RIGID BACKBONE POLYMERS .2. POLYISOCYANATES AND THEIR LIQUID-CRYSTAL BEHAVIOR

It is shown that certain isocyanate polymers are mesogenic in concentrated solutions at ambient temperatures and in bulk at elevated temperatures. These polymers may be categorized into two classes: (1) alkylisocyanate homopolymers in which the alkyl side chains are long enough to facilitate concentrated solutions, yet short enough to prevent predominant side-chain interactions; and (2) copolymers of aralkyl and alkyl isocyanate where the aromatic residue is at least two (-CH2-) units removed from the backbone. Preliminary X-ray, IR, thermal analysis, dilute solution, and mechanical properties data are also presented. © 1979, American Chemical Society. All rights reserved.