High Glass Transitions of New Polyamides, Polyimides, and Poly(amide−imide)s Containing a Triphenylamine Group:  Synthesis and Characterization

Abstract

A new triphenylamine-containing diamine monomer, 4,4′-diamino-3′′,4′′-dimethyltriphenylamine (DADT), was successfully synthesized by the cesium fluoride-mediated condensation of 3,4dimethylaniline with 4-fluoronitrobenzene, followed by reduction. The monomer was reacted with various aromatic dicarboxylic acids and tetracarboxylic dianhydrides to produce a series of novel polyamides and polyimides, respectively. A new triphenylamine-containing dicarboxylic acid monomer, 4,4′-trimellitimido-3′′,4′′-dimethyltriphenylamine (TDT), was successfully synthesized by refluxing the diamine, DADT, with trimellitic anhydride in glacial acetic anhydride. A series of new poly(amide-imide)s were prepared from TDT with various diamines by the direct polycondensation. The polymers were obtained in quantitative yields with inherent viscosities of 0.61-2.28 dL g -1 . Most of the polymers dissolved in N-methyl-2pyrrolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, pyridine, and cyclohexanone. These polymers, especially poly(amide-imide)s, showed high glass transition temperatures between 254 and 326 °C. These polymers were fairly stable up to a temperature around or above 400 °C and lost 10% weight in the range of 430-566 and 462-574 °C in nitrogen and air, respectively. These tough and flexible polymer films had a tensile strength of 82-145 MPa, an elongation at break of 5-11%, and a tensile modulus of 1.7-3.3 GPa. The UV-vis absorption spectra revealed that most of the polymers had absorption maxima around 303 nm. Cyclic voltammograms of the polyamides, polyimides, and poly-(amide-imide)s showed an oxidation wave with a peak around 0.9, 1.1, and 1.3 V, respectively.

Organosoluble, thermally stable and low dielectric constant fluorinated polyimides containing 2,4,5-triphenylimidazole moiety in the main chains

“…As expected, C-F multiple stretching absorptions were also measured at 1250 and 1145 cm À1 , respectively. Figure 1 shows a representative 1 H NMR spectrum of the fluorinated aromatic polyimide (PIEI-c) in DMSO-d 6 , in which it can be seen that all of the aromatic protons appeared in the region of 6.70-8.40 ppm and of the N-H protons of imidazol ring at 13.50 ppm.…”

“…In order to meet these requirements, structural modifications of these polymers often become essential. Therefore, considerable efforts have been made in recent years to develop highly optical transparent, low dielectric constant, and low refractive index aromatic polyimides with good processability by the incorporation of flexible linkages, [4,5] bulky pendant groups [6][7][8], and noncoplanar biphenylene moieties [9,10] into the polymer backbones. It has been observed that introduction of fluorinated substituents can impart many of these desirable properties to the polymers, making them suitable for a much wider range of applications.…”

Synthesis, characterization of pyridine-based polyimides and their use as glucose oxidase immobilization media

“…FTIR spectra of PI showed characteristic imide bands at 1780 and 1716 cm -1 (C=O stretching), 1355 cm -1 (C-N stretching), 832 and 716 cm -1 (C=O asymmetric stretching). An absorption at 1440-1660 cm -1 corresponding to the schiff base group (-CH=N-) is observed [8][9][10]. The thermal properties of the polyimides were evaluated by differential scanning calorimetry (DSC) ( Figure 4.…”

“…Polyimides have been especially used widely in microelectronic, film, adhesive and membrane industry [3][4][5][6][7] due to these prior properties. Recently significant synthetic effort has been centered on improving processability and solubility through the synthesis of new diamine or dianhydride monomers [8][9][10]. In recent years, many polymers including conducting and nonconducting ones have been widely used for immobilization of enzymes at electrode surface [11][12][13][14][15][16][17].…”

Synthesis and Characterization of Highly Organosoluble Polyimides Based on a New Asymmetric Dianhydride

“…Therefore, much research effort has been concentrated on design and preparation of organosoluble polyimides without deterioration of their attractive properties. Some of the approaches to soluble polyimides are introduction of flexible linkages [4,5], bulky lateral substituents [6][7][8][9][10][11][12], noncoplanar [13][14][15][16][17][18][19], kinked [20][21][22][23][24][25] or alicyclic structures [26][27][28][29][30]. Among them, introduction of 2,2 -disubstituted twisted biphenyl structures into polyimide backbones was considered as one of the successful approaches.…”