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  • 1
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    Diisocyanato dicyclohexylmethane: structure/property relationships of its geometrical isomers in polyurethane elastomers (1992)
    Springer
    Details
    Publikationsdatum: 1992-06-01
    Print ISSN: 0372-820X
    Digitale ISSN: 1435-1536
    Thema: Chemie und Pharmazie , Maschinenbau
    Publiziert von Springer
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  • 2
    Digitale Medien
    Digitale Medien
    Uber einige neue derivate des dichlormaleinimids
    Amsterdam : Elsevier
    Tetrahedron Letters 8 (1967), S. 2801-2806 
    Details
    ISSN: 0040-4039
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0040-4039(00)90862-1
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  • 3
    Digitale Medien
    Digitale Medien
    Diisocyanato dicyclohexylmethane: structure/property relationships of its geometrical isomers in polyurethane elastomers (1992)
    Springer
    Colloid & polymer science 270 (1992), S. 543-548 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Diisocyanato dicyclohexylmethane ; polyurethane elastomer ; x-ray diffraction ; dynamic mechanical spectroscopy ; solvent resistance ; mechanical properties
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract 4,4′-Diisocyanato dicyclohexylmethane (HMDI) is a commercially available diisocyanate used as a building block for polyurethane products that require excellent light stability and hydrolysis resistance. It consists of a mixture of three geometrical isomers, the trans,trans-, cis,trans-, and cis,cis-isomers. We found that the trans,trans-isomer leads to some interesting properties in polyurethane elastomers. Surprisingly, the hardness and percent elongation (properties that usually follow an inverse relationship) both increase with increasing trans,trans- HMDI contents. We also observed dramatic increases in the ultimate tensile strength, split-tear strength, resilience, and solvent resistance. Also, the melting temperature of the elastomers increases with increasing trans,trans content. X-ray analysis of model hard segments showed that the hard segment based ont,t-HMDI is highly ordered, leading to higher melting temperatures and better separation between the hard- and soft-segment phases.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00658285
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  • 4
    Digitale Medien
    Digitale Medien
    The polyurea structure and the role of Amine-Terminated Polyethers and Polyesters in Polyurethanes (1994)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 336 (1994), S. 483-491 
    Details
    ISSN: 0941-1216
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Reaction Injection Molding (RIM) technology has made it possible to master the fast reaction of di- and polyamines with di- and polyisocyanates, leading to the preferred polyurea structure. Telechelics with amino end groups are gaining increased interest for the manufacture of polyurethane-polyurea materials by this technology. They make it possible to substitute all urethane groups in the elastomers with urea groups. The telechelics which are considered are amine-terminated polyethers (ATPE) and polyesters based on the typical soft-segment forming polycondensation polymers which are widely used in polyurethane chemistry.Isocyanate-terminated prepolymers of toluene diisocyanate and polyether polyols can be hydrolyzed in aqueous alkaline media via the carbamate intermediate to the amineterminated prepolymers. The reactivity of these aromatic ATPEs was ideally fit for the RIM process. ATPEs by the hydrolysis process are somewhat limited if products with low viscosities are required. In the reaction of chloro-nitrobenzenes with polyether polyols followed by the hydrogenation of the nitro groups of the terminal phenoxy moieties, we found a path for the synthesis of low viscosity aromatic ATPEs. Capping of polyether polyols with acetoacetate groups and subsequent reaction of the acetoacetylated polyethers with amines, leads to polyethers with terminal imine or enamine groups, which are derivates of aminocrotonic acid. We determined that this approach is a universal method for the synthesis of a large variety of aromatic as well as aliphatic ATPEs with low viscosities. Trifluoroacetic acid turned out to be the ideal catalyst for the reaction of the acetoacetylated polyethers with aromatic diamines, one amino group forming the imine link, the second one remaining intact and providing the desired reactivity towards isocyanates. Aliphatic diamines do not require a catalyst for this reaction. They lead to aminocrotonates with aliphatic amino groups that have high reactivity towards isocyanates, which is to be expected from aliphatic amines. The reaction of the chloroformates of polyether polyols with diamines can also be used to synthesize a variety of ATPEs. We recently developed an approach to low viscosity ATPEs having secondary amino end groups. The hydroxyl groups of the polyether polyols are converted to chloride or methanesulfonyl. The polyethers terminated with these leaving-groups are reacted with primary aliphatic or aromatic amines to give the secondary ATPEs in very good yields.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/prac.19943360602
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  • 5
    Digitale Medien
    Digitale Medien
    Ringschlußreaktionen mit N-(α-Chloralkyliden)-carbamidsäurechloriden (1966)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 78 (1966), S. 981-982 
    Details
    ISSN: 0044-8249
    Schlagwort(e): Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ange.19660782109
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  • 6
    Digitale Medien
    Digitale Medien
    Ringschlußreaktionen mit Polychlor-aza-alkenen (1966)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 78 (1966), S. 982-982 
    Details
    ISSN: 0044-8249
    Schlagwort(e): Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ange.19660782110
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  • 7
    Digitale Medien
    Digitale Medien
    Neuere Methoden der Präparativen Organischen ChemieFrühere Beiträge dieser Reihe sind gesammelt in fünf Bänden im Verlag Chemie, Weinheim/Bergstr., erschienen. Sie liegen auch in englischer Ausgabe vor. Herstellung, Eigenschaften und Reaktionen von Polychloraminderivaten (1968)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 80 (1968), S. 942-953 
    Details
    ISSN: 0044-8249
    Schlagwort(e): Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Die Hochtemperatur-Chlorierung von Aminen und Aminderivaten eignet sich als präparative Methode zur Herstellung hochchlorierter Aminderivate. Entscheidend für das Gelingen der Hochtemperatur-Chlorierung ist eine Temperaturführung, die der Konstitution der Amine angepaßt ist. In vielen Fällen stabilisieren sich die Chlorierungsprodukte durch Spaltungsreaktionen unter Bildung der Imidsäurechlorid- oder Isocyaniddichlorid-Gruppierung. Unter speziellen Bedingungen bilden sich cyclische Verbindungen. Nach dem beschriebenen Chlorierungsverfahren lassen sich z. B. Polychloraryl- und -alkyl-isocyaniddichloride, Polychloraryl- und -alkyl-imidsäurechloride sowie Polychlorheterocyclen gewinnen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ange.19680802204
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  • 8
    Digitale Medien
    Digitale Medien
    The structure of the hard domains in trans,trans-HMDI-based polyurethane elastomers (1996)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 47 (1996), S. 48-54 
    Details
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: X-ray methods have been used to investigate the structure of the hard domains in polyurethane elastomers based on trans, trans-dicyclohexylmethane 4,4′-diisocyanate (HMDI) with butanediol as the chain extender. The crystalline hard segments become oriented on stretching the films at room temperature, although the degree of crystallinity remains relatively low. The ordering is improved considerably by annealing the films for several hours at 130-190°C: the fiber diagram contains 25 sharp Bragg reflections which are indexed by a triclinic unit cell with dimensions a=5.1 Å, b=10.2 Å, c=37.5 Å, α=115.2°, β=84.9°, and γ=94.2°. The cell contains dimer units of two chains which are probably staggered along the c axis direction in the bc plane. In the samples annealed for shorter periods of time, a second less abundant crystal structure is observed that coexists with the first. This second structure is also triclinic with a more extended fiber repeat of c=41.3 Å and is slowly converted to the contracted form on further annealing. Molecular models show that in the extended form the butanediol units have the all-trans conformation, whereas in the contracted form they probably have the tg+tg-t or tg-tg+t conformations, which have lower potential energies than the all-trans form. The chains in both the extended and the contracted conformations are able to form a network of intermolecular hydrogen bonds, and in this regard the structures are very similar to those reported previously for the analogous diphenylmethane diisocyanate (MDI)-based elastomers. Thus the higher melting points for the HMDI-based hard segments are most likely due to hydrophobic interactions between the dicyclohexyl methanes that are stronger than those between the diphenyl methanes of the MDI-based elastomers.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/actp.1996.010470107
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  • 9
    Digitale Medien
    Digitale Medien
    Preparation, Properties and Reactions of Polychloroamine Derivatives (1968)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 7 (1968), S. 856-867 
    Details
    ISSN: 0570-0833
    Schlagwort(e): Polychloroamines ; Chloroamines ; Amines ; Chlorination ; Synthetic methods ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Highly chlorinated amine derivatives can be prepared by the high-temperature chlorination of amines and amine derivatives. Essential for the success of this reaction is an adequate temperature control suited to the constitution of the amines. In many cases the chlorination products achieve stability by cleavage reactions with formation of the imidic acid chloride or isocyanide dichloride grouping. Cyclic compounds are formed under special conditions. The chlorination process described can be used to obtain e.g. polychloroaryl and polychloroalkyl isocyanide dichlorides, polychloroaryl and polychloroalkyl imidic acid chlorides, and polychloroheterocyclic compounds.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/anie.196808561
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  • 10
    Digitale Medien
    Digitale Medien
    Ring Closure Reactions of N-(α-Chloroalkylidene)carbamoyl Chlorides (1966)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 5 (1966), S. 960-960 
    Details
    ISSN: 0570-0833
    Schlagwort(e): Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/anie.196609601
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