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 BEHAVIOR

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.