(Meth)Acrylate Liquid Crystalline Polymers For Membrane Applications

Synthesis and characterization of a series of linear copolymers with liquid crystalline side chains is reported. Methacrylate monomers containing cyanobiphenyl as a mesogenic group were prepared. These monomers were then copolymerized with 2-ethylhexyl acrylate in varying molar ratios. The structure and composition of the monomers and corresponding polymers were determined by H-1-NMR, elemental analysis and size-exclusion chromatography. Thermal properties of the polymers were studied using differential scanning calorimetry, polarized optical microscopy, and X-ray scattering techniques. Increasing mesogen content resulted in an increase of the glass transition temperature of the copolymers. In addition, above a threshold mesogen content the copolymers exhibited smectic mesophases. Using a solution casting technique, a membrane was fabricated to study single gas transport behaviors. Permeabilities, were in the order of CO2>propylene>O-2>N-2>CH4>propane. Diffusion coefficients correlated well to Lenard-Jones Diameter. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42694.