International audienceNew soluble polyimides were prepared from a series of diamines and a tetracarboxylic dianhydride with a benzhydrol unit, 3,3‘,4,4‘-benzhydrol tetracarboxylic dianhydride (BHTDA), by one-step method polymerization. The diamines containing flexible units, bulky substituents, and/or noncoplanar conformation unit were prepared by the reaction of the corresponding bisphenol precursors and p-chloronitrobenzene, followed by catalytic reduction of the dinitro compounds. The polyimides obtained were soluble in various solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, pyridine, γ-butyrolactone, m-cresol, and even tetrahydrofuran except for polymer PId. The polymers were amorphous and had number-average molecular weight (n) in the range (3.0−10.2) × 104. The glass transition temperatures (Tg) of the polymers ranged from 268 to 341 °C. These polymers exhibited good thermal stability without significant weight loss up to 420 °C. The temperatures at 10% weight loss range from 457 to 524 °C in nitrogen and 449 to 519 °C in air, respectively. The polyimide films were found to be transparent, flexible, and tough. The films had a tensile strength range 72−105 MPa, an elongation range at break of 4−7%, and a Young's modulus range of 2.18−2.85 GP

A new diamine, bis[4-(4-aminophenoxy)phenyl]diphenylmethane (BAPDM), bearing diphenylmethylene linkage was prepared starting from bis(4-hydroxyphenyl)diphenylmethane. The diamine was reacted with various aromatic dicarboxylic acids to obtain a series of new polyamides with moderate to high inherent viscosities of 0.65−0.97 dL g-1. Almost all of the polymers could be readily dissolved in NMP, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, m-cresol, pyridine, tetrahydrofuran, and cyclohexanone. All of the polymers were amorphous, and the polyamide films had a tensile strength range of 85−108 MPa. These polyamides had glass transition temperatures between 237 and 272 °C and 10% weight loss temperatures in the range 500−524 °C in nitrogen.

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1, 4‐Bis(4‐aminophenoxy)‐2‐tert‐butylbenzene was synthesized and used as a monomer to prepare a series of polyamides by the direct polycondensation with various aromatic dicarboxylic acids in N‐methyl‐2‐pyrrolidone using triphenyl phosphite and pyridine as condensing agents. All the polymers were obtained in quantitative yields with inherent viscosities of 0.75–1.75 dL g−1. All the polyamides showed amorphous nature and most of them were soluble in polar solvents. Polyamides derived from 4, 4'‐sulfonyldibenzoic acid and 4, 4'‐hexafluoroisopropylidenedibenzoic acid were even soluble in common organic solvent such as THF. All polyamide films could be obtained by casting from their DMAc or NMP solutions. The polyamide films had a tensile strength range of 35–84 MPa, an elongation range at break of 3–7%, and a tensile modulus range of 1.2–2.5 GPa. These polyamides had glass transition temperatures between 203–268°C and 10% mass loss temperatures were recorded in the range of 456–472°C in nitrogen and 453–470°C in air atmosphere.