MESOPHASIC BEHAVIOR OF SOME POLYCARBONATES OF 4,4' DIHYDROXY-ALPHA,ALPHA'-DIMETHYLBENZALAZINE

Polycarbonates of formula: {A figure is presented} have been prepared and characterized by DSC thermal analysis and X-ray diffraction methods. They show thermotropic mesophasic behaviour. The melting and clearing temperatures and the thermal stability range of the mesophase decrease with increasing length of the aliphatic part of the polymer chain. The high temperature X-ray diffraction spectra show that the liquid crystal phases are nematic. Three of the four polymers show solid state polymorphism, the observable crystal phase depending on the thermal history of the sample. © 1979.