title: Colorless and transparent copolyimide nanocomposites.
abstract: Copolyimides (Co-PIs) were synthesized from 2,2'-bis(trifluoromethyl) benzidine (TFB) and different ratios of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and pyromellitic dianhydride (PMDA). The Co-PI films were obtained from poly(amic acid) (PAA) by solution-casting through typical chemical and thermal imidizations. The thermal properties and optical transparency of the Co-PI films with various PMDA monomer contents were investigated. It was found that with increasing PMDA content, the thermal transition temperatures of the Co-PI films increased. Co-PI nanocomposites were prepared with various amounts of organically modified hectorite (STN) on a TFB:6FDA:PMDA = 1.0:0.9:0.1 mole ratio Co-PI hybrid film to examine the thermal properties, morphology, and optical transparency. The thermo-optical properties of the Co-PI hybrid films deteriorated with increasing clay content. However, the coefficient of thermal expansion (CTE) and oxygen barrier properties of the PI hybrid films improved with increasing clay content.
authors.forename: Hye-Jin
authors.initials: HJ
authors.lastname: Bae
authors.forename: Yong Seok
authors.initials: YS
authors.lastname: Kim
authors.forename: Jin-Hae
authors.initials: JH
authors.lastname: Chang
mesh_terms: D003116:Color; D007094:Imides / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry
chemical_list: D007094:Imides