Synthesis and characterization of Schiff‐base‐containing polyimides

Benzyl bisthiosemicarbazone and its complexes with nickel (NiLH₄) and copper (CuLH₄) were used as diamine monomers for the synthesis of new Schiff‐base polyimides. The solution polycondensation of these monomers with the aromatic dianhydrides afforded metal‐containing Schiff‐base polyimides with inherent viscosities of 0.98–1.33 dL/g (measured in N‐methyl‐2‐pyrrolidone at 25°C). The polyimides were generally soluble in a wide range of solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, tetrachloroethane, hexamethylene phosphoramide, N‐methyl‐2‐pyrrolidone, ethyl acetate, and pyridine at room temperature. The initial degradation temperatures of the resultant polyimides fell in the range of 220–350°C in nitrogen with char yields ranging from 36 to 64% at 700°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of new polyamides derived from 1,3-bis[4-(4-aminophenoxy)phenyl]adamantane

Several new polyamides were synthesized by direct polycondensation of the 1,3-bis[4-(4-aminophenoxy)phenyl]adamantane ( I ) with various dicarboxylic acids. The polyamides had inherent viscosities and number-average molecular weights (M_n) of 0.46–0.96 dL/g and 28,000–109,000, respectively. All polyamides III had good solubilities and were soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and pyridine. Polyamides had tensile strengths of up to 72.3 MPa, elongation to breakage values of up to 10.2%, and initial modulus of up to 2.1 GPa. Their glass transition temperatures were found to be 228–269°C and 252–307°C using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA), respectively. The melting temperature of III_f was observed at 318°C using DSC. The temperatures of polyamides III at a 5% weight loss ranged from 395 to 435°C in air and from 400 to 450°C in a N₂ atmosphere. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:315–321, 1998     

Synthesis of polyamides from substituted fluorene and diamides in the presence of a copper(I) catalyst

2,7‐Dibromo‐9,9‐dioctylfluorene was synthesized by a two‐step reaction from fluorene and n‐octylboromide. This was reacted with benzamide for the preparation of a model compound and with terephthalamide, isophthalamide, and adipamide for the preparation of polyamides in the presence of a mixture of 10 mol % CuI and 20 mol % N,N′‐dimethylethylenediamine as a catalyst and K₂CO₃ as a base. The monomer and the model compound were characterized with Fourier transform infrared, proton nuclear magnetic resonance, and elemental analysis. The prepared polyamides were characterized with Fourier transform infrared, proton nuclear magnetic resonance, differential scanning calorimetry, thermogravimetric analysis, and solubility and viscosity measurements. The obtained polyamides possessed excellent solubility in common organic solvents, and they exhibited inherent viscosities in the range of 0.93–1.19 dL/g. According to the differential scanning calorimetry analysis, the glass‐transition temperatures of the polyamides were in the range of 84–154°C. Thermogravimetric analysis indicated that a 2% weight loss of the polyamides occurred in the temperature range of 218–253°C under a nitrogen atmosphere. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of high performance polyamides utilizing copper‐catalyzed amidation of a dibromoarene with different diamides

A series of diphenylquinoxaline‐containing polyamides were prepared from the condensation polymerization of 2,3‐bis (4‐bromophenyl) quinoxaline (DBQ) with various primary and secondary diamides via copper‐catalyzed amidation reaction. The polyamides were characterized with FTIR, NMR, GPC, differential scanning calorimeter, and thermo gravimetric analysis, and their solubility and viscosity were measured. The polyamides synthesized here are amorphous and showed relatively good solubility in polar aprotic solvents and demonstrate the ability to form brownish hard films by solvent casting; their inherent viscosities ranged from 49 to 55 mL/g. The average molecular weights of polyamides were in the range of M_w = 11,950–5592 g/mol (MWD = 1.21–1.87). These polyamides had relatively high thermal stability with T_g values up to 276°C, 10% weight loss temperatures (T_10%) in the range of 364–476°C, and char yields at 600°C in N₂ up to 72%. They also exhibit emission in the solid state and in dilute (0.2 g/dL) DMAc solution at 425–484 nm with photoluminescence quantum (?_f) yields in the range of 14–23%. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and properties of polyamides based on 5,5′‐bis[4‐(4‐aminophenoxy)phenyl]‐hexahydro‐4,7‐methanoindan

A new diamine 5,5′‐bis[4‐(4‐aminophenoxy)phenyl]‐hexahydro‐4,7‐methanoindan ( 3 ) was prepared through the nucleophilic displacement of 5,5′‐bis(4‐hydroxylphenyl)‐hexahydro‐4,7‐methanoindan ( 1 ) with p‐halonitrobenzene in the presence of K₂CO₃ in N,N‐dimethylformamide (DMF), followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of new polyamides were synthesized by the direct polycondensation of diamine 3 with various aromatic dicarboxylic acids. The polymers were obtained in quantitative yields with inherent viscosities of 0.76–1.02 dl g⁻¹. All the polymers were soluble in aprotic dipolar solvents such as N,N‐dimethylacetamide (DMAc) and N‐methyl‐2‐pyrrolidone (NMP), and could be solution cast into transparent, flexible and tough films. The glass transition temperatures of the polyamides were in the range 245–282 °C; their 10% weight loss temperatures were above 468 °C in nitrogen and above 465 °C in air. © 2000 Society of Chemical Industry     

Synthesis,characterization, and properties of novel fluorine containing aromatic polyamides

A series of novel fluorine containing aromatic polyamides were synthesized by the direct polycondensation of various fluorine containing aromatic diamines and commercially available 5‐t‐butyl isophthalic acid. These polyamides have good solubility in several organic solvents such as dimethylformamide, N,N‐dimethylacetamide, 1‐Methyl‐2‐pyrrolidone, dimethyl sulfoxide, and tetrahydrofuran. The synthesized polymers exhibited inherent viscosities up to 0.93 dL/g and M_w up to 1,52,000 with PDI of 2.49. The polyamides exhibited good thermal stability up to 489°C for 10% weight loss in nitrogen and high glass transition temperature up to 273°C. Dynamic mechanical analysis showed a very good retention of storage modulus up to the glass transition temperature. The tan δ peak value at 1 Hz was used to calculate the T_g and these values are in good agreement with differential scanning calorimetry data. The polyamide films were flexible with tensile strength up to 72 MPa, elongations at break up to 14%, and modulus of elasticity up to 1.39 GPa depending on the exact repeating unit structure. X‐ray diffraction measurements indicate that these polyamides are semicrystalline. Rheology study showed same trend of melt viscosity behavior with different shear rate for all polymers. Water absorption study indicates the hydrophobic nature of the polymer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and properties of novel aromatic polyamides with xanthene cardo groups

Two novel monomers, 9,9‐bis[4‐(4‐carboxyphenoxy)phenyl]xanthene (BCAPX) and 9,9‐bis[4‐(4‐aminophenoxy)phenyl]xanthene (BAPX) were prepared in two main steps starting from nucleophilic substitution of 9,9‐bis(4‐hydroxyphenyl)xanthene (BHPX) with p‐fluorobenzonitrile and p‐chloronitrobenzene, respectively. Using triphenyl phosphite and pyridine as condensing agents, two series of polyamides containing xanthene cardo groups with the inherent viscosities (0.82–1.32 dL/g) were prepared by polycondensation from BCAPX with various aromatic diamines or from BAPX with various aromatic dicarboxylic acids in an N‐methyl‐2‐pyrrolidone (NMP) solution containing dissolved calcium chloride, respectively. All new polyamides were amorphous and readily soluble in various polar solvents such as N,N‐dimethylformamide (DMF), NMP, N,N‐dimethylacetamide (DMAc) and pyridine. These polymers showed relatively high glass transition temperatures between 264 and 308°C, decomposition temperatures at 10% weight loss ranging from 502 to 540°C and 488 to 515°C in nitrogen and air, respectively, and char yields at 800°C in nitrogen higher than 56%. Transparent, flexible, and tough films of these polymers cast from DMAc solutions exhibited tensile strengths ranging from 86 to 109 MPa, elongations at break from 13 to 22%, and initial moduli from 2.15 to 2.63 GPa. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and characterization of new photoactive polyamides containing 4‐(4‐dimethylaminophenyl)urazole units

4‐(4‐dimethylaminophenyl)‐1,2,4‐triazolidine‐3,5‐dione ( DAPTD ) was prepared from 4‐dimethylaminobenzoic acid in five steps. The compound DAPTD was reacted with excess acetyl chloride in N,N‐dimethylacetamide (DMAc) solution and gave 1,2‐bisacetyl‐4‐[4‐(dimethylaminophenyl)]‐1,2,4‐triazolidine‐3,5‐dione as a model compound. Solution polycondensation reactions of monomer with succinyl chloride (SucC), suberoyl chloride (SubC), and sebacoyl chloride (SebC) were performed under conventional solution polymerization techniques in the presence of triethylamine and pyridine as a catalyst in N‐methylpyrrolidone (NMP) and led to the formation of novel aliphatic polyamides. These novel polyamides have inherent viscosities in the range of 0.09–0.21 dL/g in N,N‐dimethylformamide (DMF) at 25°C. Fluorimetric studies of the model compound as well as polymers were performed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 947–954, 2007     

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

A 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 properties of novel aromatic polyamides derived from 2,2‐bis[4‐(4‐amino‐2‐fluorophenoxy) phenyl]hexafluoropropane and aromatic dicarboxylic acids

A series of polyamides were synthesized by the direct polycondensation of 2,2‐bis[4‐(4‐amino‐2‐fluorophenoxy)phenyl]hexafluoropropane with various commercially available dicarboxylic acids such as terephthalic acid, isophthalic acid, 5‐t‐butyl isophthalic acid, and 2,6‐naphthalene dicarboxylic acid. The synthesized polyamides were soluble in several organic solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, and chloroform, and they exhibited inherent viscosities of 0.42–0.59 dL/g. The polyamides exhibited weight‐average molecular weights of up to 26,000, which depended on the exact repeating unit structure. These polyamides showed good thermal stability up to 440°C for a 10% weight loss in synthetic air. The polyamides synthesized from 5‐t‐butyl isophthalic acid and isophthalic acid exhibited glass‐transition temperatures of 217 and 185°C, respectively (by differential scanning calorimetry) in nitrogen. The polyamides synthesized from terephthalic acid and 2,6‐naphthalene dicarboxylic acid showed melting temperatures of 319 and 385°C, respectively. The polyamides films were pale yellow, with tensile strengths of up to 82 MPa, moduli of elasticity of up to 2.3 GPa, and elongations at break of up to 9%, which depended on the exact repeating unit structure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 691–696, 2003     

Synthesis and properties of novel polyamides containing sulfone‐ether linkages and xanthene cardo groups

In order to obtain polyamides with enhanced solubility and processability, as well as good mechanical and thermal properties, several novel polyamides containing sulfone‐ether linkages and xanthene cardo groups based on a new diamine monomer, 9,9‐bis[4‐(4‐aminophenoxy)phenyl]xanthene (BAPX), were investigated. The BAPX monomer was synthesized via a two‐step process consisting of an aromatic nucleophilic substitution reaction of readily available 4‐chloronitrobenzene with 9,9‐bis(4‐hydroxyphenyl)xanthene in the presence of potassium carbonate in N,N‐dimethylformamide, followed by catalytic reduction with hydrazine and Pd/C. Four novel aromatic polyamides containing sulfone‐ether linkages and xanthene cardo groups with inherent viscosities between 0.98 and 1.22 dL g^?1 were prepared by low‐temperature polycondensation of BAPX with 4,4′‐sulfonyldibenzoyl chloride, 4,4′‐[sulfonyl‐bis(4‐phenyleneoxy)]dibenzoyl chloride, 3,3′‐[sulfonyl‐bis(4‐phenyleneoxy)]dibenzoyl chloride and 4,4′‐[sulfonyl‐bis(2,6‐dimethyl‐1,4‐phenyleneoxy)]dibenzoyl chloride in N,N‐dimethylacetamide (DMAc) solution containing pyridine. All these new polyamides were amorphous and readily soluble in various polar solvents such as DMAc and N‐methylpyrrolidone. These polymers showed relatively high glass transition temperatures in the range 238–298 °C, almost no weight loss up to 450 °C in air or nitrogen atmosphere, decomposition temperatures at 10% weight loss ranging from 472 to 523 °C and 465 to 512 °C in nitrogen and air, respectively, and char yields at 800 °C in nitrogen higher than 50 wt%. Transparent, flexible and tough films of these polymers cast from DMAc solution exhibited tensile strengths ranging from 78 to 87 MPa, elongations at break from 9 to 13% and initial moduli from 1.7 to 2.2 GPa. Primary characterization of these novel polyamides shows that they might serve as new candidates for processable high‐performance polymeric materials. Copyright © 2010 Society of Chemical Industry     

Synthesis and properties of novel aromatic copolyamides containing chloro‐substituted phthalazinone moiety in the main chain

A series of novel copolyamides were synthesized by the direct polycondensation of 1,2‐dihydro‐2‐(4‐carboxyphenyl)‐4‐[3‐chloro‐4‐(4‐carboxyphenoxyl)phenyl]‐phthalazinone ( 1 ), terephthalic acid (TPA) with three commercial diamines. The inherent viscosities of the polyamides were between 0.82 and 1.86 dL/g. When the molar ratios of 1 and TPA were higher than 1 : 1, the polymers were soluble in some polar aprotic solvents such as N‐methyl‐pyrrolidone and N,N‐dimethyl acetamide etc. These polymers were amorphous with 10% weight loss temperatures in N₂ above 490°C and their glass transition temperatures were above 269°C. Some films of the polymers were pale yellow and transparent with tensile strengths up to 147.8 MPa, initial modulus up to 2.56 GPa and elongations at break values up to 9.8%, which depended on the repeating unit structures. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis of soluble and thermally stable polyamides from diamine containing (quinolin‐8‐yloxy) aniline pendant group

A novel diamine monomer having pendant 4‐(quinolin‐8‐yloxy) aniline group was successfully synthesized via aromatic substitution reaction of 8‐quinolinol with p‐fluoronitrobenzene followed by Pd/C catalyzed hydrazine reduction, amidation reaction between 4‐(quinolin‐8‐yloxy) aniline and 3,5‐dinitrobenzoylcholoride followed by Pd/C catalyzed hydrazine reduction. The diamine monomer was fully characterized by using FTIR, ¹H‐NMR, ¹³C‐NMR, and elemental analysis. The diamine monomer was polymerized with various aromatic and aliphatic dicarboxylic acids to obtain the corresponding polyamides. The polyamides had inherent viscosity in the range of 0.30–0.41 dL/g and exhibited excellent solubility in the polar aprotic solvents such as DMAc, NMP, N,N‐dimethylformamide, Pyridine, and DMSO. The glass transition temperatures (T_g) of the polymers are high (up to 313°C) and the decomposition temperatures (T_i) range between 200 and 370°C, depending on the diacids residue in the polymers backbone. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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 novel organosoluble polyesters based on a DIOL with azaquinoxaline ring

A series of new polyesters were synthesized by polycondensation of aliphatic and aromatic dicarboxylic dichlorides with a novel quinoxaline diol, 2,3‐bis (4‐hydroxy phenyl)‐5‐azaquinoxaline (DIOL). The DIOL was synthesized by reacting 4,4′‐dihydroxy benzil with 2, 3‐diaminopyridine (yield: 85%), and characterized by FTIR and ¹H‐NMR spectra. All polyesters showed good solubility in most aprotic polar solvents such as NMP (N‐methylpyrrolidone), DMF (dimethylformamide), DMSO (dimethylsulfoxide), DMAc (dimethylacetamide), HMPA (hexamethylenephosphoramide), and Py (pyridine). The inherent viscosity of polyesters was obtained in the range of 1.1–1.22 dL/mg. The glass transition temperatures of the polyesters were in the range of 200–280°C, as determined by DSC. The initial decomposition temperatures of the polyesters were above 300°C and the char yield at 750°C ranged from 30 to 60% under nitrogen atmosphere. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of new polyamides derived from 4‐(4′‐aminophenyl)urazole and aliphatic diacid chlorides

4‐(4′‐Aminophenyl)urazole (AmPU) was prepared from 4‐nitrobenzoic acid in six steps. The reaction of AmPU with acetyl chloride was performed in N,N‐dimethylacetamide solutions at different ratios, and the resulting disubstituted and trisubstituted amide derivatives were obtained in high yields and were used as models for polymerization reactions. Polycondensation reactions of AmPU with succinyl chloride, suberoyl chloride, and sebacoyl chloride were performed with conventional solution polymerization techniques in the presence of different catalysts, such as pyridine, triethylamine, and dibutyltin dilaurate, and led to the formation of novel aliphatic polyamides. The resulting novel polyamides had inherent viscosities of 0.11–0.22 dL/g in dimethylformamide or H₂SO₄ at 25°C. These polyamides were characterized with IR, ¹H‐NMR, elemental analysis, and thermogravimetric analysis. Some physical properties and structural characterization of these novel polyamides are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3173–3185, 2004     

Interaction of polystyryl radical with Cu(DMF)2Br2

The kinetics of 2,2′-azobisisobutyronitrile (AIBN) initiated polymerization of styrene in N,N-dimethylformamide (DMF) at 60°C were investigated in the presence of dibromo(N,N-dimethylformamide)copper(II) complex. The complex was prepared in situ by mixing tetrakis (N,N-dimethylformamide)copper(II) perchlorate with LiBr in the molar ratio of 1 : 2. The equilibrium constant for [Cu(DMF)₄]²⁺ + 2Br^? ? Cu(DMF)₂Br₂ + 2DMF was calculated by the limiting logarithmic method as 1.80 × 10³ L² mol^?2. The velocity constant at 60°C for the interaction of polystyryl radical with Cu(DMF)₂Br₂ is 7.46 × 10⁴ L mol^?1 s^?1.     

Synthesis and characterization of new polyamides derived from 1,3‐(4‐carboxy phenoxy) propane and aromatic diamines

Six new polyamides 5a‐f containing flexible trimethylene segments in the main chain were synthesized through the direct polycondensation reaction of 1,3‐(4‐carboxy phenoxy) propane 3 with six derivatives of aromatic diamines 4a‐f in a medium consisting of N‐methyl‐2‐pyrrolidone, triphenyl phosphite, calcium chloride, and pyridine. The polycondensation reaction produced a series of novel polyamides containing flexible trimethylene segments in the main chain in high yield with inherent viscosities between 0.32 and 0.68 dL/g. The resulted polymers were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity, and solubility tests. Thermal properties of these polymers were investigated by using thermal gravimetric analysis (TGA) and differential thermal gravimetric (DTG). The glass‐transition temperatures of these polyamides were recorded between 165 and 190°C by differential scanning calorimetry, and the 10% weight loss temperatures were ranging from 360 to 430°C under nitrogen. 1,3‐(4‐Carboxy phenoxy) propane 3 was prepared from the reaction of 4‐hydroxy benzoic acid 1 with 1,3‐dibromo propane 2 in the presence of NaOH solution. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis,characterization, and properties of novel aromatic polyamides containing phthalazinone moiety

A unsymmetrical and kink non-coplanar heterocyclic dicarboxylic acid monomer, 4-[4-(4-carboxy phenoxy)-naphthyl]-2-(4-carboxyphenyl)phthalazin-1-one (3) was successfully synthesized with high purity and high yields. A series of novel polyamides containing phthalazinone were prepared from the newly synthesized dicarboxylic acid with various aromatic diamines by means of the phosphorylation polycondensation reaction. Molecular weights of the obtained polyamides were evaluated viscometrically, and the inherent viscosities (η_inh) measured were in the range 0.54–0.69 dL/g. These polyamides were amorphous and readily soluble in many organic solvents, such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimetheylformamide, dimethyl sulfoxide, pyridine, and m-cresol etc., and they could easily be solution-cast into transparent, flexible films with good mechanical properties, with tensile strength ranging from 63.9 to 81.6 MPa and elongation at break from 7.2 to 11.4%. These polymers still kept good thermal stability with high-glass transition temperatures in the range of 283–338 °C, and the decomposition temperature in nitrogen for a 10% weight-loss temperatures in excess of 490 °C, and char yield at 800 °C in nitrogen ranged from 56 to 63%. Furthermore, the polyamides films were essentially colorless; their cut-off wavelengths were between 365 and 379 nm.     

Synthesis and characterization of polyamides and poly(amide-imide)s based on ether-sulfone-diamines

A series of polyamides and poly(amide-imide)s were prepared by the direct polycondensation of 4,4′-[sulfonylbis(1,4-phenyleneoxy)]dianiline or 4,4′-[sulfonylbis(2,6-dimethyl-1,4-phenyleneoxy)]dianiline with aromatic dicarboxylic acids and phthalimide unit-bearing dicarboxylic acids in a N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride using triphenyl phosphite and pyridine as condensing agents. The inherent viscosities of the resulting polymers were above 0.45 dL/g and up to 1.70 dL/g. Except for the polyamides derived from terephthalic acid and 4,4′-biphenyldicarboxylic acid, all the other polyamides and all poly(amide-imide)s were readily soluble in polar organic solvents such as NMP, N, N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and m-cresol, and afforded transparent and tough films by solution-casting. Most of the polymers showed distinct glass transition on their differential scanning calorimetry (DSC) traces and their glass transition temperatures (T_g) stayed between 140–264 °C. The methyl-substituted polymers showed higher T_gs than the corresponding unsubstituted counterparts. The results of the thermogravimetry analysis (TGA) revealed that all the methyl-substituted polymers showed lower initial decomposition temperatures than the unsubstituted ones.