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In this study, a hybrid material was successfully fabricated through the hybridization of zinc-based metal–organic framework (Zn-MOF) and covalent organic framework (COF) based on melamine and terephthaldehyde (Zn-MOF/COF) and characterized by FT-IR, SEM, XRD, and STA analysis. Then, the resultant hybrid was employed as an amazing and cost-effective catalyst in the condensation of a variety of aldehydes with malononitrile under solvent-free conditions at 25 °C in a short time (5–60 min) to offer benzylidenemalononitrile derivatives in high yields (82–100%). The catalyst could be reused without a noteworthy drop in catalytic activity at least eight times. The use of Zn-MOF/COF catalyst outcomes under mild reaction conditions in very short reaction time, exceptional catalytic activity, high recyclability and an easy work-up process for the Knoevenagel condensation.

In this research, an aqueous reflux method was utilized to synthesize copper sulfide nanostructures with different morphologies, such as flower-like based nanosheets and spherical nanoparticles. The reaction was performed in oleic acid medium, using copper(II) acetylacetonate [Cu(acac)2] and elemental sulfur as the Cu2+ and S2− sources, respectively. Then, the effect of refluxing temperature, precursor molar ratios and reaction time on the particle phase and morphology of synthesized particles was investigated. The results show that a 1 : 1 ratio of [Cu (acac)2] to S2− at 200 °C reflux temperature for 10 h exhibit optimum conditions for forming a pure hexagonal Cu7.2S4 phase. Then, the surface of the synthesized Cu7.2S4 was also modified by hydrophilic polyethylene glycol (PEG), and the modified nanoparticles were used in the release of the drug doxorubicin at pH = 5.4, pH = 7.4 under in vitro conditions, which was monitored by UV-Vis spectroscopy. The results showed that drug release under acidic conditions is greater than that under neutral conditions. Furthermore, by increasing the sulfur content, the sample's morphology was changed from a spherical shape to flower-liked based nanosheets, and the phase tends to be the CuS phase. Finally, the synthesized Cu7.2S4 nanostructures were used for the photocatalytic degradation of some dyes, including Reactive Blue 21 (RB21), Reactive Red 120 (RR120), and Reactive Orange 5 (RO5). The results showed that the highest degradation percentage for RB21 pigment was 99%.

The fabrication of magnetic porous nanocomposites is of great significance owing to their excellent properties and their application as promising catalysts. Herein, a novel covalent organic framework (COF)-modified magnetic chitosan (CS) supported copper (Fe3O4/CS/COF/Cu) nanocomposite was prepared through modification of Fe3O4 with CS, chemical attachment of melamine-rich COF on Fe3O4/CS followed by reaction with Cu(NO3)2·3H2O. The resulting nanocomposite was characterized by FT-IR, XRD, SEM, TEM, EDX, BET and VSM analyses. Fe3O4/CS/COF/Cu possesses large specific surface area and supermagnetism, making it an ideal catalyst for the organic reactions. Thus, Fe3O4/CS/COF/Cu was applied as an efficient and recoverable catalyst for the green and rapid synthesis of biologically active polyhydroquinoline derivatives via the unsymmetric Hantzsch reaction under solvent-free conditions. Fe3O4/CS/COF/Cu exhibits high reactivity and selectivity for the preparation of different derivatives of polyhydroquinolines under mild reaction conditions and short time. Furthermore, the catalyst was recovered and reused several times without an important decrease in efficiency.

In this study, by hybridization of zinc-based metal–organic framework-5 (MOF-5) and melamine-terephthaldehyde-based intergrade two-dimensional π-conjugated covalent organic framework (COF), a novel MOF-5/COF (M5C) hybrid material was prepared and characterized by Fourier transform infrared, field emission scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. MOF-5 has a well-defined cubic structure, and the proposed COF has an orderly and spherical nanosize shape. The prepared MOF-5/COF was applied as an effective adsorbent for rapid and high-efficient simultaneous removal of auramine O (AO) and rhodamine B (RB) cationic dyes via electrostatic, H-bonding, Lewis acid–base interactions, and π–π stacking from aqueous solution. The effect of experimental parameters such as pH, M5C mass, contact time, and AO and RB dyes concentration was investigated for removal efficiency and optimized. The M5C adsorbent showed an adsorption capacity of 17.95 and 16.18 mg/g for AO and RB dyes, respectively, at pH 9.5. The adsorption study of AO and RB dyes by M5C comprises both isotherm and kinetic studies. The equilibrium adsorption data followed by Langmuir isotherm and the adsorption kinetic process were found to be a pseudo-second-order model. The robustness adsorption efficiency of MOF/COF hybrids can be attributed to the formation of amide bonds between COF and MOFs, which improve the stability of the adsorbent.

A tetramine monomer containing porphyrin moiety is prepared in high purity by the propionic acid-mediated condensation of pyrrole with 4-cyanobenzaldehyde and then reduction in the tetracyano intermediate. The thermally stable porphyrin-based polyimides (PI)s are prepared using tetramine and four aromatic tetracarboxylic dianhydrides via a two-step method in quantitative yields with inherent viscosities of 0.34–0.63 dL/g. The PIs are soluble in some organic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and dimethyl sulfoxide. The resultant PIs had high glass transition temperatures and displayed outstanding thermal stability up to 500 °C. The resulting polymers revealed strong UV–Vis absorption band around 422 nm in DMF. Wide-angle XRD measurements exhibited that the PIs were amorphous. The polymer films had tensile strengths 101–128 MPa, elongates at break of 7–11% and tensile moduli of 2.0–2.2 GPa. One of the PIs was applied to examine the adsorption properties of two heavy metal ions (Cd2+ and Hg2+) at pH 7. The results revealed that the applied PI was an outstanding sorbent for heavy metal ions. The goal of this study is the preparation of hydrophobic PIs for ion-selective membranes and chemical sensors to adsorb of toxic heavy metals.

The present study focused on utilizing the advantages of porous covalent organic frameworks by preparing them in a usable magnetite support form with Fe3O4 nanoparticles using the solvothermal meth...

Two novel optically active poly(amide-imide)s (PAI)s were prepared by the direct polycondensation of diamine, 3,5-diamino-N-(4-(5-(4,5-diphenyl-1H-imidazol-2-yl)furan-2-yl)phenyl)benzamide with two optically active dicarboxylic acids such as N,N′-(pyromellitoyl)-bis-l-phenylalanine and N,N′-(4,4′-carbonyldiphthaloyl)-bis-l-phenylalanine in molten tetrabutylammonium bromide (TBAB) as a green medium with triphenyl phosphite as condensing agent. The diamine was synthesized via the direct condensation of 2-[5-(4-aminophenyl)furan-2-yl]-4,5-diphenyl-1H-imidazole with 3,5-dinitrobenzoyl chloride and following reduction in the dinitro compound. The resulting PAIs had inherent viscosities of 0.38 and 0.35 dL g−1. The PAIs were dissolved in polar organic solvents, such as NMP, DMAc, DMSO and DMF at room temperature. These polymers were solution-cast from DMAc solution into transparent, flexible and tough films. Wide-angle X-ray measurement exhibited that the PAIs were amorphous. These PAIs had 10% weight loss temperatures of 427 and 440 °C under nitrogen atmosphere. The polymer films had a tensile strength of 102 and 108 MPa and a tensile modulus of 2.2 and 2.3 GPa. The adsorption capability of one of the PAIs for removal Cu2+ from aqueous solutions was tested at pH 5.

The exploration of magnetic polymer nanocomposites is of great importance owing to their unique properties and promising applications. Herein, for the first time, the ternary superparamagnetic nanocomposites of Fe3O4 nanoparticles, graphene oxide (GO) and optically active poly(amide–imide) (Fe3O4@GO/PAI) were prepared and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometer, scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The preparation was attained via a three-stage process consisting of a facile one-pot in situ growth of Fe3O4 on GO, resulted in the preparation of the magnetic Fe3O4@GO, modification of Fe3O4@GO by 3-aminopropyltriethoxy silane to introduce amino groups on its surface and subsequently its compositing by various levels of 4.0, 6.0, 8.0, and 10.0 wt% with chiral PAI through ultrasonic irradiation afforded the magnetic nanocomposites (NanoFe3O4@GO/PAI). The SEM analysis showed Fe3O4 nanoparticles with 30 nm size were successfully decorated the GO nanosheets. The TGA analysis established the expected thermal stability for Fe3O4@GO/PAI nanocomposites. Furthermore, incorporation of Fe3O4@GO in polymer matrix improved the mechanical properties substantially.

Ultrasound-assisted solid-phase microextraction (SPME) by a functionalized high surface area ZnO nanoparticle (NP)-based molecularly imprinted polymer (MIP) followed by UV-Vis spectrophotometry was described as a selective, economic and rapid technique which was established for the extraction and preconcentration of meloxicam (MEL) in water media and plasma. ZnO@MIP-NPs were fabricated via a surface molecular imprinting polymerization method, and subsequently, were characterized by FT-IR, SEM and DLS techniques. The operational variables such as solution pH, dosage of MIP, type and volume of eluent, and adsorption and desorption time were investigated and optimized. After optimization, kinetic and isotherm models for the adsorption of MEL onto ZnO-NPs@MEL-MIP were assessed and fitted. Under the optimum experimental conditions, the calibration curve exhibited a linear range of 0.1–10.0 mg L−1 of the MEL concentration with a detection limit of 0.008 mg L−1. The relative standard deviation for the analyte was found to be lower than 2.81%. The ZnO-NPs@MEL-MIP adsorption capacity was found to be 53.47 mg g−1. The preconcentration factor was found to be 25. The results showed that the prepared sorbent could be successfully applied for the determination of MEL in water and plasma samples.

In this investigation, a novel aromatic diamine containing imidazole, furan and benzamide units in the side chain was successfully synthesized via direct condensation of 2-[5-(4-aminophenyl)furan-2-yl]-4,5-diphenyl-1H-imidazole with 3,5-dinitrobenzoyl chloride and following reduction in the dinitro compound. A series of novel polyimides (PI)s with aromatic heterocyclic structure were synthesized by a conventional two-step polymerization process from the reaction of aromatic diamine monomer with tetracarboxylic dianhydrides. These polymers were characterized using Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), X-ray diffraction (XRD) and elemental and thermogravimetric analysis techniques. The resulting PIs exhibited good thermal stability and small mass loss before temperature of 400 °C in nitrogen. They showed high solubility in polar organic solvents, such as NMP, DMAc, DMSO and DMF at room temperature. XRD studies exhibited that the obtained polymers exhibit amorphous morphology. In this research, PIs were used as a novel and efficient adsorbent for removal of malachite green dye from aqueous solution. The results showed that prepared PIs are an effective adsorbent for the removal of Cu ions from aqueous solutions.

Fe3O4 nanoparticles were prepared and coated with 3-aminopropyltriethoxysilane (APTES). The formed amine-surfaced Fe3O4@APTES NPs were further chemically modified with maleic anhydride (MAH) to generate Fe3O4@APTES·MAH NPs. This catalyst was characterized by FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TG), energy dispersive X-ray analyzer (EDAX), vibrating sample magnetometry (VSM) and the dynamic light scattering (DLS) measurement technique. The catalyst showed high thermal stability and good reusability. Some new bulky heterocyclic compounds such as bis(2,4,5-triarylimidazole), bis(1,4-dihydropyridine), bis(1,8-dioxooctahydroxanthene) and bis(1,8-dioxo-decahydroacridine) derivatives were synthesized using 4,4′-(alkylazanediyl)dibenzaldehyde as substrate and Fe3O4@APTES or Fe3O4@APTES·MAH as catalyst. The high purity products were isolated and the catalyst was easily separated with a simple work-up with magnetic field and was recycled several times without noticeable loss of reactivity under the described reaction conditions.

A novel aromatic chiral dicarboxylic acid, 5-[4-(2-tetrabromophthalimidylpropanoylamino)benzoylamino]isophthalic acid was synthesized in three steps in high yield and purity starting from tetrabromophthalic anhydride and l-alanine. A series of new soluble, thermally stable and optically active polyamides (PA)s having pendent tetrabromophthalimide, flexible asymmetrical and benzamide groups with flame retardancy properties have been successfully prepared using triphenyl phosphite/pyridine in the presence of calcium chloride and N-methyl-2-pyrrolidone (NMP). The resulting new polymers were obtained in good yields, inherent viscosities ranging between 0.36 and 0.63 dL g−1 and were characterized with FT-IR, 1H NMR, specific rotation and thermogravimetric analysis techniques. Bulky pendent groups of the polymer chains disturb interchain and intrachain interactions and make these polymers readily soluble in various solvents, such as NMP, N,N-dimethylacetamide, dimethyl sulfoxide, and N,N-dimethylformamide. The resulting PAs were thermally stable, with 10 % weight loss recorded at 432 and 478 °C in the nitrogen atmosphere. In addition, due to existence of chiral center and optical activity of these polymers, they have potential to be utilized as chiral stationary phase in chromatography technique for the separation of racemic mixtures.

A novel chiral poly(amide–imide) (PAI) containing triptycene and S-valine moieties was prepared from the polycondensation reaction of N,N′-(pyromellitoyl)-bis-S-valine diacid chloride with bis(4-aminophenoxy)phenyl triptycene. The new PAI/α-Fe2O3 nanocomposites were prepared via ultrasonic irradiation process by dispersing silane coupling agent modified α-Fe2O3 nanoparticles in the polymer matrix. The resulting nanocomposites were characterized by Fourier transform infrared, powder X-ray diffraction, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The TEM results indicated that the nanoparticles were dispersed homogeneously in PAI matrix on nanoscale. TGA confirmed that the thermal stability of the nanocomposite was improved in the presence of α-Fe2O3 nanoparticles.

A triptycene-containing dicarboxylic acid monomer, bis(4-trimellitimido phenoxy)phenyl triptycene, was successfully synthesized by refluxing the diamine, bis(4-aminophenoxy)phenyl triptycene with trimellitic anhydride in glacial acetic anhydride. A series of aromatic poly(amide-imide)s were prepared by condensation polymerization of the dicarboxylic acid monomer and seven different commercially available diamines. The resulting poly(amide-imide)s were soluble in various solvents, such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, and pyridine. The polymers were amorphous and had inherent viscosities in the range 0.40–0.67 dL/g. These polymers had low dielectric constants ranging from 2.09 to 2.18. The glass transition temperatures of these polymers were observed between 229°C and 277°C. These polymers showed good thermal stability without significant weight loss up to 500°C. The temperatures at 10% weight loss ranged from 512°C to 570°C in nitrogen. The UV-Vi...

An optically active poly(amide-imide) (PAI) was synthesized from the polymerization reaction of N,N'-(Pyromellitoyl)-bis-l-alanine diacid chloride with 2,5-diaminotoluene. The obtained inorganic metal oxide nanocomposites composed of PAI/nanostructured hematite (α-Fe2O3) were synthesized through ultrasonic irradiation. The resulting nanocomposites were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The TEM results indicated that the nanoparticles were dispersed homogeneously in PAI matrix on nanoscale. TGA confirmed that the heat stability of the nanocomposites was improved in the presence of α-Fe2O3 nanoparticles. POLYM. COMPOS., 2014. © 2014 Society of Plastics Engineers

Thermally stable polyimide/titania (PI/TiO2) hybrid nanocomposite films have been successfully synthesized through the in situ formation of TiO2 within a PI matrix via sol-gel process. Poly(amic acid) (PAA) solution is prepared from 3,5-diamino benzoyl amino phenyl-14H-dibenzo[a,j]xanthene and 4,4′-(hexaflouroisopropylidene)diphthalic anhydride in N-methyl-2-pyrrolidinone solvent. The different amounts of tetraethyl orthotitanate and actylacetone are incorporated into PAA matrix, and then thermally imidized to form PI/TiO2. The chelating agent, acetylacetone, was applied to reduce the gelation rate of titanium alkoxide. Thermal decomposition temperatures of nanocomposites with a 10% weight loss were in excess of 500°C, and char yields higher than 63% at 800°C in nitrogen. The chemical and morphological structures of the hybrid nanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy. The results show that the TiO2 particles are well dispersed in the PI matrix with particle size between 10 and 30 nm in diameter. POLYM. COMPOS., 35:1486–1493, 2014. © 2013 Society of Plastics Engineers

A new triptycene-containing dicarboxylic acid monomer was successfully synthesized by refluxing the diamine, bis(4-aminophenoxy)phenyl triptycene with trimellitic anhydride in glacial acetic anhydride. A series of novel thermally stable poly(ester-imide)s were prepared from dicarboxylic acid, bis(4-trimellitimido phenoxy)phenyl triptycene with various diols by the direct polycondensation. The polymers were obtained in quantitative yields with inherent viscosities of 0.27–0.74 dL g−1. The resulting polymers dissolved in N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, and pyridine. These polymers were fairly stable up to a temperature >450°C and lost 10% weight in the range of 477°C and 575°C in nitrogen. The UV–V is absorption spectra revealed that most of the polymers had absorption maxima around 310 and 341 nm. POLYM. ENG. SCI., 54:2252–2257, 2014. © 2013 Society of Plastics Engineers

A new xanthene-containing diamine monomer was successfully synthesized in four steps by the condensation of β-naphthol and 4-nitrobenzaldehyde in the presence of p-toluenesulfonic acid catalyst, reduction of the nitro intermediate, the nucleophilic substitution reaction of amine compound and 3,5-dinitrobenzoyl chloride, and subsequent reduction of the dinitro compound. The diamine monomer could be obtained in quantitative yield. A series of novel organosoluble aromatic polyimides were prepared by direct polycondensation of synthesized diamine with four tetracarboxylic dianhydrides via a conventional two-step polymerization process. The polymers were obtained in quantitative yields with inherent viscosities of 0.20–0.74 dL/g. Most of the polymers dissolved in N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and dimethyl sulfoxide. The resulting polyimides exhibited good thermal stability; no weight loss was detected before a temperature of 450 °C in nitrogen. Wide-angle X-ray diffraction measurements showed that these polyimides were predominantly amorphous.

An ionic liquid (IL) (1,3-dipropylimidazolium bromide) in combination with triphenyl phosphite was employed for the synthesis of highly organosoluble and chiral polyamides bearing l-phenylalanine and anthracenic units via the phosphorylation polyamidation reaction with the assistance of a microwave-accelerated reaction system. Compared with conventional solvents, this approach exhibited higher inherent viscosities and shorter reaction time, which indicated coupling of IL and microwave irradiation was an efficient, rapid, and simple preparation technique for the synthesis of polyamides. The yields and thermal stability of the polymers were comparative under two methods. All of the resulting polymers were amorphous with excellent solubility in many organic solvents, such as N-methyl-2-pyrrolidinone and N,N-dimethylacetamide. The obtained polyamides had glass transition temperatures of about 183 °C, 10% weight-loss temperatures in excess of 340 °C, and char yields at 800 °C in nitrogen higher than 42%.

A new diacid monomer, 5-[3-phenyl-2-(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)propanoylamino]isophthalic acid was successfully synthesized starting from cis -9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid anhydride and l -phenylalanine. A highly effective, very fast microwave method is described to synthesize optically active aromatic polyamides (PA)s under microwave heating for only 3 min. Generally, better yields are obtained under faster and cleaner reactions when compared to those from conventional heating. Therefore, this approach could considerably reduce the synthesis time, cost, and energy. The resulting PAs had inherent viscosities in the range of 0.35–0.58 dL/g. All of the these polymers having bulky anthracenic and amino acid functionality in the side chain showed excellent solubility and readily dissolved in various solvents such as N- methyl-2-pyrrolidinone, N,N -dimethylacetamide and N,N -dimethylformamide. PAs were thermally stable, with 10% weight loss recorded at 385 °C and 341 °C in the nitrogen atmosphere, and char yields at 800 °C higher than 50% and glass transition temperature above 180 °C.

In the present study, the solid-state thermal polymerization of 4-(4-dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione (DAPTD) with diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate and toluylene-2,4-diisocyanate as a new method for synthesis of polyureas are described. The influence of reaction parameters, such as presence of catalyst in the starting material and ratio of DAPTD to diisocyanate were investigated. Polycondensation was successfully preceded without any solvent, which is used in conventional method. The resulting polyureas were obtained in high yields with inherent viscosities ranging from 0.14 to 0.25 dL/g. This method was also compared with two other polycondensation methods for the polymerization reactions which were reported before: conventional solution method and a method using tetrabutylammonium bromide as a molten ionic liquid media.

The reaction of 4-(3-hydroxynaphthalene)-1,2,4-triazolidine-3,5-dione (3HNTD) with n-propylisocyanate was performed at different molar ratios. The resulting monosubstituted urea and disubstituted urea-urethane derivatives were obtained in high yields and were used as model compounds for polymerization reactions. 3HNTD as a monomer was used in the preparation of heterocyclic poly(urea-urethane)s to produce photoactive polymers, by polycondensation with different diisocyanates in N,N-dimethylacetamide (DMAc) solution. Chromophoric heterocyclic polymers containing naphthalene group, obtained in quantitative yields, possessed inherent viscosities in the range of 0.14–0.38 dL/g. The resulting poly(urea-urethane)s is insoluble in most organic solvents, but easily soluble in polar solvents such as dimethyl sulfoxide (DMSO), DMAc, and N-methylpyrrolidone (NMP). The polymers were characterized by IR, 1H-NMR, elemental analysis, and TGA. Fluorimetric and UV–vis studies of the monomer as well as polymers were performed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

4-(3-Hydroxy-naphthalene)-1,2,4-triazolidine-3,5-dione (3HNTD) was synthesized in six steps starting from 3-hydroxy-2-naphthalene carboxylic acid. The reaction of monomer 3HNTD with acetyl chloride was performed in N,N-dimethylacetamide (DMAc) solution at different molar ratios, and the resulting mono-, di- and trisubstituted derivatives were obtained in high yields and were finally used as models for polymerization reactions. A series of novel aliphatic–aromatic poly(amide-ester)s (PAE)s containing a naphthalene pendent moiety were prepared from 3HNTD and various diacid chlorides (including succinyl chloride, adipoyl chloride and sebacoyl chloride) by polycondensation reactions with three methods: low-temperature solution polycondensation, solution polymerization under gradual heating and reflux conditions in the presence of pyridine and triethylamine as a proton scavenger and without a proton scavenger, respectively. PAEs from aliphatic diacid chlorides and 3HNTD have been studied in great detail via th...

4-(4-dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione (DAPTD) was prepared from 4-dimethylaminobenzoic acid in five steps. The compound DAPTD was reacted with excess acetyl chloride in N,N-dimethylacetamide (DMAc) solution and gave 1,2-bisacetyl-4-[4-(dimethylaminophenyl)]-1,2,4-triazolidine-3,5-dione as a model compound. Solution polycondensation reactions of monomer with succinyl chloride (SucC), suberoyl chloride (SubC), and sebacoyl chloride (SebC) were performed under conventional solution polymerization techniques in the presence of triethylamine and pyridine as a catalyst in N-methylpyrrolidone (NMP) and led to the formation of novel aliphatic polyamides. These novel polyamides have inherent viscosities in the range of 0.09–0.21 dL/g in N,N-dimethylformamide (DMF) at 25°C. Fluorimetric studies of the model compound as well as polymers were performed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 947–954, 2007

4-(4-Dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione (DAPTD) was prepared from 4-dimethylaminobenzoic acid in five steps. The reaction of monomer DAPTD with n-isopropylisocyanate was performed at room temperature in N,N-dimethylacetamide (DMAc) solution and the resulting bis-urea derivative was obtained in high yield and was finally used as a model compound for polymerization reaction. The step-growth polymerization reactions of monomer with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI) and toluene-2,4-diisocyanate (TDI) were performed in DMAc solution in the presence of pyridine, triethylamine or dibutyltin dilurate as catalysts. Some physical properties and structural characterization of these novel polyureas are reported. Fluorimetric studies of the model compound as well as polymers were performed.

4-(4′-Aminophenyl)-1,2,4-triazolidine-3,5-dione (1) was reacted with 1,8-naphthalic anhydride (2) in a mixture of acetic acid and pyridine (3 : 2) under refluxing temperature and gave 4-(4′-N-1,8-naphthalimidophenyl)-1,2,4-triazolidine-3,5-dione (NIPTD) (3) in high yield and purity. The compound NIPTD was reacted with excess n-propylisocyanate in N,N-dimethylacetamide solution and gave 1-(n-propylamidocarbonyl)-4-[4′-(1,8-naphthalimidophenyl)]-1,2,4-triazolidine-3,5-dione (4) and 1,2-bis(n-propylamidocarbonyl)-4-[4′-(1,8-naphthalimidophenyl)]-1,2,4- triazolidine-3,5-dione (5) as model compounds. Solution polycondensation reactions of monomer 3 with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), and tolylene-2,4-diisocyanate (TDI) were performed under microwave irradiation and conventional solution polymerization techniques in different solvents and in the presence of different catalysts, which led to the formation of novel aliphatic-aromatic polyureas. The polycondensation proceeded rapidly, compared with conventional solution polycondensation, and was almost completed within 8 min. These novel polyureas have inherent viscosities in a range of 0.06–0.20 dL g−1 in conc. H2SO4 or DMF at 25°C. Some structural characterization and physical properties of these novel polymers are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2861–2869, 2003

4-(4′-Aminophenyl)-1,2,4-triazolidine-3,5-dione was reacted with 1 mol of acetyl chloride in dry N,N-dimethylacetamide (DMAc) at −15°C and 4-(4′-acetamidophenyl)-1,2,4-triazolidine-3,5-dione [4-(4′-acetanilido)-1,2,4-triazolidine-3,5-dione] (APTD) was obtained in high yield. The reaction of the APTD monomer with excess n-isopropylisocyanate was performed at room temperature in DMAc solution. The resulting bis-urea derivative was obtained in high yield and was finally used as a model for the polymerization reaction. The step-growth polymerization reactions of monomer APTD with hexamethylene diisocyanate, isophorone diisocyanate, and tolylene-2,4-diisocyanate were performed under microwave irradiation and solution polymerization in the presence of pyridine, triethylamine, or dibutyltin dilaurate as a catalyst. Polycondensation proceeded rapidly, compared with conventional solution polycondensation; it was almost completed within 8 min. The resulting novel polyureas had an inherent viscosity in the range of 0.07–0.17 dL/g in dimethylformamide or sulfuric acid at 25°C. These polyureas were characterized by IR, 1H-NMR, elemental analysis, and thermogravimetric analysis. The physical properties and structural characterization of these novel polyureas are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2103–2113, 2004

For the first time, acidic monomer chiral N-acryloyl-L-phenylalanine was polymerized directly by atom transfer radical polymerization under mild conditions. Controlled polymerization was carried out in pure water, methanol/water mixture, or pure methanol using water-soluble initiators, such as 2-hydroxyethyl-2′-methyl-2′-bromopropionate and sodium-4-(bromomethyl)benzoate at room temperature. The corresponding optically active biocompatible amino acid-based homopolymers were obtained in good yields with narrow molecular weight distributions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Novel bioactive and optically active poly(N-acryloyl-L-phenylalanine) (PAPA) was synthesized by atom transfer radical polymerization. PAPA-silver (Ag) nanocomposites have been successfully prepared via in situ reducing Ag+ ions anchored in the polymer chain using hydrazine hydrate as reducing agent in an aqueous medium. By controlling of the amount of Ag+ ions introduced, we have produced an organic/inorganic nanocomposite containing Ag nanoparticles with well controlled size. Nanocomposites were characterized by X-ray diffraction (XRD), UV–Vis spectrophotometry, transmission electron microscopy, and Fourier transform infrared. XRD pattern showed presence of Ag nanoparticles. The PAPA/Ag nanocomposites with 1 : 10 silver nitrate (AgNO3) : PAPA ratio revealed the presence of well-dispersed Ag nanoparticles in the polymer matrix. All of these Ag nanoparticles formed are spherical and more than 80% of them are in the range of 15–25 nm. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011