Liquid crystalline polymers. IV. Thermotropic liquid crystalline poly(arylidene-ether)s and copolymers containing N-methylpiperidone linked to the main chain through spacers of various lengths

Two novel series of poly(arylidene-ether)s and copoly(arylidene-ether)s wer e synthesized from N-methylpiperidone and/or cyclohexanone respectively. Th e first series (homopolymers) was derived from 4,4'-diformyl-alpha,omega -d iphenoxyalkane or 4,4'-diformyl-2,2' dimethoxy-alpha,omega -diphenoxyalkane with N-methylpiperidone. The second series (copolymers) was derived from t he diphenoxyalkanes (I-VIII) with N-methylpiperidone and cyclohexanone. The inherent viscosities of the polymers thus prepared were in the range of 0. 37-0.98 dI/g. The majority of the polymers and copolymers are soluble in ch lorinated hydrocarbons. DSC measurements and microscope observation under p olarized light demonstrate that this type of poly(arylidene-ether)s form ne matic mesophase over a wide temperature range in contrast to the correspond ing copoly(arylidene-ether)s. All of the polymers and copolymers exhibited thermotropic liquid crystalline properties. In most cases, the mesophase ex tends up to 315 degreesC, where thermal decomposition prevents further obse rvation. The morphology of polymer IXb and copolymer XIb as a selected exam ple was examined by scanning electronic microscope.