Citation rates and perceptions of scientific contribution
Authors: Aksnes Dag W. 
Published: November 2005

AbstractIn this study scientists were asked about their own publication history and their citation counts. The study shows that the citation counts of the publications correspond reasonably well with the authors' own assessments of scientific contribution. Generally, citations proved to have the highest accuracy in identifying either major or minor contributions. Nevertheless, according to these judgments, citations are not a reliable indicator of scientific contribution at the level of the individual article. In the construction of relative citation indicators, the average citation rate of the subfield appears to be slightly more appropriate as a reference standard than the journal citation rate. The study confirms that review articles are cited more frequently than other publication types. Compared to the significance authors attach to these articles they appear to be considerably “overcited.” However, there were only marginal differences in the citation rates between empirical, methods, and theoretical contributions.
Link‐based similarity measures for the classification of Web documents
Authors: Calado Pável , Cristo Marco , Gonçalves Marcos André , de Moura Edleno S. , Ribeiro‐Neto Berthier , Ziviani Nivio 
Published: November 2005

AbstractTraditional text‐based document classifiers tend to perform poorly on the Web. Text in Web documents is usually noisy and often does not contain enough information to determine their topic. However, the Web provides a different source that can be useful to document classification: its hyperlink structure. In this work, the authors evaluate how the link structure of the Web can be used to determine a measure of similarity appropriate for document classification. They experiment with five different similarity measures and determine their adequacy for predicting the topic of a Web page. Tests performed on a Web directory show that link information alone allows classifying documents with an average precision of 86%. Further, when combined with a traditional text‐based classifier, precision increases to values of up to 90%, representing gains that range from 63 to 132% over the use of text‐based classification alone. Because the measures proposed in this article are straightforward to compute, they provide a practical and effective solution for Web classification and related information retrieval tasks. Further, the authors provide an important set of guidelines on how link structure can be used effectively to classify Web documents.
Schienenlängskräfte auf Brücken bei nichtlinearer Überlagerung der Lastfälle Temperatur, Tragwerksbiegung, Bremsen
Authors: Ruge Peter , Birk Carolin , Muncke Martin , Schmälzlin Gerd 
Published: November 2005

AbstractDer DIN‐Fachbericht 101, der auch für Eisenbahnbrücken gilt, sieht eine getrennte jeweils nichtlineare Betrachtung der genannten drei Lastfälle und eine anschließende Summation der Teil ergebnisse vor. Bei diesem Vorgehen wird der Einfluß der Vorgeschichte auf die nachfolgende Lastabtragung vollkommen vernachlässigt.Dieser Aufsatz zeigt erstmals den Einfluß einer korrekten Erfassung der Lastfolge Temperatur – Tragwerksbiegung – Bremsen/Anfahren bei Berücksichtigung der Vorgeschichte auf die Längsbeanspruchung lückenlos verschweißter Gleise sowohl für das Schottergleis als auch für die Feste Fahrbahn.