Design and synthesis of high heat-resistant, soluble, and hydrophobic fluorinated polyimides containing pyridine and trifluoromethylthiophenyl units

Abstract

In this study, a novel diamine monomer, 4-(4-trifluoromethylthiophenyl)-2,6-bis(4-aminophenyl)pyridine (FTPAP) was synthesized through two-step reaction from 4-trifluoromethylthiobenzaldehyde and 4-nitroacetophenone as raw materials, and then the structure of FTPAP was characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance, and mass spectrometry. A series of fluorinated polyimides were prepared from FTPAP with five commercial dianhydrides, namely, pyromellitic dianhydride, biphenyl tetracarboxylic dianhydride, oxydiphtahalic anhydride, benzophenone tetracarboxylic dianhydride, and 4,4′-(hexafluoroisopropylidene) diphthalic anhydride. The structure and performance of the fluorinated polymers were fully characterized by FTIR, differential scanning calorimetry, thermogravimetric analysis, and wide-angle X-ray diffraction (WAXD). The inherent viscosity of polymers ranged from 0.41 to 1.45 dL g−1. These polymers displayed good solubility in polar aprotic solvents, such as N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone, at room temperature or on heating. Furthermore, they exhibited outstanding thermal stability with glass transition temperatures beyond 305°C, and the temperature of 10% weight loss was in the range of 514–573°C with more than 56% residue at 800°C under nitrogen. Moreover, they showed high optical transparency with the cutoff wavelengths in the range of 385–457 nm and excellent hydrophobic property with contact angle in the range of 82.8–97.6°. In addition, the results of WAXD indicated that all of the polymers presented amorphous structure.

Effect of surface‐modified nano‐aluminum trihydroxide on electrical properties of silicone/nano‐silica nanocomposite

“…Therefore, in order to use it as an HVDC insulation material, its durability should be fundamentally improved. In order to improve the tracking resistance of a polymeric insulation material, hydrophobicity of the polymer surface should be modified and aluminum trihydroxide (ATH) particles are incorporated into the insulating material 15–17 . When the former condition is satisfied, moisture penetration is prevented due to the water repellency of the surface and the local distortion of electric field is prevented by suppressing the accumulation of contaminants, thereby improving tracking resistance.…”

Synthesis and characterization of new poly(diketone imide)s derived from 1,4-bis(3,4-dicarboxybenzoyl)benzene dianhydride and various diamines

“…One of the successful approaches to improve their solubility and processability is the introduction of flexible groups, such as O, S, SO 2 , CH 2 , (CH 3 ) 2 C, and (CF 3 ) 2 C moieties into the polymer backbone. [5][6][7][8][9][10][11][12][13][14][15][16][17][18] It is also recognized that ketone links inserted in the polyimide backbone could improve their solubility and mold ability, and various poly(ketone imide)s have been developed from the dianhydride or the diamine component containing ketone moieties. [19][20][21][22][23][24][25][26][27] In addition, several poly(diketone imide)s (PDKIs) using the dianhydride [28][29][30][31][32] or diamine [33][34][35][36][37][38] monomers containing diketone groups were also investigated.…”

New transparent and thermally stable cardo poly(ether imide)s derived from 10,10-bis[4-(4-amino-2-pyridinoxy)phenyl]-9(10H)-anthrone

“…5 –8 However, the intensive coloration of the PIs, owing to electronic conjugation and the formation of inter- and intramolecular charge transfer complexes (CTCs), limits their applications in optical and optoelectronic fields. Therefore, many efforts have been made to obtain highly transparent PIs through various strategies, including introduction of fluorine atoms, 9 –11 bulky substituents, 12 –14 alicyclic units, 15 –17 asymmetry, and noncoplanar structures 18,19 into polymer backbones. These structural modifications could loosen the chain packing, disrupt the conjugation, and inhibit the formation of CTC, leading to colorless PIs.…”