Characterization Of Aromatic Polyamides Research Articles

Synthesis and characterization of aromatic polyamides containing an s‐triazine ring with thiophenoxy linkages

AbstractA series of aromatic polyamides containing an s‐triazine ring with thiophenoxy linkages was synthesized from two new diacids, namely 2,4‐bis‐(4‐carboxyphenoxy)‐6‐thiophenoxy‐s‐triazine and 2,4‐bis‐(3‐carboxyphenoxy)‐6‐thiophenoxy‐s‐triazine, and commercially available aromatic diamines by using Yamazaki's phosphorylation reaction. The polyamides were obtained in good yields and were characterized by solubility tests, viscosity measurements, FTIR, 1H and 13C NMR spectroscopy, X‐ray diffraction studies and thermogravimetric analysis. The polyamides were found to have inherent viscosities in the range of 0.35 to 0.56 dl g−1 in N,N‐dimethylacetamide (DMAc) at 30 ± 0.1 °C. All the polyamides were readily soluble in solvents such as DMAc, N‐methyl‐2‐pyrrolidone (NMP), N,N‐dimethylformamide (DMF) and m‐cresol. Thermogravimetric analysis of the polyamides indicated no weight loss below 345 °C under a nitrogen atmosphere. Copyright © 2004 Society of Chemical Industry

Synthesis and characterization of aromatic polyamides containing alkylphthalimido pendent groups

AbstractA series of polyisophthalamides containing pendent phthalimido groups and flexible side spacers were prepared from four novel diacids and three commercial aromatic diamines. These polyamides were prepared in high yields and with high molecular weights by direct polycondensation with triphenyl phosphite and pyridine as condensing agents. The weight‐average and number‐average molecular weights, measured by gel permeation chromatography, were 70,000–137,000 and 47,000–86,000 g/mol, respectively. The novel polyamides were amorphous and readily soluble and showed glass‐transition temperatures of 150–240 °C, as measured by differential scanning calorimetry. Thermogravimetric analysis showed that the 10% weight‐loss temperatures in nitrogen were 355–430 °C, a significant improvement in thermal stability having been observed with the increase in the side‐chain length. A theoretical quantum mechanical study was successfully carried out to explain these results. Flexible and tough films, cast from polymer solutions, showed tensile strengths of 50–125 MPa. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3711–3724, 2002

Synthesis and characterization of aromatic polyamides based on a bis(ether-carboxylic acid) or a dietheramine derived from tert-butylhydroquinone

1,4-Bis(4-carboxyphenoxy)-2-tert-butylbenzene (2a) and 1,4-bis(4-aminophenoxy)-2-tert-butylbenzene (2b) were synthesized in two steps starting from the nucleophilic aromatic substitution reaction of p-fluorobenzonitrile and p-chloronitrobenzene, respectively, with tert-butylhydroquinone in the presence of potassium carbonate in N,N-dimethylformamide (DMF). Aromatic polyamides were synthesized by direct polycondensation from diacid 2a with various diamines or from diamine 2b with various diacids, by means of triphenyl phosphite and pyridine in N-methyl-2-pyrrolidone solution containing calcium chloride. Inherent viscosities of the polyamides ranged from 0.64 to 1.04 dL/g. Almost all the polyamides are readily soluble in various organic solvents and afford transparent and tough films by solvent casting. The polyamides display T g values of 209-267°C and 10% weight loss values above 460°C in nitrogen and 439°C in air. A comparative study of some polyamides with an isomeric repeating unit is also presented.

Preparation and characterization of aromatic polyamides from 4,4′-(2,6-naphthylenedioxy)dibenzoic acid and aromatic diamines

Preparation and characterization of aromatic polyamides from 4,4′-(2,6-naphthylenedioxy)dibenzoic acid and aromatic diamines

Preparation and characterization of aromatic polyamides from 4,4'-(2,6-naphthylenedioxy)dibenzoic acid and aromatic diamines

SUMMARY: A new aromatic dicarboxylic acid, 4,49-(2,6-naphthylenedioxy)dibenzoic acid (3), was synthesized by the fluoro-displacement reaction of p-fluorobenzonitrile with 2,6-naphthalenediol in the presence of potassium carbonate, followed by alkaline hydrolysis. A series of aromatic polyamides having inherent viscosities of 1.30 ‐ 2.19 dL/g were prepared by the triphenyl phosphite activated polycondensation from the diacid 3 with sixteen aromatic diamines. Most of the resulting polymers were noncrystalline and readily soluble in a variety of polar solvents such as N,N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP). Except for those polymers derived from p-phenylenediamine, benzidine, and 4,49-bis(p-aminophenoxy)biphenyl, transparent, tough, and flexible films were cast from the DMAc or NMP solutions. The films had tensile strengths ranging from 70 to 91 MPa, elongations at break from 6 to 50%, and initial moduli from 1.35 to 2.32 GPa. The polyamides exhibit glass transition temperatures in the range of 178 ‐ 3008C. Almost all polymers are stable up to 4008C, with 10% weight loss being recorded above 5008C, in air and nitrogen atmosphere.

Preparation and characterization of aromatic polyamides from 4,4'-(2,6-naphthylenedioxy)dibenzoic acid and aromatic diamines

Preparation and characterization of aromatic polyamides from 4,4'-(2,6-naphthylenedioxy)dibenzoic acid and aromatic diamines

Synthesis and characterization of aromatic polyamides and polyimides from trimethyl- and di- t-butylhydroquinone-based ether-linked diamines

1,4-Bis(4-aminophenoxy)trimethylbenzene ( 3a) and 1,4-bis(4-aminophenoxy)-2,5-di- t-butylbenzene ( 3b) were synthesized in two steps from the hydroquinones via nucleophilic aromatic substitution and catalytic reduction. Aromatic polyamides were synthesized from these diamines by direct polycondensation with various diacid chlorides or by reaction with diacids, triphenyl phosphite and pyridine in N-methyl-2-pyrrolidinone (NMP). Aromatic polyimides were synthesized from the trimethyl monomer using commercial dianhydrides in two-step polycondensations. Characterization of polymers was accomplished by 1H n.m.r., 13C n.m.r., FTi.r., d.s.c. and t.g.a. Intrinsic viscosities of polyamides were between 0.30 and 0.73 dl g −1 in NMP for the trimethyl polymers and between 0.57 and 1.47 dl g −1 in 5% LiCl/NMP for the di- t-butyl polyamides. Viscosities of the poly(amic acid)s ranged from 0.45 to 0.85 dl g −1. Polyamides displayed T g values of 237–305°C and 5% weight loss values above 402°C in N 2. T g values of polyimides varied between 235 and 300°C, with 5% weight loss values above 435°C in N 2. Most polyimides were only soluble in H 2SO 4, while polyamides were soluble in polar aprotics such as NMP, N, N-dimethylacetamide and dimethyl sulfoxide.

Preparation and characterization of aromatic polyamides based on ether-sulfone-dicarboxylic acids

Two ether-sulfone-dicarboxylic acids, 4,4′-[sulfonylbis(2,6-dimethyl-1,4-phenylene)dioxy]dibenzoic acid (Me-III) and 4,4′-[sulfonylbis(1,4-phenylene)dioxy]-dibenzoic acid (III), were prepared by the fluorodisplacement of 4,4′-sulfonylbis(2,6-dimethylphenol) and 4,4′-sulfonyldiphenol with p-fluorobenzonitrile, and subsequent alkaline hydrolysis of intermediate dinitriles. Using triphenyl phosphite (TPP) and pyridine as condensing agents, aromatic polyamides containing ether and sulfone links were prepared by the direct polycondensation of the dicarboxylic acids with various aromatic diamines in the N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride. The inherent viscosities of the resulting polymers were above 0.4 dL/g and up to 1.01 dL/g. Most of the polyamides were readily soluble in polar solvents such as NMP, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO), and afforded tough and transparent films by solution-casting. Most of the polymers showed distinct glass transition on their differential scanning calorimetry (DSC) curves, and their glass transition temperatures (Tg) were recorded between 212–272°C. The methyl-substituted polyamides showed slightly higher Tgs than the corresponding unsubstituted ones. The results of the thermogravimetry analysis (TGA) revealed that all the polyamides showed no significant weight loss before 400°C, and the methyl-substituted polymers showed lower initial decomposition temperatures than the unsubstituted ones. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2421–2429, 1997

Preparation and characterization of aromatic polyamides based on ether‐sulfone‐dicarboxylic acids

Preparation and characterization of aromatic polyamides based on ether‐sulfone‐dicarboxylic acids

Synthesis and characterization of aromatic polyamides containing s‐triazine rings in the main chain

Synthesis and characterization of aromatic polyamides containing s‐triazine rings in the main chain

Synthesis and characterization of aromatic polyamides containing s-triazine rings in the main chain

Ten new aromatic polyamides containing s-triazine rings in the main chain were synthesized by the low temperature interfacial polycondensation technique involving the reactions of each of the two s-triazine containing diacylchlorides, viz., 2,4-bis (4-chlorocarbonylphenoxy)-6-methoxy-s-triazine and 2,4-bis(3-chlorocarbonylphenoxy)-6-methoxy-s-triazine, with five aromatic diamines namely, 4,4′-bis(4-aminophenoxy)diphenyl sulfone, 4,4′-bis(3-aminophenoxy)diphenyl sulfone, 2,2-bis[4(4-aminophenoxy) phenyl] propane, 1,4 bis (4-amino-phenoxy) benzene, and 1,3-bis (4-aminophenoxy)benzene. The resulting polyamides were characterized by viscosity measurements, IR and 1H-NMR spectroscopy, solubility tests, x-ray diffraction, and thermogravimetry. The polyamides had inherent viscosities in the range of 0.16–1.06 dL/g in N,N-dimethylacetamide at 30°C. Most of the s-triazine containing polyamides dissolved readily at room temperature in polar solvents. Except for the polyamide PA-2, the polyamides did not lose weight below 350°C under a nitrogen atmosphere. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1077–1085, 1997

Aliphatic-aromatic poly(ether amide)s containing oxyethylene units. Synthesis and characterization

The synthesis and characterization of aromatic polyamides containing oxyethylene units is reported, and the differences observed in polycondensation yields, molecular weights, and molecular weight distributions, as a function of the method of synthesis, are discussed. Four diamines containing oxyethylene units and aromatic rings, meta and para oriented, and their corresponding hydrochlorides were prepared as condensation monomers to be combined with isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC). High molecular weight polyamides were obtained by interfacial and low-temperature solution methods. Values of (OVERLINE)M(/OVERLINE)n up to 6 × 104 g/mol and (OVERLINE)M(/OVERLINE)w up to 2 × 105 g/mol could be measured by gel permeation chromatography using aromatic polyamide standards, and values of (OVERLINE)M(/OVERLINE)n up to 2 × 105 g/mol and (OVERLINE)M(/OVERLINE)w up to 5 × 105 g/mol by using polystyrene standards. © 1996 John Wiley & Sons, Inc.

Synthesis and characterization of aromatic polyamides from 1,1‐bis(4‐aminophenyl)‐2,2‐diphenylethylene and aromatic diacid chlorides

AbstractNovel, 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.