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  • 1
    Electronic Resource
    Electronic Resource
    Phase equilibria of quasi-binary systems consisting of multicomponent polymers 1 and 2. IV: Poly(ethylene oxide)/poly(propylene oxide) systems (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 34 (1994), S. 73-80 
    Details
    ISSN: 0959-8103
    Keywords: polymer blend ; cloud point curve ; critical solution point ; phase volume ratio ; χ12 parameter ; modified Flory-Huggins theory ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: To confirm the reliability of the theory of phase equibria of multicomponent polymer 1/multicomponent polymer 2 systems (i.e. quasi-binary systems) and the method of computer experiment based on this theory (Brit. Polym. J., 23(1990)285; 23(1990)299; Polym. Int., 29(1992)219), could point curves (CPC), two-phase volume ratios (R) and critical solution points (CSP) have been determined experimentally for the quasi-binary mixtures of poly(ethylene oxide) (M¯w = 647, M¯w/M¯n = 1.15; M¯w and M¯n, the weight-average and numberaverage molecular weights, respectively) and poly(propylene oxide) (M¯w = 2028, M¯w/M¯n = 1.08; and Mw = 2987, Mw/Mn = 1.13). The hydroxyl end groups of both polymers were methoxylated in advance by the Cooper & Booth method (Polymer, 18(1977)164). The thermodynamic interaction parameter between both polymers, χ12, and the concentration dependence parameters for the above quasi-binary systems were determined by the method proposed in a previous paper (Brit. Polym. J., 23(1990)299). CPC, R and CSP values calculated on the basis of the theory are in good agreement with the values determined experimentally.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210340110
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of addition of organoaluminum and organoboron compounds in the stereospecific polymerization of acrylonitrile using dialkylmagnesium as catalyst (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 34 (1994), S. 397-405 
    Details
    ISSN: 0959-8103
    Keywords: stereospecific polymerization ; polyacrylonitrile ; tacticity ; dialkylmagnesium ; alkylaluminum ; additive ; anionic polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An attempt was made to clarify the effect of addition of organoaluminum and organoboron compounds in the stereospecific polymerization of acrylonitrile (AN) initiated by dialkylmagnesium (R2Mg) above 100°C. The triad isotacticity (i.e. the content of mm (m: meso)) as well as the viscosity-average molecular weight (M̄v) of polyacrylonitrile (PAN) increased when trialkylaluminum (R3Al) and trialkylboron (R3B) were used as additives. Diisobutylaluminum hydride [(i-C4H9)2AlH] was found to be the best additive. in the stereospecific polymerization of AN, giving PAN with higher (mm) content (0.63), higher M̄v value (5.2 × 104), and a yield approximately double that obtained using (n-C6H13)2Mg alone. When the (n-C6H13)2Mg/(i-C4H9)2AlH system was used, the yield, (mm), and M̄v of PAN increased with polymerization temperature (Tp); maximum values of yield, (mm), and M̄v were obtained at c. 130°C. The optimum amount of additives was approximately equimolar to R2Mg as initiator. The 13C chemical shift of α-carbon in R2Mg at 90°C shifted by mixing with R3Al and R3B, respectively, indicating the existence of interaction between R2Mg and the additives. The main role of the additives is considered to be suppression of the self-association of R2Mg by strong interaction with R2Mg.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210340408
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  • 3
    Electronic Resource
    Electronic Resource
    Highly isotactic polyacrylonitriles prepared using dialkylmagnesium/water systems as initiators (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 35 (1994), S. 249-255 
    Details
    ISSN: 0959-8103
    Keywords: stereospecific polymerization ; polyacrylonitrile ; tacticity ; dialkylmagnesium ; alkylaluminum ; water ; high molecular weight ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An attempt was made to synthesize stereoregular polyacrylonitrile (PAN) with high molecular weight (e.g. viscosity-average molecular weight (M̄v) 〉 1 × 105) by anionic polymerization. The triad tacticities (i.e. the content of mm, mr and rr (m, meso; r, racemo)) of the polymers obtained were analyzed by 13C NMR and their M̄v was determined by viscometry in dimethylsulfoxide at 25°C using Kamide et al.'s Mark-Houwink-Sakurada equation. Highly isotactic and high molecular weight PAN with M̄v 〉 2.5 × 105 ((mm) ∼ 0.57) was synthesized in anisole at 130°C when the reaction product of di-n-hexylmagnesium with water supplied by heating sulfate hydrates (Na2SO4 10H2O, CuSO4 5H2O, and MgSO4 7H2O) was used as a polymerization catalyst. The M̄v of PAN was increased significantly by using the catalyst combined with triethylaluminum (Et3Al). Maximum M̄v attained was 9.7 × 105 ((mm) = 0.64). The main role of Et3Al added is explained as the reduction of OH groups in the catalyst and of residual H2O in the catalyst solution.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210350306
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis of highly isotactic (mm 〉 0.70) polyacrylonitrile by anionic polymerization using diethylberyllium as a main initiator (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 35 (1994), S. 207-213 
    Details
    ISSN: 0959-8103
    Keywords: stereospecific polymerization ; polyacrylonitrile ; tacticity ; diethylberyllium ; additive ; anionic polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An attempt was made to synthesize steroregular polyacrylonitrile (PAN) with a high triad isotacticity (i.e. the content of mm (m, meso)) exceeding 0.70 by the anionic polymerization method. In the stereospecific polymerization of acrylonitrile (AN) initiated by diethylberyllium (Et2Be) in xylene at 130°C, the (mm) content as well as the viscosity-average molecular weight (MÞv) of PAN increased by addition of diisobutylaluminum hydride (i-C4H9)2AlH) as an additive to the polymerization system. Maximum (mm) content, attained in the molar ratio region of (i-C4H9)2AlH/Et2Be 〉 1.0, was about 0.73. The stereospecific polymerization of AN was also initiated using a mixture of Et2Be and di-n-hexylamagnesium ((Et2Be/(n-C6H13)2 Mg system), where both Et2Be and (n-C6H13)2 Mg can induce the stereospecific polymerization of AN at 130°C. The (mm) content of the PAN sample prepared using the Et2Be/(n-C6H13)2 Mg system ((mm) = 0.64) was higher than that of PAN samples synthesized using Et2Be alone ((mm) = 0.56) and (n-C6H13)2Mg alone ((mm) = 0.51) under the same conditions except initiator. A significant difference in 13C chemical shifts of α-carbons between Et2Be (1.35 ppm) and (n-C6H13)2Mg (10.72 ppm) dissolved in hydrocarbon solvent at 110°C leads us to the conclusion that when Et2Be induces the stereospecific polymerization in the Et2Be/(n-C6H13)2Mg system as initiator, the main role of (n-C6H13)2Mg is considered to be the suppression of the association of Et2Be (active site) itself.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210350211
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  • 5
    Electronic Resource
    Electronic Resource
    Monomer sequence length distributions of hard segments of linear segmented poly(urethane-urea)s 1: chromatographic study (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 38 (1995), S. 277-286 
    Details
    ISSN: 0959-8103
    Keywords: sequence length distribution ; hard segments ; poly(urethane-urea)s ; chromatograms ; unequal reactivities ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An attempt was made to determine, by the chromatographic method, monomer sequence length distributions of the hard segments in segmented poly(urethane-urea)s (PURs) synthesised in a two-step process: (1) a prepolymer formation reaction of an excess of methylenebis(4-phenylisocyanate) (MDI) with poly(tetramethyleneoxide) (PTMO) and (2) a polymerisation reaction of the prepolymer containing unreacted MDI with ethylenediamine, giving PUR. The monomer sequence length of the hard segment was found to become longer and its distribution to broaden as the initial concentration ratio of MDI to PTMO increased. This result is attributable to an increase of the concentration ratio of the unreacted MDI to the prepolymer, leading to gelation of the polymer solution. By comparing the chromatographic results with the theoretical data calculated in the simple case of the equal reactivity of the reactants in the prepolymerisation and polymerisation reactions, respectively, the existence of unequal reactivities of the reactants in both reactions, is predicted.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1995.210380310
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  • 6
    Electronic Resource
    Electronic Resource
    Monomer sequence length distributions of hard segments of linear segmented poly(urethane-urea)s 2: computer simulation by the Monte Carlo method (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 38 (1995), S. 287-298 
    Details
    ISSN: 0959-8103
    Keywords: sequence length distribution ; hard segments ; poly(urethane-urea)s ; simulation ; Monte Carlo method ; unequal reactivities ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An attempt was made to calculate, by the Monte Carlo method, monomer sequence length distributions of the hard segment (MSLDH) within a linear segmented poly(urethane-urea) (PUR) synthesised by the prepolymer method in which an isocyanate-terminated prepolymer. A…A, an unreacted monomer diisocyanate, BB, and a diamine as chain extender, XY, are reacted to form PUR. MSLDH is governed by the molar ratio of [A…A]/[BB] and is dramatically affected when three kinds of unequal reactivity associated with the reactants are significant simultaneously; the induced asymmetry, the penultimate effect of an NCO group, and the induced asymmetry of an amino group. By applying the above simulation technique, the unequal reactivities are estimated in both the prepolymerisation and polymerisation reactions based on methylenebis(4-phenylisocyanate), MDI, poly(tetramethyleneoxide), PTMO, and ethylenediamine, EDA. In addition, the effect of the one-shot method instead of the prepolymer method on MSLDH is also examined.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1995.210380311
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis of ultra-high molecular weight polyacrylonitrile with highly isotactic content (mm 〉 0.60) using dialkylmagnesium/polyhydric alcohol system as catalyst (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 36 (1995), S. 87-99 
    Details
    ISSN: 0959-8103
    Keywords: stereospecific polymerization ; polyacrylonitrile ; tacticity ; anionic polymerization ; dialkylmagnesium ; polyhydric alcohol ; ultra-high molecular weight ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An attempt was made to synthesize a catalyst having high activity for synthesis of highly isotactic polyacrylonitrile (PAN) with high molecular weight by anionic polymerization. The reaction products of di-n-hexylmagnesium [(n-C6H13)2Mg] with alicyclic alcohols such as 1,4-cyclohexanediol or 1,5-decalindiol were found to be effective as polymerization catalysts for preparation of PAN samples whose triad isotacticity [the content of mm (m, meso configuration)] is about 0.64 and viscosity-average molecular weight (Mv) exceeds 1 × 105. The triad tacticities [mm, mr, and rr contents (r, racemo configuration)] of the polymers obtained were analysed by 13C NMR and their Mvs were determined by viscometry in dimethylsulphoxide at 25°C using Kamide et al.'s Mark-Houwink-Sakurada equation.Mv of PAN increased significantly by after-treatment of the catalysts, prepared from (n-C6H13)2Mg and alicyclic alcohols, with triethylalyminium (Et3Al). Ultra-high molecular weight PAN samples ranging in Mv from 2 × 106 to 6 × 106 [(mm) = 0.57-0.66] were obtained in anisole at 135°C by using the above catalyst system. A main role of Et3Al in these catalyst systems is considered to reduce, in advance, OH groups on the catalyst, resulting in a significant suppression of termination reactions of propagating PAN chains during the polymerization.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1995.210360112
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  • 8
    Electronic Resource
    Electronic Resource
    New class of cellulose fiber spun from the novel solution of cellulose by wet spinning method (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 44 (1992), S. 691-698 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A novel cellulose solution, prepared by dissolving an alkali-soluble cellulose, which was obtained by the steam explosion treatment on almost pure natural cellulose (soft wood pulp), into the aqueous sodium hydroxide solution with specific concentration (9.1 wt %) was employed for the first time to prepare a new class of multifilament-type cellulose fiber. For this purpose a wet spinning system with acid coagulation bath was applied. The mechanical properties and structural characteristics of the resulting cellulose fibers were compared with those of regenerated cellulose fibers such as viscose rayon and cuprammonium rayon commercially available. X-ray analysis shows that the new cellulose fiber is crystallographically cellulose II, and its crystallinity is higher but its crystalline orientation is slightly lower than those of other commercial regenerated fibers. The degree of breakdown of intramolecular hydrogen bond at C3[Xam(C3)] of the cellulose fiber, as determined by solid-state cross-polarization magic-angle sample spinning (CP/MAS) 13C NMR, is much lower than other, and the NMR spectra of its dry and wet state were significantly different from each other, indicating that cellulose molecules in the new cellulose fiber are quite mobile when wet. This phenomenon has not been reported for so-called regenerated cellulose fibers.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070440416
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  • 9
    Electronic Resource
    Electronic Resource
    Gas permeability of composite membranes (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 32 (1986), S. 4625-4637 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The permeability of a composite membrane consisting of a homogeneous layer and a porous layer has been derived theoretically by assuming that the permeation through the homogeneous layer obeys Fick's law and that permeation through the porous layer is free molecular flow. The activation energy of the flow is described by three-dimensionless parameters, φ = |P12/|P2, θ = d1/d2, and σ = |P1/|P2. |P12, |P1, and |P2 are the permeability coefficients of the composite membrane, the homogeneous layer and the porous layer, respectively, d1 and d2 are the thickness of the two layers. Once these parameters are determined, information on the structure of the membrane can be obtained (i.e., the pore size and the pore density). The permeabilities of various gases through homogeneous polycarbonate membrane, neutron-irradiated, nonsodium hydroxide-etched polycarbonate membrane, and their composite membrane were tested. A two-layer series model, incorporating the effect of neutron irradiation which produces some nonpenetrating pores in the porous membrane layer, is proposed and agreed quite well with the experimental data.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070320427
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  • 10
    Electronic Resource
    Electronic Resource
    Molecular characterization of polyacrylonitrile polymerized by gamma-ray irradiation (1972)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 155 (1972), S. 25-33 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Polyacrylnitril, welches durch Bestrahlung eines Harnstoff-Einschluß-Komplexes von Acrylnitril hergestellt worden war (U-PAN), wurde aus einer Dimethylsulfoxid(DMSO)-Lösung bei 25°C mit Toluol als Fällungsmittel fraktioniert. Die Viskositäten dieser Fraktionen in DMSO und in Äthylencarbonat (EC) wurden gemessen, um eine Aussage über die ungestörten Knäueldimensionen und über die durch Polymer-Lösungsmittel-Wechselwirkung hervorgerufenen Querkräfte zu erhalten. Es wird geschlossen, daß U-PAN, welches relativ isotaktisch ist, fast die gleichen ungestörten Knäueldimensionen (K = 2,95·10-3) hat wie das ataktische Polyacrylnitril, welches in konventioneller Weise radikalisch hergestellt worden ist (R-PAN). Dagegen ist der Parameter der Querkräfte bei U-PAN in einem schlechten Lösungsmittel wesentlich kleiner als bei R-PAN. Die Schlüsse, die aus diesen experimentellen Tatsachen gezogen wurden, sind in sehr guter Übereinstimmung mit denen bei anderen Polymeren mit geringerem Unterschied in der Stereoregularität.
    Notes: Polyacrylonitrile prepared by gamma-ray irradiation to urea-canal complex of acrylonitrile (U-PAN) was fractionated from a solution in dimethylsulfoxide (DMSO) at 25°C, using toluene as a precipitant. Viscosities of fractions, thus prepared, in DMSO and in ethylenecarbonate (EC), were measured for elucidating the unperturbed-chain dimensions together with the long-range polymer/solvent interaction parameter. In conclusion, U-PAN which is comparatively isotactic has almost the same value (the K value is 2.95·10-3) of the unperturbed-chain dimensions as the atactic polyacrylonitrile prepared by conventional, radical polymerization (R-PAN), whilst the long-range parameter of U-PAN is extremely smaller than R-PAN in a poor solvent. The conclusions reached from these experimental facts are in very good consistence with those of other polymers with less difference in the stereoregularity.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1972.021550103
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