Liquid crystalline polymers, 9 - Synthesis and thermal behavior of some oligomers containing a diethyletheric spacer

Polyethers based on bis(2-chlorolthyl) ether and various bisphenols were ob tained using a phase transfer catalys is technique in a liquid/liquid syste m. 4,4'-Dihydroxyazobenzene, 4,4'-dihydroxybiphenyl, bisphenol A, 2,7-dihyd roxynaphthalene and 4,4'-dihydroxydiphenyl) sulfide were used. Only the pol ymers with azobenzene and biphenyl units exhibited mesophases, since the ot hers have semi-crystalline or amorphous structures. The polymers were chara cterized by H-1 NMR, DSC and optical microscopy in polarized light. The mol ecular weights of the samples were low, situated in the oligomeric domain. The various transfer rates of the bisphenols from the aqueous to the organi c phase, in some cases, led to very different copolymerization ratios as co mpared to the feed ratios. The LC polymers exhibited monotropic mesophases, probably for conformational reasons. A comparison between similar polyethe r structures containing the diethyletheric spacer and an oxetanic one was e ffectuated.