Synthesis and characterization of symmetrical banana shaped liquid crystalline polyethers

A series of banana shaped allyl terminated liquid crystalline bis{[4′(10-undecenoyloxy)-1,1′biphenyl-4-carboxylate}s varied with H, COOCH3, Cl and NO2 substituents in the central phenyl ring were synthesized and characterized by FT-IR, 1H NMR and 13C NMR spectroscopy. Effect of substituents on the mesomorphic property was examined by polarized optical microscopy (POM) and exhibited B1 and nematic mesophases. Differential scanning calorimetry (DSC) measurements confirmed the LC property. Allyl group in the terminal position was epoxidized and polymerized to get banana shaped liquid crystalline ladder polyethers by ring opening polymerization and characterized spectroscopically. POM investigations displayed the development of enantiotropic grainy textures for polyethers and confirmed by DSC. Thermogravimetric analysis revealed that they were decomposed at high temperatures with good char yield.