Bis Trifluoromethyl Benzidine Research Articles

Novel rigid semi-alicyclic dianhydride with large side groups for high performance colorless polyimides (CPIs)

A new dianhydride 9,10-diphenyl-9,10-bis(trifluoromethyl)-9,10-dihydroanthracene-2,3,6,7-tetraacid dianhydride (6FDPDA) with rigid semi-alicyclic structure was reported. CPI materials were prepared by copolymerizing 6FDPDA with 3,3′,4,4′-biphenyl tetracarboxylic dianhydride (BPDA) or 4,4’-(hexafluoroisopropene) diphthalic anhydride (6FDA) respectively, with 2,2′-bistrifluoromethyl benzidine (TFDB) as the diamine building blocks. Due to the ladder semi-alicyclic structure as well as –CF3 and phenyl large side groups, this new dianhydride exhibits two important advantages, the cut-off conjugated in the polymer backbone and suppressed intermolecular stacking. When 6FDA as the dianhydride comonomer, the obtained CPIs exhibits distinguished performance with transmission of 90 % at 550 nm, YI of 2.45, CTE of 16.5 ppm/K and Tg over 450 °C. These results demonstrated that 6FDPDA is an excellent building block to prepare the high performance CPIs in optoelectronic devices, for an example the substrates for flexible AMOLED display.

Synthesis of a Novel Rigid Semi-Alicyclic Dianhydride and Its Copolymerized Transparent Polyimide Films' Properties.

A new series of colorless polyimides (CPIs) with outstanding thermal properties and mechanical properties were fabricated by the copolymerization of a novel dianhydride and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) with 2,2′-bistrifluoromethyl benzidine (TFDB). The novel dianhydride, 10-oxo-9-phenyl-9-(trifluoromethyl)-9,10-dihydroanthracene-2,3,6,7-tetraacid dianhydride (3FPODA), possessed a rigid semi-alicyclic structure, –CF3 and phenyl side groups, and an active carbonyl group. Benefitting from the special structure of 3FPODA, the glass transition temperatures (Tg) of the new CPIs improved from 330 °C to 377 °C, the coefficient of thermal expansion (CTE) decreased from 46 ppm/K to 24 ppm/K, and the tensile strength (TS), tensile modulus (TM), and elongation at break (EB) increased from 84 MPa to 136 MPa, 3.2 GPa to 4.4 GPa, and 2.94% to 4.13% with the increasing amount of 3FPODA, respectively. Moreover, the active carbonyl group of the 3FPODA could enhance the CPI’s adhesive properties. These results render the new dianhydride 3FPODA an ideal candidate monomer for the fabrication of high-performance CPIs.

Synthesis and Properties of Polyimide Silica Nanocomposite Film with High Transparent and Radiation Resistance.

In order to prepare flexible glass cover sheet materials suitable for space solar cells, fluorinated diamine 2,2’-bistrifluoromethyl benzidine (TFDB) and fluorinated dianhydride 4,4’ (hexafluoroisopropyl) diphthalic dianhydride (6FDA) as the monomer, polyimide (PI)/SiO2 composite film was synthesized by in situ polymerization, and the influence of coupling agent and SiO2 nanoparticle content on the film structure and properties was studied. The results show that PI synthesized from fluorine-containing monomers has better light transmittance, and the highest transmittance can reach 91.4%. The average visible light transmittance of the composite film decreases with the increase of SiO2 content, and the transmittance of the film decreases less in the high-wavelength region and greatly decreases in the low-wavelength region. The tensile strength and elastic modulus of PI/SiO2 composite film increase with the increase of SiO2 content, first increase and then decrease, reaching the maximum when the content is 10%; while the elongation at break of the composite film gradually increases with the increase of SiO2 content reduce. The thermal stability of PI/SiO2 composite film increases with the increase of SiO2 content. The doping of nano-SiO2 significantly suppresses the influence of irradiation on the mechanical properties of the film.

Facile Fabrication of Polymer Waveguide by Using Photosensitive Polyimides

New soluble photosensitive poly(amide- co -imide) containing p -phenylenediacryloyl moiety was synthesized and its photoreactivity was characterized by UV-Vis spectroscopic methods. The copolymer was synthesized from p-phenylenediacryloyl chloride, bis(3,4-dicarboxyliphenyl)hexafluoropropane dianhydride (6FDA) and two equivalents of 2,2'-bis(trifluoromethyl)benzidine (BTBz) followed by chemical imidization. From the refractive index measurement by prism coupling method, it was found that the refractive index could be varied precisely with respect to the exposure time. Fabrication of passive waveguide was attempted by the photo-modulation of refractive index. Straight waveguide was easily fabricated and the single mode near-field pattern was observed by using 1.55 and 1.3 µm near-IR light.

Facile Fabrication of Polymer Waveguide by Using Photosensitive Polyimides

New soluble photosensitive poly(amide-co-imide) containing p-phenylenediacryloyl moiety was synthesized and its pholoreaclivity was characterized by UV-Vis spectroscopic methods. The copolymer was synthesized from p-phcnylenediacryloyl chloride, bis(3,4-dicarboxyliphenyl)hexafluoropropane dianhydride (6FDA) and two equivalents of 2,2'-bis(trifluoromethyl)benzidine (BTBz) followed by chemical imidization. From the refractive index measurement by prism coupling method, it was found that the refractive index could be varied precisely with respect to the exposure time. Fabrication of passive waveguide was attempted by the photo-modulation of refractive index. Straight waveguide was easily fabricated and the single mode near-field pattern was observed by using 1.55 and 1.3 μm near-IR light.

Measurement of Refractive Index and Thickness of Fluorinated Copolyimide Films by Spectroscopic Reflectometry

Various fluorinated copolyimide films were prepared on a Si wafer from copoly(amic acid) solution of pyromellitic dianhydride (PMDA) or bis(3,4-dicarboxyliphenyl)hexafluoropropane dianhydride (6FDA) and a diamine mixture of 4,4′-oxydianiline (ODA) and 2,2′-bis-(trifluoromethyl)benzidine (BTBz). Refractive index and thickness of polyimide films were measured by means of spectral reflectance measurement. A gradual increase of the refractive, index was observed in the course of imidization for PMDA series polyimides and almost no change or a slight decrease for 6FDA series polyimides. Film thickness decreased about 30% after imidization. The refractive indices of final polyimides depended on the fluorine content as well as the structure of the copolyimide.

Rigid-Rod Polyimides Based on Noncoplanar 4,4‘-Biphenyldiamines: A Review of Polymer Properties vs Configuration of Diamines

X-ray crystal structures of three substituted 4,4‘-biphenyldiamines, namely, 2,2‘,6,6‘-tetramethylbenzidine (TMBZ), 2,2‘-dimethylbenzidine (DMBZ) and 2,2‘-bis(trifluoromethyl)benzidine (BFBZ), were determined. The torsional angles between the two phenyl rings for TMBZ, DMBZ, and BFBZ are φ = 83°, 75°, and 59°, respectively. A structure−property relationship between the three-dimensional configuration of diamine monomers and the corresponding polyimides is discussed.