Synthesis, characterization and liquid crystalline properties of polyacrylates and polymethacrylates containing aryl ester pendant unit

Aryloxycarbonylphenyl acrylates and methacrylates were prepared by reacting 4-acryloyloxybenzoyl chloride and 4-methacryloyloxybenzoyl chloride with d ifferent phenols. They were homopolymerized using benzoyl peroxide as the i nitiator at 65 degrees C in dimethylformamide. The polymers were characteri zed by IR and H-1-NMR spectra and size exclusion chromatography. Differenti al scanning calorimetry and polarizing optical microscopy studies revealed that the phenyl esters of poly(4-acryloyloxybenzoic acid) and poly(4-methac ryloyloxybenzoic acid) did not show any liquid crystalline properties, but, the para-aryl-substituted phenyl esters did exhibit mesophase properties i n the temperature range of 98-265 degrees C depending on the nature of the aryl substituent. Polymethacrylates exhibit higher T-g, and lower T-m and T -i than the polyacrylates having the same pendant mesogen. Thermogravimetri c analyses have shown that the initial decomposition temperatures of the po lymers are above 230 degrees C. (C) 2000 John Wiley & Sons, Inc.