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Heat‐resistant polyimides with low CTE and water absorption through hydrogen bonding interactions
Author(s) -
Chen Haiquan,
Dai Fengna,
Hu Mengjie,
Chen Chunhai,
Qian Guangtao,
Yu Youhai
Publication year - 2021
Publication title -
journal of polymer science
Language(s) - English
Resource type - Journals
eISSN - 2642-4169
pISSN - 2642-4150
DOI - 10.1002/pol.20210305
Subject(s) - bpda , diamine , polyimide , materials science , benzimidazole , polymer chemistry , absorption of water , hydrogen bond , siloxane , ether , intramolecular force , condensation polymer , adsorption , chemical engineering , nuclear chemistry , chemistry , organic chemistry , polymer , composite material , molecule , layer (electronics) , engineering
A novel diamine, 1 H ,1′ H ‐(2,2′‐bibenzimidazole)‐5,5′‐diamine (DPABZ), containing bisbenzimidazole unit was successfully synthesized, and used to prepare a series of copolyimides BPDA:(ODA m /DPABZ n ) by polycondensation with 4,4‐diaminodiphenyl ether (ODA) and 4,4‐biphthalic anhydride (BPDA). For comparison, a series of copolyimides BPDA:(ODA m /PABZ n ) based on another benzimidazole diamine 5‐amino‐2‐(4‐aminobenzene)‐benzimidazole (PABZ) was also prepared. As a result, with the increase of PABZ or DPABZ content, the heat resistance ( T g and T d ) and mechanical properties ( σ and E ) of the resulting polyimide (PI) films increased, while the coefficient of thermal expansion (CTE) decreased. Overall, the DPABZ‐based PIs showed higher T g values and much lower CTE values than PABZ. As the content of PABZ increased, the water absorption of PABZ‐based PIs increased obviously, but no significant change in DPABZ‐based PIs. The intramolecular hydrogen bonding in DPABZ‐based PIs caused by the diamine DPABZ was believed to be the reason for the aforementioned differences. The BPDA: DPABZ film with low‐water adsorption of 2.1%, high‐ T g value of 436°C and low‐CTE value of 5.4 ppm /°C could be a promising new generation of flexible display substrates.