Synthesis of liquid crystalline moiety containing N-cyclohexylmaleimide copolymers

Atom transfer radical polymerization (ATRP) was applied to copolymerize liquid crystalline acrylate (6-(4-cyanobiphenyl-4′-oxy)hexyl acrylate) (LC6) monomer and N-cyclohexylmaleimide (NCMI) monomer. Copolymerization of LC6 and NCMI in the presence of Cu(I)Br/N, N, N′, N″, N″-pentamethyldiethylene-triamine (PMDETA) catalyst system using anisole as a solvent at 110°C initiated by 2-bromopropionyl bromide afforded well-defined copolymers. In addition, free radical polymerization (FRP) was applied using 2,2′-azodiisobutyronitrile (AIBN) as an initiator in toluene at 70°C for the same monomers. The influences of several factors such as monomer ratio and time on the copolymerization, spectral, and thermal properties of resultant copolymers were investigated. The glass transition temperature and thermal stabilities of the copolymers were increased by increasing the N-substituted maleimide (N-cyclohexylmaleimide) content. As a result, thermally stable liquid crystalline alternating copolymers were synthesized by introducing maleimide segments into the polymer.