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 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 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 novel aromatic polyamides from 3,4-bis(4-aminophenyl)-2,5-diphenylfuran and aromatic diacid chlorides

A new highly phenylated heterocyclic diamine, 3,4-bis(4-aminophenyl)-2,5-diphenylfuran, was synthesized in three steps from 4–-nitrodeoxybenzoin. The low temperature solution polycondensation of the diamine with various aromatic diacid chlorides afforded tetraphenylfuran-containing aromatic polyamides with inherent viscosities of 0.2–0.8 dL/g. Copolyterephthalamides were obtained from the diamine and 4,4′-oxydianiline. The polyamides were generally soluble in a wide range of solvents that included N,N-dimethylacetamide, N-methyl-2-pyrrolidone, pyridine, and m-cresol. Glass transition temperatures of the polyamides and copolyamides ranged from 302–342°C, and 10% weight loss was observed above 480°C in nitrogen.     

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 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 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 characterization of aromatic polyesteres and polyamide–esters from bisphenols and aromatic aminophenols,and 2,5-bis(4-chloroformyl)-3,4-diphenylthiophene

Polycondensation of 2,5-bis(4-chloroformyl)-3,4-diphenylthiophene ( I ) with various bisphenols afforded tetraphenylthiophene-containing aromatic polyesters by the interfacial or solution polycondensation method. Polyamide–esters were obtained from I and aminophenols by means of the interfacial technique. These polymers had inherent viscosities of 0.4–0.8 dL/g. All the polymers were readily soluble in various organic solvents, and could be cast into transparent and flexible films. Their glass transition temperatures were in the range of 235–335°C. These polymers did not lose weight below 400°C in either air or nitrogen.     

Bismaleimides and bisnadimides derived from 2,5-bis(4-aminophenyl)-3,4-diphenylthiophene and their polymerization to heat-resistant matrix resins

Six new structurally different bismaleimides or bisnadimides based on 2,5-bis(4-aminophenyl)-3,4-diphenylthiophene (BADT) were synthesized and characterized by infrared (IR) and proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Chain-extension of several bismaleimides was accomplished by incorporating various imide, amide, and urea groups. The bismaleimide and bisnadimide prepared by reacting BADT with maleic or nadic anhydride, respectively, were soluble in various organic solvents. The monomers were thermally polymerized or by a Michael reaction with certain aromatic diamines. Curing behavior was investigated by differential thermal analysis (DTA). The thermal and thermo-oxidative stability of polymers was evaluated by dynamic thermogravimetric analysis (TGA) and isothermal gravimetric analysis (IGA). The polymers derived from bismaleimide of BADT as well as from the bismaleimides chain-extended by imide groups were stable up to 355–392°C in N₂ or air and afforded anaerobic char yield 66–74% at 800°C. The polymers obtained by curing the bismaleimide-diamine adducts showed a relatively lower thermal stability.     

Synthesis and characterization of new soluble aromatic polyimides from diaminotetraphenylimidazolinone and aromatic tetracarboxylic dianhydrides

A series of new soluble aromatic polyimides with inherent viscosities of 0.65–1.12 dL/g were synthesized from 1,3-bis(4-aminophenyl)-4,5-diphenylimidazolin-2-one and various aromatic tetracarboxylic dianhydrides by the conventional two-step procedure that included ring-opening polyaddition and subsequent thermal cyclodehydration. These polyimides could also be prepared by the one-pot procedure in homogeneous m-cresol solution. Most of the tetraphenyl-pendant polyimides were soluble in organic solvents such as N,N-dimethylacetamide, 1,3-dimethyl-2-imidazolidone, and m-cresol. Some polyimides gave transparent, flexible, and tough films with good tensile properties. The glass transition temperatures and 10% weight loss temperatures under nitrogen of the polyimides were in the range of 287–326 and 520–580°C, respectively. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1767–1772, 1998     

Synthesis and properties of polyimides derived from 1,6-bis(4-aminophenoxy)naphthalene and aromatic tetracarboxylic dianhydrides

1,6-Bis(4-aminophenoxy)naphthalene ( I ) was used as a monomer with various aromatic tetracarboxylic dianhydrides to synthesize polyimides via a conventional two-stage procedure that included ring-opening polyaddition in a polar solvent such as N,N-dimethylacetamide (DMAc) to give poly(amic acid)s, followed by thermal cyclodehydration to polyimides. The diamine ( I ) was prepared through the nucleophilic displacement of 1,6-dihydroxynaphthal-ene with p-chloronitrobenzene in the presence of K₂CO₃, followed by catalytic reduction. Depending on the dianhydrides used, the poly(amic acid)s obtained had inherent viscosities of 0.73–2.31 dL/g. All the poly(amic acid)s could be solution cast and thermally converted into transparent, flexible, and tough polyimide films. The polyimide films had a tensile modulus range of 1.53–1.84 GPa, a tensile strength range of 95–126 MPa, and an elongation range at break of 9–16%. The polyimide derived from 4,4′-sulfonyldiphthalic anhydride (SDPA) had a better solubility than the other polyimides. These polyimides had glass transition temperatures between 248–286°C (DSC). Thermogravimetric analyses established that these polymers were fairly stable up to 500°C, and the 10% weight loss temperatures were recorded in the range of 549–595°C in nitrogen and 539–590°C in air atmosphere. © 1995 John Wiley & Sons, Inc.     

Synthesis and properties of polyimides derived from 1,7-bis(4-aminophenoxy)naphthalene and aromatic tetracarboxylic dianhydrides

The novel diamine, 1,7-bis(4-aminophenoxy)naphthalene (1,7-BAPON), was synthesized and used to prepared polyimides. 1,7-BAPON was synthesized through the nucleophilic displacement of 1,7-dihydroxynaphthalene with p-fluoronitrobenzene in the presence of K₂CO₃ followed by catalytic-reduction. Polyimides were prepared from 1,7-BAPON and various aromatic tetracarboxylic dianhydrides by the usual two-step procedure that included ring-opening polyaddition to give poly(amic acid)s, followed by cyclodehydration to polyimides. The poly(amic acid)s had inherent viscosities of 0.74-2.48 dL/g. Most of the polyimides formed tough, creasible films. These polyimides had glass transition temperatures between 247–278°C and their 10% weight loss temperatures were recorded in the range of 515–575°C in nitrogen atmosphere. © 1995 John Wiley & Sons, Inc.     

Polyimides from 1,5-bis(4-amino-2-trifluoromethylphenoxy)naphthalene and aromatic tetracarboxylic dianhydrides

A new trifluoromethylated bis(ether amine), 1,5-bis(4-amino-2-trifluoromethylphenoxy)naphthalene, was synthesized in two steps starting from 1,5-dihydroxynaphthalene and 2-chloro-5-nitrobenzotrifluoride via nucleophilic aromatic substitution and catalytic reduction. A series of novel fluorinated polyimides with moderate to high molecular weights were synthesized from the diamine with various aromatic tetracarboxylic dianhydrides using a conventional two-stage process. All polyimides could afford flexible and tough films and most of them were soluble in strong polar solvents such as N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc). The polyimides showed glass-transition temperatures (T_g) in the range of 253-315 °C (by DSC) and softening temperatures (T_s) in the range of 250-300 °C (by TMA). Decomposition temperatures for 5% weight loss all occurred above 500 °C in both air and nitrogen atmospheres. The dielectric constants of these polymers ranged from 3.17 to 3.64 at 1 MHz. The properties of these fluorinated polyimides were also compared with those of polyimides prepared from 1,5-bis(4-aminophenoxy)naphthalene with the same dianhydrides.     

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 properties of new polyimides derived from 1,5-bis(4-aminophenoxy)naphthalene and aromatic tetracarboxylic dianhydrides

Novel aromatic polyimides containing bis(phenoxy)naphthalene units were synthesized from 1,5-bis(4-aminophenoxy)naphthalene (APN) and various aromatic tetracarboxylic dianhydrides by the usual two-step procedure that included ring-opening polyaddition in a polar solvent such as N,N-dimethylacetamide (DMAc) to give poly(amic acid)s, followed by cyclodehydration to polyimides. The poly(amic acid)s had inherent viscosities between 0.72 and 1.94 dL/g, depending on the tetracarboxylic dianhydrides used. Excepting the polyimide IVb obtained from 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA), all other polyimides formed brown, flexible, and tough films by casting from the poly(amic acid) solutions. The polyimide synthesized from BPDA was characterized as semicrystalline, whereas the other polyimides showed amorphous patterns as shown by the x-ray diffraction studies. Tensile strength, initial moduli, and elongation at break of the APN-based polyimide films ranged from 105–135 MPa, 1.92–2.50 GPa, and 6–7%, respectively. These polyimides had glass transition temperatures between 228 and 317°C. Thermal analyses indicated that these polymers were fairly stable, and the 10% weight loss temperatures by TGA were recorded in the range of 543–574°C in nitrogen and 540–566°C in air atmosphere, respectively. © 1993 John Wiley & Sons, Inc.