Phosphonic acid‐containing polysulfones as anticorrosive layers

As a part of research work to elaborate polymeric materials for metal corrosion protection, we have developed a new family of phosphonic acid‐containing polymers. The synthesis and the characterization of polysulfones bearing alkyl phosphonate ester side groups are first described. These polymers are synthesized by direct polycondensation of a phosphonate ester‐containing bisphenol by aromatic nucleophilic substitution. The physicochemical properties of the resulting polymers are described. Acidic hydrolysis of phosphonate esters results in the formation of phosphonic acid groups. A series of phosphonic acid‐containing polysulfones is therefore obtained and characterized. A preliminary evaluation of the anticorrosive properties of these polymers is described. In 0.25M Na₂SO₄ solution, the corrosion rate of a polymer‐coated mild steel sample is much lower than of the free metal substrate. These results suggest that phosphonic acid‐containing polysulfones might be interesting as anticorrosive coatings. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41890.     

Effect of gamma irradiation on the metal sorption and separation of some divalent metals by some new polymeric bifunctional resins

The metal sorption and separation of some divalent metals from solutions of varying acidity by a new series of gamma-irradiated ionic polymer resins have been investigated. Three polymeric resins, viz., phosphonic acid, phosphonate monoethyl ester, and phosphonate diethyl/monoethyl ester, were used in this study. The results of metal sorption and separation were compared with those of the well-known cation exchange resin Dowex X8. The results were correlated in the usual manner of distribution coefficients (D) of three divalent metals Sr(II), Co(II), and Ni(II). The results of metal sorption by the ionic resins under investigation compared with that of sulfonic acid resin, showed that Ni showed the highest affinity for the unirradiated monoethyl ester/phosphonic acid resin, while Sr showed the highest affinity for phosphonic acid resin and Co showed the highest affinity for mono/diethyl ester phosphonic acid resin. Moreover, the three metals (Sr, Co, Ni) showed the lowest affinity toward sulfonic acid resin. The calculated separation factors for the different resins indicate that the unirradiated phosphonic acid resin has the highest capacity to separate Sr from Ni, whereas mono/diethyl ester/phosphonic acid resins have the highest capacity to separate Co from Sr and Ni. Furthermore, the affinity of the ionic polymers for the metal ions was not greatly changed after gamma irradiation. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:1091–1101, 1997     

Thermotropic liquid crystalline polyphenylphosphates containing aryl ester mesogens

A series of main‐chain liquid crystalline polyphosphate esters with varying center core in a triad ester mesogen were prepared. The phosphorus is incorporated in the middle of the spacer unit. All the monomers and polymers were characterized by spectral and thermal techniques. Thermogravimetric analysis shows that these polymers were stable up to 295–340°C. The char yields of the polymer were in range of 11–31%. Differential scanning calorimetry (DSC) thermal analysis confirms the mesophase formation of the polymers. Some of the polymers exhibited micro‐grainy textures with low glass transition. The DSC and microscopic analysis reveal that the polymer containing central unit which increases the aspect ratio shows liquid crystalline properties, whereas the unit that decreases the aspect ratio failed to show the mesophase formation. Energy minimized structures for the mesogenic units reveal that the polymers containing phenyl, pyridazine, diphenyl ester, and biphenyl unit shows high aspect ratio compared to nonmesogenic phenolphthalein, bisphenol‐A, and bisphenol‐S units. It revealed that increasing the length of the mesogen and incorporating heteroatoms in the aromatic moiety increased the mesophase stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3924–3930, 2007     

Studies of phosphonate‐containing bismaleimide resins. I. Synthesis and characteristics of model compounds and polyaspartimides

Two phosphonate‐containing bismaleimide (BMI) [(4,4′‐bismaleimidophenyl)phosphonate] monomers with different melting temperatures and similar curing temperatures were synthesized by reacting N‐hydroxyphenylmaleimide with two kinds of dichloride‐terminated phosphonic monomers. The BMI monomers synthesized were identified with ¹H‐, ¹³C‐, and ³¹P‐nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. The phosphonate‐containing BMI monomers react with a free‐radical initiator to prepare phosphonate‐containing BMI polymers and also with various aromatic diamines to prepare a series of polyaspartimides as reactive flame retardants. The polymerization degrees of polyaspartimides depend on the alkalinity and nucleophility of diamines as chain extenders. Differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) were used to study the thermal properties of the phosphonate‐containing BMI resins such as the melting temperature, curing temperature, glass transition temperature (T_g), and thermal resistance. All the phosphonate‐containing BMI resins, except the BMI polymers, have a T_g in the range of 210–256°C and show 5% weight loss temperatures (T_5%) of 329–434 and 310–388°C in air and nitrogen atmospheres, respectively. The higher heat resistance of cured BMI resin relative to the BMI polymer is due to its higher crosslinking density. Since the recrosslinking reactions of BMI polymers and polyaspartimides occur more easily in an oxidation environment, their thermal stabilities in air are higher than are those in nitrogen gas. In addition, the thermal decomposition properties of polyaspartimides depend on the structures and compositions of both the diamine segments and the BMI segments. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1919–1933, 2002     

Synthesis and properties of novel aromatic poly(ester–amide)s derived from 1,5‐bis(3‐aminobenzoyloxy)naphthalene and aromatic dicarboxylic acids

A new naphthalene‐ring‐containing bis(ester–amine), 1,5‐bis(3‐aminobenzoyloxy)naphthalene, was prepared from the condensation of 1,5‐dihydroxynaphthalene with 3‐nitrobenzoyl chloride followed by catalytic hydrogenation. A series of novel naphthalene‐containing poly(ester–amide)s was synthesized by direct phosphorylation polyamidation from this bis(ester–amine) with various aromatic dicarboxylic acids. The polymers were produced in high yields and had moderate inherent viscosities of 0.47–0.81 dL g^?1. The poly(ester–amide) derived from terephthalic acid was semicrystalline and showed less solubility. Other polymers derived from less rigid and symmetrical diacids were amorphous and readily soluble in most polar organic solvents and could be solution‐cast into transparent, flexible and tough films with good mechanical properties. The amorphous poly(ester–amide)s displayed well‐defined glass transition temperatures of between 179 and 225 °C from differential scanning calorimetry and softening temperatures of between 178 and 211 °C from thermomechanical analysis. These poly(ester–amide)s did not show significant decomposition below 400 °C in nitrogen or air. Copyright © 2004 Society of Chemical Industry     

Synthesis and characterization of copolyimides with high solubility

A series of copolyimides were prepared from various diamines (polysiloxane and isophorone units) with aromatic tetracarboxylic dianhydrides via a two‐step (thermal imidization) method. The monomers and polymers were produced in high yields, and the copolyimides containing Si? O? C bonds and asymmetric meta catenation in the polymer backbone exhibited good solubility. The glass‐transition temperatures (T_g's) of all the copolyimides were found to be 201–262 and 215–258°C by differential scanning calorimetry (DSC) and dynamic mechanical analysis, respectively. Thermogravimetric analyses indicated that the polymers were fairly stable up to 502–578°C (10 wt % loss in N2) and 490–574°C (10 wt % loss in air). The char yields at 800°C in N2 and air atmospheres were 26–59 and 20–53%, respectively. The copolymerization results, determined with 1H‐NMR and DSC, indicated a random copolymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1963–1970, 2003     

Synthesis and properties of novel naphthalene-containing bismaleimides

New aromatic bismaleimides containing bis(phenoxy) naphthalene unit, were synthesized. They were prepared by reacting a diamine-containing naphthalene and maleic anhydride by the usual two-step procedure that included ring-opening addition to give bismaleamic acid, followed by cyclodehydration to bismaleimide. The monomers were characterized by infrared (IR), proton nuclear magnetic resonance (H-NMR), elemental analyses (EA), and mass spectra (MS). Their thermal polymerization was investigated by differential scanning calorimetry (DSC). The presence of a naphthalene group in the backbone of the bismaleimide had increased the curing temperature and reduced the reactivity of the maleimide bond. The glass transition temperatures of the polymers were in the range of 291–334°C. Thermogravimetric analyses of the cured resins showed higher thermal stability and char yield for naphthalene-containing bismaleimides than for the corresponding benzene analog. The observed char yield of the bismaleimide resins are in accordance with the calculated C/H ratios. © 1996 John Wiley & Sons, Inc.     

Studies on thermotropic liquid crystalline polymers part XIII. Synthesis and properties of fully aromatic liquid crystalline poly(amide-ester)s

Four series of novel fully aromatic thermotropic liquid crystalline high molecular weight poly(amide-esters were prepared by direct polycondensation from terephthalic acid (TPA) and 2,6-naphthalene dicarboxlic acid with various aromatic diols and diamines in the presence of diphenyl chlorophosphate (DPCP), LiCl, and pyridine. The structures and thermal properties of the synthesized poly(amide-ester) s were examined by FTIR spectrum, wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermal optical polarized microscope and thermogravimetric analysis (TGA). The effects of the amounts and kinds of the aromatic diols and diamines (bisphenyl units, naphthalene and (un)substituted phenylene structures) on the molecular weight and thermal properties of the synthesized poly (amide-ester) s were investigated in this study. When a portion of the amide groups were replaced with the ester groups, most of the synthesized poly(amide-ester)s containing naphthalene or substituted hydroquinone units showed excellent mesophase and thermal stability, but the poly(amide-ester)s containing bisphenyl structures lost the mesophase behaviors. The P3 series of poly(amide-ester)s derived from TPA and 2,6-naphthalene dicarboxlic acid with phenylhydroquinone and various diamines possess liquid crystalline properties, even some of the diamines containing kink structures.     

Synthesis and photopolymerizations of new phosphonated methacrylates from alkyl α‐hydroxymethacrylates and glycidyl methacrylate

Novel aromatic mono‐ and di(phosphonate) or phosphonic acid monomers for use in dental composites were synthesized. Synthesis of monomer 1a involved three steps: (i) reaction of t‐butyl α‐bromomethacrylate (t‐BuBMA) and Bisphenol A, (ii) conversion to diacid chloride derivative using thionyl chloride, (iii) reaction of diacid chloride with diethyl (2‐hydroxyphenyl) phosphonate. Monomer 2a was synthesized from the reaction of 2‐chloromethacryloyl chloride and diethyl (2‐hydroxyphenyl) phosphonate. Synthesis of monomer 3a involved reaction of glycidyl methacrylate (GMA) with diethyl (2‐hydroxyphenyl) phosphonate. Hydrolysis of the phosphonate groups of monomers 1a and 2a with trimethylsilyl bromide (TMSBr) gave monomers 1b and 2b with phosphonic acid functionality, which is intended to improve binding ability of dental composites. The homopolymerization and copolymerization behaviors of the synthesized monomers with (Bis‐GMA) were investigated using photodifferential scanning calorimetry at 40°C with 2,2′‐dimethoxy‐2‐phenyl acetophenone as photoinitiator. The interaction of the monomer 1b with hydroxyapatite (HAP) was investigated using Fourier transform infrared technique. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of Soluble,Curable, and Thermally Stable Aromatic Polyamides Bearing Thiourea and Pendent 4-Pyridylformylimino Groups

A new aromatic dicarboxylic acid monomer 4-pyridylformylimino-N-(phenyl,2′,5′ – dicarboxylic acid) (PPDC) containing pyridine and azomethine units was synthesized through a simple one-step condensation reaction between 2-aminoterephthalic acid and 4-pyridinecarboxaldehyde. A series of new polyamides was prepared through the direct one-pot phosphorylation polycondensation of PPDC with simple aromatic commercial diamines and diamines bearing phenylthiourea groups. The polyamides were characterized by FT-IR, ¹H-NMR, and ¹³C-NMR spectroscopy. Thermal stability of the polymers was evaluated using thermogravimetric analysis. The polyamides with inherent viscosities in the range of 0.30–0.51 dL/g showed an outstanding solubility in various solvents such as 1-methyl-2-pyrrolidone (NMP), dimethly sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimetylacetamide (DMAc), and pyridine. The cured polyamides displayed significantly higher thermal stability than the uncured polyamides. The conductivity of the polyamides, when blended with 20% by weight of doped polyanilines, was in the range 3.09–4.21 × 10^?3 S cm^?1.     

Synthesis and characterization of tetrafluorophenyl phosphonic acid functionalized polyacrylates as potential proton conducting materials in fuel cells

Novel acrylate polymers functionalized with tetrafluorophenyl phosphonic acid groups were prepared by free radical polymerization of phosphonic ester acrylate monomers. Liberation of the free acid functions was realized by ester cleavage with Me₃SiBr and the subsequent hydrolysis with methanol. The obtained polymers were analyzed by NMR and IR spectroscopy. The ion exchange capacity of the phosphonic acid functionalized methacrylate polymer was determined to 2.8 mmol/g by titration with 0.1 M NaOH. The proton conductivity under anhydrous conditions was determined to 6.84 × 10⁻⁶ Scm⁻¹ at 120°C by electrochemical impedance spectroscopy.     

One-pot synthesis of soluble wholly aromatic liquid crystalline copoly(ester amide)s with high thermal and dimensional stability

Abstract

Thermotropic liquid crystalline polymers (LCPs) have been of great interest for electronic packaging. Herein, we introduce a series of wholly aromatic, thermotropic LCPs from copoly(ester amide)s of 6-hydroxy-2-naphthalic acid, isophthalic acid, terephthalic acid, and 4-aminophenol, prepared by a convenient one-pot melt polycondensation. Almost synthesized copoly(ester amide)s exhibited good solubility in common organic solvents at room temperature. Furthermore, they possessed high thermal stability with 2% degradation temperatures (T_id) of 359–368?°C and the char yields (at 600?°C) of 50.3–55.6%. The synthesized copoly(ester amide)s had relatively low coefficient of thermal expansion (CTE) values, which were 35.85–41.21?ppm °C^?1 in the temperature range of 50–200?°C. Furthermore, an annealing process could be employed to improve the thermomechanical properties of synthesized polymers. For instance, the CTE of sample LCP3 in range temperature of 275–315?°C was reduced by more than 90% after annealing at 320?°C for 1?h, implying the feasibility for electronic packaging.     

Synthesis and properties of new aromatic copolyesters containing phosphorous cyclic bulky groups

A series of phosphorus‐containing copolyesters was prepared by polycondensation of 2‐(6‐oxido‐6H‐dibenz<c,e><1,2>oxaphosphorin‐6‐yl)‐1,4‐naphthalene diol, 1 , or of an equimolecular amount of 1 and different bisphenols 2 , such as 4,4′‐isopropylidenediphenol, 4,4′‐(hexafluoroisopropylidene)diphenol and 2,7‐dihydroxynaphthalene, with an aromatic diacid chloride containing two preformed ester groups 3 , namely, terephthaloyl‐bis‐(4‐oxybenzoyl‐chloride). The copolyesters exhibited good thermal stability having the temperature of 5% weight loss above 380°C and char yield at 700°C in the range of 20–31.2%. The glass transition temperature was in the range of 136–147°C. The polymers exhibited thermotropic liquid crystalline behavior, as was observed with polarized optical microscopy, differential scanning calorimetry, and X‐ray experiments. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

New poly(amide‐imide) syntheses. 24. Synthesis and properties of fluorinated poly(amide‐imide)s based on 2,2‐bis[4‐(trimellitimidophenoxy)phenyl]hexafluoropropane and various aromatic diamines

An imide ring‐performed dicarboxylic acid bearing one hexafluoroisopropylidene and two ether linkages between aromatic rings, 2,2‐bis[4‐(4‐trimellitimidophenoxy)phenyl]hexafluoropropane (II), was prepared from the condensation of 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane and trimellitic anhydride. A novel series of poly(amide‐imide)s having inherent viscosities of 0.72 ∼ 1.86 dL g⁻¹ was prepared by the triphenyl phosphite‐activated polycondensation from the diimide‐diacid (II) with various aromatic diamines in a medium consisting of N‐methyl‐2‐pyrolidone, pyridine, and calcium chloride. Several of the resulting polymers were soluble in polar amide solvents, and their solutions could be cast into transparent, thin, flexible films having good tensile properties and high thermal stability. The 10% weight loss temperatures were all above 495°C in air or nitrogen atmosphere, and the glass transition temperatures were in the range of 237°–276°C. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 823–831, 1999     

Synthesis and characterization of aromatic–aliphatic polyamides

A new monomer, 2,5‐bis(4‐carboxy methylene phenyl)‐3,4‐diphenyl thiophene (V) has been synthesized and characterized by physical and spectroscopic methods. A series of eight aromatic–aliphatic polyamides was prepared from the (V) and different aromatic diamines using Yamazaki's direct phosphorylation reaction. The polyamides were characterized by IR spectroscopy, viscosity measurements, and thermal analysis. An excellent yield of these polyamides was obtained, with inherent viscosities in the range of 0.28 to 0.67 dL/g, and the polyamide were readily soluble in aprotic polar solvents such as N‐methyl‐2‐pyrrolidone, N‐N‐dimethyl acetamide, dimethyl sulphoxide, and so forth. Polyamides could be cast into transparent and flexible films. They had glass‐transition temperatures of 225–273°C. When evaluated by thermogravimetry, thermal analysis of the polyamides showed no weight loss below 311°C, and the char yield in air at 900°C was 55%–67%. The structure–property correlation among these polyamides is also discussed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 566–571, 2001     

Synthesis and characterization of new thermally stable aromatic copoly(ester–amide)s from diester‐dicarboxylic acids

Two new aromatic diester‐dicarboxylic acids containing furan rings, namely, benzofuro[2,3‐b]benzofuran‐2,9‐dicarboxyl‐bis‐pyridyl ester‐4,4′‐dicarboxylic acid and benzofuro[2,3‐b]benzofuran‐2,9‐dicarboxyl‐bis‐phenyl ester‐4,4′‐dicarboxylic acid were synthesized by the reaction of benzofuro[2,3‐b]benzofuran‐2,9‐dicarbonyl chloride with 6‐hydroxynicotinic acid and 4‐hydroxybenzoic acid, respectively. These monomers were converted to aromatic copoly(ester–amide)s by reaction with various aromatic diamines via direct polycondensation. Polymers were characterized by FTIR and ¹H NMR spectroscopy, thermogravimetry, viscosity and solubility tests. The inherent viscosity of the polymers was in the range 0.23–0.46 dl g^?1 in dimethyl sulfoxide at 30 °C. They dissolved readily in polar solvents at room temperature. They possess a glass‐transition temperature in the range 210–260 °C and exhibit excellent thermal stability. Copyright © 2004 Society of Chemical Industry     

Characterization of the polymer of a dipyrrolyl monomer by pyrolysis mass spectrometry

In this work, characterization of a homopolymer of succinic acid bis(4‐pyrrol‐1‐ylphenyl) ester prepared by galvonastatic polymerization was carried out by direct pyrolysis mass spectrometry. Although decomposition of the monomer yielding mainly butadionic acid and pyrrole occurred under the galvonastatic polymerization conditions, growth of the polymer through the pyrrole moieties was also achieved, yielding a ladder‐type polymer film. The polypyrrole chains contained both quinoid and aromatic units as in the case of polypyrrole, yet the extent of network structure was significantly diminished. A three‐step mechanism is proposed for the thermal decomposition process. The first step involves the cleavage of C₄H₄NC₆H₄O end groups. In the second step, decomposition of phenyl ester units and polypyrrole chains having quinoid structure takes place. The final stage of thermal degradation was attributed to decomposition of polypyrrole chains having aromatic structure. Copyright © 2004 Society of Chemical Industry     

Main‐chain liquid crystalline poly(ester‐amide)s containing lithocholic acid units

A series of poly(ester‐amide)s based on an ester group containing lithocholic acid derivative [3‐(3‐carboxypropionyl) lithocholic acid] and several aromatic diamines (naphthalene‐1,5‐diamine, 4,4′‐diaminodiphenyl ether, 4,4′‐diaminodiphenylmethane, 4,4′‐diaminodiphenylsulfone, benzidine, m‐phenylenediamine, p‐phenylenediamine, and tetraphenylthiophene diamine) was synthesized and characterized by solubility, viscosity, IR, differential scanning calorimetry, thermogravimetric analysis, and optical microscopy. The polymers were soluble in most of the organic solvents and had inherent viscosities in the range of 0.21–0.38 dL/g. All the polymers exhibited a nematic mesophase, but only on shearing. Thermal transitions due to mesophase formation were not seen in the differential scanning calorimetry thermograms. However, the liquid crystalline character of the polymers was observed under an optical microscope. Thermogravimetric analyses revealed the maximum decomposition temperature was 390–435°C for these polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 73–80, 2006     

Phosphorylation of cellulose with phosphorous acid and thermal degradation of the product

The reaction of cellulose with phosphorous acid in molten urea afforded a white, water-soluble product. The product was a monoester of phosphorous acid, and all the phosphorus residues were in phosphonic form, i.e., cellulose phosphonate. Quantitative addition of acrylonitrile to the P? H bonds in cellulose phosphonate occurred in the presence of sodium ethoxide. By alkali hydrolysis of the adduct, a polyelectrolyte having two different ionization groups, P? OH and COOH, could be prepared. Thermal degradation of three cellulose phosphonates, ammonium cellulose phosphonate (I), ammonium cellulose 2-cyanoethlyphosphonate (II), and ammonium cellulose 2-carboxyethylphosphonate (III), was examined. All three samples decomposed at a temperature around 270°C, but their thermal behaviors were different. Replacement of hydrogen in the phosphonic residue by 2-cyanoethyl and 2-carboxyethyl groups retarded dehydration of cellulose. Sample I had a satisfactory flame retardance; samples II and III were not flame resistant. Reduction of flame retardance may be due to the electron-withdrawing effect of the cyano and carboxyl groups.     

Structure and high‐resolution thermogravimetry of liquid‐crystalline copoly(p‐oxybenzoate‐ethylene terephthalate‐p‐benzamide)

Thermotropic liquid‐crystalline copoly(ester‐amide)s consisting of three units of p‐oxybenzoate (B), ethylene terephthalate (E) and p‐benzamide (A) were studied by proton nuclear magnetic resonance at 200 and 400 MHz, wide‐angle X‐ray diffraction, and high‐resolution thermogravimetry to ascertain their molecular and supermolecular structures, thermostability and kinetics parameters of thermal decomposition in both nitrogen and air. The assignments of all resonance peaks of [¹H]NMR spectra for the copoly(ester‐amide)s are given and the characteristics of X‐ray equatorial and meridional scans are discussed. Overall activation energy data of the first major decomposition have been evaluated through three calculating techniques. The thermal degradation occurs in three steps in nitrogen and air. The degradation temperatures are higher than 447 °C in nitrogen and 440 °C in air and increase with increasing B‐unit content at a fixed A‐unit content of 5 mol%. The temperatures at the first maximum weight‐loss rate are higher than 455 °C in nitrogen and 445 °C in air and also increase with an increase in B‐unit content. The first maximum weight‐loss rates range between 11.1 and 14.5%min⁻¹ in nitrogen and between 11.9 and 13.5%min⁻¹ in air. The char yields at 500 °C in both nitrogen and air range from 45.8 to 54.3 wt% and increase with increasing B‐unit content. But the char yields at 800 °C in nitrogen and air are quite irregular with the variation of copolymer composition and testing atmosphere. The activation energy and Ln (pre‐exponential factor) for the first major decomposition are usually higher in nitrogen than in air and increase slightly with an increase in B‐unit content at a given A‐unit content of 5 mol%. The activation energy, decomposition order, and Ln (pre‐exponential factor) of the thermal degradation for the copoly(ester‐amide)s in two testing atmospheres, are situated in the ranges of 210–292 kJmol⁻¹, 2.0–2.8, 33–46 min⁻¹, respectively. The three kinetic parameters of the thermal degradation for the aromatic copoly(ester‐amide)s obtained by high‐resolution thermogravimetry at a variable heating rate are almost the same as those by traditional thermogravimetry at constant heating rate, suggesting good applicability of kinetic methods developed for constant heating rate to the variable heating‐rate method. These results indicate that the copoly(ester‐amide)s exhibit high thermostability. The isothermal decomposition kinetics of the copoly(ester‐amide)s at 450 and 420 °C are also discussed and compared with the results obtained based on non‐isothermal high‐resolution thermogravimetry. © 1999 Society of Chemical Industry