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  • 1
    Electronic Resource
    Electronic Resource
    Reaktion an Ziegler-Natta-katalysatoren, 11.Mitt. 10: cf.9. Kinetik des metathese-abbaus von teilweise chloriertem polybutadienHerrn Prof. Dr. O. Hromatka (Wien) zum 70. Geburtstag gewidmet (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 1703-1712 
    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: 1,4-Polybutadiene was partially chlorinated with chlorine in dichloromethane and degradated by olefin metathesis with 4-octene. Low molecular weight substances were analysed by gas chromatography. Products with one isolated chlorinated unit and with two neighbouring chlorinated units of polybutadiene were found. Kinetics of product formation and yields were different for unmodified and chlorinated units.
    Notes: 1,4-Polybutadien wurde mit Chlor in Dichlormethan teilweise chloriert und durch Olefin-Metathese mit 4-Octen abgebaut. Die niedermolekularen Substanzen wurden gaschromatographisch analysiert. Produkte mit einer isolierten chlorierten Einheit und mit zwei benachbarten chlorierten Einheiten des Polybutadiens wurden gefunden. Die Kinetik der Produktbildung und die Ausbeuten waren für unmodifizierte und chlorierte Einheiten unterschiedlich.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.021760614
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  • 2
    Electronic Resource
    Electronic Resource
    Metathesis degradation of partially phenylated 1,4-polybutadiene (1987)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1795-1808 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 1,4-Polybutadiene was partially phenylated in allyl position by bromination with N-bromosuccinimide and subsequent Grignard-Wurtz reaction with phenylmagnesium bromide. Substitution was to a certain degree coupled with double bond shift. The polymer structure was investigated via metathesis degradation with (E)-4-octene. The degradation products were identified by means of a GC/MS system and determined by GC. Cases of isomerism of products with one phenyl group were investigated. A metathesis product with two phenyl groups in one constitutional unit was found. A distribution function, based on a statistical scission of the macromolecules, was used for evaluations at different metathesis reaction times. Proofs of the reduced reactivity of CC double bonds in the neighbourhood of substituents were received. The yields of the different constitutional units in metathesis products were determined. These were compared with the results of computer simulations in a simplified model. The validity of computer simulations was thereby confirmed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1987.021880803
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  • 3
    Electronic Resource
    Electronic Resource
    Bildung von Cyclopentenylverbindungen beim Metathese-Abbau von modifiziertem 1,4-Polybutadien (1980)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 1847-1860 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This investigation deals with metathesis degradation products of modified 1,4-polybutadiene (poly(1-butenylene)) which have not been taken into consideration as yet, e.g. substituted cyclopentene and linear isomerization products. Substituents were introduced into 1,4-poly-butadiene either by partial bromination with N-bromosuccinimide followed by a Grignard-Wurtz reaction or by reaction with the corresponding methyl compound and dicumyl peroxide. Polymers with 2-methylbenzyl, 4-methylbenzyl, 4-chlorobenzyl, 4-methoxybenzyl, 2-naphthylmethyl, 2,4,6-trimethylphenyl, 1-naphthyl, 9-anthryl, and 9-phenanthryl substituents were degraded by metathesis with 4-octene using WCl6/(CH3)4Sn as a catalyst and were analyzed by gas chromatography/mass spectrometry and by liquid chromatography.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1980.021810907
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of ethylene-propylene rubber in crosslinked blends with 1,4-polybutadiene (1987)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 155 (1987), S. 143-149 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Vernetzte Blends aus Ethylen-Propylen-Kautschuk (EPR) und 1,4-Polybutadien (BR) wurden durch Metathese-Abbau der BR-Komponente untersucht; der Prozentsatz des EPR wurde durch Wägen des polymeren Rückstandes bestimmt. Die Metathese-Reaktion wurde mit einem überschuß von 1-Octen in Anwesenheit des Katalysators WCl6/(CH3)4Sn ausgeführt. Bei Vernetzung mit Dicumylperoxid wurden die besten Resultate mit 10 bis 30 Gew.-% EPR und mittleren Vernetzungsgraden erhalten. Die Analyse von Schwefel-Vulkanisaten (erhalten mit dem Beschleuniger N-Cyclohexyl-2-benzothiazylsulfenamid) ergab vertretbare Resultate nur für niedrige Schwefelgehalte (1,5 Gew.-%). EPR konnte auch in unvernetzten Blends mit BR bestimmt werden.
    Notes: Crosslinked blends of ethylene-propylene rubber (EPR) and 1,4-polybutadiene (BR) were investigated by metathesis degradation of the BR component; the percentage of EPR was determined by weighing the polymeric residue. The metathesis reaction was carried out with an excess of 1-octene in the presence of the catalyst WCl6/(CH3)4Sn. In crosslinking with dicumyl peroxide, the best results were obtained with 10 to 30 wt.-% of EPR and medium crosslinking degrees. Analysis of sulphur vulcanizates (received with the accelerator N-cyclohexyl-2-benzothiazyl sulphenamide) gave tolerable results only for low sulphur contents (1.5 wt.-%). Determination of EPR was also possible in non-crosslinked blends with BR.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1987.051550112
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  • 5
    Electronic Resource
    Electronic Resource
    Ring-opening metathesis polymerization of 11-alkylidenebenzonorbornadienes (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 2699-2707 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 11-(α-Phenylbenzylidene)benzonorbornadiene (3) and other similar monomers were synthesized by cycloaddition of dehydrobenzene with different fulvenes. Ring-opening metathesis polymerization of the resulting monomers using Mo-carbene initiators gave highly stereoregular polymers. Variation of the substituents allows control of the stereoregularity of these polymers. Poly[11-(α-phenylbenzylidene)benzonorbornadiene] is completely cis connected, whereas poly[11-(α-methylbenzylidene)benzonorbornadiene] is completely trans linked. The polymers contain two very reactive carbon-hydrogen bonds that are both allylic and benzylic. Elimination of these bridgehead hydrogens gives a fully conjugated polymer that can be described as having “fulvenoid” or “quinoid” geometry.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1994.021950802
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  • 6
    Electronic Resource
    Electronic Resource
    Side-chain liquid crystal polymers of 2,3-disubstituted norbornenes via ring-opening metathesis polymerization, 2Part 1: cf. ref.11a. Methoxybiphenyl as mesogenic group, influence of flexible spacer length m = 4 to 10 on the thermotropic behaviourDedicated to o. Univ. Prof. Dr. Klaus Hummel, Technical University of Graz, on the occasion of his 66th birthday (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 2343-2357 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We report the synthesis and ring-opening metathesis polymerization of (±)-exo,endo-bis[ω-(4′-methoxybiphenyl-4-yloxy)alkyl] bicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylates using the molybdenum-carben initiator Mo(CH-t-Bu)(NAr)(OCCH3)(CF3)(2)2 with NAr = 2,6-diisopropylaniline. The spacer length was varied from m = 4 to 10 methylene groups. All monomers and polymers show mesophases of the smectic type. Independently of the spacer length no glass transition was detected. An odd-even effect of transition temperatures was observed for both the monomers and polymers. The monomers with m 〉 5 showed more phase transitions in the DSC-heating runs. Dependency of liquid crystalline transition temperatures on molecular weight is shown for one polymer (m = 6). Transition temperatures are roughly constant for polymers consisting of more than 30 repeating units. In contrast, the enthalpy changes of these transitions are nearly independent of the molecular weights once the polymers contain more than 10 repeating units, but they are strongly dependent on spacer length, with a minimum at m = 6.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1996.021970724
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  • 7
    Electronic Resource
    Electronic Resource
    Side chain liquid crystal polymers of 2,3-disubstituted norbornenes via ring-opening metathesis polymerisation, 3.Part 2: cf. ref.2 Influence of backbone microstructure and grafting ratio on the thermotropic behaviour (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 1391-1410 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The ring opening metathesis polymerisation (ROMP) of (±)- and (-)-exo, endo-bis[(4′-cyanobiphenyl-4-yl)oxyalkyl]norborn-5-ene-2,3-dicarboxylates using three different Schrock type molybdenum alkylidene complexes ([Mo(NAr)(CH-t-Bu)(OR)2] with R=C(CH3)3, —C(CH32)(CF3) or —C(CH3)(CF3)2) resulted in the formation of side chain liquid crystalline polymers (SCLCP's). The different initiators caused changes in the backbone tacticity which were determined by means of NMR techniques. The influence of the type of tacticity on the thermotropic behaviour of the SCLCP's was investigated. The thermal properties were determined by differential scanning calorimetry (DSC). The transition temperatures increased with rising molecular weight up to a degree of polymerisation of about 40. Above this value the thermal properties remained constant with increasing molecular weight. The types of phases for the liquid crystalline polymers were elucidated by polarising optical microscopy (POM). In general, the highly tactic polymers showed a broader thermal range of the LC phase. The kind of initiator used caused changes of the thermal and thermotropic behaviour of the SCLCP's. A grafting ratio model is introduced to explain the findings. From the experimental data a structure/property relationship is developed which might help to predict liquid crystalline properties of unknown polymers.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021980508
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  • 8
    Electronic Resource
    Electronic Resource
    A novel side-chain liquid crystal polymer of 5-substituted cis-cyclooctene via ring-opening metathesis polymerization (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 1417-1425 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this communication, we report the synthesis and ring-opening metathesis polymerisation (ROMP) of a 5-substituted cyclooctene-derivative, (±)-cis-[11-(4′-cyanobiphenyl-4-yloxy)undecyl]cyclooct-4-enecarboxylate. A highly active molybdenum-carbene was used as initiator. The prepared polymer is liquid crystalline and shows a nematic phase between -5 and 53°C.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021980510
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  • 9
    Electronic Resource
    Electronic Resource
    Side chain liquid crystal polymers of 2,3-disubstituted norbornenes via ring-opening metathesis polymerization, 1 influence of flexible spacer length m = 2 to 12 on the thermotropic behaviourDedicated to Prof. emerit. Dr. Josef Schurz, Karl-Franzens-Universität Graz, on the occasion of his 70th birthday (1995)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 196 (1995), S. 3623-3641 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Bis[(4′-cyanobiphenyl-4-yl)oxy-n-alkyl]norborn-5-ene-2,3-dicarboxylates with alkyl chain lengths m = 2 - 12 were synthesized. Most of the monomers exhibit thermodynamically metastable liquid crystalline phases with respect to the crystalline phases. Polymers were prepared by ring-opening metathesis polymerization (ROMP) using the molybdenum carbene initiator [Mo(CH-t-Bu) (NAr) (t-BuO)2] (t-Bu = tert-butyl) with NAr = 2,6-diisopropylaniline. All polymers show thermotropic liquid crystalline phases. Results on characteristic phases and the influence of the number of methylene units m in the flexible spacer on the thermal behaviour (glass transition temperature, isotropization temperature, odd-even effect, enthalpy change) of these new side chain liquid crystal polymers (SCLCP's) are given. They are compared to monosubstituted polynorbornene derivatives and to SCLCP's with other backbones.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1995.021961116
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  • 10
    Electronic Resource
    Electronic Resource
    Molecular mechanics calculations on cyclopentenyl compounds, products obtained by olefin metathesis of norbornadiene derivatives (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 6 (1985), S. 302-311 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Molecular mechanics calculations (MM2) are used to elucidate energies and structures of possible reaction products in olefin metathesis of 2,3-dimethylnorbornadiene. The comparison of experimental and calculational results concerning norbornadiene itself shows excellent agreement both in energy and structure. The predicted isomers of lowest energy in a series of three different reaction products seem highly reliable and will lead to a more precise interpretation of the olefin metathesis reaction and the resulting product distribution. Some sixty different isomers have been considered and structures and energies are given. Nonplanarity of double bonds and van der Waals repulsions of closely related hydrogen atoms in polycyclic cycloolefins are considered in some detail. In order to reduce computing time and efforts in obtaining starting coordinates, a computer program for some dimeric structures was devised, which can combine minimized structures stemming from MM2 calculations.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540060407
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