Author:

Keywords:

phase-transfer catalysis, molecular-weight, main-chain, sequential copolymers, functional polymers, flexible spacers, mesogenic groups, carbonic-acid, polycarbonates, transitions, Science & Technology, Physical Sciences, Polymer Science, PHASE-TRANSFER CATALYSIS, MOLECULAR-WEIGHT, MAIN-CHAIN, SEQUENTIAL COPOLYMERS, FUNCTIONAL POLYMERS, FLEXIBLE SPACERS, MESOGENIC GROUPS, CARBONIC-ACID, POLYCARBONATES, TRANSITIONS, 0303 Macromolecular and Materials Chemistry, 0912 Materials Engineering, Polymers, 3403 Macromolecular and materials chemistry, 5104 Condensed matter physics

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 penta-respectively octamethylene diphenyl dicarbonate in varying concentrations. These random copolycarbonates show liquid crystalline behavior, with the formation of a nematic phase over a temperature range of maximum 22 degrees C respectively 47 degrees C, this for at least 75 mol-% of biphenyl units. Incorporation of 1,5-bis[(6-hydroxyhexyl)oxy]naphchalene 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 degrees 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 degrees C for the nematic phase region.