Polychalcones Based on Carbazole-derived Building Blocks: Synthesis by Acetylative Polycondensation

A new carbazole-based soluble polychalcone, poly(9-dodecyl-6-acryloylcarbazole-3,β-diyl), has been synthesized by acetylation of 3-formyl-9-dodecyl-carbazole followed by in situ polycondensation of the acetylated intermediate; it has been characterized by means of nuclear magnetic resonance spectroscopy. The acetylative polycondensation of N-substituted 3-formyl-carbazoles has been shown to provide a promising approach to the synthesis of low band gap polymers via acid-induced quaternization of the nitrogen atoms in the carb-azole moieties of the resulting polychalcone to form a conjugated azoquinoid structure. © of SCI.     

Synthesis and biological activity of some 5-substituted aminomethyl-8-hydroxyquinoline-7-sulphonic acids

5-Aryl (or alkyl)-8-hydroxyquinoline-7-sulphonic acids have been prepared by the Mannich reaction of 8-hydroxyquinoline-7-sulphonic acid with primary and secondary amines. Their bactericidal activities have been determined.     

Lutetium-177 and iodine-131 loaded chelating polymer microparticles intended for radioembolization of liver malignancies

We describe the synthesis, characterization and radiochemical studies on macroporous chelating polymer beads as carriers of beta-emitters lutetium-177 and iodine-131 intended for radioembolization of liver tumors. The starting poly(glycidyl methacrylate-co-ethylene dimethacrylate) (bead size 20–40 μ) was reacted with ammonia or methylamine to introduce primary and secondary amino groups, respectively. The primary amino groups containing polymer was used for the attachment of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) moieties, while quinoline-8-ol or 8-hydroxyquinoline-5-sulfonic acid moieties, respectively, were introduced onto the secondary amino groups containing polymer. All the polymers were labeled quantitatively by lutetium-177 in ammonium acetate buffer, DOTA containing beads however required heating to 80 °C while the quinoline-8-ol or 8-hydroxyquinoline-5-sulfonic acid moieties containing polymers were quantitatively radiolabeled within 1 h at room temperature. The quinoline-8-ol groups containing polymer was radioiodinated in 95% yield by a chloramine method. Both lutetium-177 and iodine-131 radiolabels were stable in an in vitro study in rat blood plasma. Quinoline-8-ol or 8-hydroxyquinoline-5-sulfonic acid moieties are thus more suitable for the radiolabeling of macroporous beads with lutetium-177 for radioembolization purposes than well-established DOTA moieties and in addition, quinoline-8-ol also allows radiolabeling with iodine-131.     

Synthesis and metal uptake studies on poly(8‐hydroxy‐5‐azoquinolinephenylacrylate‐formaldehyde) resin and its metal complexes

8‐hydroxy‐5‐azoquinolinephenylacrylate‐formaldehyde (8H5AQPA‐F) macromonomer was prepared from acryloylchloride, with condensation products of 8‐hydroxy‐5‐azoquinolinephenol‐formaldehyde, and polymerized in DMF at 70°C using benzoyl peroxide as free radical initiator. Poly(8H5AQPA‐F) was characterized by infrared and nuclear magnetic resonance spectroscopic techniques. Polychelates were obtained in alkaline solution of polymeric ligand, with the aqueous solution of Cu(II) and Ni(II). Elemental analysis of polychelates suggests that the metal to ligand ratio is about 1:2. The polymer metal complexes were also characterized by IR, XRD, magnetic moments, and thermal analysis. The effects of pH and electrolyte on the metal uptake behavior of the resin were also studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 797–802, 2007     

8-Hydroxy quinoline-furfural polymers

Poly(8-hydroxyquinoline-furfural) (8HQ-Fu) was prepared by condensing 8-hydroxyquinoline with furfural in the presence of aqueous K₂CO₃ and NaOH as catalysts using equimolar proportions of the two reactants. The polymer samples were characterized by elemental analysis, IR spectra, and thermogravimetric analysis. The number average molecular weight (M _n) was determined both by vapour pressure osmometry and by non-aqueous titration. Intrinsic viscosities of all the polymer samples were measured in DMF. Polymeric metal chelates of Cu²⁺, Fe³⁺, Co²⁺, Zn²⁺, Mn²⁺, Ni²⁺ with the 8HQ-Fu polymer were prepared and characterized.     

Studies on curing and thermal behavior of diglycidyl ether of bisphenol‐A and benzoxazine mixtures

This article describes the synthesis and characterization of benzoxazine monomers prepared by reacting the mixture of amine (aniline [A], 3‐chloroaniline [C], o‐toluidine [T]) and phenol (bisphenol‐A [B], phenol [P]) with formaldehyde [F]. The benzoxazine monomers prepared by reacting B and F with A, C, and T have been designated as BAF, BCF, and BTF, respectively. Structural characterization of benzoxazines was done using FTIR, ¹H NMR, and elemental analysis. The curing behavior of benzoxazine monomers was investigated by differential scanning calorimetry in the presence of diglycidyl ether of bisphenol‐A (DGEBA). In all the samples, the molar ratio of benzoxazine monomer:DGEBA, was varied as 1 :0, 3 : 1, 1 : 1, and 1 :3. The peak exotherm temperature (T_p) was lowest in all the samples having molar ratio of 3 : 1 benzoxazine:DGEBA and highest in samples having molar ratio of 1 : 3. The heat of polymerization (ΔH) was found to be maximum during curing of mixture of DGEBA and benzoxazine monomer prepared from phenol, aniline and formaldehyde (PAF). Thermal stability of benzoxazines:DGEBA mixture cured isothermally was evaluated by recording thermogravimetric traces in nitrogen atmosphere. The char yield was highest for a mixture having benzoxazine : DGEBA in the ratio of 3 : 1. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Surface-active fluorocarbon end-functionalized polylactides

The synthesis and surface properties of a 2 × C₈F₁₇ fluorocarbon di-functionalized poly(d,l-lactide), “F2PLA” are described. Small fractions ∼5% w/w of F2PLA, when blended with unfunctionalized poly(d,l-lactide), “PLA”, render the surface both hydrophobic and lipophobic. Contact angle analysis indicates that the properties of the blend surface approach those of PTFE. Rutherford backscattering analysis of the surface shows that at saturation, approximately 50% of the blend surface is covered by C₈F₁₇ fluorocarbon units. Using self-consistent field theory simulations, we estimate that adsorption of the F2PLA is characterized by a thermodynamic sticking energy of the difunctional group of approximately 6 k_BT. Bilayer samples were prepared in which a blend of F2PLA in PLA was initially covered with a layer of pure PLA. The rate of surface modification in these films was analysed to obtain a diffusion coefficient of up to 160 nm² s⁻¹ for 21.6 kg/mol F2PLA at 90 °C.     

一种新偶氮胂酸型试剂及荧光法测定铍的研究

新试剂７－（２＇－胂酸基－５＇－羧基）苯偶氮－８－羟基喹啉－５－磺酸的基本性能。详细研究了此试剂荧光法测定铍的条件，并用于水及铜中铍的测定。     

Effects of hydrothermal ageing on the thermal behaviour of poly(vinyl chloride) filled with wood flour

The hydrothermal ageing of wood‐flour‐filled PVC produced by dry‐blending in a high‐speed mixer in the presence of a plasticizer and other processing additives was carried out to investigate its thermal behaviour, and the results obtained were compared with those for the unfilled material. The dry‐blended compounds were prepared as films by a calendering process. The accelerated hydrothermal ageing was carried out by immersing the samples in boiling water at 100 °C for 110 h. The thermal behaviour of the reference and the aged samples in water was characterized by differential scanning calorimetry (DSC) and determination of the weight changes. The study has shown that during hydrothermal ageing, the samples from the whole formulations absorbed water, for instance, for 30 wt% filled PVC (F30), 16 wt% of water absorption was obtained, while this was only 2.2 wt% for unfilled PVC (F0). It was also noticed that the formulations filled with wood flour up to 10 wt% exhibited similar water absorption kinetics, i.e. the water was mostly absorbed during the first 50 h and the amount absorbed was less than 5 wt%. On the other hand, the 30 wt% filled samples regularly absorbed water up to almost 16 wt% after 100 h of immersion. The DSC data showed that hydrothermal ageing significantly affected the onset temperature of decomposition (T_d) of the unfilled samples by decreasing this temperature from 228 to 215 °C. For the 30 wt% filled samples, only additive migration was observed, while the T_d remained almost unchanged. Furthermore, from the DSC data, processability of the 30 wt% filled PVC samples at elevated temperatures, i.e. 180 to 200 °C was shown. Copyright © 2004 Society of Chemical Industry     

Poly(Ester Amide) with Pendent 8-Quinolinol Moiety as a Novel Oligomeric Ligand

The poly(ester amide) (PEA) was prepared by polycondensation of 1,4-phenylenebisphthalamic acid and the epoxy resin diglycidyl ether of bisphenol-A. The PEA was then treated with 5-chloromethyl-8-quinolinol hydrochloride. The resultant oligomer, designated as PEA-8-quinolinol (PEAQ), was characterized by elemental analysis, IR spectral studies and thermogravimetry. The metal chelates of PEAQ with Cu²⁺, Zn²⁺, Mn²⁺, Ni²⁺, and Co²⁺ metal ions were prepared and characterized by metal:ligand ratio, IR and reflectance studies, magnetic properties, thermogravimetry and microbicidal activity.     

Novel composite polymer electrolyte membranes based on poly(vinyl phosphonic acid) and poly (5‐(methacrylamido)tetrazole)

Heterocyclic molecules are generally used in the proton conducting membranes as dopant or polymer side group due to their high proton transfer ability. Composite proton conducting membranes based on poly(vinylphosphonic acid) (PVPA) and poly(5‐(methacrylamido)tetrazole) (PMTet) were produced. The homopolymers, prepared from their corresponding monomers, were blended at several mol ratios to obtain the polymer electrolyte membranes. All samples were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differantial scanning calorimetry (DSC), cyclic voltammetry (CV), and impedance analysis. Besides, the morphology of the membranes was studied by X‐ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). FTIR spectra confirmed the formation of hydrogen bonding network between PVPA and PMTet units. TGA showed that the polymer electrolyte membranes were thermally stable up to ～210°C. CV curves demonstrated the oxidative stability of the samples in 3 V region. In anhydrous conditions, the maximum proton conductivity was determined as 0.06 Scm^?1 at 150°C for PMTetP(VPA)₄. POLYM. ENG. SCI., 55:260–269, 2015. © 2014 Society of Plastics Engineers     

Preparation and performance of cobalt-doped carbon aerogel for supercapacitor

Carbon aerogels were prepared by polycondensation of resorcinol with formaldehyde in ambient conditions. The effect of resorcinol-to-catalyst ratio (R/C ratio) on volume shrinkage, BET surface area, and electrochemical property was investigated by changing R/C ratio from 50 to 2000. Carbon aerogel prepared at R/C ratio of 500 showed less than 2% of volume shrinkage and the highest BET surface area (706 m²/g). Specific capacitance of carbon aerogel prepared at R/C ratio of 500 was found to be 81 F/g in 1M H₂SO₄ electrolyte. Cobalt-doped carbon aerogels were then prepared by an impregnation method with a variation of cobalt content, and their performance was investigated. Among the samples prepared, 7 wt% cobalt-doped carbon aerogel showed the highest capacitance (100 F/g) and the most stable cyclability. The enhanced capacitance of cobalt-doped carbon aerogel was attributed to the faradaic redox reactions of cobalt oxide.     

Polychalcones based on triphenylamine and carbazole building blocks via Claisen–Schmidt route

Alternating and random copolymers of carbazole and triphenylamine containing polychalcones are prepared by adopting simple Claisen–Schmidt route via A₂ + B₂ approach. Terephthaldehyde derivative was used as an additional comonomer along with bisaldehyde of triphenylamine to obtain a random copolymer. The prepared polymers are readily soluble in common organic solvents and the polymers exhibited narrow poly dispersity. The polymers are thermally stable and no observable degradation is observed until 350°C. Further, the spin cast thermally annealed films on glass substrate indicated corrugated surface as measured by scanning electron microscope and atomic force microscopy, which could facilitate for greater interaction at the interfaces. Photophysical properties of the polymers in solution and in thin film showed excellent emission characteristics. Both alternating and random copolymers showed a high quantum yield of 0.74 on comparison with quinine sulfate. Polychalcones with triphenylamine/carbazole showed oxidative response in cyclic voltammetry which suggested the suitability as electrochemical sensors and antioxidant coating material.     

Sintering behavior and thermal shock resistance of aluminum titanate (Al2TiO5)-toughened MgO-based ceramics

In order to improve the thermal shock resistance of MgO-based ceramics, aluminum titanate (Al₂TiO₅)-toughened MgO-based ceramics were successfully prepared by solid state sintering at 1450 °C and 1550 °C for 3 h starting from MgO and as-synthesized Al₂TiO₅ powders. The effects of various contents of Al₂TiO₅ second phase on the sintering behavior and thermal shock resistance of MgO-based ceramics were investigated. The sintering behavior of sintered samples was evaluated by comparing the relative density, apparent porosity, bending strength, phase composition as well as microstructure. The thermal shock resistance of sintered samples was characterized by using the residual bending strength after three thermal cycles and thermal expansion coefficient. The obtained samples with 10 wt% Al₂TiO₅, which were sintered at 1550 °C for 3 h, showed the highest relative density, lowest apparent porosity as well as optimum bending strength. In addition, the samples added 15 wt% Al₂TiO₅ at 1550 °C with a dwell time of 3 h were the highest residual bending strength and lowest thermal expansion coefficient. It revealed that the enhancement in thermal shock resistance was ascribed to the reduction of thermal expansion coefficient.     

Effect of preparation method and particle size on LaMnO3 performance in butane oxidation

LaMnO₃ with different crystal domain sizes and surface areas were prepared by citrate and sol-gel combustion methods and tested as catalysts for butane total oxidation reaction. The catalysts were characterized by N₂ physisorption, XRD and SEM. LaMnO₃ with crystal domain sizes in the range of 30–90 nm were detected by XRD characterization when high calcination temperature, at least 500 °C for sol-gel combustion method and 700 °C for citrate method, was required to prepare pure nanocrystalline phase. Although LaMnO₃ prepared by these two methods had similar crystal domain sizes, BET surface areas of samples by citrate method were significantly larger than that of samples prepared by combustion method. The difference of surface area lies in the morphology differences between the two series of samples (SEM micrographs) generated by strong sintering of samples prepared by combustion method. The catalytic activity of LaMnO₃ in butane total oxidation increased with increasing surface area being higher for materials prepared by citrate method. Thus, citrate method showed significant advantages over combustion method in preparation of perovskite catalysts.     

Preparation of Co3O4/ZrO2(Y2O3) Catalyst and its Enhanced Catalytic Oxidation of CO

Yttria-stabilized zirconia powders were prepared by the sol–gel method coupled with supercritical CO₂ fluid-drying technology, using ZrOCl₂·8H₂O as the precursor, urea as the precipitant, and yttria as the stabilizer. The particles were characterized by X-ray diffraction, TEM and BET. The Co₃O₄/ZrO₂(Y₂O₃) catalysts were prepared by the impregnation method. The content of cobalt was varied from 5 to 12 wt%. The prepared catalysts were calcined at 200–500 °C and the pretreating temperature was varied from 200–400 °C. The performance of CO catalytic oxidation was tested and the catalyst with 8% Co loading, calcined at 200 °C, and with a pretreating temperature of 300 °C, showed the highest catalytic activity. The temperature for 95% CO conversion was as low as 113 °C; and, the catalyst showed both good cycling stability and excellent long-term stability.     

Physico-Chemical Features and Catalytic Activity of Sulfated Zirconia Prepared by Sol–Gel Method. The Role of the Solvent Evaporation Step

ZrO₂–SO₄ powders have been prepared by following a single-step sol–gel preparative route using zirconium propoxide as the starting compound. Sulfuric acid was employed both as the sulfating agent and as the catalyst of the polycondensation reaction in the gel formation. Two different series of dried precursors were obtained by either evaporating the solvent in an oven at 100°C (xerogels) or in supercritical conditions (aerogels). All the samples were calcined at three temperatures (470, 550, and 630°C) for the same time length (5 h). The powders were characterized for phase composition–crystallinity, surface area–porosity, sulfur content and surface state (XPS). The catalytic activity of the calcined samples was tested in the isomerization of n-butane in a continuous system at 150°C in absence of H₂ and 250°C in presence of H₂. The role played by the conditions of the solvent elimination, at the end of the sol–gel reaction, in affecting the physico-chemical and catalytic properties of the powders is discussed.     

Development of composites based on recycled polyethylene/sugarcane bagasse fibers

In this work, sugarcane bagasse fibers were used as filler in composites having recycled high‐density polyethylene (PEr) as matrix. Because of the poor interaction between fibers surface and the PEr, the surface of bagasse was chemically modified. This modification consists of washing with water at 80°C, a mercerization process using sodium hydroxide and acetylation reaction with acetic anhydride. The chemical modification was characterized by Fourier transform infrared–horizontal attenuated total reflectance (FTIR‐HATR) and ¹³C nuclear magnetic resonance spectroscopies (NMR), thermogravimetric analysis (TGA), and scanning electronic microscopy (SEM). The composites were prepared from modified and unmodified fibers into PEr matrix, containing 5, 10, and 20% (w/w) of fiber. The samples were processed by extrusion and molds were prepared by injection process in order to perform mechanical tests. These materials were analyzed by SEM, TGA, and the water uptake was evaluated. Also, their mechanical properties were analyzed. Morphological analysis indicated that the chemical modification of sugarcane bagasse increased the compatibility between matrix and reinforcement. Tensile, flexural, and impact tests showed that the mechanical properties of the composite were improved compared to PEr due to the presence of the fibers. POLYM. COMPOS., 35:768–774, 2014. © 2013 Society of Plastics Engineers     

Surface characteristics and electrochemical capacitances of carbon aerogels obtained from resorcinol and pyrocatechol using boric and oxalic acids as polymerization catalysts

Carbon aerogels were prepared by carbonizing (at 500–1500 °C) organic aerogels obtained from the polymerization reaction of resorcinol and/or pyrocatechol with formaldehyde using boric and oxalic acids as polymerization catalysts. Prepared samples were characterized by different techniques to ascertain their composition, surface chemistry, morphology, and surface physics, determining their electrochemical capacitances in acidic medium. The use of pyrocatechol yielded carbon aerogels that were micro–mesoporous, showing Type IV N₂ adsorption isotherms with Type H2 hysteresis cycles. The volume and size of mesopores depended on the acid catalyst used and the temperature at which the carbon aerogel was obtained. Conversely, the sample prepared with resorcinol and boric acid as catalyst was micro–macroporous and that obtained with a resorcinol–pyrocatechol mixture was micro–mesoporous but with large mesopores. Most of the boric acid used was lost during the exchange of water with acetone in the organic hydrogels before their supercritical CO₂ drying. Carbon aerogels obtained at 900 °C and using boric acid as polymerization catalyst showed a capacitance between 17 and 24 μF/cm². Boron influenced the capacitance because it increased the oxygen content. Sample synthesized using pyrocatechol, formaldehyde, and oxalic acid and heat-treated at 900 °C had the highest capacitance, 34 μF/cm².     

Synthesis,Characterization and Ion–Exchanging Properties of Novel Ion-Exchange Resin,Part 1

A polyamine (PA) was prepared by condensation of 1,4-bischloromethyl benzene and 1,2-ehanedeamine. The PA was then treated with cyanuric chloride at 0°C followed by reaction with sulfanilic acid in THF in concentration. NaOH (PH 9–10) at room temperature for 8 h. The resultant polymer, designated as polyamine-s-triazine-sulfanilic acid (PATS), was characterized by elemental analysis, IR spectral studies, and thermogravimetry. The PATS sample was monitored for its ion-exchanging properties by batch equilibrium method.