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 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     

Preparation and properties of new polycyclic aliphatic polyamides base on diamantane

A series of novel polycyclic aliphatic polyamides was synthesized by direct polycondensation of the 1,6-diamantane dicarboxylic acid with various alicyclic diamines in N-methyl–2–pyrrolidone (NMP) containing lithium chloride, using triphenyl phosphite and pyridine as a condensing agent. The polyamides had inherent viscosities of 0.33–0.49 dL/g. The glass transition temperatures of the these polyamides were in the range of 200–220°C, and the 5% weight loss temperatures were in the range were 290–319°C in nitrogen. © 1995 John Wiley & Sons, Inc.     

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 and characterization of polyamides X 18

Step heating melt polycondensation was adopted in the preparation of polyamides based on 1,16‐octadecane diacid and α,ω? (CH₂)_2n diamines (n = 1–6). The structure was confirmed by various spectroscopic techniques (IR, Raman, ¹H‐NMR, and ¹³C‐NMR). High molecular masses were obtained only in the presence of an excess of diamine and when the diamine possessed low volatility. The molecular masses were between (0.94 and 2.1) × 10⁴ Da for all polyamides under consideration. An excellent correlation between size exclusion chromatography and ¹H‐NMR data was demonstrated in the measurement of the degree of polymerization. The melting temperatures of the polyamides decreased from polyamide 12 18 to polyamide 2 18 as the amide density along the molecular chain declined. No significant variation was observed in the glass‐transition and decomposition temperatures of the polyamides that were obtained. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1565–1571, 2005     

Solution‐processable and electroactive aromatic polyamides with 3,5‐bis(trifluoromethyl)triphenylamine moiety

New fluorine‐containing, triphenylamine‐based diamine and dicarboxylic acid monomers, namely 3,5‐bis(trifluoromethyl)‐4′,4″‐diaminotriphenylamine and 3,5‐bis(trifluoromethyl)‐4′,4″‐dicarboxytriphenylamine, were synthesized and polymerized with commercially available aromatic dicarboxylic acids and diamines, respectively, leading to two series of aromatic polyamides, 5a–h and 7a–e . Most of the polyamides were amorphous and readily soluble in many common organic solvents and could be solution‐cast into transparent, flexible and strong films with good mechanical properties. The polyamides had useful levels of thermal stability associated with high glass transition temperatures of 273–305 °C and 10% weight‐loss temperatures in excess of 500 °C. Cyclic voltammograms of films of polymers 5a–h on indium–tin oxide‐coated glass substrates exhibited reversible oxidation redox couples with E_1/2 around 1.15 V versus Ag/AgCl in tetrabutylammonium perchlorate/acetonitrile solution, accompanied by a color change from colorless neutral state to reddish brown oxidized state. The 7 series polymers displayed a higher oxidation potential and less electrochemical stability as compared to the 5 series analogues. © 2017 Society of Chemical Industry     

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     

Polyamides from 1,4-cyclohexanebis(ethylamine) and aliphatic dicarboxylic acids

A homologous polyamide series of 1,4-cyclohexanebis(ethylamine) (CBEA) was prepared with C₆ to C₁₂ linear, aliphatic dicarboxylic acids. Polymer and fiber properties were found to be quite dependent upon the cis and trans structure of the cycloaliphatic ring. Polyamides based on trans-1,4-CBEA had higher melting and higher glass transition temperatures than their cis analogs. In addition, trans polyamides were quite crystalline, whereas the cis polymers were almost completely amorphous. The boiling water shrinkage, tenacity, and moisture regain of the fibers reflected the differences in molecular fit between the cis and trans polyamides.     

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,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     

Metal adhesive properties of polyamides having the 2,3‐bis(1,4‐phenylene)quinoxalinediyl structure

Polyamides were synthesized by interfacial polycondensation of 2,3‐bis(4‐chloroformylphenyl)quinoxaline (BCFPQ) and several aliphatic diamines using a phase transfer catalyst, and their adhesive property for stainless steel was investigated. The inherent viscosity of the obtained polyamides ranged from 0.37 to 1.24 dL g⁻¹. The glass transition temperatures of the polyamides ranged between 154 and 201°C, and their thermal decomposition temperatures were above 450°C. The polyamides were soluble in several organic solvents, including m‐cresol, N‐methyl‐2‐pyrrolidone (NMP), and formic acid. The adhesive property for stainless steel was examined by a standard tensile test. One member of the series, polyamide P8, derived from BCFPQ and 1,8‐octanediamine, displayed high tensile strength with values of 232 kgf cm⁻² at 20°C, 173 kgf cm⁻² at 120°C, and 137 kgf cm⁻² at 180°C. Thus, the tensile strength of P8 decreased at 180°C, but the decrease was much smaller than that of an epoxy resin in wide use as a metal adhesive. Heat distortion temperature, measured by thermal mechanical analysis, of P8 was 191°C. This suggested that P8 possessed high thermal resistance in metal adhesives. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1366–1370, 1999     

Facile synthesis of processable aromatic polyamides containing thioether units

Aromatic polyamides containing thioether units were synthesized by interfacial polycondensation of 4,4′‐thiodibenzoyl chloride (or 4,4′‐bis(4‐chloroformylphenylthio)benzene) with aromatic diamines containing a nitrile unit. Their structure was established using ¹H NMR and Fourier transform infrared spectroscopy. The inherent viscosities of the polyamides prepared with optimum synthesis conditions were in the range 0.71–0.84 dL g^?1. These polyamides showed excellent thermal properties with glass transition temperatures of 210.5–219.6 °C, melting temperatures of 313.8–315.0 °C and initial degradation temperatures of 440–459 °C. They could be processed by melting due to their relatively wide processing window. Their tensile strengths were 71.3–79.1 MPa, water absorption was 0.17–0.22 wt%, and melt flowability was in the range 64.5 to 315.2 Pa s and 68.5 to 422.3 Pa s at different shear rates. At the same time, they were soluble in aprotic solvents such as N‐methyl‐2‐pyrrolidone, dimethylformamide and dimethylsulfoxide. The results suggest that these aromatic polyamides containing thioether units represent a promising type of heat‐resistant and processable engineering plastic. © 2012 Society of Chemical Industry     

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 soluble polyamides from bis-[(4′-aminobenzyl)-4-benzamide] ether and various diacids

New aromatic diamine containing preformed amide, ether, and methylene; bis-[(4′-aminobenzyl)-4-benzamide] ether (BABE), was synthesized and characterized by FT-IR, NMR, and mass spectrometry. Aromatic–aliphatic polyamides were prepared from BABE with aliphatic/aromatic diacids via Yamazaki’s polymerization. The polyamides were characterized by FT-IR, ¹H NMR, inherent viscosity [η_inh], solubility tests, differential scanning calorimetry [DSC], thermogravimetric analysis [TGA], and X-ray diffraction [XRD]. Polyamides had inherent viscosities 0.35–0.84 dL/g, soluble in aprotic polar solvents like N-methyl-2-pyrrolidone, N, N-dimethyl acetamide and dimethyl sulphoxide containing LiCl due to an amorphous to partially crystalline morphology; as XRD patterns indicated. DSC analysis of polyamides showed glass transition temperatures 166–268 °C. Polyamides showed high thermal stability as they did not degrade below 300 °C, had 10% weight loss temperature higher than 375 °C, and the char yields at 900 °C were 22–55%; indicating potential applications as engineering materials.     

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     

High‐optical transparency and low‐dielectric constant of new organosoluble polyamides containing trifluoromethyl and xanthene groups

A series of fluorinated polyamides was prepared directly by low‐temperature polycondensation of a new cardo diacid chloride, 9,9‐bis[4‐(4‐chloroformylphenoxy)phenyl]xanthene (BCPX), with various diamines containing trifluoromethyl substituents in N,N‐dimethylacetamide (DMAc). Almost all polyamides showed excellent solubility in amide‐type solvents such as DMAc and could also be dissolved in pyridine, m‐cresol, and tetrahydrofuran. These polymers had inherent viscosities between 0.77 and 1.31 dL g^?1, and their weight‐average molecular weights and number‐average molecular weights were in the range of 69,000–102,000 and 41,000–59,000, respectively. The resulting polymers showed glass transition temperatures between 240–258°C and 10% weight loss temperatures ranging from 484°C to 517°C and 410°C to 456°C in nitrogen and air, respectively, and char yields at 800°C in nitrogen higher than 55%. All polymers were amorphous and could be cast into transparent, light‐colored, and flexible films with tensile strengths of 81–100 MPa, elongations at break of 8–12%, and tensile modulus of 1.6–2.1 GPa. These polymers had low‐dielectric constants of 3.34–3.65 (100 kHz), low‐moisture absorption in the range of 0.76–1.91%, and high transparency with an ultraviolet–visible absorption cut‐off wavelength in the 322–340 nm range. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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     

Hybrid Sol–Gel Glasses with Glass‐Transition Temperatures Below Room Temperature

Melting gels are hybrid gels that have the ability to soften and flow at around 100°C for some combinations of mono‐ and di‐substituted alkoxysiloxanes, where substitutions are either all aromatic or all aliphatic. In this study, melting gels were prepared using phenyltriethoxysilane (PhTES) and dimethyldiethoxysilane (DMDES), meaning both an aromatic and aliphatic substitution. Differential scanning calorimetry was performed to identify glass‐transition temperatures, and thermal gravimetric analysis coupled with differential thermal analysis (TGA‐DTA) was performed to measure weight loss. The glass‐transition temperatures (T_g) ranged from ?61°C to +5.6°C, which are between the values in the methyl only system, where all T_g values are less than 0°C, and those values in the phenyl only system, where T_g values are greater than 0°C. The T_g decreased with an increase in the DMDES fraction. Below 450°C, the gels lost little weight, but around 600°C there was a drop in weight. This temperature is lower than the temperature for gels prepared with only aromatic substitutions, but higher than that for gels prepared with only aliphatic substitutions. Final heat treatment was carried out at 150°C for the gel with 80%PhTES‐20%DMDES (in mol%), and the consolidation temperature increased with increasing DMDES content to 205°C for the gel with 50%PhTES‐50%DMDES. After this heat treatment, the melting gels no longer soften.     

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     

Polyamides based on diamines containing aryloxy groups: Structure-property relationships

Aromatic polyamides containing different numbers of p-oxyphenylene groups and different catenated positions in the benzene rings were prepared from terephthalic acid (TPA) and isophthalic acid (IPA) with various aryloxy-containing diamines by means of the phosphorylation polycondensation reaction. Most of the polyamides were moderately to highly crystalline, as indicated by X-ray diffraction and DSC measurements. Polyisophthalamides were readily soluble in polar amide-type solvents such as N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc). Some non-crystalline polyamides could afford tough films by solution casting. Most polyisophthalamides revealed discernible glass transition on their DSC curves, and their T_g values were recorded in the range of 215–238 °C. No discernible glass transitions were observed for the polyamides of TPA by DSC. The thermal stability of these polymers did not show clear dependence on the structure of the diacid or the diamine. In addition, a series of polyamides having pendant groups was synthesized from the polycondensation of TPA and IPA with 1,4-bis(4-aminophenoxy)benzene and its derivatives with methyl, tert-butyl, or phenyl substituent on the central benzene ring. In most cases, the incorporation of pendant groups generally resulted in an enhanced solubility and a decreased T_g and crystallinity.