caa a22 4500 465787274 CHVBK 20180323112012.0 cr unu---uuuuu 170327e19901001xx s 000 0 eng 10.1007/BF00294095 doi (NATIONALLICENCE)springer-10.1007/BF00294095 4,4′-diisocyanatoazobenzene a mesogen for liquid crystalline polyurethanes? [Elektronische Daten] [Werner Mormann, Amir Baharifar] The mesomorphic properties of 4,4′-diisocyanatoazobenzene were investigated by polarizing microscopy and DSC. It shows a nematic phase when thoroughly purified by distillation. The nematic range, however, is smaller than that of other liquid crystalline diisocyanates like 4,4′diisocyanatophenyl benzoate. A number of binary hard segment type polyurethanes was made with several diols as chain extenders and in addition ternary copolyruethanes containing two different mesogenic diisocyanates. They are crystalline materials with poor solubility. The melt temperatures of these polyurethanes are higher than those of the corresponding polymers with 4,4′-diisocyanatophenyl benzoate. Liquid crystalline behaviour could not be observed in any of the polymers probably because of the high melting transitions and relatively lower izotropization temperatures which result from the higher rigidity and symmetry of the azobenzene structure. Springer-Verlag, 1990 Mormann Werner Laboratorium für Makromolekulare Chemie, Universität GH Siegen, Adolf-Reichwein-Strasse 2, D-5900, Siegen, Germany aut Baharifar Amir Laboratorium für Makromolekulare Chemie, Universität GH Siegen, Adolf-Reichwein-Strasse 2, D-5900, Siegen, Germany aut Polymer Bulletin Springer-Verlag 24/4(1990-10-01), 413-419 0170-0839 24:4<413 1990 24 289 https://doi.org/10.1007/BF00294095 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00294095 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mormann Werner Laboratorium für Makromolekulare Chemie, Universität GH Siegen, Adolf-Reichwein-Strasse 2, D-5900, Siegen, Germany aut NATIONALLICENCE 700 1- Baharifar Amir Laboratorium für Makromolekulare Chemie, Universität GH Siegen, Adolf-Reichwein-Strasse 2, D-5900, Siegen, Germany aut NATIONALLICENCE 773 0- Polymer Bulletin Springer-Verlag 24/4(1990-10-01), 413-419 0170-0839 24:4<413 1990 24 289 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer