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A series of new fluorinated aromatic poly(ether imide)s (PEIs) were prepared from highly contorted 2,2′-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride and various trifluoromethyl-containing bis(ether amine)s via chemical or thermal imidization. All the PEIs showed good solubility in a variety of organic solvents and could afford flexible, colorless, and transparent thin films via solution-casting. They showed cut-off wavelengths of Uv-vis absorptions below 380 nm and very low yellowness index ( b* < 7.0). They also showed high thermal stability with the 10% weight loss temperature from 503 to 585 °C of in nitrogen or air atmosphere. The glass transition temperatures ( T s) are recorded in the range of 194-254 °C by DSC. For a comparative study, another series of non-fluorinated PEIs derived from the same biphenyl-2,2′-diol bis(ether anhydride) with various bis(ether amine)s without the trifluoromethyl substituents were also synthesized and characterized. [ABSTRACT FROM AUTHOR]

Two new aliphatic diamine monomers, one containing cyclohexane moiety and the other containing both cyclohexane and trifluoromethyl moieties, were synthesized. Two series of semi-aromatic polyimides (PIs) derived from the two diamines were prepared by one-step solution polycondensation using m-cresol as solvent. These PIs had inherent viscosities between 0.32 and 1.20 dL/g and could be processed to colorless, flexible and tough films. Compared with the PIs without trifluoromethyl group, the PIs with trifluoromethyl group showed better solubility in many solvents such as DMAc, NMP and m-cresol. It was also found that all the PI films had high optical transparency in the visible region with the cut-off wavelength of 291-379 nm. However, compared with the non-fluorinated PI 5 series, the PI 4 series showed lighter color. Furthermore, thermal analysis showed that the synthesized PIs had 5 % weight lost temperature ( T) in N of 372-425 °C, and the glass transition temperature ( T) of 221-270 °C. Moreover, all the PIs showed good mechanical properties with the tensile strengths of 80-114 MPa, tensile moduli of 2.7-3.5 GPa, and elongation at breaks of 5.1-26.5 %. [ABSTRACT FROM AUTHOR]

Three aromatic diamines, 2,2′-diiodo-4,4′-oxydianiline (DI-ODA 2), 2,2′-bis[ p-(trifluoromethyl)phenyl]-4,4′-oxydianiline (BTFP-ODA 3) and 2,8-diaminodibenzofuran (DADBF 5) were synthesized by using 4,4-oxydianiline (4,4′-ODA) as the starting material. New aromatic polyamides 6, 7 and 8 were prepared from these three diamines and six commercially available aromatic diacids by direct polycondensation, respectively. Polyamides 6 and 7 contained bulky iodide and p-trifluoromethylphenyl substitutents that would hinder the chain packing and increase the free volume. They exhibited good optical transparency in visible light region and showed excellent solubility in organic solvents such as DMSO, DMAc, DMF and NMP. Polyamides 8 containing planar dibenzofuran moieties had the highest glass transition temperatures and decomposition temperatures among these polyamides. Polyamides 6 had the lowest decomposition temperatures due to the presence of weak carbon-iodine bond. All of these polyamides showed amorphous nature evidenced by wide angle X-ray diffraction. No endothermic peaks were observed from DSC thermograms up to their decomposition temperatures. High optical transparency and excellent solubility combined with good thermal stability make these polyamides attractive for potential soft electronics applications. [ABSTRACT FROM AUTHOR]