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New organo‐soluble polyimides for optical, microelectronic and fiber applications
Author(s) -
Harris Frank W.,
Li Fuming,
Lin ShengHsien,
Chen JyhChien,
Cheng Stephen Z. D.
Publication year - 1997
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19971220107
Subject(s) - materials science , polymer , casting , monomer , substrate (aquarium) , polymerization , high refractive index polymer , polymer chemistry , solvent , ether , microelectronics , refractive index , biphenyl , liquid crystal , composite material , chemical engineering , organic chemistry , optoelectronics , chemistry , oceanography , engineering , geology
A novel class of organo‐soluble polyimides has been developed based on monomers containing twisted‐biphenyl structures. Thus, 2, 2'‐disubstituted‐4, 4'‐diaminobiphenyls and 2, 2'‐disubstituted‐4, 4', 5, 5'‐biphenyltetracarboxylic dianhydrides have been prepared and polymerized in refluxing phenolic solvents. The polyimides, some of which are soluble in ketone and ether solvents, can be readily solution cast into colorless thin films. The rigid polymer chains align parallel to the substrate surface (in‐plane orientation) during the casting process, which results in anisotropy in the film properties. The anisotropy in the refractive index has been used in the development of compensation layers for liquid crystal displays. The polymers have also been dry jet‐wet spun from phenolic solutions to afford fibers that display tensile strengths of 3.5 GPa and moduli of 130 GPa.