Syntheses and properties of aromatic polyamides derived from 4,4′-oxydibenzoic acid and aromatic diamines

A series of aromatic polyamides were synthesized by direct polycondensation of 4,4-oxydibenzoic acid with various aromatic diamines inN-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride, using triphenyl phosphite and pyridine as condensing agents. The resultant polyamides had inherent viscosities of 0.21-1.48 dL/g. Most of the polymers were organo-soluble and could be solution-cast into flexible and strong films. The glass transition temperatures (T_gs) of most polyamides could be determined with the help of differential scanning calorimetry (DSC) traces, which were recorded in the range of 170–275 °C. Thermogravi metric data of these polymers indicated that most of the polyamides showed no significant weight loss before 450 °C in either air or nitrogen atmospheres.     

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.     

Synthesis and properties of polyamides and copolyamides based on 2,6-naphthalene dicarboxylic acid

A number of polyamides based on 2,6-naphthalene dicarboxylic acid (NDA) and various aromatic diamines were synthesized in N-methyl pyrrolidone (NMP) containing lithium chloride (LiCl) or calcium chloride (CaCl₂) by direct polycondensation using triphenyl phosphite and pyridine. The best reaction conditions for polycondensation were determined in terms of factors such as the amount of the solvency-promoting reagent such as LiCl or CaCl₂ and the initial reactant concentration. Thus, almost all polyamides were obtained with inherent viscosities above 1.0 and up to 3.28 dL/g. Similarly, high molecular weight copolyamides with inherent viscosities of 1.76–3.61 dL/g were prepared from 4,4′-oxydianiline (ODA) and mixed dicarboxylic acids of NDA/terephthalic acid (TPA) or NDA/isophthalic acid (IPA). The solubility of NDA homopolyamides depended on the diamine components. The polyamides derived from meta-, sulfone-, or alkylene-linked diamine showed increased solubility. Copolymerization of ODA with NDA/IPA led to a significant increase in solubility, whereas with NDA/TPA, it gave a limited improvement. All the homopolyamides and copolyamides showed an amorphous X-ray diffraction pattern. Almost all the polymers soluble in aprotic solvents can be solution-cast into strong and tough films. Glass transition shifts of some NDA polyamides can be observed in the differential scanning calorimetry (DSC) curves ranging from 243 to 345°C. Most NDA/IPA–ODA copolyamides also showed clear transitions in the range of 255–268°C. In nitrogen, all the polymers showed no significant weight loss up to 400°C, and their 10% weight loss temperatures were recorded in the range of 434–541°C. © 1994 John Wiley & Sons, Inc.     

Synthesis and properties of novel poly(coumarin‐amide)s

A novel monomer diacid, 6,6′‐methylenebis(2‐oxo‐2H‐chromene‐3‐carboxylic acid), was synthesized and used in a direct polycondensation reaction with various aromatic diamines in N‐methyl‐2‐pyrrolidone solution containing dissolved LiCl and CaCl₂, using triphenyl phosphite and pyridine as condensing agents to give a series of novel heteroaromatic polyamides containing photosensitive coumarin groups in the main chain. Polyamide properties were investigated by DSC, TGA, GPC, wide‐angle X‐ray scattering, viscosity, and solubility measurements. The copolymers were soluble in aprotic polar solvents, and their inherent viscosities varied between 0.49 and 0.78 dL g^?1. The weight‐average and number‐average molecular weights, measured by gel permeation chromatography, were 27,500–43,900 g mol^?1 and 46,500–66,300 g mol^?1, respectively, and polydispersities in the range of 1.48–1.69. The aromatic polyamides showed glass‐transition temperatures (T_g) ranging from 283 to 329°C and good thermal properties evidenced by no significant weight loss up to 380°C and 10% weight loss recorded above 425°C in air. All the polyamides exhibited an amorphous nature as evidenced by wide‐angle X‐ray diffraction and demonstrated a film forming capability. Water uptake values up to 3.35% were observed at 65% relative humidity. These polymers exhibited strong UV‐vis absorption maxima at 357–369 nm in DMSO solution, and no discernible photoluminescence maxima were detected by exciting with 365 nm. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Copolycondensation of IPA/TPA,BPA, and 4,4′‐dihydroxydipehnylsulfone and 4,4′‐dicarboxydiphenylsulfone

Copolycondensations of IPA, TPA, bisphenol A (BPA), and several cimonomers were carried out to improve thermal properties, such as, the glass transition temperature (T_g) of the IPA/TPA (50/50)–BPA polyester. Among the comonomers examined, 4,4′‐Dihydroxydiphenylsulfone (BPS) and 4,4′‐Dicarboxydiphenylsulfone (DCDPS) having a strongly dipolar sulfonyl group in the chain were significantly effective. The favorable effect upon the T_gs was studied by varying the amounts of BPS and DCDPS incorporated into the copolymers. In the copolycondensation with BPS, two‐stage copolycondensation of BPA first and then BPS, the reverse order of reaction, and their spontaneous addition were examined to investigate the effect of distribution of the BPS unit segments in the copolymer upon the T_gs of the resulted copolymers. The distribution was briefly studied from distribution of the IPA/TPA‐BPA oligomers in the initial reaction using GPC. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 875–879, 2000     

Thermal decomposition of poly(glycidyl azide) as studied by high-temperature FTIR and thermogravimetry

Thermal decomposition of poly(glycidyl azide) (PGA) has been studied by using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and high-temperature FTIR spectrometry. By using DSC and TGA techniques, the first stage weight loss of PGA due to exothermic decomposition of pendant azide ( N₃) groups was explained in terms of the energy released at every stage of decomposition. From the glass transition temperature (T_g) measurements, it was observed that T_g values of PGA increased with increasing quantity of decomposed  N₃ groups. The course of the decomposition reaction was also studied by taking successive FTIR spectra. It was observed that during the first stage weight loss process of PGA, the main chain was not decomposed thermally; inter- and intramolecular linking reactions accompanied the side chain decompositions. © 1996 John Wiley & Sons, Inc.     

Synthesis and characterization of polyamide resins from soy-based dimer acids and different amides

A series of soy-based polyamides with different dimer acids and diamines were synthesized using a condensation polymerization technique. The molecular weight of polyamides prepared from 1,4-phenylenediamine increases greatly with a reaction temperature above 260°C. The physical properties of the polyamides, such as glass transition temperature (T_g), melting point (T_m), decomposition temperature (T_d), crystalline behavior, and mechanical strength strongly depend on their molecular weight and flexibility of diamines used. The aromatic-based polyamides have a higher T_g, T_m, T_d, and stronger mechanical strength than that of aliphatic-based polyamides. X-ray diffraction patterns of the samples indicate that all of the resins synthesized present a typical semicrystalline morphology. Polyamides made from hydrogenated dimer acid possess lower T_g and higher mechanical strength, compared with polyamides from unsaturated dimer acid with different dimer and trimer ratios. These results are analyzed and discussed in accordance with the influence of rigid aromatic segments and the microstructure of different dimer acids. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:305–314, 1998     

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 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     

Aromatic polyamides bearing ether and isopropylidene or hexafluoroisopropylidene links in the main chain

Two multiring, flexible dicarboxylic acids, 4,4'-[isopropylidenebis(1,4-phenylene)dioxy] dibenzoic acid (3) and 4,4'-[hexafluoroisopropylidenebis(1,4-phenylene)dioxyldibenzoic acid (3-F), were synthesized through the nucleophilic fluorodisplacement ofp-fluorobenzonitrile by the dipotassium bisphenolates of the corresponding bisphenol precursors followed by alkaline hydrolysis. Two series of aromatic polyamides 5_a–k and 5_a–k-F containing both ether and isopropylidene or hexafluoroisopropylidene linkages between phenylene units were prepared by direct polycondensation of diacids 3 and 3-F, respectively, with various aromatic diamines using triphenyl phosphite and pyridine as condensing agents in aN-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride. The resulting polyamides of 5 and 5-F series have inherent viscosities of 0.92–1.29 dL/g and 0.60–0.92 dL/g, respectively. Most of these polymers are amorphous in nature, are soluble in polar solvents such as NMP,N,N-dimethylacetamide (DMAc), andN,N dimethylformamide (DMF), and can afford tough and flexible films by solution casting. Differential scanning calorimetry shows T_gs ranging from 175 to 239 °C for the 5 series polyamides and ranging from 172 to 267 °C for the 5-F series polymers. Both classes of polyamides show good thermal stability, with the 5-F series polyamides being more stable.     

Synthesis and characterization of polyesters based on tartaric acid derivatives

A series of aliphatic polyesters based on tartaric acid and its derivatives were synthesized starting from naturally occurring L-tartaric acid. The hydroxyl groups of the tartaric acid derivatives were first protected and the polyesters were synthesized by bulk and solution polycondensation methods. Two classes of polyesters were synthesized and characterized, the first by polycondensation of dimethyl 2,3-O-isopropylidene-l-tartrate with various alkanediols, and the second by reaction of 2,3-O-isopropylidene-l-threitol with various diacid chlorides. Acid catalyzed deprotection of isopropylidene groups gave well-defined polyesters having pendant hydroxyl functional groups regularly distributed along the polymer chain. The number average molecular weights (M_n) of the polymers were found to vary in the range of 2.3-15.7 × 10³ g mol⁻¹. Differential scanning calorimetry (DSC) analysis showed the glass transition temperatures (T_g) of the polyesters varied from −36.1 °C to 17.9 °C on varying the chain length.     

Synthesis and study of some newer polyamides for semipermeable membrane

A series of novel polyamides was prepared by low temperature solution polycondensation of N-(p/m-aminobenzoyl aminoacetyl)-N'-(4/3-aminobenzoyl) hydrazine with different diacid chlorides in dry N,N-Dimethylacetamide (DMAC). The properties of the polyamides for membrane processing were studied with the help of infrared spectra, inherent viscosity, differential thermal, and thermogravimetric analysis. The inherent viscosities were measured in concentrated sulfuric acid at 25±5°C and were in the range of 0.35–0.89 dL/g. The thermogravimetric data in air indicate that the initial decomposition temperature was in the range of 175–200°C. The polymer melt temperature (T_m) and glass transition temperature (T_g) were in the range of 230–450°C and 153.3–300°C, respectively.     

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     

Preparation of polyamides containing para-linked dimethylbiphenylene moieties

A series of wholly aromatic polyamides containing 3,3′-dimethylbiphenyl-4,4′-dicarboxylic acid (P-DMBA) and 3,4′-dimethylbiphenyl-4,3′-dicarboxylic acid (Q-DMBA) was prepared by the direct polycondensation method using triphenylphosphite and pyridine. Most of the polymers are readily soluble in polar aprotic solvents such as N-methyl-2-pyrrolidone (NMP), N,N′-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), pyridine (py), and m-cresol and could be cast into tough and flexible films. The solubilities of copolyamides containing P-DMBA and Q-DMBA as acid components were remarkably improved. These were characterized by inherent viscosity, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical spectrometry (DMS) measurements. The glass transition temperatures of these polymers were in the range of 200–300°C and the 5% weight loss temperatures were 430–470°C. Films prepared by casting from polymer solutions exhibited good tensile properties. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:847–853, 1998     

Synthesis and properties of poly(butylene succinate) with N-hexenyl side branches

N-hexenyl side branches were introduced into poly(butylene succinate) (PBS) by polymerization of succinic acid (SA) with 1,4-butanediol (BD) in the presence of 7-octene-1,2-diol (OD). Thermal properties and biodegradability of the aliphatic polyesters were investigated before and after epoxidation of the pendant double bonds. The glass-transition temperature (T_g) decreased with the branching density to give a minimum at 0.03 mol of branching units per mole of structural units. Thereafter, T_g increased due to the in situ crosslinking of the unsaturated groups during the differential scanning calorimetry (DSC) measurements. N-Hexenyl side branches decreased melting temperature (T_m) more significantly than ethyl side branches, but the effect was on par with that by n-octyl branches. Epoxidation of the double bonds decreased T_m and melting enthalpy (ΔH_m), but increased T_g of the aliphatic polyester. Biodegradability was enhanced to some extent by the presence of n-hexenyl side branches. However, the epoxidation of the unsaturated groups did not notably affect the biodegradability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2219–2226, 2001     

A simple and efficient way to synthesize optically active polyamides by solution polycondensation of di‐O‐methyl‐L‐tartaryl chloride with diamines

A series of optically active polyamides containing di‐O‐methyl‐L ‐tartaryl moieties in the main chain were synthesized by polycondensation of di‐O‐methyl‐L ‐tartaryl chloride 5 with diamines and characterized by gel permeation chromatography, UV–vis, circular dichroism (CD), IR, and NMR spectroscopies. The polycondensation reaction could be carried out under mild conditions and the reaction time was short (2–3 h). The key monomer 5 prepared from L ‐tartaric acid via esterification, etherification, hydrolysis, and chlorination was easily purified by vacuum sublimation. These polyamides with number average molecular weights ranging from 14,000 to 35,000, displayed large optical activity in dimethyl sulfoxide solution, and their specific optical rotations oscillated between 87.2° and 210.7° depending on the structures of the diamines. The glass transition temperatures of these polyamides were in the range of 106–191°C, and the 10% mass loss occurred at temperature above 300°C. The polyamides derived from aromatic diamines exhibited higher T_g and thermal stability than those derived from aliphatic diamines. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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     

Nylon 6/66/11 Copolymer Used for Hot-Melt Adhesives: Synthesis and Properties

A new copolyamide, nylon 6/66/11, used for hot-melt adhesives, was prepared by hydrolytic polymerization and melt polycondensation. Intrinsic viscosity, melting point, glass transition temperature, cold crystallization, thermogravimetry (TG) and adhesion strength of the resultant hot-melt adhesives were investigated. DSC thermograms of the copolyamide showed that both the melting point and glass transition (T _g) temperatures decreased as the molar fraction of aminoundecanoic acid increased. The T _g practically did not change as the mole fraction of aminoundecanoic acid increased from 60% to 80%, but cold crystallinity of the copolyamide decreased. The thermal gravimetric analysis indicated that the resultant copolyamide had a high thermal stability. The copolyamide had the best combination of properties when the molar fraction of aminoundecanoic acid was about 65%.     

Glass transition relations in ionomeric “comb” polymers

The glass transition temperatures (T_g) and dynamic mechanical properties of random copolymers of styrene-4-vinylpyridine quaternized with iodoalkanes are presented for vinylpyridine contents up to ten percent and pendant alkyl chains up to ten carbons in length. Two linear relationships, between ion content and glass transition temperature and between pendant alkyl chain length and the T_g, are observed. An equation is presented that can be used to predict the T_g for such copolymers based on their ion contents and alkyl chain lengths.     

Assessment of random aromatic co‐polyamides containing two different bulky pendant groups

This work reports the synthesis and assessment of random aromatic co‐polyamides containing two different bulky pendant groups. The random aromatic co‐polyamides are synthesized combining the monomers 5‐tert‐butylisophthalic acid and 5‐(9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐dicarboximido)isophthalic acid with three different diamines. The random aromatic co‐polyamides are readily soluble and possess inherent viscosities in the range of 0.47–0.60 dL g⁻¹. Co‐polyamide dense membranes are amorphous, and flexible with both good tensile strength (56.2–57.5 MPa) and tensile modulus (1.3–1.6 GPa). Permeability coefficients of the co‐polyamide dense membranes are assessed for the gases He, O₂, N₂, CH₄, and CO₂. It is found that the combination of two bulky pendant groups, dibenzobarrelene and tert‐butyl, in the backbone of the co‐polyamides improves the gas permeability coefficient in comparison with their corresponding homopolyamides. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45884.