A novel series of Schiff base type polymer liquid crystalline crown ethers was synthesized for the first time by solution polycondensation from 4

4′-(alkylene dioyloxy) dibenzaldyhyde (M1) and diamino-dibenzo-15-crown-5 (M2) as the monomers．Monomer M1 has been synthesized by esterification reaction of aliphatdiyl chloride and 4-hydroxybenzaldehyde. Monomer M2 has been synthesized by reduction reaction of dinitrodibenzo-15-crown-5 in the presence 10％ Pd／C catalyst and hydrazine hydrate．The geometric isomers of dinitrodibenzo-15-crown-5 and diaminodibenzo-15-crown-5 that were synthesized for the first time can not be differentiated by IR spectrum and 1H-NMR spectrum．The molecular weights of the polymers are not high

and the Mn of the polymers ranges from 10100～13000．The monomer structures were identified by using elementary analysis

IR

1H-NMR and MS etc．The properties of polymers were investigated by using GPC

DSC

TG

WAXD and POM．It was found that all the polymers went into a liquid crystal phase when heated to their melting temperature (Tm)．The threaded texture and schlieren texture can be observed．The glass transition temperature (Tg)

melting temperature and isotropization temperature (Ti) change with varing the flexible spacer unit in the polymers

all the polymers have higher clearning points and wide mesophase ranges．The WAXD study illustrated that the polymers of 6Ⅰa

6Ⅰc

6Ⅱb and 6Ⅱd are liquid crystalline with a nematic phase．A dispersive peak at 2θ near 20。appeared on their WAXD curves

which is a typical character for quenched nematic liquid crystal polymers．