Studies on the thermotropic liquid crystalline polycarbonates. II. Synthesis and properties of fully aromatic liquid crystalline polycarbonates

Abstract

Abstract Four series of fully aromatic polycarbonates were prepared by using melt polycondensation from various novel phenylene diphenyl dicarbonates: 1,4‐phenylenc diphenyl dicarbonate, 1,3‐phenylene diphenyl dicarbonate, methyl‐1,4‐phenylene diphenyl dicarbonate, and chloro‐1,4‐phenylene diphenyl dicarbonate with various diols—4,4′‐biphenyl diol, hydroquinone, 2,7‐naphthalene diol and 1,5‐naphthalene diol, respectively. The thermotropic liquid crystalline properties of synthesized polycarbonates were investigated by: (1) examination of the melt birefringence and stir opalescence by a polarizing microscope equipped with a heating stage, (2) characterization by a differential scanning calorimeter (DSC), and (3) analysis of the wide angle x‐ray diffraction. It was found that the 1,3‐phenylene unit is compensated for the nonlinearity of the carbonate group, and polycarbonates which contain this bent shape unit showed excellent wide mesophase transition in this study. © 1993 John Wiley & Sons, Inc.