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Thermotropic liquid‐crystalline aromatic‐aliphatic polyimides, 4. Poly(imide‐urethane‐carbonate)s based on pyromellitdiimide and 3,4:3′,4′‐biphenyldicarboximide
Author(s) -
Hirata Tomohiro,
Sato Moriyuki,
Mukaida Kenichi
Publication year - 1994
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1994.021950632
Subject(s) - thermotropic crystal , imide , differential scanning calorimetry , mesophase , polymer chemistry , liquid crystal , condensation polymer , materials science , polymer , copolymer , liquid crystalline , composite material , physics , optoelectronics , thermodynamics
Main‐chain types of thermotropic liquid‐crystalline (LC) poly(imide‐urethane‐carbonate)s were synthesized by melt polycondensation of N , N ′‐bis(6‐hydroxyhexyl)pyromellitdiimide or N , N ′‐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.