SYNTHESIS AND CHARACTERIZATION OF A GLASSY, LOW-TEMPERATURE TRANSITION, MAIN-CHAIN LIQUID-CRYSTALLINE POLYMER

A low-temperature glass transition, main-chain thermotropic liquid cry stalline polymer void of conventional three-dimensional crystallinity was synthesized at three distinct molecular weights. Glass transitions varied from about 3 degrees C to about 25 degrees C. Wide-angle X-ray diffraction (WAXD), optical polarizing microscopy, carbon-13 nuclear magnetic resonace (C-13-NMR), and differential scanning calorimetry (D SC) techniques were used to characterize the polymer. A low-energy end otherm was observed at about 50 degrees C (+/-5 degrees C). This trans ition was sensitive to compressive and/or shearing stresses. WAXD expe riments revealed glass-like scattering in the higher molecular weight samples, but long-range positional ordering approaching that of a crys tal in the low molecular weight sample. The results suggest the low-en ergy endotherm to be a liquid crystal-liquid crystal transition.