A novel series of main chain liquid crystalline copolyesters with X-shaped two-dimensional mesogenic units and crown ether cycles of cis-4

4'-bis(4-hydroxyphenylazo)dibenzo-14-crown-4 was synthesizeed via solution cocondensation polymerizations from 4

4’-(α

ω-octanedioylxy)dibenzoyl dichloride(M1)

2

5-bis(P—dodecyloxybenzoyloxy)hydro-quinone(M2)and cis-4

4'-bis(4-hyaroxyphenylazo)dibenzo-14-crown-4(M3)as the monomers．Monomer M1 was synthesized by esterification and substitution reaction of P—hydroxybenzoic acid and octanedioyl chloride．Monomer M2 was synthesized by esterfieation and reduction reaction of 2

5-dihydroxybenzoquinone and P—dodecyloxybenzoyl chloride．Monomer(M3)was synthesized by diazotization and coupling reaction of cis-diaminedibenzo-14-crown-4 and phenol．The molecular weights of copolyesters are not high

and the[η]of the copolyesters ranges from 0．35～0．25 dL／g．The monomer structures were identified by using elementary analysis

IR

UV

1H—NMR and MS etc．All the copolyester samples aie yellowish powders and insoluble at room temperature in THF and CHCl3 except for sample CP9．The properities of copolyesters were investigated by using GPC、[η]、DSC、TG、WAXD and POM．It was found that all the copolyesters went into liquid-crystal phase when they were heated over their melting temperature(Tm)．The thread texture and sehlieren texture Can be observed．Their melting temperature and isotropic temperature(Ti)change regularly with varying the cis-4

4'-bis(4-hydroxyphenylazo)dibenzo-14-crown-4 unit content in the copolyestem．The WAXD study illustrated that the copolyesters are liquid crystalline with a nemafic phase．A dispersive peak at 2θ near 20°appeared in their WAXD patterns

which is a typical character for quenched nemafie liquid crystal eopolyesters．