Polyamides having long methylene chain units

Three series of polyamides having long methylene chain units have been prepared from p-xylylenebisethylamine and 2,2′-pphenylenebisethylamine with aliphatic dicarboxylic acids of long methylene chain units; aliphatic diamines of long methylene chain units with terephthalic, p-benzenediacetic, and p-benzenedipropionic acids; and aliphatic diamines with aliphatic dicarboxylic acids, both having long methylene chain units. The effects of the length of the methylene chain units on the melting point, the glass transition temperatures and the densities of these polyamides were investigated. The aromatic polyamides, in which even methylene chains are joined between a phenylene and an amide group generally have higher melting points than the corresponding ones with odd methylene chains. On the plots of the melting points and the densities of the aliphatic series against the amide concentrations, both the melting point and the density extrapolated to the zero amide concentration are found below the values for polymethylene.     

Preparation and properties of polyamides from 4-phenoxy- and 4-phenylthio-m-phenylenediamine and both aromatic and aliphatic diacids

New soluble aramids having pendant phenoxy and phenylthio groups were prepared in high molecular weights by the polycondensation of aromatic diacids with 4-phenoxy-m-phenylenediamine and 4-phenylthio-m-phenylenediamine, respectively. Glass transition temperatures (T_g) of these aramids were in the range 195–255°C, where T_gs of phenoxy pendant aramids were higher than those of phenylthio substituted aramids. These properties were compared with those of the parent aramids derived from m-phenylenediamine and aromatic diacids. Aromatic-aliphatic polyamides were also prepared by the reaction of these three diamines with aliphatic diacids having 4–10 methylene groups and were characterized in detail.     

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.     

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.     

Synthesis and properties of new soluble N-phenyl–substituted aromatic-aliphatic and all aromatic polyamides derived from 4,4′-dianilinobiphenyl

New N-phenylated aromatic-aliphatic and all aromatic polyamides were prepared by the high-temperature solution polycondensation of 4,4′-dianilinobiphenyl with both aliphatic (methylene chain lengths of 6–11) and aromatic dicarboxylic acid chlorides. All of the aromatic-aliphatic polyamides and the wholly aromatic polyamides exhibited an amorphous nature and good solubility in amide-type and chlorinated hydrocarbon solvents, except for those aromatic polyamides containing p-oriented phenylene or biphenylylene linkages in the backbone; the latter were crystalline and insoluble in organic solvents except m-cresol. The N-phenylated aromatic-aliphatic polyamides and aromatic polyamides had glass transition temperatures in the range of 79–116°C and 207–255°C, respectively, and all the polymers were thermally stable with decomposition temperatures above 400°C in air. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2193–2200, 1998     

Thermotropic liquid crystalline polyamides from polyethyleneglycol bis(4-carboxyphenyl)ethers

New thermotropic liquid crystalline polyamides were prepared from polyethyleneglycol bis(4-carboxyphenyl)ether (PEG_n, n = 2, 3, 4) and aromatic diamines by using triphenyl phosphite in pyridine as the condensing agent. Substituted p-phenylenediamines and 4,4′-diaminobiphenyls were successfully used; melting points and isotropization temperatures of the polyamides were changed by the kind and number of the substituents. Copolymerization of long chain aliphatic dicarboxylic acids was carried out at the lower melting point of the copolymer. Kink monomers were also incorporated into the polymer backbone. © 1993 John Wiley & Sons, Inc.     

Soluble aromatic poly(ether amide)s containing aryl‐, alkyl‐, and chloro‐substituted phthalazinone segments

A series of novel aromatic diamines ( 2 – 4 ) containing the alkyl‐, aryl, or chloro‐substituted group of phthalazinone segments were synthesized via two synthetic steps starting from 4‐(3‐R‐4‐hydroxyphenyl)‐2,3‐phthalazinone‐1 (R = Ph, CH₃, Cl). Three series of aromatic polyamides containing phthalazinone moieties were prepared through diamines 2 – 4 reacting with different aromatic dicarboxylic acids via a direct Yamazaki–Higashi phosphorylation polycondensation reaction. The resulting aromatic polyamides had inherent viscosities in the range of 0.40–0.76 dL/g. The thermal property of the polyamides was examined with DSC and thermogravimetric analysis. The glass‐transition temperatures of these polyamides ranged from 298 to 340 °C. The 10% mass‐loss temperature was above 405 °C under nitrogen. Structures of monomers 2 – 4 and the polymers were confirmed by Fourier transform infrared spectroscopy, ¹H NMR, and mass spectrometry. Good solubility of these polymers in polar solvents such as N‐methylpyrrolidone, dimethylformamide, dimethylacetamide (DMAc), and m‐cresol was observed, and tough, flexible films were obtained from the polymer's DMAc solutions. The effect of the substituted group on the physical property of polymers was also investigated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2026–2030, 2004     

Synthesis and properties of new halogen‐substituted polyamides from 5‐halo‐m‐phenylenediamines and both aliphatic and aromatic dicarboxylic acids

New halogen‐substituted aromatic–aliphatic and wholly aromatic polyamides with high inherent viscosities were synthesized by the direct polycondensation of 5‐halo‐m‐phenylenediamines, where the halogens were Cl, Br, and I, with both aliphatic and aromatic dicarboxylic acids in N‐methyl‐2‐pyrrolidone with a mixture of triphenyl phosphite and pyridine as a condensing agent. The solubility of the halogen‐substituted polyamides was much higher than that of the parent polyamides derived from m‐phenylenediamine. The glass‐transition temperatures of the substituted aromatic–aliphatic polyamides increased in the order Cl < Br < I, whereas the temperatures of 10% weight loss in air decreased in the reverse order. The limiting oxygen index values, as an indication of flammability, increased for the substituted aromatic–aliphatic polyamides in the order Cl < Br < I. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3911–3918, 2000     

Preparation and properties of aromatic polymides from 2,2′-bibenzoic acid and aromatic diamines

Aromatic polyamides having inherent viscosities up to 1.8 dL/g were synthesized either by the direct polycondensation of 2,2′-bibenzoic acid with various aromatic diamines or by the low temperature solution polycondensation of 2,2′-bibenzoyl chloride with aromatic diamines. All the aromatic polyamides were amorphous and soluble in a variety of organic solvents including N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone, dimethyl sulfoxide, m-cresol, and pyridine. Transparent and flexible films of these polymers could be cast from the DMAc solutions. These aromatic polymides had glass transition temperatures in the range of 226-306deg;C and began to lose weight around 350°C in air.     

Synthesis and characterization of poly-n-alkylmalonamides: Formation of a partially disordered layer structure

Polyamides from n-alkylmalonic acids and linear aliphatic diamines, with paraffinic side chains of 3–18 carbon atoms, were prepared by melt polycondensation or by low-temperature interfacial polycondensation and were characterized by infrared, differential scanning calorimetry (DSC), and x-ray diffraction techniques. First-order transitions were found in the range of 130–210°C, depending on the number of carbon atoms in the side chain. The x-ray diffraction indicated substantially amorphous systems for polyamides with 8–18 carbon atoms in the side chain. However, long-range order arises in these polymers from a solid-state structure in which polyamide and hydrocarbon layers having partially disordered chain conformations alternate.     

Preparation and properties of aromatic polyamides from 2,2′-bis(p-aminophenoxy) biphenyl or 2,2′-bis(p-aminophenoxy)-1,1′-binaphthyl and aromatic dicarboxylic acids

New aromatic diamines having kink and crank structures, 2,2′-bis(p-aminophenoxy)biphenyl and 2,2′-bis(p-aminophenoxy)-1,1′-binaphthyl, were synthesized by the reaction of p-fluoronitrobenzene with biphenyl-2,2′-diol and 2,2′-dihydroxy-1,1′-binaphthyl, respectively, followed by catalytic reduction. Biphenyl-2,2′-diyl- and 1,1′-binaphthyl-2,2′-diyl-containing aromatic polyamides having inherent viscosities of 0.44–1.18 and 0.26–0.88 dL/g, respectively, were obtained either by the direct polycondensation or low-temperature solution polycondensation of the diamines with aromatic dicarboxylic acids (or diacid chlorides). These polymers were readily soluble in a variety of organic solvents including N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide, m-cresol, and pyridine. Transparent, pale yellow, and flexible films of these polymers could be cast from the DMAc or NMP solutions. These aromatic polyamides containing biphenyl and binaphthyl units had glass transition temperatures in the range of 215–255 and 266–303°C, respectively. They began to lose weight at ca. 380°C, with 10% weight loss being recorded at about 470°C in air. © 1993 John Wiley & Sons, Inc.     

Synthesis and properties of Ortho-linked aromatic polyamides based on 4,4′-(2,3-naphthalenedioxy) dibenzoic acid

A novel aromatic dicarboxylic acid monomer, 4,4′-(2,3-naphthalenedioxy)-dibenzoic acid ( 3 ), was prepared by the fluorodisplacement reaction of p-fluorobenzonitrile with 2,3-dihydroxynaphthalene in N,N-dimethylformamide (DMF) in the presence of potassium carbonate followed by alkaline hydrolysis of the intermediate dinitrile. A series of novel aromatic polyamides containing ortho-linked aromatic units in the main chain were synthesized by the direct polycondensation of diacid 3 and a variety of aromatic diamines using triphenyl phosphite and pyridine as condensing agents in the N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride. The resulting polyamides had inherent viscosities higher than 0.74 and up to 2.10 dL/g. All of these polyamides were soluble in polar solvents, such as NMP, DMF, N,N-dimethylacetamide (DMAc), and dimethyl sulfoxide. Transparent, flexible, and tough films could be cast from their DMAc or NMP solutions. The solvent-cast films had high tensile strengths and moduli. Extensions to break were relatively low, except for the polymers derived from 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane and 3,4′-oxydianiline, which had elongations of 82 and 62%, respectively. Except for the polyamide based on p-phenylenediamine, all the other polyamides were amorphous in nature. All the polymers are thermally stable to temperatures in excess of 450°C in either air or nitrogen atmosphere. The polymers exhibited glass transition temperatures ranging from 183 to 260°C and decomposition temperatures (10% weight loss) ranging from 462–523°C in air and 468–530°C in nitrogen. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3385–3391, 1997     

Preparation and properties of aromatic polyamides from 1,4-bis(p-carboxyphenoxy)naphthyl and aromatic diamines

A new aromatic dicarboxylic acid, 1,4-bis (p-carboxyphenoxy)naphthyl ( 3 ), was synthesized by the reaction of p-fluorobenzonitrile with 1,4-naphthalenediol, followed by hydrolysis. Aromatic polyamides having inherent viscosities of 1.27–2.22 dL/g were prepared by the triphenyl phosphite activated polycondensation of diacid 3 with various aromatic diamines. Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents including N,N-dimethyl-acetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and m-cresol. Transparent, tough, and flexible films of these polymers could be cast from the DMAc or NMP solutions. The cast films had tensile strengths ranging from 64–104 MPa, elongations-at-break from 6 to 10%, and initial moduli from 1.52 to 2.14 GPa. These polyamides had glass transition temperatures in the range of 195 to 240°C. Almost all polymers were thermally stable up to 400°C, with 10% weight loss being recorded above 480°C in air and nitrogen atmospheres. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2273–2280, 1997     

Polydisuccinimides: Polyaddition reactions of aliphatic and aromatic diamines to N,N′-bismaleimide

Polyaddition reactions of aliphatic and aromatic diamines to N,N′-bismaleimide and model compounds have been investigated in order to establish some properties of this imide. Glacial acetic acid has a catalytic effect when used as solvent in the preparation of aspartimide compounds. Aromatic diamines show a much smaller reactivity than aliphatic, the former giving polydisuccinimides and the latter polyamides under the same reaction conditions. Addition reactions of N,N′-bismaleimide proceed either by an ionic mechanism in polar solvents or by a homolytic process in solvents precluding ion formation. The thermal stability and the infrared spectra of the new polymers are discussed.     

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.     

Aromatic polyamides. V. A general synthesis of polyamides from aromatic diacids and aromatic diamines in sulfur trioxide

The reaction of terephthalic acid (TA) and para-phenylenediamine sulfate (PPD-S) in sulfur trioxide to form anisotropic, sulfonated poly(p-phenyleneterephthalamide) (SPT) dopes was reported in Part IV of this series. We have found now that the TA/PPD-S polymerization is only one example of a more general polyamide condensation reaction of aromatic diamines and aromatic diacids. Sulfonation of the aromatic diamine ring during TA/PPD-S polymerization in SO₃ was a major side reaction. Sulfonation was reduced or eliminated by aromatic diamine ring substitution with unreactive substituents, particularly chlorine and fluorine. Polymerization of 2,3,5,6-tetrafluoro-phenylenediamine with TA in SO₃ at 80°C (18% concentration) produced unsulfonated poly(tetrafluoro-para-phenyleneterephthalamide) (F-PPT) with an inherent viscosity of 2.2. The halogenated, all-para aromatic polymers formed highly anisotropic (liquid crystalline) dopes. Monomers that formed polymers in which the chain bond angle deviated from 180° (e.g., meta-oriented monomers) yielded only isotropic polymer solutions. The mechanism and rate of diamine–diacid reactivity in SO₃ was related to diamine basicity. Whereas the less basic aromatic diamines (as sulfates) polymerized with aromatic diacids in SO₃, the more basic aliphatic diamines (as sulfates) would not. Aliphatic, cycloaliphatic, and aryl-aliphatic diacids were degraded by or reacted with the solvent (SO₃). Thermogravimetric analyses of F-PPT and monosulfonated poly(chloro-para-phenyleneterephthalamide) at 20°C/min showed weight loss only above 380 and 370°C, respectively.     

N-methyl-substituted aromatic polyamides

A series of N-methyl-substituted aromatic polyamides derived from the secondary aromatic diamines 4,4′-bis(methylamino)diphenylmethane, 3,3′-bis(methylamino)diphenylmethane, 4,4′-bis(methylamino)benzophenone or 3,3′-bis(methylamino)benzophenone and isophthaloyl dichloride, and terephthaloyl dichloride or 3,3′-diphenylmethane dicarboxylic acid dichloride was prepared by high-temperature solution polymerization in s-tetrachloroethane. Compared with analogous unsubstituted and partly N-methylated aromatic polyamides, the full N-methylated polyamides exhibited significantly lower glass transition temperatures (T_g), reduced crystallinity, improved thermal stability, and good solubility in chlorinated solvents.     

Polyamides from perchloro-4,4′-dichloroformylbiphenyl

New thermally stable polyamides were prepared by low-temperature polycondensation in N,N-dimethylacetamide from perchloro-4,4′-dichloroformylbiphenyl and various aromatic and aliphatic diamines. The polymers were characterized by infrared spectroscopy, elemental analysis, TGA, and DSC and found to show higher thermal stability than other nonchlorinated polyamides.     

Direct synthesis of polyamides by N-acyl phosphoramidites

A variety of N-acyl phosphoramidites were prepared from chlorophosphites and amide derivatives, and their structures were determined with the aid of ¹H-, ¹³C-, and ³¹P-NMR, and IR spectroscopies. These phosphoramidites were employed in direct polycondensation reaction of dicarboxylic acids and diamines under various conditions resulting in polyamides with inherent viscosities of 0.1 to 1.13. The best results were obtained when aliphatic dicarboxylic acids and aromatic diamines were condensed by 2-(N-methylacetamido)-1,3,2-dioxaphospholane in nitriles.     

Substituted rod-like aromatic polyamides: Synthesis and structure-property relations

The synthesis and structure-property relations of a number of novel substituted paralinked aromatic homopolyamides and copolyamides are described. The synthesis of the polyamides was carried out by polycondensation of activated N,N'-bis-(trimethylsilyl) substitued aromatic diamines and aromatic diacid chlorides. In order to improve the solubility and to lower melting temperatures, novel arylsubstituted terephthalic acids moieties, such as p-terphenyl-2,5-dicarboxylic acid and o-terphenyl-2,5-dicarboxylic acid, were used in combination with substituted and noncoplanar diamines. Depending on the chemical structure, polyamides with very high solubility (up to 40% w/w) in polar aprotic solvents such as N,N-dimethylacetamide without the addition of inorganic salts were obtained. Lyotropic liquid crystalline behavior was observed for the first time in polyamides which contain noncoplanar biphenylene units.