Unsaturated Polyamides Research Articles

Solvent-Free and Catalyst-Free Synthesis of Cross-Linkable Polyfumaramides via Topochemical Azide-Alkyne Cycloaddition Polymerization

Unsaturated polymers are important materials having a lot of applications. Among polymers, polyamides possess a prime position due to their thermal and chemical stability. Herein, we report a simple, greener, catalyst-free, and solid-state synthesis of two unsaturated polyamides via a topochemical azide-alkyne cycloaddition reaction. Two designed fumaramide monomers M1 and M2, functionalized with complementary azide and alkyne reactive motifs at the termini, reacted upon heating their crystalline powders and resulted in the formation of triazolyl-linked unsaturated polyfumaramides P1 and P2, respectively. We have characterized the reaction using various time-dependent techniques such as NMR, FTIR, PXRD, and DSC measurements. Interestingly, the monomer M1 resulted in 1,5-disubstituted triazole-linked unsaturated polyfumaramide (P1), whereas the monomer M2 polymerized into a polyfumaramide having both 1,4-disubstituted and 1,5-disubstituted triazole linkages (P2). Also, the trans-olefinic bond of both the fumaramide monomers was unaffected in the polymerization process and hence yielded unsaturated polymers having trans-olefin units in the repeating unit. Demonstrating the scope of postsynthetic modification, we have shown that unsaturation can be exploited for cross-linking via a light-induced [2 + 2] cycloaddition reaction. This first report on the solid-state synthesis of unsaturated polyfumaramides will be of great interest.

Calculation of activation energy for unsaturated polyamide using fumaric acid and 2,6- diaminopyridine by modified Higashi-Yamazaki phosphorylation method

Calculation of activation energy for unsaturated polyamide using fumaric acid and 2,6- diaminopyridine by modified Higashi-Yamazaki phosphorylation method

Vibrational biospectroscopic study and chemical structure analysis of unsaturated polyamides nanoparticles as anti–cancer polymeric nanomedicines using synchrotron radiation

Firstly, unsaturated polyamides nanoparticles were hardened by continuous synchrotron radiation and then, the induced changes in its chemical structure were studied by Attenuated Total Reflection–Fourier Transform Infrared (ATR–FTIR) spectroscopy. It was shown that applying synchrotron radiation for hardening not only leads to reduction of hardening time but also creates cross link in polymer by breaking Carbon–Carbon double bond, without any considerable change in its chemical structure. In addition, an unsaturated polyamide nanoparticle as anti–cancer polymeric nanomedicines is hardened by synchrotron radiation. Its chemical structure before and after hardening is studied using Raman and Attenuated Total Reflection–Fourier Transform Infrared (ATR–FTIR) spectroscopy. The results show that Raman spectroscopy is considerably better than Attenuated Total Reflection–Fourier Transform Infrared (ATR–FTIR) spectroscopy in detecting the changes happened in chemical structure. Â

Photocrosslinking of a novel α,ω‐unsaturated copolyamide: mass spectrometric study on model compounds with benzophenone as photoinitiator

The aim of this work was to understand the reactions involved in the photocrosslinking processes of a alpha,omega-unsaturated copolyamide foreseen as a new UV-curable powder coating. The crosslinking reaction was photoinitiated with benzophenone. In this paper, the photochemical reaction between benzophenone and several model compounds was investigated. The model compounds contained functional groups which could be present in copolyamide. The products resulting from UV curing were identified using a combination of high-resolution mass spectrometry and MS(n) experiments. The characterization of the products allowed localization of the hydrogen abstraction by the type II photoinitiator during UV curing and, consequently, the determination of the reactive sites of the unsaturated polyamide chain which were involved in the photochemical reaction.

Unsaturated PA X,20 from Renewable Resources via Metathesis and Catalytic Amidation

AbstractThe synthesis of unsaturated polyamides that can be obtained from plant oil derivatives via two different approaches is described. First, long chain aliphatic α,ω‐dienes with two symmetrically spaced amide segments were polymerized via ADMET polymerization. Secondly, dimethyl(E)‐icos‐10‐enedioate, a bio‐based unsaturated monomer that was obtained via metathesis, was polymerized with different aliphatic diamines using strong organic bases, such as TBD, as catalysts. Both reaction pathways led to unsaturated PA X,20 and the two different routes were investigated, optimized and compared. Moreover, the polymers were characterized by 1H NMR analysis and SEC, and the properties of the resulting polyamides were investigated by DSC and TGA.magnified image

Unsaturated Polyamides from Bio‐Based Z‐octadec‐9‐enedioic Acid

AbstractA series of polyamides based on Z‐octadec‐9‐enedioic acid, a bio‐based unsaturated monomer, and aliphatic‐, cycloaliphatic‐, or benzylic diamines were synthesized and characterized by 1H and 13C NMR analysis, size exclusion chromatography (SEC), DSC, and dynamic‐mechanical analysis (DMA). The high reaction temperature (250 °C) did not lead to the degradation of diacid unit double bonds and unsaturated polyamides were obtained. The aliphatic unsaturated polyamides are semi‐crystalline polymers of high molar mass, relatively flexible at room temperature. The cycloaliphatic unsaturated polyamides are semi‐crystalline or amorphous, present higher melting and glass transition temperatures and are much more rigid. The aliphatic and aliphatic–aromatic unsaturated polyamides present lower Tg and Tm as compared to their parent saturated polymers.magnified image

Linear Unsaturated Polyamides: Nylons 6 u18 and 18 u18

AbstractSummary: Linear unsaturated nylons 6 u18 and 18 u18 have been made containing a double bond in the center of the diacid segment with potential for additional functionalization. Solution state NMR showed the presence of a small portion of cis amide units. Solid state NMR verified the presence of the double bond in the bulk, and that the polyamides were present in the α‐crystalline form. Thermal stability was comparable to linear saturated nylons, and the melting and crystallization temperatures of the unsaturated nylons were lower compared to the saturated analogs.DSC heating and cooling thermograms for nylons 6 u18 and 18 u18.magnified imageDSC heating and cooling thermograms for nylons 6 u18 and 18 u18.

Poly(α-alkyl γ-glutamate)s of microbial origin: I. Ester derivatization of poly(γ-glutamic acid) and thermal degradation

A series of poly(α-alkyl γ-glutamate)s (PAAG- n with n=1–10) were prepared from poly(γ-glutamic acid) (PGGA) of microbial origin by a two-steps synthesis procedure. The poly(α-ethyl γ-glutamate) was firstly obtained by esterification of PGGA and then transesterified with the selected alkanol to obtain the corresponding PAAG- n. The modification reactions were found to occur without alteration of the original enantiomeric composition but with a significant reduction in molecular weight. The thermal degradation of PAAG- n was examined by thermogravimetric analysis combined with IR and NMR spectroscopy. At low temperatures (<300°C) decomposition was found to take place by depolymerization with releasing of the corresponding alkyl pyroglutamate. Decarboxylation of PAAG- n to an unsaturated polyamide seemed to be the main process occurring at high temperatures (400–450°C).

Unsaturated polyamides and polyesters prepared from 1,4-bis(2-carboxyvinyl)benzene and 4-hydroxycinnamic acid

Various unsaturated polyamides and polyesters were prepared from the reactions of 1,4-bis(2-carboxyvinyl)benzene acid chloride with aromatic diamines and bisphenols, respectively. In addition, various unsaturated homo- and copolyesters were synthesized from 4-hydroxycinnamic acid and 4-hydroxybenzoic acid. They were heat-cured to thermally stable resins. The polymers were characterized by inherent viscosity measurements, FT-IR, x-ray, DTA, TMA, TGA, and isothermal gravimetric analysis. The water absorption as well as the solubility behavior of the polymers was also investigated. © 1996 John Wiley & Sons, Inc.

Unsaturated polyamides prepared from 3-amino- or 4-carboxycinnamic acid and their heat curing to thermally stable resins

Unsaturated homopolyamide was prepared from 3-aminocinnamic acid (ACA) by the phosphorylation polycondensation method. In addition, various copolyamides were prepared from ACA and 4-aminobenzoic acid. Furthermore, an Unsaturated homopolyamide was synthesized from 4-carboxycinnamic acid and 4,4′-diaminodiphenylmethane. The physical, chemical and thermal properties of the polyamides were correlated with those of the corresponding reference polyamides. The unsaturated polyamides showed an enhanced solubility in polar aprotic solvents and certain strong inorganic and organic acids compared to the reference polyamides. The X-ray diffractograms of polyamides showed some degree of crystallinity. Differential thermal analysis studies revealed melting of polyamides in the region of 237–292 °C. The crosslinked polymers obtained from unsaturated polyamides by curing at 260 °C for 20 h were remarkably more thermally stable than the reference polymers, being stable up to 310–366 °C in N 2 or air, and afforded a char yield at 800 °C of 66–80% in N 2 and 25–71% in air.

Cyano-substituted polyamides and polyimides prepared from 2,6-bis(3-aminobenzylidene)-1-dicyanomethylene-cyclohexane

Cyclohexanone was condensed with 3-nitrobenzaldehyde in the presence of dry HCl as catalyst to afford 2,6-bis(3-nitrobenzylidene)cyclohexane. The condensation of the latter with malononitrile yielded 2,6-bis(3-nitrobenzylidene)-l-dicyanomethylene-cyclohexane that was hydrogenated to the corresponding diamine. The latter was used as a reagent for preparing various unsaturated polyamides and polyimides bearing dicyanomethylene segments. In addition, a model diamide and diimide were synthesized. The polymers were soluble in polar aprotic solvents and certain strong inorganic and organic acids. They were crosslinked upon heating at 300°C for 20 hr. The crosslinked polymers were stable up to 377–408°C in N 2 or air and afforded anaerobic char yields of 65–70° at 800°C.

A study on the temperature dependence of the electrical conductivity of a pyrolysed cyano-substituted polyamide derived from 1,4-bis(2-cyano-2-carboxyvinyl)benzene

An unsaturated polyamide with pendant cyano groups was prepared from 1,4-bis(2-cyano-2-carboxy-vinyl)benzene, and its electrical conductivity was studied, as a function of temperature, following pyrolysis at 550, 650 and 700°C. The results show that the unpyrolysed polymer has insulating properties at room temperature, whereas a dramatic increase of the electrical conductivity is observed with increasing pyrolysis temperature, ranging from 6.451 × 10 −6 S cm −1 at 550°C to 8.130 × 10 −1 S cm −1 at 700°C. The temperature dependence of the electrical conductivity of the pyrolysed polymer suggests that the resulting material has semiconducting properties. The observed electrical conductivity is thermally activated, and may be associated with both intermolecular and intramolecular conduction processes, with activation energies ranging from 0.13 to 0.02 eV for the intermolecular conduction process and from 0.26 to 0.05 eV for the intramolecular process, depending on the pyrolysis temperature that is used.

Synthesis, characterization, and curing of unsaturated polyamides derived from 2,6‐di(4‐carboxystyryl)pyridine and 2,6‐bis(4‐carboxybenzylidene) cyclohexanone

AbstractTwo new series of heat‐curable polyamides were prepared utilizing the unsaturated dicarboxylic acids 2,6‐di(4‐carboxystyryl)pyridine (DCSP) and 2,6‐bis(4‐carboxybenzylidene)cyclohexanone (BCBC) as starting materials. They were prepared from the condensation of 4‐carboxybenzaldehyde with a half molar amount of 2,6‐dimethylpyridine or cyclohexanone, respectively. The dicarboxylic acids reacted with various aromatic diamines, utilizing triphenyl phosphite and pyridine as condensing agents, to yield polyamides. In addition, two model diamides were prepared by condensing the dicarboxylic acids with aniline. Characterization of starting materials, polyamides, and model compounds was accomplished by IR and 1H–NMR spectroscopy. The curing behavior of polyamides was investigated by DTA. Upon heat‐curing, the unsaturated polyamides were crosslinked through their olefinic bonds to afford insoluble, heat‐resistant resins. The thermal stability of the resins was evaluated by TGA and isothermal gravimetric analysis (IGA). The cured resins were stable up to 310–322°C in N2 or air and afforded anaerobic char yield of 57–69% at 800°C.

Synthesis and Thermal Stability of Unsaturated Polyamides

Unsaturated polyamides were prepared by condensing /3(4-ethoxyphenyl) glutaconic acid with various aromatic diamines. The polycondensates were characterized by IR spectroscopy, vapor phase osmometry, thermogravimetric analysis, differential scanning calorimetry and elemental analysis. All resins were found to decompose in the range '-210-600 °C. The kinetics of decomposition were studied. The results indicated that the resins possess reasonably good thermal stability.

Unsaturated heat-curable polyamides and polyimides derived from 2,6-bis(3-aminobenzylidene)cyclohexanone

Cyclohexanone was condensed with a double molar amount of 3-nitrobenzaldehyde in the presence of dry HCl as catalyst to yield 2,6-bis(3-nitrobenzylidene)cyclohexanone. The latter was catalytically hydrogenated to 2,6-bis(3-aminobenzylidene)cyclohexanone (BABC) by means of hydrazine hydrate. New unsaturated polyamides and polyimides were prepared by reacting BABC with terephthaloyl dichloride and pyromellitic dianhydride or benzophenone tetracarboxylic dianhydride, respectively. Model diamide and diimide were synthesized from the reactions of BABC with benzoyl chloride and phthalic anhydride, respectively. In addition, BABC reacted with maleic and nadic anhydride to yield a bismaleimide and bisnadimide which were utilized as new polymer precursors. Monomers and model compounds were characterized by i.r. and 1H-NMR spectroscopy. Characterization of polymers was accomplished by i.r., DTA and inherent viscosity measurements. Cured resins were obtained by heating the unsaturated polymers and polymer precursors at 265° for 27 hr. They were stable up to 345–363° in N 2 or air and afforded anaerobic char yields of 52–61% at 800°.

Unsaturated Polymides From β(2-Ethoxy-5-methylphenyl) Glutaconic Acid and Their Characterization

Abstract Some unsaturated polyamide resins were synthesized by condensing β(2-ethoxy-5-methylphenyl) glutaconic acid with six diamines. The polycondensates were characterized by IR. TG, DSC: VPO and elemental analysis. Most of the polymers were found to decompose in the range of ∼ 190 to 600°C. They are brownblack in nature. The kinetics of decomposition was studied. The kinetic parameters were evaluated by the method of Broido. It was observed that the energy of activation of polycondensates depends upon the presence of diamine components in the polymer.

Linear Unsaturated Polyamides and Polyhydrazides

Abstract Polyhydrazides and polyamides were prepared from hydrazine, piperazine, or substituted piperazines and muconic or α,α′ -dimethylmuconic acid chlorides by interfacial and solution polymerization. Low-temperature solution polymerization was preferred for polyhydrazides, and the interfacial technique for the piperazides. Polymers of dimethylmuconic acid exhibited better properties than those of muconic acid, e.g., molecular weight, film strength, and solubility. Optical properties, such as transparency, color, refractive index, and birefringence, were also determined and compared to aromatic polyamides and hydrazides.

Unsaturated polyamides. Studies on synthesis, properties, and crosslinking

AbstractA few unsaturated polyamides were prepared by thionyl chloride activated low temperature polycondensation and solution polymerization of fumaric, adipic, isophthalic, and terephthalic acid or their diacid chloride derivatives with 1,5‐bis‐(3‐aminophenyl)‐1,4‐pentadiene‐3‐one. The polymers were characterized by nitrogen analysis and IR spectroscopy. The solution, thermal, and electrical properties of the polymers were studied. The polymers were found to be soluble in polar solvents. The solubility parameter of the polymers were calculated from Small's group contributions which agreed well with the experimental values. The polymers readily underwent crosslinking reaction when heated alone or preferably in the presence of a suitable free radical catalyst. The crosslinked polymers were found to be insoluble in polar solvents and possessed higher thermal stability compared with the virgin polymers. The swelling behaviour of the polymers were studied in detail and the molecular weight between two crosslinked junctions were also found out. X‐ray diffraction and dielectric properties of the crosslinked polymers were also reported.

Processable heat‐resistant polymers. XI. Synthesis and characterization of unsaturated polyamideimides

AbstractPolycondensation of the diacid chloride of 2‐(3‐carboxy vinyl)phenyl‐1,3‐dioxoisoindoline‐5‐carboxylic acid with m‐phenylenediamine and the diacid chloride of 2‐(4‐carboxy phenyl)‐1,3‐dioxoisoindoline‐5‐carboxylic acid with 1,5‐bis(3‐aminophenyl)1,4‐pentadien‐3‐one was carried out in polar solvents to produce new unsaturated polyamide–imides. The solution and the thermal, electrical, and a few other properties of the polymers were studies. The polymers were soluble in highly polar solvents. The solubility parameter of the polymers was calculated from the Small's group contribution. The polymers were fairly thermostable and underwent crosslinking creaction when heated, preferably in the presence of a suitable catalyst. The crosslinked polymers were in soluble even in highly polar solvents and possessed higher thermal stability. The swelling behavior of the polymers was studied and the molecular weight between two consecutive crosslinks was determined. X‐ray diffraction and the dielectric properties of the polymers and their crosslinked products were also studied.

Structure Property Relationship in Unsaturated Polyamides

Abstract Unsaturated polyamides from fumaric acid and ortho-, meta- and para-phenylene diamine were prepared by thionyl chloride activated low temperature polycondensation in polar solvents. The polymers were found to be soluble in highly polar solvents. The solubility parameter of the polymers was calculated from Small's group contribution, which agreed well with the experimental values. X-ray diffraction study revealed that the polymers were amorphous. The isomeric effect on the thermal and electrical properties of polymers was discussed.