Molecular engineering of liquid-crystalline polymers by living polymerization. Part 24.—Synthesis of poly(vinyl ether)s exhibiting an SC* phase by living cationic polymerization of (2S,3S)-(+)-2-chloro-3-methylpentyl 4′-(6-vinyloxyhexyloxy)biphenyl-4-carboxylate and its copolymerization with (2S,3S)-(+)-2-chloro-3-methylpentyl 4′-(8-vinyloxyoctyloxy)biphenyl-4-ylcarboxylate

Abstract

The synthesis and cationic polymerization of (2S, 3S)-(+)-2-chloro-3-methlpetyl 4′-(6-vinyloxyhexyloxy)biphenyl-4-ylcarboxylate (15-6) are described. Poly [(2S, 3S)-(+)-2-chloro-3-methylpentyl 4′-(6-vinyloxyhexyloxy)biphenyl-4-ylcarboxylate][poly(15-6)] with degrees of polymerization from 4 to 20 and polydispersities ⩽ 1.13 has been synthesized and characterized by differential scanning calorimetry (DSC) and thermal optical plorized microscopy. All poly (15-6)s exhibit only a non-crystallizable enatiotropic S_C* phase. This polymer provides one of the very few examples of polymers which display an S_C* mesophase from glass-transition temperatire up to the isotropization transition temperature, and is of great interest for practical applications. Poly (15-6)s with DP 10 exhibit an additional enatiotropic unidentified smectic (S_x) phase. The nature of mesophases exhibited by poly (15-6) has been additional by the investigation of the phase diagram of the copolymers prepared from 15-6 and (2S, 3S)-(+)-2-chloro-3-methupentyl 4′-(8-vinyloxyoctyloxy)biphenyl-4-carboxylater (15-8).