| Abstract: | Copolycarbonates with flexible spacers have been prepared by melt condensation of 4,4′-bis(2-hydroxyethyl)oxy]biphenyl, 1,5-bis(2-hydroxyethyl)oxy]naphthalene and pentarespectively octamethylene diphenyl dicarbonate in varying concentrations. These random copolycarbonates show liquid crystalline behavior, with the formation of nematic phase over a temperature range of maximum 22°C respectively 47°C, this for at least 75 mol-% of biphenyl units. Incorporation of 1,5-bis(6-hydroxyhexyl)oxy]naphthalene does not lead to liquid crystallinity. Copolymers with 2,6-bis(6-hydroxyhexyl)oxy]naphthalene and 4,4′-bis(6-hydroxyhexyl)oxy]biphenyl show mesomorphic behavior, with the formation of a mesophase with a maximum width of 20°C, for incorporation up to 75 mol-% of either of the mesogenic units. Copolycarbonates which contain only biphenyl mesogenic units and which differ in the length of the flexible spacers were also obtained; they behave liquid crystalline over the entire composition range with maximum 34°C for the nematic phase region. |
