Diacid Monomer Research Articles

Biobased Pyrazine-Containing Polyesters

A set of 12 first-in-class, biobased pyrazine-containing polyesters was synthesized based on dimethylpyrazine dipropionic acid. These new diacid monomers were obtained from underutilized nitrogen-r...

Dual curing of an epoxy resin with dicarboxylic acids

In this work, we have studied the preparation and characterization of a new family of thermosets based on off-stoichiometric diacid-epoxy formulations in the presence of 1-methylimidazole as initiator. Tri-glycidyl para-amino phenol has been used as epoxy resin and isophthalic (AIFT), and terephthalic (ATFT) acids have been used as diacids. The curing has been analyzed isothermally at different temperatures by calorimetry, using an isoconversional method and the Sestak–Berggren equation to determine the activation energy, the frequency factor, and the reaction orders. The thermal–mechanical properties of the partially cured and fully cured materials were also determined by means of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The analysis of the isothermal curing by infrared spectroscopy by Fourier transform allowed monitoring the reacting groups during the process. Two peaks appeared during the isothermal curing in the DSC. The first one is associated with the reaction of the carboxylic groups of the diacids with the epoxy groups, and the second one is related to the homopolymerization of the excess of epoxy groups. ATFT reacts less with the epoxy groups than AIFT, but accelerates more the homopolymerization and the isothermal curing ends earlier than in the systems with AIFT. Incomplete solubilization of the diacid monomers led to incomplete carboxylic reaction and excess of epoxy homopolymerization. In addition, two phases could be observed.

Synthesis, characterization and properties of novel polyamides derived from 4 4ʹ bis(4-carboxy methylene) biphenyl and various diamines

ABSTRACT Novel aromatic aliphatic diacid monomer, 4 4ʹ bis(4-carboxy methylene) biphenyl was synthesized via friedel craft acylation with acetic anhydride followed by willgerodot reaction and used in the preparation of polyamides by direct polycondensation using the Yamazaki phosphorylation reaction with commercial aromatic diamines. These polyamides were obtained in good yield with moderate-to-high-molecular-weight build up as evidenced by inherent viscosities in the range of 0.52–0.96 dlg−1. The XRD studies showed that all the polyamides were amorphous in nature and these polymers dissolved in polar aprotic solvents such as N-methyl-2-pyrrolidone(NMP),N,N-dimethylsulfoxide(DMSO), N,N-dimethyl formamide (DMF) and N,N-dimethyl acetamide. The resulting polyamides were characterized by inherent viscocity measurements, FT-IR, 1H NMR and 13C NMR spectroscopy, solubility, thermogravimetry, X-ray diffraction studies. These polyamides had glass transition temperatures between 210°C and 261°C, and their temperatures at a 10% weight loss were 620 to 710°C and 497 to 597°C in nitrogen and air atmospheres, respectively, which indicates thermally stable polymers.

Solvent-driven isomerization of cis,cis-muconic acid for the production of specialty and performance-advantaged cyclic biobased monomers

Unlocking the isomerization of cis,cis-muconic acid to Diels–Alder active trans,trans-muconic acid for the production of renewable cyclic diacid monomers.

Synthesis and characterization of new diacid monomers and poly (ester-imide) s: a study of thermal property relationship and solubility

Two dicarboxylic acids [2,2'-(((4-hydroxyphenyl) methylene) bis (3-Bromo-4,1- phenylene)) bis (1,3 dioxoisoindoline 5 carboxylic acid)) and 2,2 '(((2,4dichlorophenyl) methylene) bis (4,1-phenylene)) bis (1,3-dioxoisoindoline-5-carboxylic acid)] were made by the reaction of pyromellitic anhydride (PMDA) with diamine in a solvent of g pyridine/glacial acetic acid at refluxing temperature. The organization of the diacid monomers is defined by FTIR and 1H-NMR spectroscopy. The sequence of new poly (ester-imide) s are arranged of two di acids and aromatic diols: [Bis (4hydroxyphenyl) 2 furelmethaneand 4,4'((1,4phenylene (methanylyidene)) bis (azanylylidene)) diphenol] by employing the polycondensation in the company of the dibutyltine dilaurate as a catalyst. The PEIs were defined by FTIR, 1HNMR, and TGA. Poly (ester-imide) s showed excellent solubility in polar aprotic solutions because of the existence of flexible groups in the polymer backbone. Furthermore, they displayed better thermal constancy, and the heat at that 10% loss of weight happened about700 to 800°C.

Preparation and Characterization of Flexible, Transparent and Thermally Stable Aromatic Co-polyamides

Two aromatic co-polyamides were synthesized combining two diacid monomers containing bulky pendant groups, 5-(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)isophthalic acid (DEAIA) and 5-tert-butylisophthalic acid (TERT), with 4,4′-(hexafluoroisopropylidene)dianiline (HFA) or 2,3,5,6-tetramethyl-1,4-phenylenediamine (Durene) by direct polycondensation. The structures of the obtained aromatic co-polyamides were confirmed by FTIR, Raman and 1H-NMR. The co-copolyamide films, DHTH and DDTD, exhibited rms-roughness values between 0.94 and 1.60 nm, respectively. Moreover, they presented good thermal stability up to 300 °C. Young’s moduli of the co-polyamide films were between 4.1 and 4.3 GPa. X-ray diffraction results showed that the co-polyamide films were amorphous due to the incorporation of both bulky pendant groups, tert-butyl and dibenzobarrelene. The combination of bulky pendant groups provided intrinsically transparent co-polyamide films with a transmittance higher than 88% in the range of 400−780 nm. Due to these outstanding film and optical properties, they are suggested to be flexible substrates in applications for solar cell and other portable electronic devices.

From Parkinson's chemotropic agent l-dopa to thermally resistive carbonaceous nanocomposite of a new catechol-grafted poly(amide-imide)

N,N′-Pyromellitoyl-bis-L-(3,4-dihydroxyphenyl)alanine was synthesized, as a new diacid monomer, from condensation reaction of l-dopa and pyromellitic anhydride. Polycondensation of this chiral monomer with the commercially available 4,4′-diaminodiphenylsulfone was achieved by using triphenylphosphite, as coupling agent, and calcium chloride, as dehydrating agent, in a mixture of N-methyl-2-pyrolidone and pyridine, giving a fairly high yield of a novel optically active poly(amide-imide) (PAI). This catechol containing PAI shows excellent adhesion to carboxylated carbon nanotubes, as forcing it to adopt a semi-crystalline structure in the interface with the nanotubes and thereby results in formation of a thermally stable and nearly homogeneous nanocomposite. FT-IR study revealed that much of this adhesion arises from H-bonding of the carboxylated nanotubes with the carbonyl groups of the PAI. The uniform distribution of the nanotubes in the PAI matrix was confirmed by FE-SEM and TEM micrographs of their nanocomposite. Thermogravimetric analysis of the PAI and its nanocomposites with 5, 10, and 15 wt% of carboxylated carbon nanotubes indicates that their decomposition occur in the temperature range of 347–365 °C. The limiting oxygen indices for the PAI and its nanocomposites were found to be in the range of 37.9–43.1. The polymer and its nanocomposites were characterized by additional techniques.

Investigation of morphological aspects and thermal properties of ZnO/poly(amide–imide) nanocomposites based on levodopa-mediated diacid monomer

Hybrid nanocomposites (NCs) manufactured by distribution of zinc oxide (ZnO) nanoparticles (NPs) in poly[hydroxy(amide–imide)] (PHAI) are considered and produced by using an ultrasonic-assisted method. A novel monomer namely N,N′-pyromellitoyl-bis-l-(3,4-dihydroxyphenyl)alanine (NPDA) was synthesized by using levodopa as a starting material. The monomer structure was characterized by FT-IR and NMR spectroscopy. Reaction of the monomer containing pendent catechol moieties by a diamine by Yamazaki method provided the thermally stable PHAI matrix with well-designed units. FT-IR and 1H-NMR spectra confirmed the accomplishment of preparation step for the PHAI. The surface of ZnO NPs was functionalized with 3-aminopropyltriethoxysilane (KH550) coupling agent and donated a better dispersion and ornamental interactions with catechol functional units of PHAI matrix by hydrogen bonds. Provided NCs were characterized by FT-IR, X-ray powder diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and thermogravimetric analysis. The FE-SEM and TEM pictures confirm the coral-like structures for NCs. The FE-SEM and AFM analyses show the good dispersion of ZnO nanostructure in the PHAI matrix. The XRD patterns of NCs show the presence of crystalline ZnO NPs in amorphous PHAI matrix.

New fluorinated aromatic polyamides based on N,N-bis(4-carboxyphenyl)-4-trifluoromethylaniline

A new aromatic diacid monomer, N, N-bis(4-carboxyphenyl)-4-trifluoromethylaniline, was synthesized by the substitution reaction of 4-trifluoromethylaniline with 4-fluorobenzonitrile, followed by alkaline hydrolysis of the dinitrile intermediate. Several polyamides with 4-trifluoromethyltriphenylamine moieties were prepared from the diacid and various aromatic diamines via the direct phosphorylation polycondensation. All the polyamides were amorphous and readily soluble in many polar organic solvents such as N, N-dimethylacetamide and N-methyl-2-pyrrolidone, and could be solution-cast into transparent, tough, and flexible films with good mechanical properties. They exhibited good thermal stability with glass transition temperatures of 260–330°C, 10% weight-loss temperatures above 500°C, and char yields higher than 60% at 800°C in nitrogen. These polymers had low dielectric constants of 3.35–3.72 (100 Hz), low water uptake of 1.80–2.60%, and high transparency with an ultraviolet–visible absorption cutoff wavelength in the range of 378–390 nm. Cyclic voltammograms of the polyamide films cast onto an indium-tin oxide–coated glass substrate exhibited a reversible oxidation redox coupled with oxidation half-wave potentials ( E 1/2) of 0.95–1.04 V versus silver/silver chloride in an acetonitrile solution.

Aromatic polyesters derived from 5,5′-disubstituted bis(m-phenylene) crown ethers

A new monomer of the AB type, 5-carboxy-1,3-phenylene-5′-hydroxy-1′,3′-phenylene-32-crown-10 (5), was synthesized. Direct polymerizations of bis(5-hydroxy-1,3-phenylene)-32-crown-10 (13), an AA diphenolic macrocyclic monomer, with BB diacid monomer bis(5-carboxy-1,3-phenylene)-26-crown-8 (14) and its larger analog bis(5-carboxy-1,3-phenylene)-32-crown-10 (16) were accomplished via the Higashi method. The resultant polyesters 15 and 17, which both contain two macrocycles per repeat unit, were soluble in common organic solvents such as chloroform and tetrahydrofuran, amorphous in nature and possessed high thermal stability (5% weight loss > 370 °C in air). Main chain poly(ester crown ether)s 18 and 19 based on bis(5-carboxy-1,3-phenylene)-32-crown-10 (16), and hydroquinone (HQ) and biphenol (BP), respectively, were synthesized; these two polyesters also possess high thermal stability (5% weight loss > 386 °C in air) and are amorphous. These polymacrocycles are suitable polytopic hosts for complexation with 4,4′-bipyridinium derivatives, as demonstrated by the binding of paraquat diol (21a) by polyester 20 with Ka = 2.0 (±0.7) x 102 M−1 (23 °C, 4:6 w:w CD3CN:CDCl3). Threading of the cyclic units in these polyesters by linear polymers such as polystyrene and PMMA leads to compatiblized blends via polypseudorotaxane formation; this methodology represents a new approach to compatibilization.

Synthesis and characterisation of alkyd resins with glutamic acid-based monomers.

Alkyd resins are versatile polymers which have applications in inks and various coatings like decorative paints. They are mainly composed of fatty acids, polyols and aromatic diacids. In this work, glutamic acid as well as N-acylated and N-alkylated derivatives there of were evaluated as bio-based substitutes for these aromatic diacid monomers in the synthesis of alkyd resins. The resins were characterised in terms of structure, molecular weight, viscosity, oxidative thermal stability and colour. N-Palmitoylglutamic acid dimethyl ester can be successfully incorporated when the polycondensation is performed in two steps. In this approach, the bio-based diacid monomer is only supplied in the second step, because the removal of water in the first step is essential to avoid hydrolysis of the monomer amide bond and the subsequent formation of pyroglutamate groups. The molecular weight, viscosity and oxidative thermal stability are lower than for conventional alkyd resins. The mechanism of the discolouration of alkyd resins during polymerisation is mediated by free radical species, which were generated easily in the presence of free amino groups and/or unsaturated fatty acids. Light-coloured resins could be obtained by using saturated fatty acids or radical scavengers during polymerisation.

Synthesis and characterization of poly(amide-imide)s derived from a new ortho-functional unsymmetrical dicarboxylic acid

Herein, we report a new diacid monomer containing an imide ring and a methoxy pendant group, 3-trimellitimido-4-methoxybenzoic acid TMBA, for the preparation of poly(amide-imide)s.

Synthesis of thermotropic polybenzoxazole using 3-amino-4-hydroxybenzoic acid

Bio-based polybenzoxazoles (PBOs) are prepared by polycondensation of diacid monomer derived from 3-amino-4-hydroxybenzoic acid with a series of aliphatic diamines. Resulting bio-based PBOs have high weight average molecular weight ranging 5.70–7.20 × 104 g/mol and show ultrahigh thermal resistance with T 10 values over 400 °C and T g values over 170 °C, which are higher than those of conventional bio-based polymers, polyamides 11 (around 60 °C) or poly(lactic acid) (56 °C). Especially hydrazide group of the bio-based PBO were cyclized to form diazole ring by annealing at 330 °C for 20 min. The resultant PBO show liquid crystalline (LC) behavior to spin fiber in a melting state. The resultant PBO fibers showed high values of Young’s modulus and mechanical strength as compared with conventional polymers polyamide 11 and poly(lactic acid) (PLA).

Accessing New Monomers from Biopriviledged Molecules By Coupling Metabolic Engineering and Electrosynthesis

Recent progress in metabolic engineering has generated new microorganisms able to convert carbohydrates and waste lignin into biopriviledged molecules.1 One of these molecules, muconic acid, can be further diversified to adipic acid and terephthalic acid, which are central to the production of Nylon-6,6 and polyethylene terephthalate (PET). Its semi-hydrogenation also leads to new molecules such as trans-3-hexenedioic acid (3HDA), a compound that enables the synthesis of bio-advantaged Nylon-6,6. However, to achieve economically sustainable conversion, it is crucial to streamline the fermentation and downstream catalytic processing steps. This generates new challenges as biogenic impurities inherent to the fermentation broth can deactivate Pt-group metal catalysts. An alternative approach would be to utilize novel conversion schemes using robust base metals that are stable in the presence of biogenic impurities.2 We show that electrosynthesis represents a promising approach for the direct processing of unpurified broths.2,3 The water, salts, and acidic impurities already present in the medium provide a suitable electrolyte, while protons in the solution provide the hydrogen required for the desired transformation. Muconic acid was converted to 3HDA with a 94% yield and 100% faradaic efficiency using lead (Pb) electrodes.4 Under these conditions, 3HDA can be produced at a competitive price of $2.00 kg-1. The reaction mechanism and the origin of the high selectivity to 3HDA will be discussed. 1. B.H. Shanks and P. Keeling, Bioprivileged Molecules: Creating Value from Biomass, Green Chem. 2017, advance article. https://dx.doi.org/10.1039/C7GC00296C2. M. Suastegui, J. E. Matthiesen, J. M. Carraher, N. Hernandez, N. Rodriguez Quiroz, A. Okerlund, E. W. Cochran, Z. Shao, J.-P. Tessonnier, Combining Metabolic Engineering and Electrocatalysis: Application to the Production of Polyamides from Sugar, Angew. Chem. Int. Ed., 2016, 55, 2368-2373. http://dx.doi.org/10.1002/anie.2015096533. J. E. Matthiesen, J. M. Carraher, M. Vasiliu, D. A. Dixon, J.-P. Tessonnier, Electrochemical Conversion of Muconic Acid to Biobased Diacid Monomers, ACS Sustainable Chem. Eng., 2016, 4, 3575-3585. http://dx.doi.org/10.1021/acssuschemeng.6b006794. J. E. Matthiesen, M. Suástegui, Y. Wu, M. Viswanathan, Y. Qu, M. Cao, N. Rodriguez-Quiroz, A. Okerlund, G. Kraus, D. R. Raman, Z. Shao, J.-P. Tessonnier, Electrochemical Conversion of Biologically Produced Muconic Acid: Key Considerations for Scale-up and Corresponding Technoeconomic Analysis, ACS Sustainable Chem. Eng., 2016, 12, 7098-7109. http://dx.doi.org/10.1021/acssuschemeng.6b01981

Synthesis and characterization of novel aromatic polyamides containing 3-trifluoromethyl-substituted triphenylamine

ABSTRACTA new 3-trifluoromethyl-substituted triphenylamine-containing aromatic diacid monomer, N,N-bis(4-carboxyphenyl)-3-trifluoromethylaniline, was prepared by the substitution reaction of 3-trifluoromethylaniline with 4-fluorobenzonitrile, followed by alkaline hydrolysis of the dinitrile intermediate. Novel aromatic polyamides with 3-trifluoromethyl-substituted triphenylamine moieties were prepared from the diacid and various aromatic diamines via the direct phosphorylation polycondensation. All the polyamides were amorphous and readily soluble in many polar organic solvents such as N,N-dimethylacetamide and N-methyl-2-pyrrolidone, and could be solution-cast into transparent, tough, and flexible films with good mechanical properties. They exhibited good thermal stability with relatively high glass-transition temperatures (258–327°C), 10% weight-loss temperatures above 500°C, and char yields higher than 60% at 800°C in nitrogen. These polymers had low dielectric constants of 3.22–3.70 (100 Hz), low moisture absorption in the range of 1.75–2.58%, and high transparency with an ultraviolet–visible absorption cut-off wavelength in the 375–395 nm range. Cyclic voltammograms of the polyamide films cast onto an indium tin oxide coated glass substrate exhibited a reversible oxidation redox couple with oxidation half-wave potentials (E1/2) of 0.95–1.00 V vs. Ag/AgCl in an acetonitrile solution.

Gas separation properties of Troeger’s base-bridged polyamides

AbstractA series of new polyamides (PAs) has been prepared from a Troeger base-bridged diamine (TB), 2,8- diamino-4,10-dimethyl-6H,12H-5,11-methanodibenzo[1,5]-diazocine and different commercially available diacid monomers via the conventional polycondensation method. Dense membranes were prepared from the PAs by solution casting and solvent evaporation techniques. The synthesized PAs showed high glass transition temperature (283–290°C), 10% weight loss up to temperature 431°C in air, and tensile strength up to 91 MPa. The PA membranes showed higher permeability than some commercially used glassy polymers (PCO2 up to 109 and PO2 up to 21 Barrer) and permselectivity (PCO2/PCH4 up to 53.7 and PO2/PN2 up to 7.52) in comparison to many other PAs published in the literature.

Metal‐Coordination‐Assisted Folding and Guest Binding in Helical Aromatic Oligoamide Molecular Capsules

AbstractThe development of foldamer‐based receptors is driven by the design of monomers with specific properties. Herein, we introduce a pyridazine‐pyridine‐pyridazine diacid monomer and its incorporation into helical aromatic oligoamide foldamer containers. This monomer codes for a wide helix diameter and can sequester metal ions on the inner wall of the helix cavity. Crystallographic studies and NMR titrations show that part of the metal coordination sphere remains available and may then promote the binding of a guest within the cavity. In addition to metal coordination, binding of the guest is assisted by cooperative interactions with the helix host, thereby resulting in significant enhancements depending on the foldamer sequence, and in slow guest capture and release on the NMR time scale. In the absence of metal ions, the pyridazine‐pyridine‐pyridazine monomer promotes an extended conformation of the foldamer that results in aggregation, including the formation of an intertwined duplex.

Metal‐Coordination‐Assisted Folding and Guest Binding in Helical Aromatic Oligoamide Molecular Capsules

The development of foldamer-based receptors is driven by the design of monomers with specific properties. Herein, we introduce a pyridazine-pyridine-pyridazine diacid monomer and its incorporation into helical aromatic oligoamide foldamer containers. This monomer codes for a wide helix diameter and can sequester metal ions on the inner wall of the helix cavity. Crystallographic studies and NMR titrations show that part of the metal coordination sphere remains available and may then promote the binding of a guest within the cavity. In addition to metal coordination, binding of the guest is assisted by cooperative interactions with the helix host, thereby resulting in significant enhancements depending on the foldamer sequence, and in slow guest capture and release on the NMR time scale. In the absence of metal ions, the pyridazine-pyridine-pyridazine monomer promotes an extended conformation of the foldamer that results in aggregation, including the formation of an intertwined duplex.

Chitosan/Poly(Amide-Imide) Blend Films: Studies on Thermal and Mechanical Stability, Morphology and Biodegradability

A diacid monomer was synthesized by the condensation of L-tryptophan amino acid and pyromellitic dianhydride (PMDA). The diacid was utilized for the synthesis of three types of poly(amide-imide)s (PAIs) using three different kinds of diamines. The synthesized monomer and PAIs were characterized using FT-IR, 1H-NMR and 13C-NMR spectroscopies and the PAIs were also used for the fabrication of chitosan (CS)/PAI blend films. XRD patterns of the PAIs, CS and CS/PAI blend films were also studied. Thermal stability of PAIs, CS and CS/PAI samples were studied using thermogravimetric analysis (TGA). The blend samples showed a higher thermal stability compared to the CS film, especially at higher temperatures. Morphology of the CS and blend CS/PAI films were studied before and after the biodegradation by SEM. The mechanical stability studies showed that blend CS/PAI films had a proper mechanical strength and their young’s modulus increased compared to the pristine chitosan. The in vitro fungal colonization ofdiacid monomer, PAIs, pure CS and blend CS/PAI samples were performed using Aspergillus niger fungi. After biodegradation, the pure CS showed the highest weight loss of 21.2 wt % among the samples. The blend CS/PAI samples also showed higher weight losses compared to the pure PAIs.

Molecular design and synthesis of thermotropic liquid crystalline poly(amide imide)s with high thermal stability and solubility

Abstract A series of thermotropic liquid crystalline poly(amide imide)s (PAIs) with well-defined structure were prepared by the Yamazaki-Higashi phosphorylation method. To obtain the target polymers, several diimide diacid monomers (DIDAs) as mesogenic units were synthesized by the dehydration cyclization of aromatic anhydride with aliphatic 11-aminoundecanoic acid (AU). The chemical structure of these DIDAs and PAIs was confirmed via Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. Thermotropic liquid crystalline characteristics of the DIDAs and PAIs were investigated by differential scanning calorimetry (DSC), polarizing light microscopy (PLM) and X-ray diffraction (XRD) analysis. Encouragingly, all of these liquid crystalline PAIs exhibited good thermal stability, in which the decomposition temperatures are much higher than the melting temperatures of PAIs. Furthermore, the liquid crystalline PAIs can be dissolved into some common solvents such as dimethyl sulfoxide (DMSO) and m-cresol, which indicates these liquid crystalline PAIs could be processed not only by melting-processing but also by solution spin-coating.