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  • Articles  (7,793)
  • Springer  (7,332)
  • American Chemical Society  (461)
  • 2010-2014
  • 1995-1999  (7,793)
  • 1997  (7,793)
  • Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics  (7,793)
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  • Articles  (7,793)
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Publisher
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  • 2010-2014
  • 1995-1999  (7,793)
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  • 1
    Electronic Resource
    Electronic Resource
    Dehydrogenative polycondensation of telechelically bis(dimethylsilyl)functionalized oligo(dimethylsiloxane)s or aromatics and 1,3,3,5,5,7,7,7-octamethyltetrasiloxane (1997)
    Springer
    Polymer bulletin 38 (1997), S. 1-5 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Telechelically bis(hydrodimethylsilyl)-functionalized oligo(dimethylsiloxane)s or aromatics were found to give polymers constituting of alternating disilylene and oligodimethylsiloxane or 4,4′-diylaromatics as repeating units by dehydrogenative coupling reaction in the presence of palladium dibenzylideneacetone complex. The same catalyst gave polysilylenes with trisiloxane pendant from 1,1-dihydro-1,3,3,5,5,7,7,7-octamethyltetrasiloxane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050011
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of polyorganosiloxane particles (1997)
    Springer
    Polymer bulletin 38 (1997), S. 23-25 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Hybrid particles have been synthesized from methyltriethoxysilane (MTEOS) by the sol-gel process. The particle size, size distribution, particle surface morphology conductivity and pH of the reaction solution at different reaction times were determined. Compared with tetraethyl orthosilicate (TEOS) and p-(chloromethyl)phenyl-trimethoxysilane (CMPTOS), MTEOS has a slower hydrolysis rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050014
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  • 3
    Electronic Resource
    Electronic Resource
    Polymerization of 4-n-alkylstyrenes with typical Ziegler-Natta and metallocene catalysts (1997)
    Springer
    Polymer bulletin 38 (1997), S. 43-48 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Polymerization of 4-n-alkylstyrenes (alkyl side group; methyl, ethyl, propyl and buthyl) was carried out with the η-C5(CH3)5TiCl3-methylaluminoxane (MAO) and TiCl3-triethylaluminum (TEA) catalyst systems. When the η-C5(CH3)5TiCl3-MAO catalyst was used, the stereoregularity of resulting polymers markedly depended on the length of substituted alkyl groups, i.e., the catalyst gave highly syndiotactic poly(4-methylstyrene), but produced atactic polymers for the monomers with ethyl, propyl and buthyl substituents. On the other hand, all the poly(4-n-alkylstyrene)s obtained with the TiCl3-TEA catalyst were highly isotactic. As a result, a large difference was observed in the thermal properties of polymers obtained between the two catalyst systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050017
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  • 4
    Electronic Resource
    Electronic Resource
    Enzyme-catalyzed peptide syntheses in aqueous polymer two-phase systems (1997)
    Springer
    Polymer bulletin 38 (1997), S. 49-53 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Peptide synthesis in the aqueous polymer two-phase system was examined. Water soluble polymers adopted were dextran and polyethyleneglycol (PEG). By the modification of a proteolytic enzyme, trypsin, with dextran carrying a very small number of carboxyl groups, a separation of the enzyme from its peptide product, N-benzoyl-L-arginine glycinamide, which is relatively more soluble in a PEG phase could be realized. This separation drastically reduced a so-called "mass-law" effect, and increased the yield of the reaction product. The aqueous polymer two-phase system would be useful to enhance the usefulness of biocatalysts in organic syntheses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050018
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of the crosslinking with 1,1,1-trimethylolpropane trimethacrylate on 5-fluorouracil release from poly(2-hydroxyethyl methacrylate) hydrogels (1997)
    Springer
    Polymer bulletin 38 (1997), S. 55-62 
    Details
    ISSN: 1436-2449
    Keywords: Key words: Poly(2-hydroxyethyl methacrylate) (PHEMA) – 5-fluorouracil (5-FU) – 1,1,1-trimethylolpropane trimethacrylate (TPT) – hydrogel – controlled release – diffusion coefficient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The aim of this study is to examine the influence of crosslinking density on 5-Fluorouracil release from poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels crosslinked with 1,1,1-trimethylolpropane trimethacrylate (TPT). PHEMA hydrogels were synthesized by bulk polymerization with different proportions of TPT (1 – 10 wt%) as crosslinker agent and ammonium persulphate as initiator, enabling polymerization in the feed mixture in the presence of water. As a result, 5-FU could be trapped by including it as a sodium salt in the feed mixture of polymerization. Discs with 5-FU loads between 1 – 16 mg/disc were obtained. Swelling and 5-FU release kinetics studies were carried out in saline solution at 310 K. The diffusion studies were in accordance with Fick's second law during the initial stages, enabling the diffusion coefficients of the process to be determined. The time required for discs to reach total 5-FU release was between 35 h and 160 h and was a function of crosslinking density of the gels and 5-FU load of the discs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050019
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of surfactant concentration, pH, and shear rate on the rheological properties of aqueous systems of a hydrophobically modified chitosan and its unmodified analogue (1997)
    Springer
    Polymer bulletin 38 (1997), S. 71-79 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Oscillatory shear, shear relaxation and viscosity experiments have been carried out on semidilute solutions of chitosan and on a hydrophobically modified analogue (HM-chitosan) in 1% acetic acid. This was done in the presence of various amounts of cetyltrimethylammonium bromide (CTAB) and at different pH values. All the rheological measurements on the HM-chitosan solutions revealed significant polymer-surfactant interaction and pH effects. The observed rheological effects were least pronounced at pH ≈ 4, while a strong viscoelastic response was found at pH values of 1 and 5 in HM-chitosan solutions of low surfactant concentration. At these conditions, significant shear-thinning effects were observed. In semidilute solutions of unmodified chitosan, the influence of pH, surfactant concentration and shear rate on the rheological properties was moderate or insignificant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050021
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  • 7
    Electronic Resource
    Electronic Resource
    Electrical conductivity of polystyrene/styrene-butadiene block copolymer blends containing carbon black (1997)
    Springer
    Polymer bulletin 38 (1997), S. 95-100 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The electrical resistivity and mechanical properties of carbon black (CB)-filled polystyrene (PS)/styrene-butadiene block copolymer (SB) blends have been studied. Good electrical performance was achieved with pure SB and PS/SB blends indicating an inhomogeneity of these materials and the heterogeneous micro-dispersion of the CB particles. The percolation threshold of the filler inside SB or PS/SB blends is around 3.6 wt%, which is lower than that expected for incompatible PS/PBD blend. The addition of small amount CB decreases the elongation at break of PS/SB blends indicating some disturbance at the interface of these compatible material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050024
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  • 8
    Electronic Resource
    Electronic Resource
    Homo-, co- and terpolymerization of 1,5-hexadiene using a methylalumoxane activated mono-Cp-amido-complex (1997)
    Springer
    Polymer bulletin 38 (1997), S. 141-148 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Homo- and copolymerizations of 1,5-hexadiene with ethene and styrene using halfsandwich metallocene catalyst Me2Si(Me4Cp)(N-tert.-butyl)TiCl2/MAO (Cp = cyclopentadienyl, Me = methyl, MAO = methylalumoxane) were investigated. According to 13C-NMR spectroscopic microstructure analysis, cyclopolymerization of 1,5-hexadiene afforded randomly distributed cis- and trans-cyclopentane rings in the homo- and copolymer backbone. 1,5-hexadiene incorporation reached 52 mol-%. The ratio of vinyl side chains to cyclopentane rings was controlled by 1,5-hexadiene concentration, where low 1,5-hexadiene concentration promoted cyclopolymerization. Copolymer glass transition temperatures increased with increasing content of cyclic units in the backbone. Styrene was used successfully as termonomer in ethene/1,5-hexadiene polymerization, resulting in a semicrystalline terpolymer with cyclic and styrenic units in the polymer backbone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050030
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis and properties of polyurethanes containing phosphatidylcholine analogues in the main chains and long-chain alkyl groups in the side chains (1997)
    Springer
    Polymer bulletin 38 (1997), S. 133-140 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. New phospholipid polyurethanes containing phosphatidylcholine analogues in the main chains and octyl or oleyl groups in the side chains were synthesized by the addition polymerization of diols, bis[2-(2-hydroxyethyldimethylammonio)ethyl]2-octyl-1,3-propanediphosphate or bis[2-(2-hydroxyethyldimethylammonio)ethyl]2-oleyl-1,3-propanediphosphate, with diisocyanates such as 4,4′-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), and 2,4-tolylene diisocyanate (TDI). The new phospholipid diols and polyurethanes were characterized by their IR and 1H-NMR spectral data and elemental analysis. The new phospholipid polyurethanes exhibit common polyelectrolyte viscosity behaviours revealed by viscosity measurements. Moreover, π-A isotherms for these polyurethanes were also prepared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050029
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  • 10
    Electronic Resource
    Electronic Resource
    Photoinitiated cationic ring-opening polymerization of a cyclosiloxane (1997)
    Springer
    Polymer bulletin 38 (1997), S. 165-168 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Hexamethylcyclotrisiloxane was found to undergo photoinitiated cationic ring-opening polymerization in solution and bulk, upon exposure to UV radiation, in the presence of either sulfonium or iodonium salts or an iminosulfonate derivative. Glass transition temperatures were below − 100 °C. Molecular weights, determined by size exclusion chromatography relative to polystyrene standards, increased with photolysis lamp intensity. Use of an iodonium photoinitiator afforded poly(dimethylsiloxane) with Mn = 172,000. Polymerization of hexamethylcyclotrisiloxane was accompanied by a small increase in volume (3 – 4%).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050033
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  • 11
    Electronic Resource
    Electronic Resource
    An alternating copolymer for a blue light-emitting diode (1997)
    Springer
    Polymer bulletin 38 (1997), S. 169-176 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. An alternating copolymer composed of 9,9′-dihexylfluorene and N-2-ethylhexyl carbazole was synthesized to use as an emissive polymer in a light-emitting diode (LED). The copolymer is soluble in organic solvents and spin-cast to make a fine film. An LED fabricated by sandwiching the alternating copolymer between indium-tin oxide and aluminum emits a white color with the full width at half maximum of 150 nm. The electroluminescence spectrum becomes simplified to have an emission peak at 460 nm for fine blue color when the copolymer is blended with poly(vinylcarbazole) with a ratio of 1 to 4 before the use as an emissive layer. The forward bias turn-on voltage for the LED is 13, and quantum efficiency is 0.002%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050034
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  • 12
    Electronic Resource
    Electronic Resource
    IR study of hydrogen bonding in novel liquid crystalline epoxy/DGEBA blends (1997)
    Springer
    Polymer bulletin 38 (1997), S. 439-445 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The hydrogen bonding of LCE/DGEBA blend was studied using FT-IR. IR spectra of hydroxyl region and carbonyl region were investigated according to the content of LCE. IR spectra of LCE/DGEBA blend before and after curing were compared. Most hydroxyl group in DGEBA rich blends formed intermolecular or intramolecular hydrogen bonding after curing, while free hydroxyl group was present in LCE rich blends. Intramolecular hydrogen bonding was popular in DGEBA rich blends due to the conformational reason. Most carbonyl group was hydrogen bonded with hydroxyl or amine group after curing and the fraction of hydrogen bonded carbonyl was high in DGEBA rich blends.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050071
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  • 13
    Electronic Resource
    Electronic Resource
    A route to polysiloxanes with pendant imidazole groups Hydrosilylation of N-allylimidazole hydrochloride with methyldichlorosilane (1997)
    Springer
    Polymer bulletin 38 (1997), S. 371-378 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Hydrosilylation of N-allylimidazole hydrochloride by methyldichlorosilane (MeCl2SiH) under mild conditions leads to a high yield of N-[γ-(methyldichlorosilyl)propyl]imidazole hydrochloride – highly reactive monomer for synthesis of imidazole modified polysiloxanes. This compound was used as the substrate for the generation of new cyclooligosiloxanes with the imidazole group attached through the trimethylene bridge to a siloxane ring. The anionic ring-opening polymerization of these cyclics permits the controlled synthesis of polysiloxanes with imidazole groups pendant to the polymer chain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050062
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  • 14
    Electronic Resource
    Electronic Resource
    Novel aprotic polar polymers 1. Synthesis of aliphatic polysulfoxides (1997)
    Springer
    Polymer bulletin 38 (1997), S. 379-386 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Aliphatic polysulfoxides having sulfoxide groups in the main chain were prepared by the selective oxidation of aliphatic polysulfides using aqueous hydrogen peroxide in chloroform. Degree of oxidation to sulfoxides was calculated from the integral ratios of methylene protons adjacent to sulfur atoms in 1H-NMR spectra. Poly(hexamethylene sulfoxide) was subjected to Swern oxidation of primary or secondary alcohols, in which 1-octanol and 6-undecanol were oxidized to give octanal and 6-undecanone, respectively, in quantitative yields.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050063
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  • 15
    Electronic Resource
    Electronic Resource
    Electrical conductivity in iodine-doped nonconjugated polyanilinefurfural (1997)
    Springer
    Polymer bulletin 38 (1997), S. 573-577 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Polyanilinefurfural (PAF) has been prepared. Its chain contains aromatic and furan rings, but the backbone is nonconjugated. However, when treatment with iodine, the color of PAF turns metallic black, and PAF becomes electrically conductive. The electrical conductivity of I2-doped PAF can reach 10−3 S ⋅ cm−1 which is more than 10 orders of magnitude higher than what was observed at the pristine state. The effects of iodine content on the conductivity of PAF and the conductivity stability were investigated. FTIR spectra, U.v./vis absorption spectra, E.s.r. measurement and X.p.s. measurement of the undoped and doped PAF were studied. This paper will demonstrate that: if given appropriate substituents and dopants, significant charge transfer may be expected even for nonconjugated polymers and it may display electronic conductivity to a certain level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050090
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  • 16
    Electronic Resource
    Electronic Resource
    Factor analysis in the NMR characterization of multicomponent polymers (1997)
    Springer
    Polymer bulletin 38 (1997), S. 555-562 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Factor analysis has been found to be suitable for the analysis NMR data of polymers which contain multiple components. Two series of ethylene/propylene copolymers have been studied by this technique. In general, the number of components that can be resolved from NMR data depends on both the quality and the quantity of available experimental data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050087
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  • 17
    Electronic Resource
    Electronic Resource
    The role of complex formation in the anionic polymerization of l-lactide (1997)
    Springer
    Polymer bulletin 38 (1997), S. 609-612 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The rate lowering effect of crown ethers in the anionic polymerization of l-lactide is interpreted by the formation of activated monomer-cation complex. This interpretation is supported by molecular mechanics calculations. The formation of a 1 : 1 complex between lithium ion and l-lactide in THF was proved by 1H NMR and the formation constant was measured to be 3.8 M−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050095
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  • 18
    Electronic Resource
    Electronic Resource
    Application of a statistical method to study the spherulitic growth of polymer blends (1997)
    Springer
    Polymer bulletin 38 (1997), S. 601-608 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. This paper has two objectives. Firstly, to plan experimental blends (based on PVDF, PMMA and PVA) according to a statistical method proposed by Scheffé and subsequently to apply the model to the study of the spherulitic growth of PVDF with the aim of assess its suitability. In case it proved adequate, a simple method would become for the design of new materials from the polymer under study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050094
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  • 19
    Electronic Resource
    Electronic Resource
    An investigation into the synthesis of polycarbazole squaraine derivatives (1997)
    Springer
    Polymer bulletin 38 (1997), S. 493-499 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The polycondensation of squaric acid with 1,2-(9-Ethylcarbazol-3-yl)ethene and N-ethyliminostilbene in polyphosphoric acid yielded insoluble polymers which included substituted phosphate groups on the phenyl rings. The presence of phosphorus in these polymers was identified using solid-state 31P NMR and EDAX techniques. Furthermore the phosphate groups were not ionic, hence no charge-balancing anions were present. Both polymers did not electrically conduct but exhibited dielectric breakdown values of 0.1 and 0.06 MV cm−1 respectively.
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    URL: http://dx.doi.org/10.1007/s002890050078
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  • 20
    Electronic Resource
    Electronic Resource
    Comparative study on the lamellar crystal structure of high and low density polyethylenes (1997)
    Springer
    Polymer bulletin 38 (1997), S. 707-714 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. A comparative study was undertaken on well characterized HDPE and LDPE samples in order to obtain a better understanding of the morphology of the crystalline phase. Thickness of the lamellae was determined by WAXS. The melting points were calculated by empirical and Gibbs-Thomson equations, considering either folded or extended chains, and compared to DSC data. The results confirm that in HDPE the chains are folded, the segment between folds containing about 100 carbon atoms, while in LDPE, the chains are extended, with segments of about 73 carbon atoms in the crystalline core, linked to the paracrystalline layer and amorphous zones, which contain long folds and chain ends, as proposed in the 3-phase model by Vile et al.
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    URL: http://dx.doi.org/10.1007/s002890050109
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  • 21
    Electronic Resource
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    The synthesis and thermotropic liquid crystalline behavior of the novel poly(aryl ether ketone)s containing chloro-side group (1997)
    Springer
    Polymer bulletin 38 (1997), S. 621-625 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The novel poly(aryl ether ketone)s containing chloro-side group were synthesized by nucleophilic substitution reactions of 4,4′-biphenol and chlorohydroquinone with either 4,4′-difluorobenzophenone (BP/CH/DF) or 1,4-bis(p-fluorobenzoyl)benzene (BP/CH/BF) and their thermotropic liquid crystalline properties were characterized by a variety of experimental techniques. The thermotropic liquid crystalline behavior was observed in the copolymers containing 50 and 70% biphenol. Melting transition (Tm) and isotropization transition (Ti) both appeared in the DSC thermograms. A banded texture was formed after shearing the sample in the liquid crystalline state. The novel poly(aryl ether ketone)s had relatively higher glass transition temperature (Tg) in the range of 168 ∼ 200 °C and lower melting temperature (Tm) in the range of 290 ∼ 340 °C. The thermal stability (Td) was in the range of 430 ∼ 490 °C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050097
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  • 22
    Electronic Resource
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    Synthesis and characterization of wholly aromatic polyamides containing pendent amino and cyano groups (1997)
    Springer
    Polymer bulletin 38 (1997), S. 635-642 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The new pyrazole-ring containing diamine monomer with amino and cyano groups, 1,3-di-p-aminophenyl-4-cyano-5-aminopyrazole (PYA), was prepared from 4-nitrobenzoyl chloride and 4-nitrophenyl hydrazine with 4 steps. The monomer was converted to polyamides with terephthaloyl chloride and isophthaloyl chloride. The amino and cyano groups on the pyrazole-ring were not affected during polymerization. The synthesized polyamides having intrinsic viscosities of 0.92 – 1.18 dL/g were amorphous, and soluble in polar aprotic solvents and boiling acetone and THF. The polymers had high glass transition temperatures and high thermal stability. 5% weight loss temperatures in nitrogen occurred around 490 °C, but these polymers are partially degraded at 300 °C in air due to the amino group on the pyrazole-ring.
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    URL: http://dx.doi.org/10.1007/s002890050099
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  • 23
    Electronic Resource
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    On-line HPLC 1H NMR coupling for the analysis of fatty alcohol ethoxylates (1997)
    Springer
    Polymer bulletin 38 (1997), S. 673-679 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The characterisation of fatty alcohol ethoxylate based surfactants by on-line LC-NMR coupling is described. Different surfactant mixtures were separated by a mixed exclusion-adsorption method of liquid chromatography and simultaneously characterised by 1H-NMR spectroscopy. Information about the degree of oligomerisation of the ethylene oxide chain and the chemical structure of the endgroups can be obtained in a one-step experiment.
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    Synthesis and characterization of polyamides based on cubane-1,4-dicarboxylic acid (1997)
    Springer
    Polymer bulletin 38 (1997), S. 651-655 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The direct polycondensations of cubane-1,4-dicarboxylic acid with 1,4-phenylenediamine (2 a), 4,4′-oxydianiline (2 b), 4,4′-sulfonyldianiline (2 c), and 9,9′-bis(4-aminophenyl)florene (2 d) were carried out in N-methyl-2-pyrrolidone/pyridine containing triphenylphosphite and lithium chloride at 110 °C for 9 h. Polyamide 3 a obtained from 2 a was scarcely soluble in organic solvent even during heating, and was soluble only in conc-H2SO4, whereas 3 c and 3 d derived from 2 c and 2 d, respectively, were readily soluble in N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethylsulfoxide. After treating polyamide 3 d with the rhodium complex catalyst in NMP, cubane units were quantitatively converted into cyclooctatetraenes.
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    Separation of block copolymers from parent homopolymers by means of liquid chromatography at the critical adsorption point (1997)
    Springer
    Polymer bulletin 38 (1997), S. 681-688 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The characterization of a block copolymer consisting of blocks of tetrahydrofuran, THF, and methyl methacrylate, MMA, was attempted with the aid of liquid chromatography, LC, at the critical adsorption point, CAP. The conditions applying to the CAP at 30 °C for the homopolymers are: PTHF: eluent composition: THF : acetonitrile = 50 : 50, w/w; column: Nucleosil C18. PMMA: eluent composition: THF : n-hexane = 81.8 : 18.2, w/w; column: bare silica gel. The presence of homo PTHF and of homo PMMA in the crude block copolymer was evidenced. Moreover, chromatography at the CAP for PMMA showed that the block copolymer contains multiblock (triblock) fractions. The formation of triblock copolymer is expected when the polymerization of MMA is terminated (partially) by combination. In conclusion, LC at the CAP is a powerful tool to characterize block copolymers regarding the presence of homopolymer and multiblock (triblock) fractions.
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    New thermoplastic polyolefin elastomers from the novel Multicatalysts Reactor Granule Technology: their relevant physical-mechanical properties after crosslinking (1997)
    Springer
    Polymer bulletin 38 (1997), S. 701-705 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. A new process for the sequential copolymerization of olefins has been devised (Multicatalysts Reactor Granule Technology); it allows the synthesis of thermoplastic polyolefin elastomers having polypropylene from Ti-based catalysts and ethylene-propylene rubbers from metallocenes. Such new materials have been cured with peroxides and the relevant mechanical properties measured in comparison with those of heterophasic copolymers synthesized with traditional catalysts. It resulted that the new materials present an improved balance between strength and elasticity, especially at high temperature.
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    Synthesis of graft copolymers by ring-opening polymerization of 2-nonyl- and 2-phenyl-2-oxazoline initiated by macroinitiators containing benzylchloride functions (1997)
    Springer
    Polymer bulletin 38 (1997), S. 657-664 
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    ISSN: 1436-2449
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    Notes: Abstract. Graft copolymers with poly(2-nonyl-2-oxazoline) and poly(2-phenyl-2-oxazoline) graft arms have been synthesized using the "grafting from" method. Slightly branched statistical copolymers of isobutene and (m,p)-chloromethylstyrene, synthesized cationically, as well as linear homo-poly((m,p)-chloromethylstyrene) have been used as macroinitiators for the ring-opening polymerization of the substituted oxazolines. The graft copolymerizations were carried out in bulk and in benzonitrile solutions with and without addition of potassium iodide. The influence of the reaction conditions on the rate of polymerization and the different reactivities of 2-nonyl-2-oxazoline and 2-phenyl-2-oxazoline were discussed.
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    The effect of stereoregularity on the thermal behavior of poly(methacrylic acid)s I. Thermal analysis studies (1997)
    Springer
    Polymer bulletin 39 (1997), S. 85-91 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The thermal degradation of a series of poly(methacrylic acid)s (PMADs) with different tacticities has been investigated under inert atmosphere. All the samples showed two main degradation stages. The first decomposition process of isotactic PMAD consisted of the formation of anhydride groups, almost quantitatively, by dehydration. In the case of PMADs with lower isotactic content, the elimination of water between neighboring carboxylic groups is less favored and the anhydridization shifts at higher temperatures where other degradation reactions may take place at the same time. The temperatures of maximum volatilization rates at the second step of decomposition increased in the order isotactic 〉 atactic 〉 syndiotactic.
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    Rheometrical behavior and equilibrium swelling in NR/BR/CEL II composites (1997)
    Springer
    Polymer bulletin 39 (1997), S. 117-124 
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    ISSN: 1436-2449
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    Notes: Abstract. Natural rubber/butadiene rubber/cellulose II blends (NR/BR/CEL II) have been obtained by coprecipitation of the rubber latex-cellulose xanthate mixtures through acidulation. The elastomer ratio NR/BR has been varied from 100/0 to 25/75 and the cellulose content from 0 to 25 phr. The cure behavior of the compositions has been investigated by a Monsanto Oscillating Disk Rheometer. The results are a function of cellulose filler, NR, and BR contents. Some compositions were also analysed by equilibrium swelling in order to investigate polymer-filler interaction. The results show that composites with higher BR contents exhibit higher elastomer-filler attachment.
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    Polymerization by phase transfer catalysis 22. Synthesis of poly(amide-carbonate)s and poly(amide-thiocarbonate)s derived from diphenols with the amide group in the side chain (1997)
    Springer
    Polymer bulletin 39 (1997), S. 9-14 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Poly(amide-carbonate)s and poly(amide-thiocarbonate)s derived from the diphenol-amides N-(2,6-dichloro-4-nitrophenyl)-2,2-bis(hydroxyphenyl)-propylamide (I), N-(2,6-dichloro-4-nitrophenyl)-3,3-bis(hydroxyphenyl)-butylamide (II), and N-(2,6-dichloro-4-nitrophenyl)-4,4-bis(hydroxyphenyl)-pentylamide (III), and phosgene or thiophosgene, have been synthesized under phase transfer conditions using several quaternary ammonium salts as phase transfer catalysts. Benzyltriethylammonium chloride (BTEAC) was effective in practically all cases due the hydrophilicity of this catalysts.
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    Interpolymer complex formation between form I helical and form II helical poly(l-proline) and poly(carboxylic acids) (1997)
    Springer
    Polymer bulletin 39 (1997), S. 45-52 
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    ISSN: 1436-2449
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    Notes: Abstract. Interpolymer complex formations between Form II helical poly(l-proline) [PLP(II)] and Form I helical poly(l-proline) [PLP(I)] and poly(carboxylic acids) such as polyacrylic acid (PAA), atatic polymethacrylic acid (at-PMAA), and syndiotatic polymethacrylic acid (st-PMAA) have been studied by FT-IR, X-ray diffraction, and light scattering measurements. It was found that the interpolymer complexes were formed via hydrogen bonding. The helical PLP(II) formed polymer complex more favorably with PAA and at-PMAA having a disordered structure than with st-PMAA having a ordered structure. In contrast, the helical PLP(I) formed polymer complex more favorably with st-PMAA than with PAA and at-PMAA. In addition, PLP(II) helix was destroyed on the complexation with PAA and at-PMAA, but the PLP(II) helix was perserved on the complexation with st-PMAA. However, the PLP(I) helix was all perserved on the complexation with poly(carboxylic acids). These findings could be explained in terms of molecular conformation of the complementary polymers associated with the complex formation.
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    Local motion of crosslinks for poly(methyl methacrylate) gels by the fluorescence depolarization method (1997)
    Springer
    Polymer bulletin 39 (1997), S. 109-116 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Poly(methyl methacrylate) (PMMA) gels labeled at crosslinks with anthracene were prepared. Anthracene fluorescence depolarization was monitored to probe the local motion of crosslinks for PMMA gels at different equilibrium swelling states. The relaxation times and the activation energies of local motion were measured for PMMA gels at the swollen states in various solvents through fluorescence anisotropy decays. The local motion of PMMA gel at crosslinks became faster with the increase of swelling ratio. When the swelling ratios were almost the same, the mobility of crosslinks was the same irrespective of the molecular weights between crosslinks. These results indicate that the local motion of crosslinks for PMMA gel is mainly governed by the segment density of network chains in the vicinity of crosslinks.
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    Influence of the structure and composition on surface tension of aqueous solution of graft copolymers of polyacrylamide backbone and polyalkyleneoxide branches (1997)
    Springer
    Polymer bulletin 39 (1997), S. 73-78 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Polyacrylamide homopolymers and graft copolymers of poly(acrylamide-g-ethylene oxide) and poly(acrylamide-g-propylene oxide) were synthesized, characterized by SEC, FTIR and 13C-NMR and the behavior of their aqueous solutions was evaluated by surface tension measurements. By using the macromonomer technique, it is more difficult to incorporate poly(propylene oxide) branches than poly(ethylene oxide) branches. Graft copolymers of polyacrylamide and poly(propylene oxide) showed higher reduction of surface tension than poly(acrylamide-g-ethylene oxide) since they present a structure made up of hydrophilic and hydrophobic segments. Poly(acrylamide-g-propylene oxide) exhibits surfactant behavior, and the surface tension of its aqueous solution depends on the poly(propylene oxide) graft chain length and amount.
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    Transition temperature control of liquid crystalline poly(heptene sulphone)s (1997)
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    Polymer bulletin 39 (1997), S. 179-184 
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    Notes: Abstract. Liquid crystalline poly(heptene sulphone)s containing cholesteryl undecylenic ester and cholestanyl undecylenic ester were synthesized. The polymers displayed cholesteric mesophases during thermal transition. The clearing temperatures were from 114 to 172 °C depending on the molar ratio of mesogenic esters in the polymers.
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    Molecular dimensions of poly(ethylene isophthalate) and poly(ethylene naphthalene-2,6-dicarboxylate) (1997)
    Springer
    Polymer bulletin 39 (1997), S. 257-263 
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    Notes: Abstract. The rotational isomeric state (RIS) model was used to calculate the molecular dimensions of poly(ethylene isophthalate) (PEI) and poly(ethylene naphthalene-2,6-dicarboxylate) (PEN) by introducing new description for aromatic segments and by adopting the statistical weight parameters of PET. The mean square dimension ratios ((〈r2〉0/M)∞) of PEN and PEI were 0.653 and 1.167, respectively, and the entanglement molecular weight (Me) of PEI and PEN were 1850 and 1810, respectively.
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    Effects of cyclization and pendant vinyl group reactivity on the swelling behavior of polyacrylamide gels (1997)
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    Polymer bulletin 39 (1997), S. 233-239 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. A series of polyacrylamide (PAAm) gels were prepared by free-radical crosslinking copolymerization of acrylamide and N,N′-methylenebis(acrylamide) (BAAm) in water at various crosslinker (BAAm) and chain transfer agent (isopropyl alcohol, IPA) concentrations. It was shown that only 5% of the crosslinker used in the feed forms effective crosslinks in the final hydrogels. At BAAm contents as high as 3 mole%, the equilibrium swelling ratio of the gels in water is independent of the crosslinker content in the feed. This is due to the prevailing multiple crosslinking reactions during the gel formation process. At a fixed crosslinker content, the onset of gelation is shifted towards higher conversions and reaction times as the amount of IPA increases. Addition of IPA in the monomer mixture also increases the equilibrium swelling ratio of PAAm gels. It was shown that the gel crosslinking density increases on rising IPA concentration in the feed due to the increasing rate of intermolecular crosslinking reactions.
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    Highly flexible heterophasic copolymers through the novel multicatalysts reactor granule technology (1997)
    Springer
    Polymer bulletin 39 (1997), S. 241-247 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. New heterophasic copolymers with high rubber content have been synthesized by combining heterogeneous Ti-based catalysts with metallocenes. The molecular, morphological and mechanical features of these materials were evaluated: it was pointed out that the new copolymers, having more than 60 Wt.% of rubber, perform as reinforced elastomers whereas traditional ones show a more plastomeric behaviour. This suggests that new polyolefin materials can augment rather than compete with the traditional ones.
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    Ethylene-propylene copolymers by a supported Ziegler-Natta catalyst based on TiCl4/MgCl2 (1997)
    Springer
    Polymer bulletin 39 (1997), S. 133-140 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Ethylene-propylene copolymers have been prepared by using Ziegler-Natta catalysts based on TiCl4, MgCl2, PCl3 and (n-Bu)3PO4. The catalysts TiCl4/MgCl2/PCl3 and TiCl4/MgCl2/(n-Bu)3PO4 were prepared by reacting TiCl4 with pretreated MgCl2. The support was prepared by ball milling of MgCl2 with varied amounts of PCl3 or (n-Bu)3PO4. The addition of PCl3 has remarkably increased the MgCl2 surface area in comparison with (n-Bu)3PO4. The effects of PCl3 and (n-Bu)3PO4 on ethylene homopolymerization, ethylene-propylene copolymerization and on copolymer properties were evaluated. The catalyst system containing PCl3 permitted to synthesize propylene-ethylene copolymers with up to 75% (w/w) of propylene and provided control of copolymer crystallinity. The reduction of the copolymer molecular weight distribution suggested that PCl3 acted as an internal donor, poisoning some active catalytic sites.
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    Grafting of side chain liquid crystal monomers onto polyethylene film (1997)
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    Polymer bulletin 39 (1997), S. 489-494 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. In order to obtain films of liquid crystalline polymers, a commercial polyethylene film was grafted with acryloyl chloride using γ-irradiation, and two tolane-containing alcohols were reacted with the chloride to obtain the corresponding acrylates. The morphology changes were studied by DSC, X-ray diffractometry and optical microscopy. The crystallinity of polyethylene films decreased by grafting, and mesophase with spherulites was observed over a wide temperature range.
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    Polymer-polymer interaction and modeling (1997)
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    Polymer bulletin 39 (1997), S. 519-526 
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    Notes: Abstract. The nature of intermolecular interaction in PVC/EVA system was investigated. Bathochromic shifts in infrared region revealed that not only EVA carbonyl but the ester group participates on interaction with PVC chain. These shifts were proportional to acetate content in the copolymer and the composition of EVA in the blend. The PVC group that effectively participates on interaction was not elucidated by infrared spectrometry, but molecular modeling of low molecular weight analogues indicated that hydrogen bonding is the most probable kind of intermolecular interaction present in this system.
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    Application of an association model to the PVC/EVA system (1997)
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    Polymer bulletin 39 (1997), S. 527-534 
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    Notes: Abstract. A thermodynamic association model was applied to the PVC/EVA system. In this model the enthalpy component is related quantitatively to intermolecular interaction forces. Molecular modeling was applied to obtain the parameters related with interaction forces. The phase diagrams showed lower critical solution temperature (LCST) behavior and also biphasic regions in PVC rich compositions.
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    Synthesis, characterization, and properties of an efficient and selective adsorbent to mercury(II) (1997)
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    Polymer bulletin 39 (1997), S. 445-452 
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    Notes: Abstract. The synthesis of a water-insoluble adsorbent resin was carried out by radical polymerization of [2-(methacryloyloxy)ethyl] trimethyl ammonium chloride by using ammonium peroxydisulfate as initiator and N,N′-methylene-bis-acrylamide (MBA) as crosslinking reagent. The adsorbent was characterized by elemental analyses, and FT-IR spectroscopy. The thermal stability was studied in the presence of Hg(II). The ability to bind Hg(II), Cd(II), Zn(II), Pb(II), Cu(II), Cr(III), and U(VI) as well as the maximum adsorption capacity, and elution of the Hg(II) from the loaded resin was studied. At pH 2 the adsorbent retained 95% of Hg(II) from an aqueous solution containing 1 g/L in Hg(II). The retention of other metal ions was lower than 15%. Sorption selectivity from the binary mixtures Hg(II)-Cd(II), Hg(II)-Zn(II), Hg(II)-Pb(II), and Hg(II)-Cr(III) was studied at the optimum sorption pH value.
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    Dendrite polymers from vinyl ether (1997)
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    Polymer bulletin 39 (1997), S. 399-406 
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    Notes: Abstract. 1-[(2-Vinyloxy)ethoxy]ethyl acetate (1) was prepared by the addition reaction between ethylene glycol divinyl ether and acetic acid. 1 contains both a cationically polymerizable C=C double bond and a dormant initiating moiety for cationic polymerization. It can, therefore, undergo self condensing cationic polymerization in the presence of a Lewis acid activator, such as zinc chloride. Using this procedure, a novel dendritic polymer consisting of vinyl ether was prepared and its hyperbranched molecular structure confirmed by FT-IR and 1H NMR spectra.
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    On a novel molecular microstructure based approach to the extrinsic space charges releasing in polypropylene (PP) (1997)
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    Polymer bulletin 39 (1997), S. 639-646 
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    Notes: Abstract. The release of the extrinsic charges produced when applying an electric stress has been studied for four polypropylene samples of distinct well controlled molecular microstructure by Thermal Stimulated Discharge Current (TSDC), with the aim of stating the correlation between the ρ relaxation (intensity and temperature) and the tacticity induced polymer microstructure, and of, demonstrating that the traps of space charges are not chain defects as usually proposed but that they relate to some normal local chain configurations. The results are discussed in the light of the space charge distributions as measured in earlier recent work.
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    Regioselective introduction of β-galactoside branches into chitosan and chitin (1997)
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    Polymer bulletin 39 (1997), S. 543-549 
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    Notes: Abstract. β-d-Galactoside branches have been introduced into chitosan and chitin regioselectively through a series of controlled modification reactions based on N-phthaloyl-chitosan. The glycosylation reaction between a chitosan derivative having a reactive group only at C-6 and an orthoester of d-galactose proceeded efficiently to give a protected product with a degree of substitution up to about 0.5. Deprotection gave a branched chitosan, and the subsequent N-acetylation afforded a branched chitin. Unlike chitosan and chitin, the resulting nonnatural branched polysaccharides were characterized by high affinity for solvents and readily soluble in neutral water. Furthermore, branched chitin was easily degraded by lysozyme.
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    Effective catalysts for polymerization of cyclohexene oxide: Preparation of novel Martin-type pentacoordinate silicates (1997)
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    Polymer bulletin 39 (1997), S. 573-579 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The novel dialkylanilinium salts of pentacoordinate Martin-type silicates were prepared. They were found to be air stable catalysts for polymerization of cyclohexene oxide. The preparation of those silicates bearing a bulky substituent such as mesityl group was not successful.
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    Molecular packing of poly(azomethine)s having flexible (n-alkyloxy)methyl side chains in films (1997)
    Springer
    Polymer bulletin 39 (1997), S. 701-705 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The molecular packing of poly(azomethine)s having (n-alkyloxy)methyl side chains in films was studied by wide-angle X-ray scattering. Solution-cast films on silicon wafer and melt-sheared films show the same type of molecular packing, i.e. the main chain layers are aligned parallel to the film surface but the main chains are macroscopically isotropic in the film surface plane. In the melt-sheared films, the shear does not orient the main chains but the main chain layers, which can be easily understood by their geometric shapes.
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    Characteristics of permeation and separation of dimethyl acrylamidemethyl methacrylate random and graft copolymer membranes for a benzene/cyclohexane mixture (1997)
    Springer
    Polymer bulletin 39 (1997), S. 733-740 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. When a benzene/cyclohexane mixture was permeated through poly(dimethyl acrylamide-random-methyl methacrylate) (DMAA-r-MMA) and poly(dimethyl acrylamide)-graft-poly(methyl methacrylate) (DMAA-g-MMA) membranes by pervaporation, the benzene-permselectivity of the DMAA-r-MMA membrane changed from the diffusivity selectivity to the solubility selectivity with increasing DMAA content but DMAA-g-MMA membranes with a high DMAA content had the higher apparent diffusivity selectivity than the apparent solubility selectivity. Furthermore, the apparent solubility selectivity for a benzene/cyclohexane mixture between the DMAA-r-MMA membrane and the DMAA-g-MMA membrane with a high DMAA content was remarkably different. These results were attributed to the difference of structure between the copolymers.
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    Oriented overgrowth of vapour deposited tin on highly oriented PTFE substrates (1997)
    Springer
    Polymer bulletin 39 (1997), S. 761-765 
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    ISSN: 1436-2449
    Keywords: metal/polymer interface – friction transfer – ultra-thin films
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The vapour deposition of tin on highly uniaxially oriented PTFE causes an oriented overgrowth of tin islands. The origin of this orientation is not clear. Classic epitaxy as well as graphoepitaxy seems to be an explanation for the occurring orientation. The appearance of this orientation was observed in a temperature range from −80 °C to 90 °C. An orientation by crystallization from the melt could not be achieved so far. In this short communication, a metal/polymer system is introduced which offers new possibilities to investigate the origin of oriented overgrowth.
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    Polymerization of methyl and phenyl oxazoline initiated with carboxylic acid chlorides (1997)
    Springer
    Polymer bulletin 38 (1997), S. 7-13 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Methyl and phenyl oxazoline were polymerized using carboxylic acid chlorides as initiators. The first step of the reaction was shown to consist in a fast reaction of the carboxylic acid chloride with the oxazoline. Resulting product, which was isolated and identified, act as the proper initiator of the polymerization of the oxazoline, which proceeds via covalent or, when chloride counter ion is replaced with iodide or triflate, ionic active species. Apparent rate constants of the chain growth were determined. When methacryloyl chloride is used as initiator macromonomers are obtained, which were copolymerized with styrene. Macromolecular carboxylic acid chlorides initiate the polymerization of oxazolines, yielding graft polymers.
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    Photodegradation of chain halogenated polystyrene: Poly(c-chloro and c-bromostyrene)s (1997)
    Springer
    Polymer bulletin 38 (1997), S. 191-196 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The photodegradation of films of poly chain-chlorostyrene (PCCS) and poly chain-bromostyrene (PCBS) achieved by exposure to 254-nm radiation under dynamic vacuum was studied. The minor gaseous products obtained were hydrogen halides and monomer. The polymers were investigated by ir, gel permeation chromatography, and microanalysis. Both polymers undergo main chain scission. The ir spectra of the degraded polymers indicate the presence of unsaturated species. An initial α-carbon-halogen bond fission is required to account for the present reaction products. Possible mechanism of the various photoreactions are discussed.
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    Compatibilization of low-density polyethylene/polystyrene blends by segmented EB(PS-block-EB)n block copolymers (1997)
    Springer
    Polymer bulletin 38 (1997), S. 203-210 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Hydrogenated segmented poly[butadiene-block-(styrene-block-butadiene)n] block copolymers, which were developed by use of a polymeric iniferter technique, were tested on their compatibilizing effectiveness for (10/90) LDPE/PS blends. They were found to be effective compatibilizers for this mixture, already giving a pronounced improvement in both tensile strength and strain of the blend at block copolymer concentrations of one percent. A concentration of five weight percent of segmented block copolymer provided a tenfold improvement in blend toughness. The effectiveness of the segmented block copolymers was found be dependent on the block copolymer composition. Block copolymer compositions of close to 50 : 50 EB : PS gave the best results.
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    Dynamic mechanical behaviour of random copolymers of a LC-methacrylate and octyl methacrylate (1997)
    Springer
    Polymer bulletin 38 (1997), S. 219-226 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The dynamic mechanical behaviour of random copolymers of LC monomer-1-(hexyloxycarbonyl)ethyl 4-[4-(methacryloyloxy)benzoyloxy]benzoate (HB) and octyl methacrylate (OMA) was studied in the main transition and flow regions. Even though the aliphatic end groups of the side chain of HB and OMA are roughly the same, the T g temperature of poly(HB) is ∼ 80 K higher than that of poly(OMA); this fact is due to the presence of the stiff phenyl benzoate mesogenic group in the side chain of HB. With increasing content of OMA in the copolymer the superimposed curves of the storage G′ p and loss G′′ p moduli at a constant temperature shift towards shorter frequencies. It has been shown that this shift is mainly due to an increase of the free volume in the copolymers with increasing content of OMA. While HB monomer shows liquid crystalline (LC) properties, its polymer (poly(HB)) and random copolymers with OMA show only isotropic thermal behaviour because no flexible spacer is present in the side chain of HB which would decouple the main chain and mesogenic group motions. This means that neither the homopolymer of HB, nor its copolymers with a flexible comonomer retain the LC properties of the starting LC monomer, HB.
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    A new approach to anisotropic conductive networks A liquid-crystalline side-chain polymer containing a thienyl moiety at the extremity of its side chain (1997)
    Springer
    Polymer bulletin 38 (1997), S. 551-554 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. A liquid-crystalline bifunctional monomer with two different reactive moieties was prepared by esterification of 4-(6-(acryloyloxy)hexyloxy)benzoic acid and 4-[11-(3-thienyl)undecyloxy]-4′-hydroxybiphenyl. A mesogenic side-chain polyacrylate containing a thienyl moiety at the extremity of its side chain was obtained by radical polymerization of the monomer. The subsequent reaction of the thienyl moiety with FeCl3 leads to the formation of an anisotropic network with a poly(thiophene) unit.
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    Asymmetric polymerization of N-triphenylmethylmaleimide with chiral anionic initiators (1997)
    Springer
    Polymer bulletin 38 (1997), S. 509-514 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Asymmetric polymerization of N-triphenylmethylmaleimide (TrMI) is performed with chiral anionic initiators in tetrahydrofuran and toluene at − 78 and 0 °C to obtain optically active polymer. It is found that the (S)-(+)-1-(2-pyrrolidinylmethyl) pyrrolidinelithium [Li-(+)-PMP] and lithium (−)-menthoxide are effective for the asymmetric polymerization of N-triphenylmethylmaleimide in THF. The polymers obtained are characterized by circular dichroism (CD). It is inferred that the propagation reaction of polymerization of TrMI with Li-(+)-PMP is dominated by ion pair mechanism and meanwhile free ion mechanism cannot be ignored based on GPC analysis.
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    Synthesis and characterization of some polyazomethine conducting polymers and oligomers (1997)
    Springer
    Polymer bulletin 39 (1997), S. 1-7 
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    ISSN: 1436-2449
    Keywords: Key words: polyazomethines – oligomers – conducting polymers – synthesis – characterization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Polyazomethine polymers were prepared from the polycondensation of terephthaldehyde with different diamines, namely, benzidine, 2,3-diaminopyridine, 1,4-diaminoanthraquinone and 3,5-diamino-1,2,4-triazole. The electrical conductivities of the polymers were studied with doping with H2SO4 and 5% I2 together with the undoped polymers. The crystallinity and morphology of the polymers were studied using XRD and scanning electron microscopy. A comparative study of the electrical conductivities of oligomers of polyazomethines and those of their corresponding polymers was performed.
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    Syntheses and radical ring-opening polymerizations of 1,1-bis(hydroxymethyl)-2-vinylcyclopropane and 1,1-bis(methoxymethyl)-2-vinylcyclopropane (1997)
    Springer
    Polymer bulletin 39 (1997), S. 141-148 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Syntheses and radical ring-opening polymerization of 1,1-bis(hydroxymethyl)-2-vinylcyclopropane (1 a) and 1,1-bis(methoxymethyl)-2-vinylcyclopropane (1 b) were examined. Novel polymers bearing hydroxyl and methyl ether moieties in the side chains as well as olefinic moieties in the main chain were obtained. The main structure of the polymers, obtained by radical polymerization, originated from the cleavage of the cyclopropane ring near the hydroxymethyl or methoxymethyl groups. The difference in the two-center energies and bond orders of the C−C bonds of the cyclopropane ring well explained the selectivity in the direction of the cleavage. The number-average molecular weights (Mˇ n) of poly(1 a) and poly(1 b) were 94 200 and 11 200 in the polymerization in bulk at 60 °C, respectively. The intermolecular hydrogen bonding of 1 a might increase the radical polymerizability. The oxygen permeability of poly(1a) was 6.19 mL ⋅ 20 mm ⋅ m−2 ⋅ day−1 ⋅ atm−1 at 35 °C, demonstrating that poly(1 a) could be a good oxygen barrier material.
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    Radical polymerization of (trimethylsilylethynyl)styrene and thermal properties of polystyrene with ethynyl group (1997)
    Springer
    Polymer bulletin 39 (1997), S. 173-178 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The radical polymerizations of 2-, 3-, and 4-(trimethylsilylethynyl)styrenes (1 a – c) and copolymerizations of 1 a – c (M1) with styrene (M2) have been studied. Copolymerization parameters were determined as r1 = 1.22 and r2 = 0.54 for 1 a, 1 = 1.10 and r2 = 0.90 for 1 b, and r1 = 1.42 and r2 = 0.38 for 1 c. The deprotection of the trimethylsilyl groups in poly[(trimethylsilylethynyl)styrene] (2 a – c) and poly[(trimethylsilylethynyl)styrene-co-styrene] (4 a – c) using (C4H9)4NF smoothly proceeded to yield poly(ethynylstyrene) (3 a – c) and poly(ethynylstyrene-co-styrene) (5 a – c), respectively, which underwent curing reactions at elevated temperature to form crosslinking polystyrenes.
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    Surface activity of water soluble amphiphilic chitin derivatives (1997)
    Springer
    Polymer bulletin 39 (1997), S. 209-215 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Chitin was derivatized to extend its applications in the field of water soluble systems. It was first carboxymethylated and then alkylated. Two technics were used for that purpose: ionic surfactants playing the role of counterions form an electrostatic complex, and covalent derivatization. The difference between covalent alkylation and dynamic association (SPEC) is discussed in relation with the length of the alkyl chain and the density of alkylation.
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    Study of siloxane-modified epoxy resin using thermally stimulated current(II) (1997)
    Springer
    Polymer bulletin 39 (1997), S. 193-199 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Thermally stimulated current (TSC) and relaxation map analysis (RMA) was used to characterize the low temperature relaxation of epoxy resin modified with siloxane oligomers. In aminopropyl-terminated siloxane oligomer (ATSO) the β-relaxation of epoxy resin and the glass transition temperature of siloxane oligomer were folded regardless of the concentration of diphenyl. The β-relaxation of epoxy resin and the glass transition temperature of oxiranylmethoxy-terminated siloxane oligomer (OTSO) were folded and shifted to higher temperature as the concentration of diphenyl in siloxane oligomer increased. In the systems containing of diphenyl in siloxane oligomer a new relaxation peak due to the space charge was observed in the range of − 80 °C to − 50 °C and − 30 °C to 5 °C. As the concentration of diphenyl increased the compensation temperature (Tc) and the degree-of-disorder (DOD) were increased while the compensation time, τ c was decreased.
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    Microwave assisted polymerisation of phenylacetylenes (1997)
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    Polymer bulletin 39 (1997), S. 333-337 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary. Methathesis Polymerisation of phenylacetylenes using in situ generated (arene)M(CO)3 complexes under unconventional microwave energy condition was achieved successfully. The reaction time was reduced to 1 hour in contrast to refluxing conditions of 24 hours.
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    Transition metal complex induced morphology change in an ABC-triblock copolymer (1997)
    Springer
    Polymer bulletin 39 (1997), S. 361-368 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary. The short 1,2-polybutadiene center block of the ternary polystyrene-block-polybutadiene-block-poly(methyl methacrylate) S45B6M49 225-triblock copolymer (subscripts indicating the weight fractions and the superscript indicating the total molecular weight in kg/mol) has been selectively modified by complexation with metal complexes of two different transition metals, namely Pd and Fe. These modifications cause significant variations in the microphase morphology. The original ls-morphology (spheres at lamellar interphase) belonging to the lamellar class changes via a cocontinuous morphology in the case of the Pd-complex to a morphology belonging to the cylindrical class for the Fe-complex.
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    Kinetics of formation of polyurethane/polymethylmethacrylate grafted semi-interpenetrating polymer networks based on the functional prepolymers (1997)
    Springer
    Polymer bulletin 39 (1997), S. 339-346 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary. The kinetics of formation of the polyurethane network by crosslinking the polyurethane prepolymer in polyurethane/polymethacrylate grafted semi-interpenetrating networks (semi-IPN) was monitored by Fourier transform infrared spectroscopy, and the kinetic parameters were thus determined. It was found that carboxylic groups in the hard segments of the Pu component substantially decrease the reaction rate and increase the activation energy. Tertiary amine groups in the PM component catalyse the crosslinking reaction. The PM component acts as a diluent in the mixture of PU and PM reducing the reaction rate and increasing the activation energy of the corsslinking reaction. At temperatures below the Tg of the PM component, the reaction of formation of IPN becomes diffusion controlled.
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    Synthesis of polystyrene/silica gel polymer hybrids by in-situ polymerization method (1997)
    Springer
    Polymer bulletin 39 (1997), S. 303-310 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary. Homogeneous polystyrene and silica gel polymer hybrids were prepared by in-situ radical polymerization method. Styrene monomer was introduced into a sol-gel reaction mixture of tetramethoxysilane (TMOS) and the polymerization was initiated by Azobisisobutyronitrile (AIBN), while sol-gel reaction of TMOS proceeded to form a silica gel. The homogeneity of the hybrids was found to be dependent on the amount of the acid catalyst. The homogeneity was confirmed quantitatively by measuring porosity of charred hybrids with nitrogen porosimetry method. It was found that polystyrene was dispersed at a nano-meter level in the silica gel matrix.
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    Synthesis of novel organoboron polymers by haloboration polymerization of bisallene compounds and their reactions (1997)
    Springer
    Polymer bulletin 39 (1997), S. 295-302 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary. Novel organoboron polymers were prepared by haloboration polymerization of bisallene compounds. The polymers obtained have allylborane halide units in their main chain and can be expected as a novel type of reactive polymers. For example, the polymer prepared by haloboration polymerization between tribromoborane (1) and 1,2,10,11-dodecatetraene (2 b) was subjected to chain transformation reaction (dichloromethyl methyl ether rearrangement) to give the corresponding polyalcohol or polyketone. Haloboration-phenylboration polymerization of aliphatic bisallenes by using diphenylbromoborane also gave the corresponding polymers.
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    Anionic polymerization of vinylsilanes VII. Effects of N,N,N',N'-tetramethylethylenediamine on the polymerization of tetravinylsilane (1997)
    Springer
    Polymer bulletin 39 (1997), S. 287-293 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary. The anionic polymerization of tetravinylsilane (TeVS) was carried out in the presence and absence of N,N,N',N'-tetramethylethylenediamine (TMEDA). Without TMEDA, the polymerization proceeded extremely slowly and the polymer yield was still low even after an extended polymerization time. When TMEDA was added to the system, the polymerization was remarkably accelerated and gelation was suppressed. Such polymerization behavior of TeVS is closely similar to that of methyltrivinylsilane under similar conditions. The effects of TMEDA are explained by its coordination to the propagating end that increases the selectivity in the reaction of the propagating end with vinyl groups.
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    Investigation of adhesive performances by scanning force microscopy (1997)
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    Polymer bulletin 39 (1997), S. 613-620 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. In this work an original investigation of the polymer adhesive properties by scanning force microscopy (SFM) is proposed. Polyethylene terephthalate (PET)/ethylene vinylacetate copolymers (EVA) assemblies have been separated using a peel test. SFM (tapping mode) is used to study the adhesive surface (EVA) after the mechanical separation. The topographic analysis allows to determine the average roughness due to the polymer surface deformation. A tentative correlation between the surface deformation and the adherence force is proposed. The result show that the polymer which possess the higher adhesive strength presents the greater surface deformation, measured on the SFM image. A relatively good correlation between the evolution of the adherence force and the variation of the surface topography analysed by SFM is highlighted in this original work.
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    Conductive polyaniline/poly(vinylphosphonic acid) blends (1997)
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    Polymer bulletin 39 (1997), S. 627-632 
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. In-situ polymerization of aniline in poly(vinylphosphonic acid) (PVPA) resulted in conductive polyaniline/PVPA blends with conductivities in the order of 10−2 S/cm. The blends were characterized by FTIR and UV-vis spectroscopy. Thermogravimetric analysis showed that the blends have good thermal stability.
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    Poly(allylammonium acrylate) as a drug-releasing matrix I. Release of drugs mixed and sintered with the polyelectrolyte complex (1997)
    Springer
    Polymer bulletin 39 (1997), S. 707-714 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. A poly(allylammonium acrylate) complex was tested for drug release in aqueous solution. Sintered tablets of the polyelectrolyte complex, mixed respectively with human serum albumin, vitamin B12, 5-fluorouracil and tetracycline, were made and dipped into Dulbecco's PBS (pH 7.3). The release kinetics, followed spectrophotometrically, is poorly reproducible and very different for the different drugs. An explanation of such behaviours is proposed, based on the chemical structures of the drugs and of the polyelectrolyte complex, as well as on two concurrent processes: the drug extraction and the saturation by the buffer of the poorly uniform drug-complex mechanical mixtures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050206
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    Synthesis of fullerene-containing poly(alkyl methacrylate)s with narrow polydispersities (1997)
    Springer
    Polymer bulletin 39 (1997), S. 661-667 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Copolymers of allyl methacrylate with methyl methacrylate or n-butyl methacrylate were synthesized by group transfer polymerization. The pendant allyl groups of the copolymers were then hydrobrominated, followed by reaction with sodium azide. Fullerene was incorporated via an addition reaction of fullerene with azide group. The resulting fullerene-containing poly(alkyl methacrylate)s have fairly narrow polydispersities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050200
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    Development of an information model for composites design data (1997)
    Springer
    Engineering with computers 13 (1997), S. 48-64 
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    ISSN: 1435-5663
    Keywords: Composite materials ; Conceptual modeling ; Database design ; Fiber-reinforced plastics ; information modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Material properties data, particularly those of advanced composite materials such as fiber-reinforced plastics, provides a very complex domain which is difficult to computerize. As a foundational activity supporting the development of material property databases, we have examined and modeled the data contained within this large, diverse, and intricate domain. Our primary objective was to gain a better understanding of the data involved in this system and their transformation and use. We examined the life cycle of a fiber-reinforced composite material, from a raw material to a manufactured product, focusing on the various applications which require and/or supply materials data and the types of materials data which must be included. A high-level information model was created to illustrate the overall picture of composite materials data which emerged from this analysis. This model provides a global view of the data encompassed in the domain of composite materials, and forms the basis of a formal conceptual model from which databases may be developed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01201860
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    A data management model for collaborative design in a CAD environment (1997)
    Springer
    Engineering with computers 13 (1997), S. 65-86 
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    ISSN: 1435-5663
    Keywords: Collaborative design ; Version control ; Configuration scheme ; Change management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract This paper presents a data management model to support collaborative design. More specifically, it addresses the storing and managing of changes among designers in a multidisciplinary design project. We propose a three-layered model ofversions, assemblies, andconfigurations. Versions maintain evolving descriptions of primitive entities within a single discipline.Assemblies integrate component instances to describe more complex entities, as well as designs within individual disciplines.Configurations provide a framework to represent an overall project design which is composed of designs from the participating disciplines. We apply a concept ofequivalent operations for developing operators that store, detect and manage changes among versions of a primitive design entity. The close coupling of the version, assembly, and configuration layers enables computed version changes to be recursively combined to characterize changes at the assembly and configuration levels. This applies for both project coordination throughasynchronous communication of changes among designers, and project monitoring through systematic tracking of evolving project descriptions. This paper also presents an implementation of the data management model in a CAD paradigm. We use a simple multidisciplinary facility design example to demonstrate the change management capabilities of the proposed model. This example has been tested on a prototype implementation in an AUTOCAD environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01350751
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    Using objects to handle complexity in finite element software (1997)
    Springer
    Engineering with computers 13 (1997), S. 99-111 
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    ISSN: 1435-5663
    Keywords: Finite elements ; Object oriented methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Engineering software is becoming ever more complex. Finite element programs have sophisticated graphical input and output facilities, and are increasingly required to be linked to other software such as CAD or databases. The paper shows how an object oriented approach to finite element programming can be used to handle this complexity. This requires an approach that is very different from that adopted in more traditional programming. A foundation finite element class system is developed. This represents the essential data structure of the main finite element classes. It is then shown how this system can be used in a graphical model of two dimensional structures. The finite element system imposed no constraints on the development of the graphical model, yet could still be used easily. An important feature is that the nodes and elements are distributed around the graphical model, rather than being held centrally. For instance nodes may belong to points or lines of the graphical model. This means that the data structure used in the program more closely matches the way that the user of the program is likely to think.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01350753
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    Elimination of the adverse effects of small model features by the local modification of automatically generated meshes (1997)
    Springer
    Engineering with computers 13 (1997), S. 134-152 
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    ISSN: 1435-5663
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Issues related to the automated identification and elimination of the adverse influence of small geometric model features on the quality of automatically generated meshes, using local mesh modification operators, are addressed. The definition of mesh validity with respect to the geometric model is extended to include multiple mesh entity classifications. Checks based on mesh topology are used to ensure no dimensional reductions in the locally modified mesh. Example geometric models of varied complexity containing small geometric features are used to demonstrate the ability of presented procedures to improve mesh quality in terms of aspect ratio and small angle metrics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01221211
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    Local refinement of three-dimensional finite element meshes (1997)
    Springer
    Engineering with computers 13 (1997), S. 165-174 
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    ISSN: 1435-5663
    Keywords: Mesh refinement ; Mixed element meshes ; Unstructured meshes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Mesh refinement is an important tool for editing finite element meshes in order to increase the accuracy of the solution. Refinement is performed in an iterative procedure in which a solution is found, error estimates are calculated, and elements in regions of high error are refined. This process is repeated until the desired accuracy is obtained. Much research has been done on mesh refinement. Research has been focused on two-dimensional meshes and three-dimensional tetrahedral meshes ([1] Ning et al. (1993) Finite Elements in Analysis and Design, 13, 299–318; [2] Rivara, M. (1991) Journal of Computational and Applied Mathematics 36, 79–89; [3] Kallinderis; Vijayar (1993) AIAA Journal,31, 8, 1440–1447; [4] Finite Element Meshes in Analysis and Design,20, 47–70). Some research has been done on three-dimensional hexahedral meshes ([5] Schneiders; Debye (1995) Proceedings IMA Workshop on Modelling, Mesh Generation and Adaptive Numerical Methods for Partial Differential Equations). However, little if any research has been conducted on a refinement algorithm that is general enough to be used with a mesh composed of any three-dimensional element (hexahedra, wedges, pyramids, and/or retrahedra) or any combination of three-dimensional elements (for example, a mesh composed of part hexahedra and part wedges). This paper presents an algorithm for refinement of three-dimensional finite element meshes that is general enough to refine a mesh composed of any combination of the standard three-dimensional element types.
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    URL: http://dx.doi.org/10.1007/BF01221213
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    A simple genetic algorithm for the design of reinforced concrete beams (1997)
    Springer
    Engineering with computers 13 (1997), S. 185-196 
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    ISSN: 1435-5663
    Keywords: Artificial intelligence ; Design optimization ; Genetic algorithms ; Structural optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract We present an optimization model for the design of rectangular reinforced concrete beams subject to a specified set of constraints. Our model is more realistic than previously published models because it minimizes the cost of the beam on strength design procedures, while also considering the costs of concrete, steel and shuttering. Thus our method leads to very practical designs. As there is an infinite number of possible beam dimensions and reinforcement ratios that yield the same moment of resistance, an efficient search technique is preferred over the more traditional iterative methods. We employ a simple genetic algorithm as the search engine, and we compare our results with those obtained via geometric programming. Since the adjustment of parameters in a genetic algorithm (e.g., population size, crossover and mutation rates, and maximum number of generations) is a significant problem for any application, we present our own methodology to deal with this problem. A prototype of this system is currently being tested in México, in order to evaluate its potential as a reliable design tool for real world applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01200046
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    Object-oriented analysis of spatial multibody systems based on graph theory (1997)
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    Engineering with computers 13 (1997), S. 211-221 
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    ISSN: 1435-5663
    Keywords: Graph theory ; Joint coordinate method ; Linked lists of objects ; Object oriented hierarchy ; System matrices
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The purpose of this paper is to illustrate the implementation of efficient methods in the analysis of general multibody systems. The main goal is a total general purpose program which is able to handle the analysis of open as well as closed loop systems. The development of a general purpose program necessitates considerations concerning storing of code and data access facilities of the analysis code. Many of the building blocks for the analysis are supposed to solve the same problems although this is obtained in different ways depending on the specific type of block. These considerations lead to the creation of an object oriented structure of the analysis code. The development of the analysis algorithms is based on the kinematics of the system. The implementation of these schemes is based on graph theory and is presented through an example by the end of the paper.
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    URL: http://dx.doi.org/10.1007/BF01200048
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    Design of multi-component structural systems for optimal layout topology and joint locations (1997)
    Springer
    Engineering with computers 13 (1997), S. 235-243 
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    ISSN: 1435-5663
    Keywords: Structural connections ; Structural optimization ; Topology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Present day topology optimization techniques for continuum structures consider the design of single structural components, while most real life engineering design problems involve multiple components or structures. It is therefore necessary to have a methodology that can address the design of multi-component systems and generate designs for the optimal layouts of individual structures and locations for interconnections. The interconnections include supports provided by the ground, joints and rigid connections like rivets, bolts and welds between components. While topology optimization of structures has been extensively researched, relatively little work has been done on optimizing the locations of the interconnections. In this research, a method to model and define domains for the interconnections has been developed. The optimization process redistributes material in the component design domains and locates the connections optimally based on an energy criterion. Some practical design examples are used to illustrate the capability of this method.
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    URL: http://dx.doi.org/10.1007/BF01200050
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    A study of mechanical configuration optimisation in micro-systems (1997)
    Springer
    Research in engineering design 9 (1997), S. 46-60 
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    ISSN: 1435-6066
    Keywords: Configuration ; Macro ; Micro ; Scale
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract This paper shows that there are three main categories of factors that make the optimum mechanical design of micro-systems different from macro-systems: scale effects, a limited range of materials, and a limited range of production processes. The combined effect of these factors can make the optimum configuration of a micro-system potentially very different from that of the same system on a macro-scale. In particular, the use of flexible elements for hinges is much more feasible and desirable on a micro-scale.
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    URL: http://dx.doi.org/10.1007/BF01607057
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    Reliability centered prediction technique for diagnostic modeling and improvement (1997)
    Springer
    Research in engineering design 9 (1997), S. 35-45 
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    ISSN: 1435-6066
    Keywords: Dependability ; Diagnosability ; Maintainability ; Reliability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract A diagnosability prediction metric is developed for system modeling of component failure rates and unjustified removals. The metric emphasizes ambiguity of system component indications as well as system structure. The metric is evaluated using historical data from the bleed air control system (BACS) on the Boeing737-300. Four design changes are suggested based on improving system diagnosability by changing component functions, modifying indications, and adding or changing sensors. The resulting designs are compared via Boeing's life cycle cost mechanism, DEPCOST model, based on cost improvements. It is shown that system improvements based on this prediction technique will increase the quality of a product since increased diagnosability decreases life cycle costs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01607056
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    A conceptual framework for combining artificial intelligence and optimization in engineering design (1997)
    Springer
    Research in engineering design 9 (1997), S. 20-34 
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    ISSN: 1435-6066
    Keywords: Artificial intelligence ; Design ; Operations Research ; Optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Research in artificial intelligence and optimization (OR) has had significant impact on the formulation and solution of computational methods in engineering design. This paper presents a conceptual framework for understanding a more powerful technology that is evolving from a combination of these approaches. The paper first proposes generalized representations of engineering design models that involve quantitative and qualitative aspects. Second, it presents a general classification of AI and OR models in terms of model attributes, in order to establish mappings with generic solution techniques. Third, the requirements of solution methods are discussed, as well as several schemes for the integration of AI and optimization to identify future research directions. Several specific approaches are included to illustrate various ways in which AI and optimization can be combined for tackling computational design models.
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    URL: http://dx.doi.org/10.1007/BF01607055
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    Teamwork and design methodology—Observations about teamwork in design education (1997)
    Springer
    Research in engineering design 9 (1997), S. 61-69 
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    ISSN: 1435-6066
    Keywords: Design education ; Mechanical engineering ; Methodical design ; Teamwork
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Description / Table of Contents: Zusammenfassung Der vorliegende Beitrag beschäftigt sich mit der Frage, wie man Studenten schon in der Ausbildung die Fähigkeiten zur Zusammenarbeit in Konstruktions-Teams beibringen kann, um sie auf die Praxis vorzubereiten. Anhand eines Projekts, in dem Studenten im Team ein Gerät konstruierten und herstellten, werden Vor- und Nachteile der Teamarbeit beim Konstruieren beobachtet. Die Nachteile, die diskutiert werden, enstehen vor allem durch Probleme der Kommunikation zwischen den Teammitgliedern. Ein Vorschlag für die Ausbildung von Studenten beim methodischen Konstruieren im Team wird vorgestellt und die Erfahrungen bei der Umsetzung werden dargestellt. Anregungen für die Konstruktionsausbildung, die aus dem dargestellten Projekt enstanden, sowie Ansätze für die Forschung schließen den Beitrag ab.
    Notes: Abstract This paper focuses on the topic how students can learn to cooperate in design teams, to be prepared for industrial practice. Advantages and disadvantages of teamwork in design are observed in a project. In this project students designed and manufactured a device in teams. Most of the disadvantages which are discussed, occur because of problems of communication between the team members. An approach for the education in systematic design and the experiences in using this approach are presented. The paper concludes with suggestions for design education and for research.
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    URL: http://dx.doi.org/10.1007/BF01596482
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    Managing the integrity of design data generated by multiple applications: The principle of patching (1997)
    Springer
    Research in engineering design 9 (1997), S. 125-145 
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    ISSN: 1435-6066
    Keywords: Change management ; Concurrent engineering ; Design ; Engineering databases ; Integrity management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The purpose of this work is to develop automatic methods of semantic integrity maintenance, in support of concurrent engineering. Semantic integrity relations in any final engineering design are built up incrementally, through the use of different computer applications. Here, the structure of these integrity relations are formalised for representation within a database. When changes to a design have to be made, they can invalidate integrity relations in other parts of the design. Formal methods are defined for identifying what data and integrity relations are invalidated by any change. Methods for making changes that minimise re-design are described and formalised. Opportunities for using semantic integrity to assess progress on a design are reviewed.
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    URL: http://dx.doi.org/10.1007/BF01596599
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    GGREADA: A graph grammar-based machine design algorithm (1997)
    Springer
    Research in engineering design 9 (1997), S. 195-213 
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    ISSN: 1435-6066
    Keywords: Configuration design ; Generative design ; Grammar-based design ; Machine design
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract A class of graph grammar-based design algorithms for the generation of near-optimal machine designs is proposed. The GGREADA algorithm is implemented to design scale model carts from Meccano® Set components. A graph grammar for the carts is defined. GGREADA successfully designs minimum-weight carts that provide specified load-bed areas. GGREADA's exploration capability is also demonstrated by creating probability frequency plots of likely cart surface areas and weights from random samples taken from the space of all possible cart designs. The advantages that a designer may gain from grammar-based design tools are discussed along with the representational challenges that remain in exploiting grammars for this purpose.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01589682
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    What to do next: Using problem status to determine the course of action (1997)
    Springer
    Research in engineering design 9 (1997), S. 214-227 
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    ISSN: 1435-6066
    Keywords: Bayesian decision model ; Decision sensitivity analysis ; Team decision making
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Formal decision support tools are little used in engineering design. This paper explores the reasons for this and presents a method which is tailored to problems characterized by teams of stakeholders with inconsistent views who generate multiple alternatives and criteria, and who work to reach consensus. This method is especially designed to support activity when much of the information is qualitative, immature, and there is a diversity of views. The methodology assists the team in determining which alternative attributes to invest time in refining in their effort to reach consensus. The underlying mathematical structure (a Bayesian model of multi-attribute team decision making) is presented. This model supports team member belief about an alternative's ability to meet a criteria on two dimensions, knowledge and confidence. The methodology forces recording the rationale used to reach the final decision. A running example is used to explain the details.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01589683
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    Standardized observation of team-work in design (1997)
    Springer
    Research in engineering design 9 (1997), S. 1-9 
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    ISSN: 1435-6066
    Keywords: Design methods ; Engineering design analysis ; Team-work
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract In the research project ‘Team-work in Engineering Design Practice’, engineers and psychologists investigate design processes in industry by detailed observation. The aim is to comprehend how the external conditions in conjunction with the individual designer's and the group's prerequisites influence the design process and the solution. Therefore, the design process has to be documented in a standardized form. The paper presents a method for standardized observation of design team-work in industrial practice. In an example of an observed and recorded group setting, some abilities of the protocol analysis methods are demonstrated. After discussing the non-participating observation of design processes with on-line recordings, the planned future work is introduced. Apart from further investigation methods, experiences from first investigations in industry are mentioned.
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    URL: http://dx.doi.org/10.1007/BF01607053
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    A model for synchronous collaborative design using CAD and database management (1997)
    Springer
    Research in engineering design 9 (1997), S. 85-98 
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    ISSN: 1435-6066
    Keywords: CAD ; Collaboration ; Databases ; Design
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Collaborative design is currently supported through the integration of graphical representations with relational databases and the distribution of data and applications across local and wide area networks. Recent developments in computer support for synchronous collaboration have led to the development of multi-user drawing boards and video conferencing software for remote meetings. The extension of CAD for use in a collaborative design session changes the focus of collaborative design from a distribution of data to a shared workspace. Combining CAD with the concept of multi-user software introduces issues of shared visualisation and shared decision making. A model for the integration of CAD and database management in a collaborative design session is presented within a client server architecture, and an implementation of this model using AutoCAD as the shared CAD system is described.
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    URL: http://dx.doi.org/10.1007/BF01596484
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    Generalised models of design interation using signal flow graphs (1997)
    Springer
    Research in engineering design 9 (1997), S. 112-123 
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    ISSN: 1435-6066
    Keywords: Design iteration ; Design process modeling ; Product development lead time ; Signal flow graphs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Changing customer preferences, demand for quality, and new technologies have led to very short product life cycles. This requires firms to have short product development lead times while keeping product costs low and quality high in order to stay competitive. In this context, we focus on improved understanding of time-consuming design iterations. We are creating tools for modeling product development projects in order to predict the performance of product development organisations. In this paper, signal flow graphs are presented as a flexible tool for design process modeling, and illustrated using an industrial example. Analysis of the model allows computation of the probability distribution of lead time and identification of the key drivers of lead time.
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    URL: http://dx.doi.org/10.1007/BF01596486
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    Mechanism concept retrieval using configuration space (1997)
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    Research in engineering design 9 (1997), S. 99-111 
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    ISSN: 1435-6066
    Keywords: Computer-aided design ; Conceptual design ; Database ; Mechanism design ; Qualitative configuration space ; Spatial reasoning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract When designing mechanisms, making use of examples in past designs and handbooks should lead to cost reduction by promoting the sharing of parts and subassemblies among the products as well as reduction of time and effort. At present, however, the process of surveying design examples is left almost entirely to human designers and little computerised aid has been developed. We propose a computerised method of retrieving mechanism concepts from a library by specifying a required behaviour using qualitative configuration space as a retrieval index. First, mechanism concepts and their kinematics characteristics are described and stored in a computerised library using qualitative configuration spaces accompanined by additional information such as motion type and motion transmission direction. To retrieve mechanism concepts which realise specific kinematic behaviour, designers specify the required behaviour as timing charts of given input and intended output motions. Motion types, motion transmission direction, and motion speed dependence of the input and output motions can also be specified. Computer programs translate the required timing charts into required locus patterns in motion parameter space, and then available mechanism concepts to realise the behaviour are retrieved based on pattern matching between the qualitative configuration spaces and the locus patterns. The method is implemented as an experimental computer program written in Prolog and applied to simple mechanism design problems as examples to confirm the effectiveness of the approach.
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    URL: http://dx.doi.org/10.1007/BF01596485
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    A tool for the conceptual design of production and operations systems (1997)
    Springer
    Research in engineering design 9 (1997), S. 146-167 
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    ISSN: 1435-6066
    Keywords: Conceptual design ; Ideation ; Inferential design theory ; Operations systems ; Production systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract This paper proposes a conceptual design tool, based upon inferential design theory. It has been specifically developed for the design of production and operations systems, but its use can be extended to other engineering areas, such as mechanical and structural systems. Inferential design theory and its foundation in the inferential theory of learning are briefly outlined. Both theories are based on the idea of using specialised knowledge operators in learning and design, termed knowledge transmutations and design knowledge transmutations respectively. The 24 transmutations existing in the two theories are outlined, and a further 12 design-specific transmutations are proposed. These have been developed as a result of our research. A conceptual design process is proposed, in which design knowledge transmutations are used. A software tool for design, CREDO, is also described and an example of its use in the generation of design concepts for an after-sales service facility is presented. The conclusions discuss the initial methodological experience of using CREDO to generate design concepts. They are based on the introductory use of CREDO at Technion in Israel for teaching purposes. Directions for further research are also provided.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01596600
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  • 91
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    Sensitive factor for position tolerance (1997)
    Springer
    Research in engineering design 9 (1997), S. 228-234 
    Details
    ISSN: 1435-6066
    Keywords: Deviation orientation ; Position tolerance ; Sensitivity study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract A tolerance sensitivity study evaluates the influence of each component tolerance on the assembly tolerance. It is crucial to the improvement to tolerance design. This paper discusses a difficulty in evaluating the sensitive factors of some geometric tolerances (e.g. the position tolerance), due to their connections with a random orientation angle α. An average sensitive factor over α is proposed for the position tolerance. The usefulness of the average sensitive factor is demonstrated through a mechanical example.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01589684
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  • 92
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    Phase behavior of polyoxyethylene oleyl ether in water (1997)
    Springer
    Colloid & polymer science 106 (1997), S. 49-51 
    Details
    ISSN: 1435-1536
    Keywords: Polyoxyethylene oleyl ether ; liquid crystal ; phase behavior of nonionic surfactant ; small-angle X-ray scattering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Phase behavior of penta-deca- and eicosa-oxyethylene oleyl ether in water were investigated. Differently from ordinary oleyl surfactants, the lipophilic chains of the present surfactants consist of pure oleyl group. The basic feature of the phase behavior extremely resembles that of pure polyoxyethylene hexadecyl ether systems although the solid present regions in the oleyl surfactant systems are very narrow due to the low melting point of oleyl group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01189489
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  • 93
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    Structure and dynamics of networks formed in concentrated solutions of nonionic surfactants (1997)
    Springer
    Colloid & polymer science 106 (1997), S. 57-60 
    Details
    ISSN: 1435-1536
    Keywords: Dynamic light scattering self-diffusion ; micelle ; nonionic surfactant ; lyotropic liquid crystal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Dynamic light scattering has been measured on semidilute solutions of nonionic surfactant (C16E7) where formation of networks of worm-like micelles is suggested from our previous studies. In addition to the diffusion mode, we have found the so-called slow mode in time correlation function of the scattered field. By comparing concentration and temperature dependence of the correlation time of the slow mode with that of the surfactant selfdiffusion coefficient, dynamics of networks are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01189491
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  • 94
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    Analysis by SAXS and cryo-TEM on polymerization with a surfactant (1997)
    Springer
    Colloid & polymer science 106 (1997), S. 141-143 
    Details
    ISSN: 1435-1536
    Keywords: Small-angle X-ray scattering ; polypyrrole polymerization ; low-temperature electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The polymerization process in a solution was examined by SAXS and cryo-TEM in the case of chemical polymerization of pyrrole in aqueous solution using sodium cellulose sulfonate (SCS) and FeCl3 as oxidizing agents. Observations with SAXS and cryo-TEM indicated the formation of micelle of SCS in SCS + water system. By adding FeCl3 in the solution, large spherical aggregates were formed as revealed by cryo-TEM, which is considered to be a precursor for the polymer spherical particles produced with a constant diameter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01189508
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  • 95
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    The relationship between the interfacial curvatures and phase behavior in bicontinuous microemulsions — a SANS study (1997)
    Springer
    Colloid & polymer science 106 (1997), S. 14-23 
    Details
    ISSN: 1435-1536
    Keywords: Interfacial curvatures ; microemulsion ; SANS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract We introduce a new technique using small-angle neutron scattering (SANS) to measure the average Gaussian curvature and the average square-mean curvature of the oil-water interface in a threecomponent, nearly isometric (equal volume fractions of water and oil) ionic microemulsion system. The microemulsion is composed of AOT/brine/decane. SANS measurements are made as a function of both the volume fraction of surfactant and salinity at a constant temperature, 45 °C, within the one-phase channel. The temperature is chosen at the hydrophile-lipophile balance (HLB) temperature for a salinity of 0.49%. The SANS data taken with an oil-water contrast are analyzed by using a random-wave model with an appropriate spectral function. The spectral function is an inverse eighth-order polynomial in wave numberk, containing three length scales 1/a, 1/b, and 1/c, and has finite second and fourth moments. This three-parameter spectral function is then used in conjunction with Cahn's clipping scheme to obtain the Debye correlation function for the microphase-separated bicontinuous microemulsions. The model shows good agreement with the intensity data in an absolute scale. We then use the three parameters so obtained to calculate the average Gaussian curvature and the average square-mean curvature of the interface. We determine the variation of these curvatures as functions of the surfactant volume fraction and salinity and discuss their implication on the degree of local order of the bicontinuous structure. We also show a 3-D morphology of the microemulsion at the contact point of the three-phase and the one-phase region of the phase diagram generated by this model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01189485
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  • 96
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    Nanorheology of thin liquid crystal film studied by shear force resonance method (1997)
    Springer
    Colloid & polymer science 106 (1997), S. 262-265 
    Details
    ISSN: 1435-1536
    Keywords: Nanorheology ; shear force apparatus ; surface forces ; mechanical resonance ; thin liquid crystal films ; cyano-alkylbiphenyls
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The structure and mechanics of very thin liquid crystal films depend on the intermolecular interactions in confined dimensions. The rheology of such films has been investigated by a shear force apparatus constructed as an attachment to the surface forces apparatus. The novelty of this method is that the rheological parameters are extracted from the amplitude and the phase of the output signal as a function of the resonance frequency. The apparent viscosity of the liquid crystal film is calculated from the damping coefficient by using a simple theoretical model. The viscosity of nanometer thin films of 4-cyano-4-hexylbiphenyl was found to be larger than the bulk value due to increased interactions in the molecular layers adjacent to the solid surfaces transferring shear. Further decreasing of the film thickness (increasing of the normal load) results in an increase of the resonance frequency due to the transition from viscous to contact friction. The latter observation opens the door to gaining tribological information at the nanodimension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01189534
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  • 97
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    Formation and property of HCO-10 vesicles new method to prepare HCO-10 vesicles with high entrapment efficiency (1997)
    Springer
    Colloid & polymer science 106 (1997), S. 281-286 
    Details
    ISSN: 1435-1536
    Keywords: HCO-10 vesicles ; heating-cooling cycle ; high entrapment efficiency ; narrow size distribution ; calcein release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract When the vesicle suspension of HCO-10 was heated to 40–45 °C and then cooled to room temperature, larger vesicles were produced, which not only encapsulated an increased fraction of the solutes but also was narrow in size distribution. The improvement of their size uniformity was dependent on the rate of cooling. During the heating and cooling of HCO-10 suspensions, the transformation process of the vesicles was investigated by observing the freeze fracture electron microscopic appearances and the temperature dependence of the calcein release from those vesicles. It was found that HCO-10 vesicles were transformed into the small vesicles during heating and the aggregation and fusion of those small vesicles formed a larger vesicle during cooling. This method is characterized by the physicochemical features of the dehydration and rehydration of HCO-10 molecules and does not require extensive use of organic solvents, detergents or dialysis systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01189539
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  • 98
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    Annihilation dynamics of two-dimensional magnetic vortex systems (1997)
    Springer
    Colloid & polymer science 106 (1997), S. 287-290 
    Details
    ISSN: 1435-1536
    Keywords: Magnetic vortex ; superconductor ; annihilation ; power law ; crossover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract We numerically study the pair-annihilation process of magnetic vortices in two-dimensional type-II superconductors. The dynamics for interacting vortices is described in terms of the Langevin-type stochastic equation. Carrying out the Langevin dynamics simulation, we find that the power-law behavior of the mean distance among vortices exhibits a crossover phenomenon as a function of timet from thet 1/2-law at short times tot 1/3 at long times, and the crossover time is an increasing function of temperature. The present results are also found to be explained by a simple dimensional analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01189540
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  • 99
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    Assessment of the depletion forces in mixtures of a latex and a non-adsorbing polymer by turbidimetry (1997)
    Springer
    Colloid & polymer science 104 (1997), S. 23-30 
    Details
    ISSN: 1435-1536
    Keywords: Latex light scattering ; structure factor ; turbidimetry ; depletion forces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A turbidimetric analysis of the depletion interaction in mixtures of latexes and non-adsorbing polymers is presented. It is demonstrated that turbidimetry explores the small-angle part of the structure factorS(q) (q=(4π/λ)sin(θ/2),θ is the scattering angle, andλ the wavelength of the radiation in the medium) and allows to extrapolate to S(0) in very good accuracy. Turbidimetry is insensitive towards multiple scattering and the analysis can therefore be extended to high latex concentrations. The measured turbidityτ is fully determined by the scattering intensity of the latex spheres, whereas the dissolved polymer does not contribute appreciably toτ. Therefore,S(0) thus obtained can be used to assess the attractive depletion forces between the latex particles in these mixtures. It is shown that the volume-exclusion potential as modified by Lekkerkerker et al. [17] allows to account quantitatively for the dependence ofS(0) on latex concentration as well as on polymer concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01182411
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  • 100
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    Single-mode DLS: colloids in opaque porous media (1997)
    Springer
    Colloid & polymer science 104 (1997), S. 49-58 
    Details
    ISSN: 1435-1536
    Keywords: Single-mode dynamic light scattering ; opaque porous media ; diffusion ; convection ; tortuosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Single-mode fiber optical receivers have become the instrumentation standard for Dynamic Light Scattering (DLS). In a regular homodyne experiment one values their superb signal-to-noise ratio as well as the simplicity of the optical setup. Moreover, mode-selective DLS enables the researcher to tackle seemingly hopeless experimental problems, such as colloidal motions inside an opaque porous medium consisting of a water filled packing of small glass grains. The particles to be measured are completely masked by strong diffuse scattering in the porous matrix. Nevertheless, mode-selective DLS makes it possible not only to detect the motions of the colloids within the pores but also to determine their diffusion coefficient and, simultaneously, their average convective speed. We outline the theoretical background of these measurements and present data on diffusion and convection of latex particles in dense packings of glass-beads in a Chromatographic column. Our technique allows an accurate determination of the tortuosity of the interstitial flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01182414
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