Synthesis and liquid crystalline properties of thermotropic homo‐ and copolycarbonates

摘要: Nondirect-type thermotropic homo- and copolycarbonates which have flexible spacers between mesogens carbonate linkages (-mesogenic unit-flexible spacer-carbonate link-flexible spacer-) were derived from dihydroxyalkyleneoxy derivatives containing biphenyl, i.e., 4,4′-bis (ω-hydroxyalkyleneoxy)biphenyl (Ia Ib), as the structure-liquid crystallinity relationships evaluated by thermal analysis with polarizing microscope. Homopolycarbonates high molecular weight were prepared (Ia) (Ib), alkylene diphenyl dicarbonates (II) melt polycondensation. The polymers form mesomorphic phases exhibit linear decrease of phase-transition temperatures increment spacer lengths without displaying odd-even number fluctuations. They show lower narrower temperature ranges than analogous direct-type unit-functional group-flexible biphenyl-containing polycarbonates polyesters , but wider nondirect-type spacer-functional . These results indicate that incorporation segments having reasonable mesophasic can be obtained. Copolycarbonates mixtures (Ib) 1,4-bis(2-hydroxyethyleneoxy)benzene (IV), nonmesogenic moiety, taken in definite molar ratio feed (m = 2 4). copolymers except only moiety liquid crystalline mesophases homopolymers. Maximum are observed composition 1 : 1. Stable obtained over entire range compositions, even though contain units backbones.