Abstract
Thermally stimulated current (TSC) as well as differential scanning calorimetry (DSC) was used to determine the glass transition temperature of anisotropic glasses for semi-flexible polyesters with polymethylene spacers. The highly sensitive technique of thermal-windowing polarization or relaxation map analysis (RMA) was used to further study the relaxation behavior of the anisotropic glasses as well as the heterogeneity of the samples. Experimental results indicate that phase separation is dependent upon the length of the polymethylene chain, i. e., the configuration of polymethylene segments and the number (n value) of methylene groups. The longer the polymethylene segment the larger the difference in the two transition temperatures, the higher transition temperature (T g, H ) and lower transition temperature (T g, L ). For a polymer with even value of n, ΔT g (T g, H minus T g, L ) of the anisotropic glass is lower than that for the neighboring two polymers with odd n values. In addition, the distortion effect of the polymethylene segment with even number of methylene groups on the polymer chains under polarization was studied by the Vogelian relaxation behavior of the p-peak. These results indicated that the maximum fractional volume of the polymethylene segments of the anisotropic glass for a polymer with even n value would be smaller than that for a polymer with odd n value under polarization.