Synthesis of polynorbornene with aliphatic and aromatic side chains.

As functionalization of the polynorbornene backbone has shown to be a viable route towards altering the thermal and chem. properties of the resulting polymeric material, our focus has been on the prepn. of norbornene monomers contg. a side-chain consisting of a rigid mesogen and/or an aliph. spacer. Ring-opening metathesis polymn. (ROMP) of these highly strained systems was readily accomplished using (Cy3P)2Cl2Ru≡CHPh, which liberated the substituted polynorbornenes in very good yield. Thermal anal. on both types of polymer showed higher decompn. temps. for the polymers contg. the pendent rigid mesogen, and slightly lower for those contg. the aliph. spacer.