Synthesis of polyamides by ring-opening polyaddition: Reaction of 4,4′-disubstituted bisazlactones with diamines

Ring-opening polyaddition of 4,4′-disubstituted bisazlactones with various diamines was carried out in N-methyl-2-pyrrolidone to afford polyamides with pendant amide group having inherent viscosities of 0.17-0.51 in quantitative yields. The solution polymerization with aliphatic diamines was almost complete at room temperature within 24 hr. Nearly all of the polyamides were soluble in polar in polar aprotic solvents and in acidic solvents. These polymers began to decompose at around 200–300°C as determined by DTA and TGA under nitrogen.     

Synthesis of polyamides by ring-opening polyaddition of benzobis[1,2]oxazinediones with aliphatic diamines

Novel oxime-containing polyamides have been prepared by the ring-opening polyaddition of combinations of two benzobis[1,2]oxazinediones, 4,6-diphenylbenzo[1,2-d:5,4-d′]bis[1,2]oxazine-1,9-dione and 4,9-diphenylbenzo[1,2-d:4,5-d′]bis[1,2]oxazine-1,6-dione, with two aliphatic diamines in a polar aprotic solvent such as N-methyl-2-pyrrolidone. The polymerization was almost completed within a day at room temperature. These polymers had inherent viscosities in the range of 0.12–0.38 and were soluble in a wide range of solvents, including formic acid and hot m-cresol, as well as a number of polar aprotic solvents. All the polymers softened at a temperature ranging from 165 to 185°C. Thermal characterization of the polyamides by TGA and DTA showed polymer decomposition temperatures of about 240°C in air.     

Preparation and properties of polyamides from 2,2′-p-phenylenebis-5-oxazolones with diamines

Novel phenylated polyamides having inherent viscosities in the range of 0.2–0.4 were prepared by the ring-opening polyaddition of 2,2′-p-phenylenebis(4,4-diphenyl-5-oxazolone) with aliphatic diamines in polar aprotic solvents. Similarly, unsubstituted polyamides were obtained from 2,2′-p-phenylenebis-5-oxazolone and both aliphatic and aromatic diamines. The phenylated polyamides were highly soluble in a wide range of solvents including tetrahydrofuran and dioxane, while the unsubstituted polymers showed limited solubility in the solvents. No marked differences in thermal stability between the phenylated and unsubstituted polyamides were noted, and all the polyamides began to decompose at around 250°C in both air and nitrogen.     

Syntheses of polyamides and polybenzodipyrrolediones from pseudo diacetylphthaloyl chlorides and diamines

Novel diacetylphthalic acids, 2,5-diacetylterephthalic and 4,6-diacetylisophthalic acids, were synthesized starting from pyromellitic dianhydride. These diacids were subsequently converted to the corresponding pseudo diacetylphthaloyl chlorides. The ring-opening polyaddition, followed by dehydrochlorination, of the pseudo diacetylphthaloyl chlorides with aliphatic diamines in a polar aprotic solvent afforded almost quantitatively polyamides having inherent viscosities of 0.3–0.7. The solution polymerization was almost completed within 1 hr at room temperature. These polyamides were soluble in acidic solvents like m-cresol. Subsequent cyclodehydration of the polyamides by heating at 200°C gave insoluble polybenzodipyrrolediones, which underwent weight losses of 10% at around 400°C under nitrogen.     

Synthesis of polyphthalamides by ring-opening polyaddition reaction of N,N′-disubstituted bisphthalisoimides with diamines

The ring-opening polyaddition reaction of N,N′-disubstituted bisphthalisoimides with various diamines in amide-type solvents at room temperature afforded polyphthalamides having inherent viscosity of up to 0.26 in excellent yields. Some of the polymers thus obtained are a new class of ordered alternating copolyphthalamides. These polyamides were soluble in polar aprotic solvents, as well as in acidic solvents. They showed relatively low melt temperature in the range of 120–220°C and further low level of thermal stability.     

New Organosoluble and Optically Transparent Polyamides Containing Xanthene Units and Methyl Pendant Groups From 9,9-Bis[4-(4-carboxyphenoxy)-3-methylphenyl]xanthene

A new aromatic dicarboxylic acid, 9,9-bis[4-(4-carboxyphenoxy)-3-methylphenyl]xanthene (BCAMPX) was prepared from the nucleophilic substitution reaction of 9,9-bis(4-hydroxy-3-methylphenyl)xanthene with p-fluorobenzonitrile, followed by alkaline hydrolysis. Then BCAMPX was polycondensated with various aromatic diamines to afford the polyamides with the number-average molecular weight in the range of 45,300–51,500 and the polydispersity index ranged from 1.67 to 1.85. These polyamides showed glass transition temperatures between 260–286°C and 10% weight loss temperatures ranging from 490 to 504°C and 480 to 490°C in nitrogen and air respectively, and char yields above 52% at 800°C in nitrogen. Nearly all polyamides were readily soluble polar aprotic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide (DMAc), tetrahydrofuran and pyridine, and afforded transparent, strong and flexible films upon casting from DMAc solvent. All polyamides were amorphous and exhibited tensile strengths of 80–91 MPa, elongations at break of 9–13%, and initial moduli of 1.95–2.82 GPa, as well as low moisture absorption in the range of 2.65–3.65%, and high transparency with an ultraviolet–visible absorption cut-off wavelength in the 360–378 nm range.     

Preparation and characterization of aromatic polyamides based on a bis(ether‐carboxylic acid) or a dietheramine extended from 1,1‐bis(4‐hydroxyphenyl)‐1‐phenylethane

Thermoplastic and organic‐soluble aromatic polyamides containing both bulky triphenylethane units and flexible ether linkages were prepared directly from 1,1‐bis[4‐(4‐carboxyphenoxy)phenyl]‐1‐phenylethane ( III ) with various aromatic diamines or from 1,1‐bis[4‐(4‐aminophenoxy)phenyl]‐1‐phenylethane ( V ) with various aromatic dicarboxylic diacids via triphenyl phosphite and pyridine. These polyamides had inherent viscosities ranging from 0.71 to 1.77 dL/g. All the polymers easily were dissolved in aprotic polar solvents such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylacetamide, and some even could be dissolved in less polar solvents such as tetrahydrofuran. The flexible and tough films cast from the polymer solutions possessed tensile strengths of 89 to 104 MPa. The polyamides were thermally stable up to 460°C in air or nitrogen. Glass‐transition temperatures of these polyamides were observed in a range of 179 to 268°C via differential scanning calorimetry or thermomechanical analysis. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 247–260, 2000     

Polyamides incorporating phosphine oxide groups. I. Wholly aromatic polymers

Five novel polyamides incorporating phosphine oxide groups have been synthesized by the condensation reaction of bis(4-carboxyphenyl)phenylphosphine oxide with a series of aromatic diamines. The thermal properties of these polymers were investigated by differential scanning calorimetry and thermogravimetric analysis. Glass transition temperatures in the 225–254°C range were recorded, together with good thermooxidative stability (5% weight loss occurring at >420°C) and high char yield upon prolonged heating at 650–800°C (24–50%). Also, good solubility in aprotic polar solvents was observed for all polyamides synthesized. © 1996 John Wiley & Sons, Inc.     

Synthesis and properties of aromatic polyamides derived from 1,7-bis(4-aminophenoxy)naphthalene and various aromatic dicarboxylic acids

A series of novel bis(phenoxy)naphthalene-containing polyamides having inherent viscosity up to 2.02 dL/g were synthesized by the direct polycondensation of the diamine 1,7-bis(4-aminophenoxy)naphthalene with various aromatic dicarboxylic acids in N-methyl-2-pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. Most of the polyamides could be readily dissolved in polar aprotic solvents such as N,N-dimethylacetamide and NMP, and could be solution-cast into transparent, flexible, and tough films. These polymers had glass transition temperatures in the range of 139–263°C, and 10% weight loss temperatures in nitrogen and air were above 499 and 484°C, respectively. © 1996 John Wiley & Sons, Inc.     

Phenazasiline-containing polyamides and polyesters

A Phenazasiline ring was incorporated into a polymer backbone by polycondensation of 2,8-dichloroformyl-5,10-dihydro-5-methyl-10,10-diphenylphenazasiline (V) with aromatic diamines or bisphenols, and phenazasiline-containing polyamides and polyesters were obtained. The polyamides were prepared by low-temperature solution polycondensation in N-methyl-2-pyrrolidone (NMP) in the presence of lithium chloride. The polyesters were synthesized by interfacial polycondensation in a mixture of 1,2-dichloroethane and aqueous alkali in the presence of tetrabutylammonium chloride as an accelerator. These reaction conditions gave the corresponding polymers with high viscosities. The phenazasiline-containing polyamides exhibited good solubilities in polar aprotic solvents such as dimethylformamide, dimethylacetamide, and NMP, and also in m-cresol, although the polyesters showed limited solubilities in organic solvents. Under nitrogen, the phenazasiline-containing polyamides and polyesters showed little degradation below 400°C and had good heat resistance.     

Polyamides incorporating phosphine oxide groups. III. Polymerisation of bis[4-(2-aminoethyl)aminophenyl]-phenylphosphine oxide with dicarboxylic acids

The new polymerisation monomer bis[4-(2-aminoethyl)aminophenyl]-phenylphosphine oxide (p-BAPPO) was prepared in good yield by the nucleophilic substitution reaction between bis(4-fluorophenyl)phenylphosphine oxide and a large excess of 1,2-diaminoethane. Five novel polyamides, incorporating phosphine oxide groups within the polymer backbone were synthesised by the condensation reaction of p-BAPPO with a series of aromatic and aliphatic dicarboxylic acids. The thermal properties of these polymers were investigated by differential scanning calorimetry and thermogravimetric analysis. Glass transition temperatures in the 180–215°C range were recorded. Although we observed their thermooxidative stabilities (5% weight loss > 345°C) to be lower by 40–70°C than those previously found for wholly aromatic polyamides with phosphine oxide groups within the parent chain, char yields upon prolonged heating at 650°C were still excellent (26–38%). Also, good solubility in aprotic polar solvents was observed for all polyamides synthesised. The new polyamides clearly represent significant progress in the quest for processible fire retardant materials. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2865–2870, 1997     

Synthesis and characterization of Schiff-base-containing polyamides

A series of new Schiff base polyamides（PAs） were synthesized by polycondensation of benzilbisthiosemicarbazone diamine（LH₆） with different commercially available aliphatic and aromatic diacid chlorides. The monomer and all the PAs were characterized by FTIR,¹H-NMR,and elemental analysis.The prepared polyamides showed inherent viscosities in the range of 0.30-0.36 dL/g in DMF at 25℃,indicating their moderate molecular weight.The PAs were completely soluble in aprotic polar solvents such as dimethylformamide（DMF）,N-methylpyrolidone（NMP）, tetrachloroethane（TCE）,dimthylsulfoxide（DMSO） and also in H₂SO₄ and partially soluble in THF,acetone and chloroform at room temperature.Thermal analysis showed that these PAs were practically amorphous and exhibited 10%weight loss above 220℃.     

Synthesis and characterization of fluorine-containing polyamides derived from 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane by direct polycondensation

A fluorine-containing diamine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (BAPPH) ( II ), was synthesized in two steps on condensation of 2,2-bis(4-hydroxyphenyl)hexafluoropropane with p-chloronitrobenzene in the presence of potassium carbonate, giving 2,2-bis[4-(4-nitrophenoxy)phenyl]hexafluoropropane ( I ), followed by reduction with hydrazine monohydrate/Pd—C. Fluorine-containing polyamides and copolyamides having inherent viscosities 0.41–0.88 dL g⁻¹ were prepared by direct polycondensation of BAPPH with various aromatic diacids or with mixed diacids, by triphenyl phosphite and pyridine in N-methyl-2-pyrrolidinone (NMP). The polyamides were examined by elemental analysis, IR spectra, inherent viscosity, x-ray diffraction, solubility, DSC, and TGA. The diffractogram showed that the polyamides were crystalline except IVb , IVc , IVf , and Vc . Almost all polyamides were soluble in polar aprotic solvents. The polymers obtained from BAPPH lost no mass below 350°C, with 10% loss of mass being recorded above 467°C in nitrogen. These aromatic polyamides had glass transition temperatures in the 221–253°C range. © 1996 John Wiley & Sons, Inc.     

Synthesis of polypropionamide-ureas from N-mesyloxysuccinimide and diamines

A series of polypropionamide-ureas was synthesized by the polymerization of N-mesyloxysuccinimide with diamines in polar aprotic solvents in the presence of acid acceptors. The polymerization proceeded through the formation of ring-opened adducts, followed by elimination and rearrangement yielding β-isocyanatopropionamide derivatives, which in turn were polymerized to afford polypropionamide-ureas. These polymers had inherent viscosities in the range of 0.1–0.2. Polymers having aliphatic chains which were fusible below 240°C were soluble in acidic solvents, whereas those with aromatic residues dissolved in polar aprotic solvents. Marked decomposition of the polyamide-ureas under thermogravimetric analysis generally occurred at around 320°C under nitrogen.     

Synthesis and characterization of aromatic polymers containing pendant silyl groups. II. Aromatic polyamides

In order to improve the solubility of aromatic polyamides without significant loss of thermal stability, synthesis of aromatic polyamides containing pendant silyl groups was carried out by direct polycondensation of silylated aromatic diacids such as 2-trimethylsilylterephthalic acid (TSTA), 2,5-bis (trimethylsilyl) terephthalic acid (BTSTA), 5-trimethylsilylisophthalic acid (TSIA), 5-dimethylphenylsilylisophthalic acid (DMSIA), and 5-triphenylsilylisophthalic acid (TPSIA) with various aromatic diamines. The resulting polyamides had inherent viscosities in the range of 0.18–1.10 dL/g and showed improved solubilities toward aprotic polar solvents such as NMP, DMF, DMSO, etc. The prepared aromatic polyamides exhibited fairly good thermal stabilities, which were almost comparable to those of corresponding nonsubstituted aromatic polyamides. That is, thermogravimetric analysis (TGA) data revealed 10% weight losses at 358–500°C and residual weights at 700°C were 46–67% under nitrogen atmosphere. © 1992 John Wiley & Sons, Inc.     

Polyamides incorporating phosphine oxide groups. II. Aromatic polymers containing sulfone functionality

Four novel polyamides have been prepared in high yields by the polycondensation reactions of bis(3-carboxyphenyl)- and bis(4-carboxyphenyl)phenylphosphine oxide with 3,3′- and 4,4′-diaminodiphenylsulfone. The thermal properties of these materials were studied using differential scanning calorimetry and thermogravimetric analysis. It was found that the presence of both phosphine oxide and sulfonyl groups within the polymer backbone brought about remarkable modifications in the thermal behavior. Glass transition temperatures 40–50°C lower than those of conventional polyamides i.e., in the range 170–200°C, were recorded. However, we observed greater thermooxidative stability (5% weight loss at >410°C) and high char yield upon prolonged heating at 800°C (20–34%). Also, good solubility in polar aprotic solvents was observed for all polyamides together with some solubility in aqueous solvent mixtures, e.g. tetrahydrofuran/water (95:5). © 1997 John Wiley & Sons, Inc.     

Synthesis of polybenzodipyrrolediones by thermal cyclodehydration of polyamides derived from dibenzylidenebenzodifurandiones and aliphatic diamines

A new class of polyheterocycles, polybenzodipyrrolediones (PBP), has been synthesized successfully by the two-step polymerization of dibenzylidenebenzodifurandiones with aliphatic diamines. New bislactone monomers, 3,5-dibenzylidene-3,5-dihydro-1H,7H-benzo[1,2-c:4,5-c′]difuran-1,7-dione and 3,7-dibenzylidene-3,7-dihydro-1H,5H-benzo[1,2-c:4,5-c′]-difuran-1,5-dione, were synthesized from pyromellitic dianhydride and phenylacetic acid. The ring-opening polyaddition reaction of the bislactones with aliphatic diamines in a polar solvent afforded novel polyamides having inherent viscosities of 0.1–1.0 in quantitative yield. The solution polymerization was almost completed within several hours at 80°C, while it required approximately a week to its completion at room temperature. Dimethyl sulfoxide and N-methyl-2-pyrrolidone were preferred solvents for the polymerization. The open-chain polyamides were subsequently cyclodehydrated by heating at 240°C to give PBP having high molecular weight. The aliphatic PBP were soluble in hot polar solvents such as N-methyl-2-pyrrolidone, m-cresol, and nitrobenzene. They began to decompose at about 400°C in a nitrogen atmosphere as determined by thermogravimetric analysis.     

Optically high transparency and light color of organosoluble polyamides containing trifluoromethyl and kink diphenylmethylene linkage

New polyamides were prepared directly from a diamine, bis[4‐(2‐trifluoromethyl 4‐aminophenoxy)phenyl] diphenylmethane, containing an electron‐withdrawing trifluoromethyl group and a kink diphenylmethylene linkage with various aromatic dicarboxylic acids having inherent viscosities ranging from 0.66 to 0.83 dL g^?1. All the polyamides showed outstanding solubility and could be easily dissolved in amide‐type polar aprotic solvents (e.g., N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, and N,N‐dimethylformamide) and even dissolved in less polar solvents (e.g., pyridine, cyclohexanone, and tetrahydrofuran). The dielectric constants of the polyamide films were 3.37–3.87 (100 KHz) and decreased with an increase in the frequency, which ranged from 1 Hz to 100 KHz. A low coefficient of thermal expansion for the polyamides was observed in the range of 54–78 ppm/°C (by thermomechanical analysis). These polyamides showed excellent thermal stability, and the 10% weight loss temperatures were in the range of 484–507 °C in an atmosphere of nitrogen. The polymers had an initial modulus of 1.8–2.2 GPa. The polyamides with kink and electron‐withdrawing trifluoromethyl units afforded light‐color polymer films with high transmittance in the visible region (400–700 nm), and their cutoff wavelength was lower than 362 nm. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4559–4569, 2005     

Syntheses of polyamides and polypyrrolones from 2,2′-disubstituted bis(3-buten-4-olides) and diamines

The ring-opening polyaddition of 2,2′-disubstituted bis(3-buten-4-olides) with aliphatic diamines in m-cresol at room temperature afforded in quantitative yields polyamides with a pendant ketone moiety having inherent viscosities of up to 0.7. On the other hand, the polymerization in m-cresol at 80°C with acidic catalysts and at 160°C without any catalyst yielded directly polypyrrolones, a novel class of polyheterocycles. The cyclodehydration of the open-chain polyamides to polypyrrolones was also achieved by simply treating the polyamide films with methanolic hydrochloric acid at room temperature. Both of the polymers were generally soluble in hot polar solvents such as dimethylformamide, m-cresol, and nitrobenzene. The polypyrrolones began to lose weight gradually at around 250°C in nitrogen as determined by thermogravimetric analysis, while the thermograms in air showed an appreciable weight increase at about 230°C.     

Preparation and properties of polyamides containing thianthrene units

New polyamides containing thianthrene tetraoxide were synthesized from 2,7-dichloroformylthianthrene-5,5′,10,10′-tetraoxide (A) and various diamines by the low temperature solution polycondensation technique. The resulting polyamides were characterized by i.r. and ¹H-NMR spectra and elemental analysis. The polyamides had inherent viscosities of 0.56–1.21 dl/g in DMA at 30°. All the polymers dissolved readily at room temperature in polar aprotic solvents. Density, crystallinity and thermal stability of these polyamides have been determined. In order to characterize the polymers, a model compound was also prepared from A and p-toluidine.