Synthesis and characterization of polyimides containing heterocyclic units

Five new polyimides containing phenoxaphosphine as well as dibenzothiophene, phenoxathiin, and thianthrene units have been synthesized from 10-phenylphenoxaphosphine-2,3,7,8-tetracarboxylic dianhydride-10-oxide and heterocyclic diamines by the cyclopolycondensation method. These polyimides had inherent viscosities in the 0.75–1.10 dL/g range in conc. H₂SO₄ at 30°C. All the polymers were characterized by elemental analysis, density, solubility, crystallinity, IR spectra, and thermal methods.     

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.     

Preparation and properties of polyamides containing p-terphenyl units

Novel polyamides that contained p-terphenyl units were prepared with inherent viscosities in the range of 0.4–1.7 dL/g by the polycondensation of 4,4″-dichloroformyl-p-terphenyl with aromatic diamines and 4,4″-diamino-p-terphenyl with aromatic dicarbonyl chlorides. Polyamides composed of only paraoriented phenylene units were insoluble in all solvents and showed a high degree of crystallinity. A series of polyamides that contained p-terphenyl units were more thermostable than corresponding polymers with p-phenylene or biphenylene linkages.     

Preparation and properties of fluorine-containing aromatic polyamides from tetrafluorophthaloyl chlorides and aromatic diamines

New fluorine-containing aromatic polyamides with inherent viscosities of 0.4–1.8 dL/g were prepared by the low temperature solution polycondensation of tetrafluoroisophthaloyl and tetrafluoroterephthaloyl chlorides with N,N′-bis(trimethylsilyl)-substituted aromatic diamines. The aromatic polyperfluoroisophthalamides were amorphous polymers with glass transition temperatures around 280°C, whereas the polyperfluoroterephthalamides were crystalline. Most of these aromatic polyamides were soluble in organic solvents, and began to decompose around 330°C in air or nitrogen atmosphere.     

Synthesis and properties of polyimides derived from 9,10‐dialkyloxy‐1,2,3,4,5,6,7,8‐octahydro‐2,3,6,7‐anthracenetetracarboxylic 2,3:6,7‐dianhydrides

A series of new polyimides containing alicyclic units and alkyloxy side chains were prepared from 9,10‐dialkyloxy‐1,2,3,4,5,6,7,8‐octahydro‐2,3,6,7‐anthracenetetracarboxylic 2,3:6,7‐dianhydrides and various aromatic diamines. Their physical properties and structures were investigated. Polymers were obtained with inherent viscosities of 0.24–0.53 dL/g. In comparison with the aromatic polyimides, most polymers were readily soluble in common organic solvent such as N‐methylpyrrolidone and m‐cresol. These polymers had glass‐transition temperatures between 111 and 296 °C depending on the structure of the repeating unit and 10% weight‐loss temperatures of 418–477 °C in nitrogen. Wide‐angle X‐ray diffractometry for as‐polymerized samples revealed very low crystallinity and layered structures, which were better developed in the polymers with longer side chains. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1764–1774, 2002     

Synthesis of wholly aromatic polysulfonamides from aromatic disulfonyl chlorides and aromatic diamines

Wholly aromatic polysulfonamides of high molecular weight were prepared by the solution poly-condensation of aromatic disulfonyl chlorides with aromatic diamines in tetramethylene sulfone and substituted pyridines as the acid acceptor. Polysulfonamides with inherent viscosities as high as 1.2 were readily obtained by initiating polycondensation at a temperature of 5–10°C to control the side reactions. The polycondensation was fairly fast and was completed in 10 min at 60°C. All the aromatic polysulfonamides dissolved in a wide range of solvents, including acetone and tetrahydrofuran. These polymers were less thermally stable than the corresponding aromatic polyamides.     

Synthesis and characterization of random poly(amide-sulfonamide)s. II. Polymers from unsymmetrical diamine monomers

Novel poly(amide-sulfonamide)s have been prepared by reacting terephthalic, isophthalic, and sebacic acid and their acid chlorides with variously substituted diamines containing preformed sulfonamide linkages utilizing solution polymerization techniques. Inherent viscosities of the prepared polymers varied from 0.22 to 1.21 dL/g. Those having inherent viscosities greater than 0.4 dL/g formed clear, tough, flexible films. Glass transition temperatures ranged from 87 to 273°C. Thermogravimetric analyses of the polymers showed moderate thermal stability.     

Heat-resistant polymers containing bipyridyl units. I. Polyimides

Polyimides containing bipyridyl units were synthesized. The bipyridyl units were successfully incorporated by polymerization of various bipyridyl diamines with aromatic tetracarboxylic acid dianhydrides. The resulting polyamic acids had inherent viscosities in the range 0.07 to 2.26, and they were converted to the polyimides by thermal cyclization. The polyimides containing the bipyridyl units exhibited varying degrees of solubility in dimethylacetamide and m-cresol and were found to be very soluble in dichloroacetic acid.     

High-pressure synthesis and properties of aliphatic–aromatic polyimides via nylon-salt-type monomers derived from aliphatic diamines and benzophenonetetracarboxylic acid

Aliphatic polyimides (P-XBTA) having inherent viscosities of 0.4–1.4 dL/g were readily synthesized by the high-pressure polycondensation of the salt monomers, composed of aliphatic diamines having various methylene chain lengths (X = 4–12) and 3,3′,4,4′-benzophenonetetracarboxylic acid (BTA), under 200–250 MPa at 200–320°C. The salt monomers with odd-numbered methylene units were found to be more susceptible to crosslinking than those containing even-numbered methylene chains. The polyimides having even-numbered methylene units were highly crystalline, whereas those with odd-numbered methylene chains were crosslinked and therefore amorphous with only one exception, i.e., P-11BTA. The thermal behavior of these polymers was also studied. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 39–47, 1998     

One-pot synthesis of polyimides via Ni-catalyzed coupling of bis(chlorophthalimide)s

A one-pot synthesis method for the preparation of polyimides containing biphenyl units was developed via nickel-catalyzed coupling reaction of bis(chlorophthalimide)s which were prepared from chlorophthalic anhydrides and diamines in xylene. The resulting polyimides had inherent viscosities of above 0.60 dL g⁻¹. In the meantime, the copolymerizations from a mixture of three isomeric bis(chlorophthalimide)s gave the polymers with inherent viscosities of 0.36-0.55 g dL⁻¹. The solubility and film formability of the copolymers were better than those of homopolymers from bis(4-chlorophthalimide). The 10% weight loss of these polyimides was between 470 and 531 °C.     

Preparation and properties of polyamides from 2,8-phenoxathiin-bis-(γ-ketobutyric acid), 2,7-thianthrene-bis(γ-ketobutyric acid), and aromatic diamines

Aromatic-aliphatic polyamides containing phenoxathiin and thianthrene heterocyclic units were prepared by the direct polycondensation of 2,8-phenoxathiin-bis(γ-ketobutyric acid) ( I ) or 2,7-thianthrene-bis(γ-ketobutyric acid) (II) with various aromatic diamines in a triphenylphosphite-pyridine system. Prior to polymer synthesis two model diamides were prepared by condensing γ-keto acid I or II with p-toluidine. The model diamides and polyamides were characterized by spectral methods and elemental analysis. The polyamides, obtained in 56–90% yields, had inherent viscosities in the 0.82–1.1 dL/g range in concentrated H₂SO₄ at 30°C. The effect of heterocyclic units on polymer properties, such as solubility, crystallinity, and thermal stability has been discussed.     

Preparation and properties of polyamides and polymides containing bibenzyl,stilbene, and tolan structures

Polyisophthalamides and polyterephthalamides were prepared by the solution polycondensation of the corresponding diacyl chlorides with 4,4′-diaminobibenzyl, trans-4,4′-diaminostilbene, and 4,4′-diaminotolan in N,N-dimethylacetamide (DMAc). Polypyromellitimides were synthesized in two steps by the ring-opening polyaddition of pyromellitic dianhydride with the aromatic diamines in DMAc, followed by thermal cyclodehydration. The amorphous polyisophthalamides were soluble in some amide solvents containing lithium chloride, while the polyterephthalamides having fair degree of crystallinity were insoluble in these solvents. The thermal stability of these aromatic polymers decreased in the order of the tolan-containing polymers > the stilbene-containing polymers > the bibenzyl-containing polymers, both in air and under nitrogen.     

Synthesis of polyimides from 2,5-di(carboxymethyl)terephthalic dianhydride and diamines

A new six-membered tetracarboxylic dianhydride, 2,5-di(carboxymethyl)terephthalic dianhydride, was synthesized in six steps, starting with pyromellitic dianhydride. The polyimides were prepared from dianhydride and diamines in a two-step procedure. The polyamic acids, which were formed in the first step by the ring-opening polyaddition in DMAc, had inherent viscosities of 0.1–0.7 and were converted to the polyimides by thermal cyclodehydration. These polyimides were insoluble in organic solvents. Thermogravimetric analysis (TGA) in air and nitrogen atmospheres revealed that rapid decomposition began above 400°C for aromatic polyimides.     

Soluble and Colorless Polyimides from Alicyclic Diamines

Abstract

A series of novel polyimides was synthesized from alicyclic diamines and various aromatic dianhydrides by one-step polymerization in m-cresol without a catalyst. The polymerization was conducted for 4 hours with refluxing, which was enough to obtain the polymers with high molecular weight. The inherent viscosities of the resulting polyimides were in the range of 0.30 ～1.29 dL/g. The prepared polyimides showed excellent thermal stabilities and good solubility. All the polymers were readily soluble in common organic solvents such as chloroform, tetrachloroethane (TCE), dimethylacetamide (DMAc), etc and the glass transition temperatures were observed at 199 to 311°C. UV-visible spectra were obtained to measure the transparency of polymer films. All the polymers showed high transmission above 90% in the wavelength of 400 ～700 nm.     

Synthesis and characterization of soluble polyimides from 2,2-bis(4-aminophenyl)cycloalkane derivatives

New aromatic diamines [(1) and (2)] containing polycycloalkane structures between two benzene rings were synthesized by HCl-catalyzed condensation reaction of aniline hydrochloride and corresponding polycycloalkanone derivatives. The structures of diamines were identified by ¹H-NMR, ¹³C-NMR, FTIR spectroscopy, and elemental analysis. The polyimides were synthesized from the obtained diamines with various aromatic dianhydrides by one-step polymerization in m-cresol. The inherent viscosities of the resulting polyimides were in the range of 0.34–1.02 dL/g. The polyimides showed good thermal stabilities and solubility. All the polymers were readily soluble in N-methyl-2-pyrrolidone, m-cresol, tetrachloroethane, etc. Some of them were soluble even in chloroform at room temperature. The glass transition temperatures were observed in the range of 323–363°C, and all of the polymers were stable up to 400°C under nitrogen atmosphere. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3449–3454, 1999     

Soluble polyimides containing alicyclic structures

A series of novel aromatic diamines containing kinked cycloalkane structures between two phenyl rings were synthesized by HCl-catalyzed condensation reaction of excess aniline and corresponding cycloalkanone derivatives. The structures of the diamines were indentified by ¹H NMR, ¹³C NMR, FT-IR spectroscopy and elemental analysis. The polyimides were synthesized from the obtained diamines with various aromatic dianhydrides by one-step polymerization in m-cresol. The polymerization was conducted for 6∼8 h with refluxing, which was enough to obtain the polymers with high molecular weight. The inherent viscosities of the resulting polyimides were in the range of 0.37∼1.66 dl/g. All polymers were readily soluble in common organic solvents such as chloroform, tetrachloroethane, dimethylacetamide, etc. and the glass transition temperatures were observed at 290 to 372°C. UV-visible spectra were obtained to measure the transparency of polymer films. Most of the polymers showed high transmission above 90 % in the wavelength of 450 ∼ 600 nm.     

Preparation and properties of polyamides and polyimides derived from 1,3-diaminoadamantane

1,3-Diaminoadamantane (I) was used as a monomer with various aromatic dicarboxylic acyl chlorides and dianhydrides to synthesize polyamides and polyimides, respectively. Polyamides having inherent viscosities of 0.10–0.27 dL/g were prepared by low-temperature solution polycondensation. The polyamides were soluble in a variety of solvents such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), pyridine, dioxane, and nitrobenzene. These polyamides had glass transition temperatures in the 179–187°C range and 5% weight loss temperatures occurred at up to 354°C. Polyimides based on diamine I and various aromatic dianhydrides were synthesized by the two-stage procedure that included ring-opening to form polyamic acids, followed by thermal conversion to polyimides. The polyamic acids had inherent viscosities of 0.14–0.38 dL/g. The glass transition temperature of these polyimides were in the 245–303°C range and showed almost no weight loss up to 350°C under air and nitrogen atmosphere. © 1996 John Wiley & Sons, Inc.     

Preparation,characterization and analysis of novel polyimides with anthracene,carbazole and fluorene pendent architecture

Two series of new organosoluble and thermally stable polyimides containing anthracene, and fluorene pendants were prepared by a two-step solution polycondensation reaction of new synthesized diamines with commercially available dianhydrides. All intermediates and polymers were fully characterized by FTIR, NMR, and elemental analysis and their properties including solubility and thermal stability were studied. All the resulting polymers were amorphous with inherent viscosities ranged from 0.61 to 0.84 dL/g and were readily soluble in many organic solvents.     

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 organosoluble aliphatic-aromatic copolyimides based on cycloaliphatic dianhydride

A series of aliphatic-aromatic polyimides have been synthesized. These polyimides were prepared by high-temperature polycondensation of the aliphatic diamines: 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,9-diaminononane, 1,10-diaminodecane, 1,12-diaminododecane and 4,4^′-methylenebis(2,6-dimethylaniline) with 1,2,3,4-cyclopentanetetracarboxylic dianhydride. Various ratios of diamines (aromatic:aliphatic) have been applied for preparation of copolyimides. Polycondensation proceeded at 190 °C and produced copolyimides with reduced viscosities up to 0.92 dl/g. The polyimides were soluble in a wide range of organic, common solvents and showed high-thermal stability. In most cases these polymers formed flexible films which presented excellent transparency.