SYNTHESIS AND CHARACTERIZATION OF 4-CYANOBIPHENYL-4'-YLOXY-FUNCTIONALIZED POLY(7-OXANORBORNENE-5,6-EXO-DICARBOXIMIDE)S VIA RING-OPENING METATHESIS POLYMERIZATION (ROMP)

N-[n-(4-cyanobiphenyl-4'-yloxy)alkyl] -7-oxanorbornene-5,6-exo-dicarbo ximide (CBON2-CBON8) with increasing number of methylene groups in the alkyl part (n = 2-8) were synthesized by Mitsunobu condensation betwe en the appropriate alcohols (CBA(2)-CBA(8)) and 7-oxanorbornene-5,6-ex o-dicarboximide (ON). The conditions for the ring opening metathesis p olymerization of CBONn giving acceptable molecular weights and molecul ar distributions were established. Characterization of the resulting p olymers (P-2-P-8) by H-1- and C-13-NNIR has shown a high trans content . Differential scanning calorimetry and optical microscopy analysis ha ve shown that the alcohols CBA(n) are thermotropic with some variation s between the first and second heating-cooling cycles, the monomers CB ONn melt with no evidence of any mesomorphic state, the polymers P-n s how only the glass transition, and the glass transition temperature (T -g) decreases with increases in the spacer length. (C) 1998 John Wiley & Sons, Inc.