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  • 1
    Electronic Resource
    Electronic Resource
    The charge-transfer complex maleic anhydride-tetrahydrofuran and its role as photosensitizer in the polymerization of methyl methacrylate (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 2653-2661 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The formation of a charge-transfer complex (CTC) between maleic anhydride and tetrahydrofuran both in bulk and in chloroform solution is proved by electronic absorption spectroscopy, and its association constant at 35°C is determined by this technique and by 1H NMR. The effect of irradiation with monochromatic 350 nm light upon the fluorescence spectrum of the CTC excited with this same radiation is studied. Significant changes are noted in the bulk system, but the changes are much smaller in the presence of methyl methacrylate which is simultaneously polymerized. The effect of oxygen on the polymerization is discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021791107
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of polysulfone-block-polysiloxane copolymers, 4Part 3: cf. ref.5.. A model study of the limitation of hydrosilylation couplingDedicated to Professor P. Rempp on his 60th birthday (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 203-212 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hydrosilylation reactions of 1-allyloxy-3-phenoxy-2-propanol (3) as model compound were carried out with α-dimethylsilyl-ω-hydrooligosiloxane (7; M̄n = 1200) in the presence of hexachloroplatinic acid. It was found that under stoichiometric conditions only 75--80% of the allyl groups were hydrosilylated, due to some isomerization of the allyl groups into vinyl groups, which do not undergo hydrosilylation. This isomerization could be shown to be sensitive to the type of the allyloxy structure. Thus, for example, allyloxybenzene does not undergo isomerization.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021900121
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis of polysulfone-block-polysiloxane copolymers, 5Part 4: cf. ref. 1.. A model study on the hydrosilylation side-reactions (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 2789-2803 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: All the side-reactions of a hydrosilylating model system (1-allyloxy-3-phenoxy-2-propanol/. . .-Si(CH3)2H in the presence of hexachloroplatinic acid (CPA); R = [CPA]/[SiH] 〉 10-4) are identified by 13C and 1H NMR. In such conditions the vinyl ether isomers and the residual silanes, formed when R 〈 10-4, are changed into several new species. The most important side-reaction consists in a silane-alcohol condensation (secondary alcohol of the model and, to a much lower extent, tertiary alcohol(tert-butyl alcohol) used as solvent of CPA), which leads to silyloxygrafted moieities. Hydrogen formed in this condensation can partially saturate the vinyl ether isomers the remaining fraction of which is cyclized into a 2-ethyl-1,3-dioxolane derivative. All the side-reactions observed in the case of the model system take place when α,β-diallyloligosulfones are polycondensated with α-dimethylsilyl-ω-hydrooligosiloxanes.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021901111
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  • 4
    Electronic Resource
    Electronic Resource
    Visible light photopolymerization: Synthesis of new fluorone dyes and photopolymerization of acrylic monomers using them (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1691-1703 
    Details
    ISSN: 0887-624X
    Keywords: 3-alkoxy-5,7-diiodo-6-fluorones ; visible photoinitiators ; acrylate photopolymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several 3-alkoxy-5, 7-diiodo-6-fluorones (λmax ≈ 470 nm) have been synthesized and evaluated as initiators for photopolymerization triggered with the 515.5 nm line of an Ar+ laser. 2-Acyl- and 2-alkyl-4,5,7-triiodo-3-hydroxy-6-fluorones were also tested at 515.5 nm. 9-Cyano-2-Acyl- and 9-cyano-2-alkyl-4,5,7-triiodo-3-hydroxy-6-fluorones were studied and could be excited with the 632 nm line of a He-Ne laser. Dyes with long linear carbon chain alkoxy groups at C-6 showed larger molar extinction coefficients and formed polymers with better mechanical properties than did compounds with shorter carbon chains, or did the corresponding C-6 phenols. The optimum side chain length of the C-6 ether alkyl group is between 4-7 carbon atoms. With longer carbon chain alkoxy groups at C-8, e.g., octyl, the mechanical properties of the formed polymers are inferior to systems formed with the butyl isomer as photoinitiator. In the case of alkoxy groups with branched alkyl groups (e.g., 2-ethylbutyl), the relationship between dye structure and the properties of the polymers formed is less straightforward. Though the dyes react from their triplet state, the fluorescence quantum yields of the dyes and the performance of the dyes as photoinitiators appear directly related. © 1995 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331016
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  • 5
    Electronic Resource
    Electronic Resource
    Activation energy for urethane-linkage formation. An improved calculation from the differential scanning calorimetry data (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 1579-1592 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Differential scanning calorimetry (DSC) has been utilized in several studies on polymerization kinetics, at different heating rates. However, there are several factors affecting the precision of kinetic parameters. In this work, the activation energy of urethane-bond formation between 2,6-tolylene diisocyanate and diethylene glycol is reported, the latter being in excess in order to minimize problems such as thermal transitions and incomplete reaction in the final step. The DSC technique was applied at different heating rates. Both the equal conversion and equal conversion rate options of the method are discussed. The latter appears to be a more adequate option for the system studied here. The results obtained show a good agreement with the model used.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1990.080280623
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  • 6
    Electronic Resource
    Electronic Resource
    The phthalocyanine approach to second harmonic generationFinancial support was provided by CICYT (Spain) through grants MAT 96-0654, TIC 92-0094-C02-0l, and IN 93-0033. (1997)
    Weinheim : Wiley-Blackwell
    Advanced Materials 9 (1997), S. 265-269 
    Details
    ISSN: 0935-9648
    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
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/adma.19970090320
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  • 7
    Electronic Resource
    Electronic Resource
    Electrical, thermal, and photo properties of poly(phenylene vinylene) precursors: I. Laser-induced elimination reactions in precursor polymer films (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 959-970 
    Details
    ISSN: 0887-6266
    Keywords: laser-induced processes in conducting polymer precursors ; interaction of dyes with polyelectrolytes ; lithography ; microelectronics ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The elimination reaction of polyelectrolyte films of poly(phenylene vinylene) precursor polymers into the fully conjugated chain was induced by irradiation with an Ar+ laser emitting at 514.5 nm. The experiments were conducted using as cast precursor polyelec-trolyte films of both the unsubstituted poly(phenylene vinylene), H-PPV, and its 2,5-dimethoxyphenylene derivative, DMEO-PPV. Precursor polymer films impregnated with an azosulfonic dye, which had a strong absorption at the laser emission wavelength, were also irradiated. The elimination reaction was followed by comparing the elemental analysis and the infrared and visibleultraviolet spectra of the irradiated and nonirradiated areas. With the unsubstituted PPV film no elimination was detected even at power fluence levels up to approximately 350 W/cm-2, but elimination and conversion to the conjugated polymer could be observed at 10 W/cm-2 when the dye was present. For DMEO-PPV the elimination reaction occurred with or without dye impregnation, and similar marking threshold values were measured in both cases. The molecular mechanism used to explain such observations and the possible application in the area of microelectronics are also discussed. © 1993 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1993.090310806
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  • 8
    Electronic Resource
    Electronic Resource
    Poly(vinyl alcohol)/poly(acrylic acid) blends: Miscibility studies by DSC and characterization of their thermally induced hydrogels (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 50 (1993), S. 777-792 
    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: Binary blends of poly(vinyl alcohol) (PVA) with poly(acrylic acid) (PAA) and polyacrylamide (PAAm) were characterized by differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and infrared spectroscopy (IR). Molecular weight, blend composition, and heating time at 150°C were the variables used. Results obtained by DSC indicated that PAA/PVA blends are miscible in the full range of composition. Similarly, TGA traces showed that thermal stability was higher for blends than for pure polymers. Blends of PVA with high molecular weight PAA exhibited a hydrogel behavior after drying at relatively low temperature (100°C), whereas blends containing low molecular weight PAA behaved as hydrogels only after they were heated at 150°C. Hydrogel character was increased for these two PVA/PAA blends with the heating time at higher temperature (150°C). IR spectra revealed that esterification took place in these blends after thermally treated at this temperature. In contrast, addition of glyoxal in combination with heating was necessary to produce hydrogels from PAAm/PVA blends. Furthermore, the crosslinking degree of these hydrogels was estimated from their absorbency values by applying the Flory-Rehner equation. © 1993 John Wiley & Sons, Inc.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070500505
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  • 9
    Electronic Resource
    Electronic Resource
    Preparation and characterization of hydrogels obtained by grafting of acrylonitrile onto cassava starch by ceric ion initiation (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 47 (1993), S. 53-59 
    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: Graft starch-polyacrylonitrile copolymers have been obtained from cassava starch (yucca starch or tapioca), which was pre-heated at 65 and 95°C for different lengths of time. The copolymerization was carried out by using ceric ion as initiator at different concentrations (2.0 to 8.0 mmol/L) and also varying both the length of time of copolymerization and the ratio of monomer to starch. The composition, or grafting parameters, of all the obtained copolymers was determined by weight difference after they were extracted with dimethylformamide and hydrolyzed with an acidic solution. Samples of these copolymers were also hydrolyzed with an aqueous solution of potasium bydroxide to produce the corresponding hydrogels, and its absorbency in water was determined. © 1993 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070470108
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  • 10
    Electronic Resource
    Electronic Resource
    Coconut husk lignin. III. Reactivity of alkaline extracts with formaldehyde (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 47 (1993), S. 37-44 
    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: In this article we report results of the evaluation of the reactivity of polyphenolic extracts of coconut husk with formaldehyde in both acidic and alkaline media. The objective of this evaluation was to determine if the extracts could be used in the preparation of phenol-formaldehyde-type resins. Extracts were obtained using aqueous solutions of NaOH (with and without anthraquinone) and NH4OH. Because of their low Stiasny's Number values, these extracts are not suitable for phenol-formaldehyde resin preparation in acidic conditions unless they are mixed with phenol or phenolic derivatives. Nevertheless, extracts obtained with NaOH, especially at 100 and 120°C, showed sufficient reactivity with form-aldehyde in basic conditions and may therefore be considered suitable for resin preparation in an alkaline medium. The resins were characterized using infrared spectroscopy (IR), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). A transition temperature prior to decomposition was not detected; their thermal stability was similar to phenol-formaldehyde-type resins. © 1993 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070470106
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