Thermotropic liquid‐crystalline aromatic‐aliphatic polyimides, 4. Poly(imide‐urethane‐carbonate)s based on pyromellitdiimide and 3,4:3′,4′‐biphenyldicarboximide

Abstract

Main-chain types of thermotropic liquid-crystalline (LC) poly(imide-urethane-carbonate)s were synthesized by melt polycondensation of N,NP-bis(6-hydroxyhexyl)pyromellitdiimide or N,W-bis(6-hydroxyhexyl)-3,4 : 3',4'-biphenyldicarboximide with diphenyl hexamethylenedicarbamate and/or diphenyl hexamethylenedicarbonate. The poly(imide-urethane)s were also obtained from the dihydroxyalkylene diimide derivatives and hexamethylene diisocyanate by polyaddition. Yields and molecular weights of the resulting polymers tended to decrease with increasing urethane units. Differential scanning calorimetry (DSC) measurements, polarizing microscopic observations and powder X-ray analyses at various temperatures demonstrated that the carbonaterich copolymers comprising the 3,4 : 3',4'-biphenyldicarboximide derivative formed a nematic mesophase. Temperature-dependent Fourier-Transform infrared measurements suggest that hydrogen bonding of urethane linkages affects the formation of LC mesophases.

Liquid Crystallinity of Thermotropic Para-Type Homo- and Copolyurethanes Containing Biphenylene Mesogen and Their Blends

“…A number of papers concerning the preparation and physical properties of thermotropic polyurethanes have been reported, − since thermotropic polyurethanes were first reported by Iimura and co-workers − …”

“…A number of papers concerning the preparation and physical properties of thermotropic polyurethanes have been reported, [1][2][3][4][5][6][7][8][9][10] since thermotropic polyurethanes were first reported by Iimura and co-workers. 11 Although MacKnight and co-workers reported that a metatype polyurethane has enantiotropic liquid crystallinity, they later published that an almost similar polyurethane has monotropic liquid crystallinity.…”

Preparation, Thermotropic Liquid-Crystalline and Fluorescent Properties of Semi-Rigid Homo- and Copoly(ester-imide)s Composed of 3,3”,4,4”-p-Terphenyltetracarboxdiimide and 3,3’,4,4’-Biphenyltetracarboxdiimide

“…We have prepared a series of semi-rigid poly(esterimide)s and poly(imide-carbonate)s [5][6][7][8][9][10][11][12][13][14][15][16][17][18] and found that the 3,3 ,4,4 -p-terphenyltetracarboxdiimide has good mesogenic property, but that of 3,3 ,4,4 -biphenyltetracarboxdiimide is low. 8,9,18 Aliphatic chains next to the imide ring play an important role on LC formation of polymers. Among the abovementioned semi-rigid poly(ester-imide)s having the 3,3 ,4,4 -biphenyltetracarboxdiimide, homopolymers containing decamethylene chain and decamethylene chain-rich copolymers formed nematic phase, although its texture was not clear.…”