Synthesis and characterization of novel aromatic polyamides from 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole and aromatic diacid chlorides

A new polymer-forming monomer, 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole, was synthesized in three steps starting from 4′-nitrodeoxybenzoin. Tetraphenylpyrrole-containing aromatic polyamides and copolyamides were prepared from the diamine with various aromatic diacid chlorides and from a mixture of the diamine and 4,4′-oxydianiline with terephthaloyl chloride, respectively. The resultant polymers had inherent viscosities in the 0.3–1.8 dL/g range and were generally soluble in various organic solvents including N,N-dimethylacetamide and m-cresol. They have glass transition temperatures in the range of 306–333°C and showed no weight loss below 380°C in both air and nitrogen atmospheres.     

Synthesis and characterization of novel polyarylates from 2,5-bis(4-hydroxyphenyl)-3,4-diphenylfuran and aromatic diacid chlorides

New tetraphenylated heterocyclic diol, 2,5-bis(4-hydroxyphenyl)-3,4-diphenylfuran, was synthesized by the oxidative coupling of 4-methoxydeoxybenzoin as a starting material, followed by simultaneous cyclodehydration and demethylation. Tetraphenylfuran-containing polyarylates with inherent viscosities of 0.2–0.7 dL/g were prepared from various diacid chlorides by both solution polycondensation and phase transfer catalyzed two-phase polymerization methods. All the polymers were easily soluble in dichloromethane, o-chlorophenol, 1,4-dioxane, pyridine, and N-methyl-2-pyrrolidone and showed semicrystalline patterns as evidenced by the X-ray diffraction studies. These polyarylates have glass transition temperatures in the range of 222–236°C and 10% weight loss was observed above 430°C in both air and nitrogen.     

Synthesis and characterization of soluble aromatic polyamides from 2,5-bis(4-aminophenyl)—3,4-diphenylthiophene and aromatic diacid chlorides

New soluble aromatic polyamides with inherent viscosities of 1.0–1.7 dL/g were prepared by the low temperature solution polycondensation of 2,5-bis(4-aminophenyl)—3,4-diphenylthiophene, bis(4-aminophenyl) ether, and aromatic diacid chlorides in N,N-dimethylacetamide. The polyamides and copolyamides are generally soluble in amide-type solvents. They have glass transition temperatures in the range of 280–325°C and showed no weight loss below 390°C on thermogravimetry curves in both air and nitrogen atmospheres.     

Synthesis and characterization of aromatic polyamides from 1,1-bis(4-aminophenyl)-2,2-diphenylethylene and aromatic diacid chlorides

Novel, soluble aromatic polyamides and copolyamides containing tetraphenylethylene units were prepared by the low temperature solution polycondensation of 1,1-bis(4-aminophenyl)-2,2-diphenylethylene and aromatic diamines with various aromatic diacid chlorides. Highmolecular-weight polyamides having inherent viscosities of 0.6–1.5 dL/g and number-average molecular weight above 21000 were obtained quantitatively. These polymers were readily soluble in various solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide (DMAc), and dimethyl sulfoxide and gave pale yellow, transparent, flexible films by casting from DMAc solution. The polymers had glass transition temperatures between 290 and 340°C, and started to lose weight around 400°C, with 10% weight loss being recorded at about 470°C in air.     

Synthesis and characterization of new soluble aromatic polyimides from 3,4-bis (4-aminophenyl)-2,5-diphenylfuran and aromatic tetracarboxylic dianhydrides

New soluble polyimides with inherent viscosities of 0.2–0.6 dL/g were synthesized from 3,4-bis (4-aminophenyl)-2,5-diphenylfuran and various aromatic tetracarboxylic dianhydrides by the conventional two-step method which involved ring-opening polyaddition and subsequent cyclodehydration. Almost all of the polymides were generally soluble in a wide range of organic solvents such as N,N-dimethylacetamide, 1,3-dimethyl-2-imidazolidone, m-cresol, o-chlorophenol, and pyridine. The polyimide prepared from pyromellitic dianhydride was crystalline, whereas the other polyimides were amorphous. All the polyimides have glass transition temperatures in the range of 281–344°C and showed no appreciable weight loss up to 410°C in both air and nitrogen atmospheres.     

Synthesis and characterization of soluble aromatic polyazomethines from 2,5-bis(4-aminophenyl)-3,4-diphenylthiophene and aromatic dialdehydes

New soluble aromatic polyazomethines with inherent viscosities of 0.4–0.8 dL/g were prepared by the solution polycondensation of 2,5-bis(4-aminophenyl)-3,4-diphenylthiophene, bis(4-aminophenyl) ether, and aromatic dialdehydes in o-chlorophenol at 20°C. The copolyazomethines are generally soluble in chlorinated hydrocarbons, amide-type or phenolic solvents. The thermal stability of the polymers, which showed no weight loss up to 400°C in both air and nitrogen atmospheres.     

Synthesis and characterization of new soluble aromatic polyimides from 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole and aromatic tetracarboxylic dianhydrides

Novel aromatic polyimides containing tetraphenylpyrrole unit were synthesized from 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole and various aromatic tetracarboxylic dianhydrides by the usual two-step procedure that included ring-opening polyaddition and subsequent thermal cyclodehydration. These polymers had inherent viscosities in the 0.20–0.65 dL/g range and were practically amorphous as shown by the X-ray diffraction studies. All the polyimides except for polypyromellitimide were easily soluble in a wide range of organic solvents such as o-chlorophenol, pyridine, 1,3-dimethyl-2-imidazolidone, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone at room temperature. These polyimides had high glass transition temperatures of 302–359°C and exhibited 10% weight loss at temperatures above 510°C in nitrogen.     

Synthesis and characterization of soluble polymides from 2,5-bis(4-aminophenyl)-3,4-diphenylthiophene and aromatic tetracarboxylic dianhydrides

2,5-Bis(4-aminophenyl)-3,4-diphenylthiophene, a polyimide-forming monomer, was prepared in three steps starting from benzyl chloride and sulfur. Novel polyimides were synthesized from the diamine and pyromellitic dianhydride or 3,3′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA). Polymerization was carried out either by the usual two-step procedure that included ring-opening polyaddition giving polyamic acids, followed by cyclodehydration to polyimides, or by the direct one-pot procedure involving cyclodehydration in situ. The polyimide derived from the diamine and BTDA, especially that prepared by the one-pot procedure in m-cresol containing isoquinoline, is soluble in various organic solvents and gave a yellow, transparent, tough, and flexible film. Solubility of this polyimide varied by the preparative method and by the copolymerization with bis(4-aminophenyl) ether. All the polyimides are highly thermally stable and exhibited no appreciable decomposition up to 450°C in air and nitrogen atmospheres.     

Synthesis and characterization of N-phenylated aromatic polyamides from N-silylated dianilino compounds and aromatic diacid chlorides

N-Phenylated aromatic polyamides of high molecular weights were synthesized by the hightemperature solution polycondensation of N,N′ -di(trimethylsilyl)-substituted dianilino compounds derived from p-dianilinobenzene, bis(4-anllinophenyl) ether, and α,α′-dianilino-p-xylene, with isophthaloyl and terephthaloyl chloride. Almost all of the N-phenylated polyamides were amorphous, and soluble in a variety of organic solvents including dimethylformamide, m-cresol, and chloroform. Transparent and flexible films of these polymers could be cast from the dimethylformamide solutions. Four wholly aromatic polyamides had glass transition temperatures in the range of 195–255°C, and began to lose weight around 400°C in air.     

Synthesis and characterization of novel polyarylates from 2,5-bis(4-hydroxyphenyl)-3,4-diphenylpyrrole and various aromatic dicarboxylic acids

A new tetraphenylated heterocylic diol, 2,5-bis(4-hydroxyphenyl)-3,4-diphenylpyrrole, was synthesized in three steps starting from 4-methoxydeoxybenzoin. The tetraphenylpyrrole-containing polyarylates having inherent viscosities of 0.28–0.88 dL/g were prepared from the diol and various aromatic dicarboxylic acid chlorides by both phase transfer catalyzed two-phase polycondensation and high temperature solution polymerization methods. All the polyarylates were semi-crystalline, and were readily soluble in a variety of solvents including N-methyl-2-pyrrolidone, m cresol, pyridine, and 1,4-dioxane. These polymers had glass transition temperatures in the range of 223–279°C, with no weight loss below 400°C in both air and nitrogen atmospheres. © 1994 John Wiley & Sons, Inc.     

Synthesis and characterization of silicon-containing polyamides from aromatic sulfone ether diamines and aromatic organosilicon diacid chlorides

New polymides and copolyamides containing silicon and sulfone ether linkages, soluble in common aprotic solvents and having inherent viscosities of 0.3–0.6 dL/g have been synthesized by solution condensation of bis-(4-chlorocarbonyl phenyl) dimethylsilance (DMSC) and/or bis-(4-chlorocarbonyl phenyl) diphenylsilance (DPSC) with 4,4′-[sulfonylbis-(4,1-phenylenoxy)] bisbenzenamine, 3,3′-[sulfonylbis (4,1-phenyleneoxy)] bisbenzenamine, and bis (4-aminophenyl) ether. These polymers were characterized by infrared spectra, solution viscosity, thermooxidative degradation, differential scanning calorimetry, and x-ray diffraction. These polymers show good thermal stability.     

Synthesis and characterization of aromatic polyimide and polyamide-imide from 2,5-bis(4-isocyanatophenyl)-3,4-diphenylthiophene and aromatic tetra- and tricarboxylic acids

Soluble polyimide having an inherent viscosity up to 1.4 dL/g was synthesized by the high-temperature solution polycondensation of 2,5-bis(4-isocyanatophenyl)-3,4-diphenylthiophene with 3,3′,4,4′-benzophenonetetracarboxylic dianhydride. The polycondensation of the tetraphenylthiophene diisocyanate with trimellitic anhydride afforded polyamide-imide with an inherent viscosity up to 0.9 dL/g. These polymers showed limited solubility in organic solvents and had glass transition temperatures around 320°C.     

Synthesis and characterization of new soluble polyamides derived from 2,6-bis(4-aminophenyl)-3,5-dimethyltetrahydro-4H-pyran-4-one

A new oxypyrone diamine, 2,6-bis(4-aminophenyl)-3,5-dimethyltetrahydro-4H-pyran-4-one (DAPP), was prepared from 4-nitrobenzaldehyde and 3-oxa-n-pentane in a two-step reaction with a high yield and a high purity. Aromatic polyamides were obtained from this novel condensation monomer and several diacid chlorides through the conventional low-temperature solution method in N,N-dimethylacetamide. Polycondensation results were consistent with a high reactivity for DAPP because high yields and high molecular weight polyamides were obtained with inherent viscosities up to 1.8 dL/g. The reactivity of DAPP was also estimated with theoretical calculations from computer programs for molecular simulation, with orbital and charge factors considered. The polymers showed improved solubility in organic solvents, relative to conventional wholly aromatic polyamides, and high glass-transition temperatures (from differential scanning calorimetry) over 270 °C. However, the thermal resistance, as estimated by thermogravimetric analysis, was lower than that of conventional aromatic polyamides; nevertheless, decomposition temperatures well beyond 300 °C were observed in nitrogen and air. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1825–1832, 2001     

Synthesis and characterization of soluble polyamides based on 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane and 2,2-bis[4-(4-aminophenoxy)phenyl]propane and diacid chlorides

Aromatic soluble polyamides and copolyamides having hexafluoroisopropylidene and isopropylidene moieties in the molecular structure of polymer chain were prepared by reacting the aromatic diacid chlorides and fluorine or nonfluorine containing aromatic diamines using low-temperature polycondensation process. Polymers were produced with high yield and moderate to high inherent viscosity. All polyimides and copolyamides showed thermal stability above 440°C and glass transition temperature above 200°C. Some of the polyamides were cast into transparent bulk films which were further characterized by mechanical, x-ray, and water absorption analysis. Fluoro polyamides showed superior structural properties as compared to nonfluoro polyamides. © 1996 John Wiley & Sons, Inc.     

Synthesis and characterization of soluble aromatic polyamides derived from 2,5-bis-(4-chloroformylphenyl)—3,4-diphenylthiophene and aromatic diamines

A new polymer-forming monomer, 2,5-bis(4-carboxyphenyl)—3,4-diphenylthiophene, was synthesized either by the Friedel—Crafts reaction of tetraphenylthiophene with oxalyl chloride directly, or by the Friedel—Crafts acetylation of tetraphenylthiophene, followed by oxidation. The low temperature solution polycondensation of 2,5-bis(4-chloroformylphenyl)—3,4-diphenylthiophene with various aromatic diamines in N,N-dimethylacetamide (DMAc) afforded tetraphenylthiophene-containing aromatic polyamides with inherent viscosities of 0.5–1.0 dL/g. Copolyamides were obtained from a mixture of the diacid chloride and isophthaloyl or terephthaloyl chloride. Except for two polyamides, all the others were readily soluble in amidetype solvents including DMAc, and were cast into transparent and flexible films. These polymers had glass transition at around 300°C. Thermal stability of the polymers was evaluated by thermogravimetry which showed no weight loss below 390°C in both air and nitrogen atmospheres.     

Synthesis and properties of new polyamides derived from 1,4-bis(4-aminophenoxy)-2,5-di-tert-butylbenzene and aromatic dicarboxylic acids

The diamine 1,4-bis(4-aminophenoxy)-2,5-di-tert-butylbenzene, containing symmetric, bulky di-tert-butyl substituents and a flexible ether unit, was synthesized and used to prepare a series of polyamides by the direct polycondensation with various aromatic dicarboxylic acids in N-methyl-2-pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. All the polymers were obtained in quantitative yields with inherent viscosities of 0.32–1.27 dL g⁻¹. Most of these polyamides, except II _a , II _d , and II _e , showed an amorphous nature and dissolved in polar solvents and less polar solvents. Polyamides derived from 4,4′-sulfonyldibenzoic acid, 4,4′-(hexafluoro-isopropylidene)dibenzoic acid, and 5-nitroisophthalic acid were even soluble in a common organic solvent such as THF. Most polyamide films could be obtained by casting from their N,N-dimethylacetamide (DMAc) solutions. The polyamide films had a tensile strength range of 49–78 MPa, an elongation range at break of 3–5%, and a tensile modulus range of 1.57–2.01 GPa. These polyamides had glass transition temperatures ranging between 253 and 276°C, and 10% mass loss temperatures were recorded in the range 402–466°C in nitrogen atmosphere. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1069–1074, 1998     

Preparation and properties of disilane-containing photodegradable aromatic polyamides from bis(p-aminophenyl)tetramethyldisilane and aromatic diacid chlorides

1,2-Bis(p-aminophenyl)tetramethyldisilane was synthesized from 1,2-dichlorotetramethyldisilane and 4-[N,N-bis(trimethylsilyl)amino]phenyllithium. The diamine was reacted with various aromatic diacid chlorides giving disilane-containing aromatic polyamides (aramids), whose inherent viscosities were between 0.27 and 0.70 dL/g, depending on the diacid chlorides used. The aramids had glass transition temperatures between 194 and 255°C. No weight loss was observed below 350°C. Some of the polymers were found to be semicrystalline based on their x-ray diffractograms. The aramid films showed a strong ultraviolet (UV) absorption at 287 nm, which decreased during irradiation with UV light, suggesting that cleavage of the silicon-silicon bond in the aramid backbone occurs. A decrease in the inherent viscosity and molecular weight of the soluble aramid derived from phenylindanedicarbonyl chloride was also observed by irradiation with UV light.     

Novel two-step synthesis of polybenzothiazoles via precursor polyamides from 2,5-bis(isopropylthio)-1,4-phenylenediamine and aromatic dicarboxylic acid chlorides

A novel two-step method for the synthesis of polybenzothiazoles has been developed starting from 2,5-bis(isoprophylthio)-1,4-phenylenediamine and aromatic dicarboxylic acid chlorides. The low-temperature solution polycondensation of these monomer pairs in N-methyl-2-pyrrolidone afforded the aromatic polyamides with pendant isopropylthio groups having inherent viscosities in the range of 0.8 and 2.4 dL/g. The soluble precursor polyamides were subjected to thermal cyclization to the corresponding polybenzothiazoles along with the elimination of propylene and water. The resulting polymers were also characterized.