THERMOTROPIC HYDROCARBON SIDE-CHAIN LIQUID-CRYSTALLINE POLYMERS .2. POLYMER SYNTHESIS AND TACTICITY

Thermotropic hydrocarbon liquid crystalline α-olefin monomers have been polymerized with AlEt3/TiCl4 to form high molecular weight polymers. The properties of side-chain liquid crystalline polymers and poly(1-alkene)s are known to be highly dependent on tacticity. The tacticities of the new polymers range from 65% ± 10% to 90% ± 10% isotactic as determined by high-field 13C nuclear magnetic resonance (NMR) spectroscopy. A model system employing poly(1-octadecene) has been used to identify the proper polymerization catalyst for the preparation of atactic liquid crystalline polymers. 13C NMR has been used to show that atactic and isotactic poly(1-octadecene) can be distinguished on the basis of solubility and melting behavior. Preliminary experiments have not been successful in preparing atactic polymers from the new mesogenic monomers.