Diacid Monomer Research Articles

Poly(amide-imide)s obtained from 3,5-diamino-N-(thiazol-2-yl)-benzamide and dicarboxylic acids containing various amino acid units

This study reports a green approach toward the synthesis of novel optically active poly(amide-imide)s (PAI)s bearing thiazole moiety, which was formed by the polycondensation reaction of 3,5-diamino- N-(thiazol-2-yl)benzamide and various diacids containing natural amino acids in molten tetrabutylammonium bromide. Diamine monomer was synthesized by the reduction of 3,5-dinitro- N-(thiazol-2-yl)benzamide in methanol using iron oxide hydroxide as a catalyst. This catalyst can rapidly reduce the sulfur and azo-containing aromatic nitro compounds to the corresponding amines in high yield by employing hydrazine hydrate as a hydrogen donor. Chiral diacid monomers were synthesized in high yield through the reaction of pyromellitic dianhydride and amino acids (l-isoluecine, S-valine, S-methionine, and l-phenylalanine) in acetic acid. The direct polymerization reactions of these monomers provided a series of new optically active PAIs with inherent viscosities in the range of 0.20–0.28 dL g−1. The obtained polymers were characterized by Fourier-transformed infrared spectroscopy, specific rotation measurements, and the representative of them by proton nuclear magnetic resonance and elemental analysis techniques.

Synthesis and characterization of new thermally stable and organosoluble polyamides by direct polycondensation

A series new thermally stable and organosoluble polyamides (PAs) 5a–f and copolyamides 10a–f with good inherent viscosities were synthesized from the direct polycondensation reaction of 1,2-bis(4-carboxyphenoxy)ethane 3 with aromatic diamines 4a–f and from the diacid 3 as a first diacid monomer and 4,4′-bis(1,3-diphenoxypropane) diacrylic acid 9 as a second diacid monomer with aromatic diamines 4a–f, respectively. The dicarboxylic acid 9 was synthesized from the two step reactions. At first 4,4′-bis(1,3-diphenoxypropane) dialdehyde 8 was synthesized from 1,3-dibromopropane 6 and 4-hydroxybenzaldehyde 7, then 4,4′-bis(1,2-diphenoxyethane) diacrylic acid 9 was synthesized from dialdehyde 8 and malonic acid in a solvent free reaction. All of the above polymers were fully characterized by 1H NMR, Fourier transform infrared, elemental analysis, inherent viscosity, solubility tests, differential scanning calorimeter, thermogravimetric analysis, and derivative of thermogravimetric. The resulted PAs have shown admirable good inherent viscosities and thermal stability and solubility.

High Molecular Weight Poly(butylene succinate-co-butylene furandicarboxylate) Copolyesters: From Catalyzed Polycondensation Reaction to Thermomechanical Properties

Novel potentially biobased aliphatic-aromatic copolyesters poly(butylene succinate-co-butylene furandicarboxylate) (PBSFs) in full composition range were successfully synthesized from 2,5-furandicarboxylic acid (FA), succinic acid (SA), and 1,4-butanediol (BDO) via an esterification and polycondensation process using tetrabutyl titanate (TBT) or TBT/La(acac)(3) as catalyst. The copolyesters were characterized by size exclusion chromatography (SEC), Fourier transform infrared (FTIR), (1)H NMR, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and their tensile properties were also evaluated. The weight average molecular weight (M(w)) ranges from 39,000 to 89,000 g/mol. The copolyesters are random copolymers whose composition is well controlled by the feed ratio of the diacid monomers. PBSFs have excellent thermal stability. The glass transition temperature (T(g)) increases continuously with φ(BF) and agrees well with the Fox equation. The crystallizability and T(m) decrease with increasing butylene furandicarboxylate (BF) unit content (φ(BF)) from 0 to 40 mol %, but rise again at φ(BF) of 50-100 mol %. Consequently, the tensile modulus and strength decrease, and the elongation at break increases with φ(BF) in the range of 0-40 mol %. At higher φ(BF), the modulus and strength increase and the ultimate elongation decreases. Thus, depending on φ(BF), the structure and properties of PBSFs can be tuned ranging from crystalline polymers possessing good tensile modulus (360-1800 MPa) and strength (20-35 MPa) to nearly amorphous polymer of low T(g) and high elongation (~600%), and therefore they may find applications in thermoplastics as well as elastomers or impact modifiers.

Synthesis and Properties of Novel Multiblock Thermoplastic Elastomers - Poly(ester-imide-ether) - Based on Pyromellitic Dianhydride, Glycine, 1,4-Butanediol and Polytetramethylene Glycol

A series of multiblock thermoplastic ploy(ester imide ether)s elastomers derived from polytetramethylene glycol of molecule weight is 1000 (PTMG1000), 1,4-butanediol (BD), and a new imide diacid monomer were synthesized of Pyromellitic dianhydride (PMDA) and glycine (GLY). was synthesized by two-step melting polycondensation method. Their chemical structures were studied by 1H-NMR spectroscopy as well as their thermal properties of the copolymers were investigated from differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), respectively. Otherwise, the solubility of these polymers was characterized by various organic solvents. The effects of the hard/soft segment content on the thermal properties and soluble behavior were investigated. The result demonstrated that these copolymers had better thermal properties (Tm: 225~280°C and T5% : 350~353°C) than those of conventional thermoplastic elastomers due to the introduction of imide bond. At the same time, the polymers have good solubility.

Fast and eco‐friendly synthesis of novel soluble thermally stable poly(amide‐imide)s modified with siloxane linkage with reduced dielectric constant under microwave irradiation in TBAB, TBPB and MeBuImCl via isocyanate method

AbstractA new series of poly(amide‐imide)s (PAI) modified with a siloxane linkage was synthesized under microwave radiation in ionic liquids and organic salts via the isocyanate method. The polymerization reactions of a novel siloxanic diacid monomer with 4,4′‐methylene‐bis(4‐phenylisocyanate) MDI were studied in ammonium, phosphonium, and imidazolium‐type organic salts. These poly(amide‐imide‐siloxane)s (PAI‐Si)s were obtained with high yields and good inherent viscosities ranging from 0.30 to 0.55 dL/g. The normally high softening temperatures and poor solubility of PAIs in organic solvents were improved via the incorporation of the flexible siloxane segments into the polymer backbone. The PAI‐Sis showed glass transition temperatures around 100°C and their 10% mass loss was about 300°C. They have a char yield in the range of 30–40% at 800°C. Calculated limiting oxygen index values of the polymers were about 30; therefore, they can be considered as self‐extinguishing. The dielectric constants of these silane‐containing PAIs (2.5) are lower than common siloxane‐free polyimides (∼ 3). Their good thermal stability, enhanced solubility, and low dielectric constants suggest they may function as electrical insulators. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Synthesis and degradation study of novel polyamides derived from a biologically active aromatic diacid monomer 5-(2-phthalimidoethanesulfonamido) isophthalic acid

In this study, 5-(2-phthalimidoethanesulfonamido) isophthalic acid (6) as a bioactive diacid monomer derived from taurine was successfully synthesized in three steps. The direct polycondensation reactions of this diacid monomer with several aromatic and aliphatic diisocyanates were carried out under conventional heating. All of the polyamides (PAs) were characterized by Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1 H NMR) and elemental analyses methods. The thermal stability of the resulting PAs was evaluated with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques under a nitrogen atmosphere. The dehydrogenase activities of treated soils with obtained compounds were also studied. The results showed that the dehydrogenase activity of treated soils with obtained compounds was 2–3 times higher than control soil, indicating that the abundance and activity of the microbial communities in the treated soils were enhanced by the presence of monomers and obtained polymers. This may show biodegradability of polymers under soil burial in natural environments and non-toxic behavior of compounds for soil microorganisms.

Synthesis of poly(amide-imide)s from new diacid monomers

Two new diacid monomers 4,4′-bis[5-(trimellitimido)napthyloxy]diphenyl sulfone and 4,4′-bis[5-(trimellitimido)napthyloxy]benzophenone were synthesized and characterized by spectroscopic analysis. A series of poly(amide-imide)s (PAIs) were prepared from these diacids and aromatic diamines through phosphorylation reaction. The structures of the PAIs were characterized by infrared and 1H-NMR. The PAIs were characterized by X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, electrical properties, solution viscosity and solubility test. The flexible linkages and pendant groups in the PAIs chain will disturb chain–chain packing and their effects on solubility, thermal stability and electrical properties were investigated. PAIs showed excellent thermal stability and good solubility. The dielectric constants of the PAIs were in the range 4.15–4.77. The PAIs have electrical insulation character and the film can be used in insulation of electrical items operating at elevated temperatures.

Synthesis of new diacid monomers and poly(amide-imide)s: study of structure–property relationship and applications

Two diimide-diacid monomers 4,4′-bis[4″-(trimellitimido)phenyl isopropylidene-4″′-phenoxy]diphenyl sulfone and 4,4′-bis[4″-(trimellitimido)phenylisopropylidene-4″′-phenoxy] were synthesized. The structures of the monomers were characterized by FT-IR and 1H-NMR spectroscopy. A series of novel poly(amide-imide)s were prepared from this two diacids and aromatic diamines through phosphorylation reaction. The PAIs were characterized by FT-IR, 1H-NMR, XRD, TGA, and DSC, solution viscosity, solubility test and electrical properties. Poly(amide-imide)s showed excellent solubility due to the presence of flexible groups and isopropylidene unit in the polymer backbone. They also exhibited good thermal stability and the temperatures at which 10% weight loss occurred in the range 385–465 °C. These PAIs found to have a dielectric constant in the range 3.25–4.20 at 10 kHz and have excellent electrical insulation character and can be used as insulation materials for electrical items operating at elevated temperatures.

Poly(ester)s and poly(amide)s with fluorene and diphenyl‐silane units in the main chain: Effects of iodine doping on the structure and electrical conductivity

AbstractIntramolecular charge transfer interaction between the electron donor and electro acceptor units within the polymeric structure and its optoelectronic properties were studied. The monomer, 9H‐fluorene‐2,7‐dicarboxylic acid, was prepared from 9H‐fluorene‐2,7‐dicarbonitrile using CuCN/N,N‐dimethylformamide followed by the decomposition of the complex with FeCl3x6H2O in HCl and KOH/H2O. The formation of two new classes of polymers was reported at different reaction times. The poly(ester) (PEF) was synthesized by the reaction of the diacid monomer with bis(4‐hydroxiphenyl)diphenylsilane using tosyl chloride/pyridine/dimethylformamide system as condensing agent. Alternatively, the poly(amide) (PAF) was synthesized by the direct polycondensation of the diacid monomer and bis(4‐aminophenyl)diphenylsilane in N‐methyl‐2‐pyrrolidine solution containing dissolved calcium chloride. The resulting new polymers were obtained in good yields and were characterized by FTIR, NMR (1H, 13C, and 29Si), ESI, Raman, UV (optical gap) and fluorescence spectroscopy. The thermal properties were characterized by DSC and TGA. The electrical conductivity of the polymers was measured before and after exposure to iodine vapor, utilizing films of different thickness. Ellipsometric studies were used for the determination of the film thickness. Morphological differentiation was carried out by SEM‐EDX analysis. Oxidation of the polymer films of low thickness decreased their conductivities, mainly due to the small structural changes. For a polymeric sample with a higher thickness, the doping process slightly increased the conductivity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Synthesis, characterization and in vitro antimicrobial study of bioactive polyesters derived from new biobased flame retardant aromatic diacid monomer containing taurine moiety

5-(2-tetrachlorophthalimidoethanesulfonamido) isophthalic acid (6), based on taurine, was simply prepared in three steps. Also a series of novel biologically active polyesters (PEs) were synthesized by the reaction of this monomer with several aromatic diols by step growth polymerization using tosyl chloride (TsCl)/dimethylformamide (DMF)/pyridine (Py) system as a condensing agent. The resulting new polymers were obtained in good to high yields with moderate inherent viscosities. All of the PEs were characterized by FT-IR and some of them were also characterized by 1H NMR and elemental analyses methods. The thermal stability of PEs was evaluated with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques under a nitrogen atmosphere and it was found that, they have moderate stability. Limiting oxygen index (LOI) of the polymers confirmed that the synthesized compounds have flame retardant properties. Soil bioactivity behavior of the diacid 6 and all of PEs derived from this diacid was investigated in culture media and it was found that synthesized diacid monomer 6 and all PEs have possibility of biodegradation under natural microbial environmental.

Synthesis, characterization and properties of novel thermally stable copoly(amide-imide)s containing dimethylsilane moieties

AbstractNew type of poly(amide-imide)s were prepared based on novel diacid monomer containing softening siloxane groups. Bis(p-aminophenoxy) dimethyl silane (3) was prepared by the reaction of dimethyl dichlorosilane with paminophenol in toluene. N,N'-Bis(4-trimellitimidophenoxy) dimethylsilane (5) as a novel aromatic dicarboxylic acid containing silicone moiety was synthesized by condensation of bis(p-aminophenoxy) dimethylsilane with trimelitic anhydride in acetic acid. The structure of diacid 5 was confirmed using various spectroscopy methods. The direct polycondensation technique was used for the polyamidation of monomer 5 with several aromatic diamines using pyridine / 2-methylpyrrolidone / triphenyl phosphite / CaCl2 as condensing agent. The resulting novel poly(amideimide- siloxane)s were obtained in high yields and inherent viscosities. These polymers were characterized using FT-IR, 1H-NMR, thermogravimetric and elemental analysis techniques. The results show that silicone modified poly(amideimide) s show high solubility and excellent thermal stability.

A new sequence isomer of AB‐polybenzimidazole for high‐temperature PEM fuel cells

AbstractA new sequence isomer of AB‐polybenzimidazole (AB‐PBI) was developed as a candidate for high‐temperature polymer electrolyte membrane fuel cells. A diacid monomer, 2,2′‐bisbenzimidazole‐5,5′‐dicarboxylic acid, was synthesized and polymerized with 3,3′,4,4′‐tetraaminobiphenyl to prepare a polymer that was composed of repeating 2,5‐benzimidazole units. In contrast to previously prepared AB‐PBI, which contains only head‐to‐tail benzimidazole sequences, the new polymer also contains head‐to‐head and tail‐to‐tail benzimidazole sequences. The polymer was prepared in polyphosphoric acid (PPA) and cast into membranes using the sol–gel PPA process. Membranes formed from the new AB‐PBI were found to be mechanically stronger, possessed higher acid doping levels, and showed improved fuel cell performance, when compared to the previously known AB‐PBI. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Research on Structure and Properties of a Novel Type of Poly( <i>Ester-Imide</i>)

A diacid monomer was prepared from trimellitic anhydride and aminobenzoic acid,and a novel poly(ester-imide) was synthesized through the diacid monomer and the 1, 4-butanediol.The structure and chemical resistance, intrinsic viscosity and thermal property and crystallization of the poly(ester -imide) were characterized by FT-IR spectra,various organic solvents,a capillary Ubbelohde viscometer,differental scanning calorimetry (DSC) and thermogravimetric analysis (TGA) and crystallization rate instrument.The results showed that the poly(ester-imide) has excellent chemical resistance and thermal property,its intrinsic viscosity is 0.46dL/g,it has high glass transition temperature (Tg) and relatively low melting temperature (Tm).Moreover,the novel poly(ester-imide) has obvious crystallization and excellent property to spin into fibers.

Influence of Benzoic Acid End-Capping on Properties of Poly( <i>Ester-Imide-Ether</i>) Block Copolymer and its Fiber

A type of benzoic acid end-capped ploy(ester-imide-ether) (PEIE) block copolymers was synthesized by melt polycondensation from polytetrahydrofuran diol (PTMG), 1,4-butanediol (BD), benzoic acid (BA) and a diacid monomer which was synthesized of trimellitic anhydride (TMA) with para aminobenzoic acid (PABA). The structures and properties of the copolymers were investigated by FT-IR spectroscopy and Ubbelohde viscometer, DSC and TGA. Some properties of the copolymer fibers such as breaking strength, breaking elongation and elasticity were also measured. The result demonstrated that the adding of BA can effectively reduce the inherent viscosities of PEIE. Especially the breaking strength, elastic recovery and heat stability of the fibers are improved obviously when adding 1 % (of the multiblock copolymer weight percentage) BA end capping agent.

Synthesis and properties of new highly soluble poly(amide-ester-imide)s containing poly(ethylene glycol) as a soft segment

In this study, a new class of highly soluble poly(amide-ester-imide)s (PAEI)s contains poly(ethyleneglycol) (PEG) as hydrophilic and soft segment were prepared. Poly(ethylene glycol)-bis-(N-trimellitylimido-4-phenyl carboxylic acid) (3) as a novel diacid monomer was synthesized via two step. The reaction of poly(ethylene glycol) (PEG 6000) with trimellitic anhydride chloride yield poly(ethylene glycol)-bis-trimellitic anhydride (1). The reaction of dianhydride 1 with p-aminobenzoic acid (2) produces novel diacid monomer 3. The direct polycondensation technique of the diacid 1 with several aromatic diamines was carried out in pyridine/N-methyl-2-pyrrolidone/triphenylphosphite/CaCl2 as condensing agent. The resulting novel PAEIs with inherent viscosities ranging between 0.21 and 0.42 dl g−1, were obtained in good yield. This group of polymers exhibit excellent solubility in a variety of organic solvents and water. All of these polymers were characterized with FT-IR spectroscopy. Thermal properties, 1H-NMR and XRD study of these PAEIs were also reported. The results demonstrate that this polymers show crystalline structure as well as high thermal stability. In addition the effect of PEG length on solubility and thermal properties of the polymers were also studied.

Construction, Characterization and Biological Activity of Chiral and Thermally Stable Nanostructured Poly(Ester-Imide)s as Tyrosine-Containing Pseudo-Poly(Amino Acid)s

In this paper we studied the synthesis of biodegradable optically active poly(ester-imide)s containing different amino acid residues in the main chain. These pseudo-poly(amino acid)s were synthesized by polycondensation of N,N′-(pyromellitoyl)-bis-l-tyrosine dimethyl ester as a diphenolic monomer and two chiral trimellitic anhydride-derived diacid monomers containing s-valine and l-methionine. The direct polycondensation reaction of these diacids with aromatic diol was carried out in a system of tosyl chloride (TsCl), pyridine (Py) and N,N′-dimethylformamide (DMF) as a condensing agent. The structures and morphology of these polymers were studied by FT-IR, 1H-NMR, powder X-ray diffraction, field emission scanning electron microscopy (FE-SEM), specific rotation, elemental and thermogravimetric analysis (TGA) techniques. TGA profiles indicate that the resulting PEIs have a good thermal stability. Morphology probes showed these polymers were noncrystalline and nanostructured polymers. The monomers and prepared polymers were buried under the soil to study the sensitivity of the monomers and the obtained polymers to microbial degradation. The high microbial population and prominent dehydrogenase activity in the soil containing polymers showed that the synthesized polymers are biologically active and microbiologically biodegradable. Wheat seedling growth in the soil buried with synthetic polymers not only confirmed non-toxicity of polymers but also showed possibility of phyto-remediation in polymer-contaminated soils.

Synthesis and Characterization of Chiral Poly(Amide-Imide) Containing L-Alanine

A novel chiral poly(amide imide) containing L-alanine was synthesized by direct polycondensation reaction of newly synthesized N,N’-(4,4’-diphthaloyl)-bis-L-alanine diacid with 4,4’-diaminodiphenyl ether in a medium consisting of N-methyl-2-pyrrolidone (NMP), triphenylphosphite (TPP), calcium chloride (CaCl2), and pyridine. The new chiral diimide-diacid monomer was synthesized by direct reaction of 3,3’-4,4’-Biphenyl tetracarboxylic acid dianhydride with L-alanine in acetic acid under refluxing conditions. The resulting compounds were obtained in quantitative yields and high purity. The synthetic diacid monomer was characterized by elemental analysis, 1H-NMR spectroscopy, FT-IR techniques and specific rotation, the obtained polymer was characterized by FTIR techniques, specific rotation and solubility testing.

Synthesis and properties of optically active nanostructured polymers bearing amino acid moieties by direct polycondensation of 4,4′-thiobis(2-tert-butyl-5-methylphenol) with chiral diacids

Four derivatives of N-trimellitylimido-L-amino acid (4a-4d) were prepared by the reaction of trimellitic anhydride (1) with the L-amino acids (2a-2d) in acetic acid as diacid monomers and were used with the aim to obtain a new family of amino acid based poly(ester-imide)s (PEI)s. The polymerization was performed by direct polycondensation of chiral diacids (4a-4d) with 4,4'-thiobis(2-tert-butyl-5-methylphenol) (5) in the presence of tosyl chloride (TsCl), pyridine and N,N-dimethyl formamide (DMF). Step-growth polymerization was carried out by varying the time of heating and the molar ratio of TsCl/diacid and the optimum conditions were achieved. The synthesized polymers were characterized by means of specific rotation experiments, FT-IR, 1H-NMR, X-ray diffraction techniques and elemental analysis. The surface morphology of the obtained polymers was studied by field emission scanning electron microscopy. The result showed nanostructure morphology of the resulting polymers. The obtained PEIs were soluble in polar aprotic solvents such as DMF, N,N-dimethyl acetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and protic solvents such as sulfuric acid. Thermal stability and the weight-loss behavior of the PEIs were studied by thermal gravimetric analysis (TGA) techniques. TGA showed that the 10% weight loss temperature in a nitrogen atmosphere was more than 402°C, therefore they had useful levels of thermal stability associated with excellent solubility.

Synthesis and structural characterization of novel bionanocomposite poly(ester-imide)s containing TiO2 nanoparticles, S-valine, and l-tyrosine amino acids moieties

The incorporation of different percents of titanium dioxide (TiO2) nanoparticles into optically active poly(ester-imide) (PEI), afforded an opportunity to prepare several novel PEI/TiO2 bionanocomposites (BNC)s. To this point, firstly PEI was synthesized via direct polyesterification of chiral diacid monomer and an optically active phenolic diol using tosyl chloride/pyridine/N,N-dimethylformamide system as a condensing agent. Novel BNC polymers containing TiO2 nanoparticles were synthesized through ultrasonic irradiation method. With the aim of γ-amidopropyl-triethoxylsilicane as a coupling agent, the surface of nanoscale TiO2 was modified to decrease aggregation of nanoparticles in polymer matrix. The obtained PEI/TiO2 BNCs were characterized with FT-IR, thermogravimetric analysis (TGA), scanning electron microscopy, X-ray diffraction, and transmission electron microscopy (TEM) techniques. Consequently, TEM image showed that the nanoparticles of smaller than 50 nm in diameter were uniformly dispersed in the polymer matrix. TGA data demonstrated that new synthesized PEI/TiO2 BNCs are more thermally stable in compare to pure PEI.

Effect of the polyester chemical structure on the stability of polyester–melamine coatings when exposed to accelerated weathering

The effect of the polyester chemical structure on the degradation of polyester/melamine coatings was studied. Four different polyesters were synthesized using different diacid monomers: (i) isophthalic acid (IPA) and mixtures of hexahydrophthalic anhydride (HHPA) with (ii) terephthalic acid (TA), (iii) phthalic anhydride (PAN) and (iv) 1,4 cyclohexanedicarboxylic acid (1,4-CHDA). Varnishes were prepared using melamine resin and submitted to accelerated degradation cycles. The process was monitored in terms of photooxidation index (POI), based on FTIR analysis, and in terms of changes in films’ hardness, level of gloss and surface morphology. The monomers which contributed the most to polymer degradation were the couple HHPA and 1,4-CHDA. The most important factor to degradation was the high number of hydrogen atoms attached to tertiary and secondary carbons in the polymer structure, due to their high sensitivity to abstraction, which favors the photooxidation reactions. The monomer IPA presented the lowest POI and the highest gloss retention.