Synthesis of polyenamines by vinylogous nucleophilic substitution polymerization of 2,2′-disubstituted bis(4-ethoxymethylene-5-oxazolone) with diamines

A new class of polyenamines was synthesized by the vinylogous nucleophilic substitution polymerization of 2,2′-p-phenylenebis(4-ethoxymethylene-5-oxazolone) with diamines in polar aprotic solvents under very mild conditions. The polymers derived from aliphatic diamines were soluble in these solvents and had inherent viscosities in the range of 0.3–0.9. The dilute solutions showed marked decrease in viscosity with time, presumably due to hydrolytic chain scission of the enamine structures in the polymer backbone. The polymers exhibited no melting temperature, and onset of breakdown under thermogravimetric analysis in a nitrogen atmosphere occurred at 250–300°C.     

Synthesis of inherently dissymmetric polyamides,

The preparation of polyamides from derivatives of optically active biphenic acid is described. The diacid chlorides chosen were 2,2′-dinitro-6,6′-dimethylbiphenyl-4,4′-dicarbonyl chloride and 2,2′-dichloro-6,6′-dimethylbiphenyl-4,4′-dicarbonyl chloride, the diamines were phenyldiamines (o-, m-, p-) piperazine, trans-2,5-dimethylpiperazine, and 1,2-piperaazolidine. Polymerization was carried out by the method of interfacial polycondensation. The polymers of aromatic diamines were insoluble in common organic solvents but soluble in dimethylformamide containing 5% lithium chloride, triesters of phosphoric acid, and methanesulfonic acid. The polymers of aliphatic diamines were also insoluble in common organic solvents but soluble in trifluoroethanol. All polymers had melting points higher than 280°C.     

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.     

Optical properties of inherently dissymmetric polyamides

A study of the optical rotatory dispersion (ORD), circular dichroism (CD), and ultraviolet spectra (UV) of polyamides derived from optically active biphenyl acid chlorides, and aromatic, and aliphatic diamines, was made. The optically active monomers were (–)-(S)-2,2′-dinitro-6,6′-dimethylbiphenyl-4,4′-dicarbonyl chloride and (–)-(S)-2,2′-dichloro-6,6′-dimethylbiphenyl-4,4′-dicarbonyl chloride. The diamines were o-, m-, and p-phenylenediamine, piperazine, trans-2,5-dimethylpiperazine, and 1,2-pyrazolidine. The ORD spectra of the o-phenylenediaminepolyamide taken in different solvents indicated the existence of some ordered structure in the least polar solvent. All other polyamides existed in a random coil conformation in the solvents employed.     

Synthesis of polyamides from active 2-benzothiazolyl dithiolesters and diamines under mild conditions

Novel examples were presented of the use in polyamide synthesis of active 2-benzothiazolyl dithiolesters for which aminolysis is assisted by a neighboring group. Solution polycondensation of new dithiolesters, 2,2′-(adipoyldithio)bisbenzothiazole and 2,2′-(isophtahloyldithio)bisbenzothiazole, with both aliphatic and aromatic diamines in polar aprotic solvents (N-methyl-2-pyrrolidone and hexamethylphosphoramide) took place rapidly at room temperature yielding polyamides with high molecular weight. The interfacial polycondensation in a chloroform–water system was also successful for polyamide formation. S,S′-Di-p-nitrophenyl dithioisophthalate reacted much more slowly toward diamines than the 2-benzothiazolyl dithiolesters. Prior to polymer synthesis, the aminolysis of active monothiolesters was carried out as a model compound study.     

Synthesis of hydroxyl-containing polyamides by ring-opening polyaddition of 3,3′-disubstituted bis-β-propiolactone with diamines

A new bis-β-lactone monomer, 3,3′-p-phenylenebis(2,2-dichloro-β-propiolactone), was synthesized by the cycloaddition of dichloroketene with terephthalaldehyde. Hydroxyl-containing polyamides with inherent viscosities as high as 1.1 were prepared by the ring-opening polyaddition of the bis-β-lactone with various diamines in tetrahydrofuran at room temperature. They were readily soluble in a wide range of solvents, which included tetrahydrofuran and acetone. The polymers melted and decomposed at temperatures around 200°C.     

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 of hydroxyl-containing polyamides by ring-opening polyaddition of 4,4′-disubstituted bis(4-butanolide) with aliphatic diamines

Hydroxyl-containing polyamides have been prepared by the ring-opening polyaddition of 4,4′-oxydi-p-phenylenebis(4-butanolide) with aliphatic diamines in alcoholic solvents at 65–80°C. These polymers having inherent viscosities ranging from 0.1 to 0.5 were soluble in a variety of solvents including dimethylformamide, formic acid, and m-cresol. Transparent and flexible films cast from these solutions were highly hygroscopic. All the polymers had low softing temperatures in the range of 115–130°C, and began to decompose at around 250°C, both in air and under nitrogen.     

Preparation and properties of aromatic polyamides from 2,2′-bis(p-carboxyphenoxy) biphenyl or 2,2′-bis(p-carboxyphenoxy)-1,1′-binaphthyl and aromatic diamines

New aromatic dicarboxylic acids having kink and crank structures, 2,2′-bis(p-carboxyphenoxy) biphenyl and 2,2′-bis(p-carboxyphenoxy)-1,1′-binaphthyl, were synthesized by the reaction of p-fluorobenzonitrile with biphenyl-2,2′-diol and 2,2′-dihydroxy-1,1′-binaphthyl, respectively, followed by hydrolysis. Biphenyl-2,2′-diyl-and 1,1′-binaphthyl-2,2′-diyl-containing aromatic polyamides having inherent viscosities of 0.58–1.46 dL/g and 0.63–1.30 dL/g, respectively, were obtained by the low-temperature solution polycondensation of the corresponding diacid chlorides with aromatic diamines. 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 210–272 and 260–315°C, respectively. They began to lose weight around 380°C, with 10% weight loss being recorded at about 450°C in air. © 1993 John Wiley & Sons, Inc.     

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 of aliphatic–aromatic polyamides by palladium-catalyzed polycondensation of aliphatic diamines,aromatic dibromides,and carbon monoxide

Aliphatic–aromatic polyamides were synthesized by the palladium-catalyzed polycondensation of aliphatic diamines, aromatic dibromides, and carbon monoxide. The effects of variables, such as the kind and amount of base, reaction temperature, and the kind of palladium catalyst were investigated in detail on the reaction of hexamethylenediamine and bis(4-bromophenyl) ether with carbon monoxide. Inherent viscosities of the polyamides were between 0.13 and 1.21 dL/g and varied markedly with the structure of the diamine component. Solubility of the polyamides decreased with increase of chain length of aliphatic diamines, and the polyamides derived from p-dibromobenzene was insoluble in organic solvents except for m-cresol. Polyamides obtained from primary aliphatic diamines began to decompose at 210–250°C in air due to decomposition of the aliphatic chain.     

Synthesis of polyamide-pyrazolones from 2,2′-disubstituted bis(4-ethoxymethylene-5-oxazolone) and aromatic dihydrazines

A new class of polyamide-pyrazolones was synthesized by the vinylogous nucleophilic substitution polymerization, which was followed by rearrangement, from 2,2′-p-phenylenebis(4-ethoxymethylene-5-oxazolone) and aromatic dihydrazines. Solution polymerization was carried out in polar aprotic solvents under mild conditions to yield polymers having inherent viscosities in the range of 0.5–1.2 quantitatively. The polymer derived from bis(4-hydrazinophenyl) sulfone was readily soluble in strongly polar solvents, while that from bis(4-hydrazinophenyl)methane was partially soluble or swelled in these solvents. The polyamide-pyrazolones which are presumed to contain some intermediate oxazolone structure showed a low level of thermal stability.     

Synthesis of polyamides from active 1-benzotriazolyl diesters and diamines under mild conditions

The effect of the solvent on the inherent viscosity of polyamides was investigated in the polycondensation of new active 1-benzotriazolyl diesters, such as 1,1′-(adipolydioxy)bisbenzotriazole and 1,1′-(isophthaloyldioxy)bisbenzotriazole, with diamines. The preferred polymerization media were polar aprotic solvents, including N-methyl-2-pyrrolidone and hexamethylphosphoramide. The solution polycondensation at room temperature afforded a series of polyamides having inherent viscosities as high as 1.8 from both aliphatic and aromatic diamines. The 1-benzotriazolyl diesters were more reactive than di(2,4-dinitrophenyl) isophthalate toward diamines. Prior to polymer synthesis, the aminolysis of some active monoesters was carried out as a model compound study.     

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.     

Syntheses and properties of polyamides from ether diacid having the spirobichroman unit

A novel hexamethylspirobichroman (HMSBC) unit-containing dicarboxylic acid, 6,6′-bis(4-carboxyphenoxy)-4,4,4′,4′,7,7′-hexamethyl-2,2′-spirobichroman ( 3 ), was derived from nucleophilic substitution of p-fluorobenzonitrile with the phenolate ion of 6,6′-dihydroxy-4,4,4′,4′,7,7′-hexamethyl-2,2′-spirobichroman ( 1 ), followed by alkaline hydrolysis of the intermediate bis(ether nitrile). Using TPP and pyridine as condensing agents, a series of polyamides with inherent viscosities in the range of 0.82–1.14 dL/g were prepared by the direct polycondensation of dicarboxylic acid 3 with various aromatic diamines. All the obtained polymers were noncrystalline and soluble in various organic solvents such as N,N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP). Except for the polymer derived from benzidine, the other polyamides could be solution cast into transparent and tough films, and their tensile strengths, elongations at break, and tensile moduli were in the range of 56–76 MPa, 4–59%, and 1.6–2.0 GPa, respectively. These polyamides had glass transition temperatures in the range of 183–200°C with 10% weight loss above 420°C. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1479–1486, 1997     

Polyamides containing arylene sulfone ether linkages

Polyamides containing arylene sulfone ether linkages were synthesized from 4,4′-[sulfonylbis(p-phenyleneoxy)] dibenzoyl chloride (SPCI), 3,3′-[sulfonylbis(p-phenyleneoxy)] dibenzoyl chloride (SMCl), and arylene sulfone ether diamines (SED), by solution and interfacial polymerization techniques. In solution polymerization, the effect of various acid acceptors such as propylene oxide (PO), lithium chloride (LiCl)/lithium hydroxide (LiOH), and triethylamine (TEA) on molecular weight of the polyamides was studied. The effect of methyl substituted and unsubstituted aromatic sulfone ether diamines on molecular weight and thermal properties of polyamides was also studied. The polyamides prepared were characterized by solution viscosity, elemental analysis, thermal gravimetric analysis, differential scanning calorimetry, and x-ray diffraction. Physical and thermal properties of polyamides prepared from SPCl and SED were compared with the polyamides prepared from SMCl and SED.     

Synthesis of polyamides from active 4,4′-diacylbis-2-aryl-1,3,4-oxadiazoline-5-thiones and -ones and diamines under mild conditions

New active bisamides, 4,4′ -diacylbis-2-aryl-1,3,4-oxadiazoline-5-thiones and -ones having various electron accepting groups in the oxadiazoline units were synthesized, and their reactivities toward diamines were investigated. The polycondensation reactions of the bisamides derived from 2-aryl-1,3,4-oxadiazoline-5-thiones with both aliphatic and aromatic diamines occurred rapidly even at room temperature to form high-molecular-weight polyamides in quantitative yields. The reactivities of the bisamides having electron accepting groups such as p-chloro and p-nitro groups, particularly p-nitro groups, toward diamines were much higher than that of the corresponding bisamide having no such group. It was also found that reaction conditions such as solvent, monomer concentration, and temperature had a strong influence on the molecular weight of the resulting polyamides. Aminolysis of several benzoyl derivatives of 2-aryl-1,3,4-oxadiazoline-5-thiones and -ones was also carried out as a model reaction, and the effect of electron accepting groups on the reactivity of these compounds was discussed.     

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.     

Synthesis of new polydimethylsiloxane-polyamide copolymers from phenylene-bis-5-oxazolones and aminopropyl-terminated polydimethylsiloxane oligomers

Alternating polydimethylsiloxane-polyamide block copolymers were prepared in dichloromethane or chloroform solution at room temperature from 3-amino-n-propyl-terminated polydimethylsiloxane oligomers and 2,2′-p-phenylenebis(4,4-dimethyl-5-oxazolone). Solution and thermal properties of the polymers were characterized.     

Synthesis of polyamides from pseudo dibenzoylphthaloyl chlorides and aliphatic diamines

New pseudo dibenzoylphthaloyl chlorides, namely, 2,5-dibenzoylterephthaloyl, 4,6-dibenzoylisophthaloyl, and 4,6-di(p-toluyl)isophthaloyl chlorides, were synthesized as monomers. The ring-opening polyaddition reaction of the pseudo dibenzoylphthaloyl chlorides with aliphatic diamines in N-methyl-2-pyrrolidone afforded a new class of polyamides having inherent viscosities of 0.2 ～ 0.6 in quantitative yield. The solution polymerization was almost completed within 30 min at room temperature. All of the polyamides were soluble in a wide range of solvents including tetrahydrofuran. These polymers began to decompose at around 300°C both in air and under nitrogen as determined by differential thermal analysis (DTA) and thermogravimetric analysis (TGA).