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The determination of glucose concentration is very important in clinical, biological and chemical samples, as well as food processing and fermentation [1]. Chiefly glucose sensors have been studied most extensively [...], A feasible and fast method for glucose oxidase (GOx) study was developed by covalent attachment of GOx to gold-coated magnetic iron oxide nanoparticles (Fe@Au).GOx molecules were oxidized with metaperiodate to form aldehyde group. The prepared Fe@Au composite nanoparticles with 60 nm diameter were used as a carrier for the immobilization of GOx. Fe@Au nanoparticles were modified by cysteamine to produce amine groups at the surface. The GOx was covalently attached to the amine-modified Fe@Au nanoparticles through its aldehyde groups. The direct electrochemistry of GOx showed a quasi-reversible cyclic voltammogram corresponding to the flavin adenine dinucleotide (FAD/FAD[H.sub.2]) redox couple with a formal potential of -270 mV in 0.1 M phosphate buffer. The apparent charge transfer rate constant ([k.sub.s]) and transfer coefficient for electron transfer between the electrode surface and enzyme were calculated as 2.23 [s.sup.-1] and 0.45, respectively. The linear concentration range of the biosensor is 2.4-54 mM with detection limit of 0.51 mM at S/N = 3. The apparent Michaelis-Menten constant was measured to be 8.59 mM, indicating that the immobilized GOx on Fe@Au preserved its native activity. The life time of biosensor is more than 2 weeks. Keywords: biosensor, direct electrochemistry, glucose oxidase, gold-coated iron oxide nanoparticles, immobilization DOI: 10.1134/S1061934815100123

Described is the synthesis in water under ambient conditions of water-soluble, luminescent poly(acrylic acid)-encapsulated CdTe/CdS nanoparticles. Counterion-collapsed poly(acrylic acid) is used as a nanotemplate for the formation of the quantum dot core. Gram quantities of nanoparticles are easily obtained. Simply varying the amount of thioacetamide used in the synthesis can shift the emission wavelengths of the resulting nanoparticles from green to yellow to red. Key words: quantum dot, cadmium, luminescence, nanoparticle, nanotemplate. On decrit la synthese, en solution aqueuse dans des conditions ambiantes, de nanoparticules solubles dans l'eau et luminescentes de CdTe/CdS encapsule dans de l'acide polyacrylique. De l'acide polyacrylique a l'etat effondre obtenu par ajout de contre-ions est utilise comme nanogabarit pour la formation de points quantiques cceur. Des quantites de nanoparticules de l'ordre du gramme s'obtiennent facilement. La simple variation de la quantite de thioacetamide utilisee dans la synthese peut deplacer les longueurs d'onde d'emission des nanoparticules resultantes du vert au jaune et au rouge. [Traduit par la Redaction] Mots-cles: point quantique, cadmium, luminescence, nanoparticule, nanogabarit., Introduction Counterion condensation of polyelectrolytes has been a topic of research for 60 years. (1) The simplistic view is that in the absence of counterions, the polyelectrolyte exists as an [...]

One particularly promising model of electrical properties of conductive nanocomposites involves a combined quantum tunneling/percolation approach. However, two key inputs to the model--the polymer matrix barrier height and the average gap between conductive filler particles--are difficult to determine experimentally. This article demonstrates improved methods for determining barrier height in polymer materials via conductive nanoindentation, with barrier heights measured between 0.4 and 1.7 eV for five different polymers. By using dielectric spectroscopy techniques, combined with the barrier height measurements, the average junction gap was determined for the first time for nickel-nanostrand nanocomposites with six different polymer matrices; the values range from 1.31 to 3.28 nm. Using those measured values for barrier height and junction gap distances in a simple model, we have tested predictions for bulk resistivity of six polymers. The model worked well for four of the six, which suggests that for a given volume fraction of filler, knowledge of the barrier height and the junction distance may in many cases be sufficient to provide an estimate of the bulk resistivity of the polymer-nanostrand blend, an important parameter in nanocomposite engineering. POLYM. ENG. SCI., 53:2666-2673, 2013. © 2013 Society of Plastics Engineers, INTRODUCTION Interest in nanocomposites has multiplied in the past few years due to the advantageous material properties obtained when nanoscale particles are combined with a bulk material (1). Vital properties [...]

In this work, an in situ reduction method was used to prepare nanosilver-modified polyethersulfone (PES-Ag) ultrafiltration membranes by mixing up the reducing agent ethylene glycol and the protective agent polyvinylpyrrolidone to reduce AgN[O.sub.3] in the casting solution. The effects of coagulation bath temperature (CBT) on the separation performances, antifouling property, tensile strength, and stability of the nanosilver particles were researched. The results indicated that when the PES-Ag membranes were prepared in 40°C coagulation bath, the loss rate of nanosilver particles during preparation was minimum, only 18.5%. With the CBT increasing from 20 to 60°C, the water flux of the PES and PES-Ag membranes increased, whereas the rejection rate decreased. The largest flux reached 471 L*[m.sup.-2]*[h.sup.-1] for PES-Ag membranes prepared at 60°C and the rejection was over 90%. The results of contact angle and flux recovery ratio showed that PES-Ag membranes had better hydrophilicity and antifouling property. Furthermore, the PES-Ag membranes could inhibit Escherichia coli from growing. POLYM. ENG, SCl., 53:1614-1622, 2013. © 2012 Society of Plastics Engineers, INTRODUCTION Compared with conventional separation techniques such as distillation, absorption and extraction, membrane separation technology is a highly efficient separation technique with many advantages (1). Ultrafiltration (UF) technology is widely [...]

Uniformly dispersed Ag nanoparticles (AgNPs) with diameter about 5 nm embedded in electrospun polyacrylonitrile (PAN) nanofibers were synthesized by using tea polyphenols (TP) as the reductant. The reducing ability of TP toward Ag ions was characterized by Fourier transform infrared spectroscopy and ultraviolet-visible spectra, and the results revealed that TP exhibit satisfied reducing ability in the synthesis process. Transmission electron microscopy observation showed that the synthesized spherical AgNPs with diameter about 5 nm were immobilized on the surface and in the interior of PAN nanofibers by electrospinning technology. The interactions of Ag with PAN and TP were investigated by X-ray photoelectron spectroscopy (XPS), and the results suggested that PAN polymer and TP both served as stabilizer during the synthesis of AgNPs because of the chelating interactions of Ag with cyano groups and phenolic hydroxyls. The synthesized AgNPs in PAN nanofibers exhibit good antibacterial property and may be used for antibacterial and catalytic applications. POLYM. ENG. SCI., 53:1099-1108, 2013. © 2012 Society of Plastics Engineers, INTRODUCTION Ag nanoparticles (AgNPs) have deserved special attention owing to their fascinating physical and chemical properties (1-4) and, so far, diverse applications of AgNPs have been explored in chemical, catalytic, [...]

Boron doped and undoped poly(vinyl) alcohol/zirco-nium-yttrium acetate (PVA/Zr-Y) nanofibers were prepared by electrospinning using PVA as a precursor. The effect of boron doping was investigated in terms of solution properties, morphological changes and thermal properties. The effect of boron doping on calcined yttria stabilized zirconia (YSZ) fibers was evaluated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy analysis. XRD analysis revealed varying amounts of monoclinic and tetragonal zirconia present in the undoped fibers calcined at 800 C. The average crystallite sizes of the undoped YSZ were increased from 9.28 to 22.79 nm with calcining temperature increasing from 250 to 800 C. The crystallite size was enhanced with boron doping. The systematic evolution of morphological features in the spun and the processed fibers were employed by scanning electron microscopy. POLYM. ENG. SCI., 53:963-969, 2013. © 2012 Society of Plastics Engineers, INTRODUCTION Polymer-based nanocomposites in the form of nano-powders, nanospheres, nanofibers, nanowires have gained much interest due to their ability to combine the advantages of both polymers and filler components. The [...]

In the present work, an automatic generic tool for performing different syntheses of biosilica nanoparticles and the encapsulation of enzymes at the same time is described. Sequential injection analysis (SIA) allowed automation, since it enables the precise and exact control of fluidic manipulations as well as reaction conditions essential for achieving repeatable and reproducible hydrolysis, nucleation, and particle growth. An effective computer control of all the analytical parameters during run time ensured the testing of different templates, silicic acid precursors, and reaction conditions (flow rates, flow reversal, mixing, order of reagents added, pH, etc.) without physical reconfiguration of the flow setup. The effect of tetramethyl orthosilicate, sodium silicate, polyethylenimine, and protamine was evaluated not only for the morphology and size of obtained nanoparticles, but also for the stability and consequently the activity of laccase, the enzyme selected for this demonstration. This activity was evaluated using the spectrophotometric measurement (at 415 nm) of the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cationic radical, which results from the action of the encapsulated enzyme. The results obtained showed advantages, namely, reproducibility between all the samples used when compared with the small-scale batch-based process, and the absence of clogging due to the operational characteristics of the SIA technique. Besides the benign reaction conditions, such as ambient temperatures, physiological pH range, and aqueous solvents, this automatic procedure was shown to be a rapid, simple, and more sensitive alternative method for the enzyme immobilization that results in the physical entrapment of enzymes within silica nanospheres as they are formed. Key words: automation, biosilica, laccase, nanostructures, sequential injection analysis. Dans le present travail, on decrit une nouvelle methode generique et automatique qui permet de realiser en meme temps diverses syntheses de nanoparticules biosiliciees et d'encapsulation d'enzymes. L'analyse par injection sequentielle (AIS) est consideree comme le ressort de l'automatisation puisqu'elle permet de controler d'une fa^on precise et exacte les temps de manipulation des fluides ainsi que des conditions de reaction essentielles pour effectuer des hydrolyses, des nucleations et des croissances de particules qui peuvent etre repetees d'une fa^on reproductible. Un controle efficace par ordinateur de tous les parametres analytiques en temps reel d'execution a permis de verifier divers gabarits, precurseurs d'acide silicique et conditions reactionnelles (vitesses d'ecoulement, inversion de l'ecoulement, melange, ordre de l'addition des reactifs, pH, etc.) sans devoir effectuer de reconfiguration physique de l'agencement de l'ecoulement. On a evalue l'effet de l'orthosilicate de tetramethyle, du silicate de sodium, de la polyethyleneimine et de la protamine non seulement en relation avec la morphologie et la taille des nanoparticules obtenues, mais aussi en ce qui a trait a la stabilite et, en consequence, a l'activite de la laccase, l'enzyme choisi pour cette demonstration. On a evalue cette activite a l'aide de mesures spectrophotometriques (a 415 nm) du radical cationique de l'acide 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonique (ABTS) qui resulte de l'action de l'enzyme encapsule. Les resultats obtenus montrent les avantages, en particulier, la reproductibilite entre tous les echantillons utilises par comparaison avec des procedes discontinus a basse echelle et l'absence des obstructions liees aux caracteristiques operationnelles de la technique d'analyse par injection sequentielle (AIS). En plus des conditions douces utilisees, telles les temperatures ambiantes, la plage de pH physiologique et les solvants aqueux, cette methode automatique est une methode alternative rapide, simple et plus sensible pour l'immobilisation d'enzymes qui conduit a une encapsulation physique des enzymes dans les nanospheres de silices des qu'elles sont formees. [Traduit par la Redaction] Mots-cles: automation, biosilice, laccase, nanostructures, analyse par injection sequentielle (AIS)., Introduction By resorting to flow systems it is possible to get great control and reproducibility out of silica synthesis. The use of microfluidic reactors provide some advantages when compared with [...]

Double-walled nanospheres, containing meloxicam, were fabricated with poly-(D,L-lactide-co-glycolide) (PLGA) and poly(L-lactide) (PLLA) using the solvent evaporation technique. This article discusses the effect of formulation variables [sonication power, sonication time, concentration of poly(vinyl alcohol), organic/ aqueous volume ratio in the first emulsion] on the production of double-walled nanospheres. The involved phase separation of these two polymers was investigated using differential scanning calorimetry. Double-walled microspheres containing meloxicam were also produced to determine the composition of the shell and core polymer, based on different solubilities of polymers in ethyl acetate, and to examine the inner morphology and drug distribution using optical and fluorescence microscopy. The produced microparticles have shown a double-walled structure with meloxicam solubilized in the PLGA-rich phase. Therefore, adjusting the selected formulation variables and using a mass ratio of 1:1 PLLA/PLGA, double-walled nano-spheres where meloxicam is dispersed within the core can be produced. POLYM. ENG. SCI., 53:146-152, 2013. [C] 2012 Society of Plastics Engineers, INTRODUCTION The use of biodegradable polymeric microparticles/ nanoparticles for controlled drug delivery has shown numerous advantages in enhancing therapeutic efficacy and reducing systemic side effects. Despite all the advantages, the [...]

Introducing inorganic nanoparticles into the structure of polymeric membranes is an interesting approach for the enhancement of physical, chemical, and separation properties of the membranes. In this article, the performance of a two-layer nanocomposite membrane for gas separation was studied. Three different methods for embedding titanium dioxide ([Ti0.sub.2]) nanoparticle were employed for the membrane preparation. The techniques include blending [Ti0.sub.2] in the polydimethylsi-loxane (PDMS) coating layer, blending [Ti0.sub.2] in the poly-ethersulfone (PES) support and dip coating of PES support with TiO2 accompanied by PDMS coating. The aim of the current research was finding the optimum technique for introducing [Ti0.sub.2] into the membrane to obtain superior performance for gas separation. The results indicated that PES support containing [Ti0.sub.2] nanoparticles possessed favorable effect on gas separation capability. The optimum performance was obtained by PDMS-coated membranes prepared with 7 wt% [Ti0.sub.2]-embedded PES support. Carbon dioxide ([CO.sub.2]) permeance, [CO.sub.2]/nitrogen, and [CO.sub.2]/methane selectivity were obtained as 188.7 GPU, 8.6, and 3.4, respectively. POLYM. ENG. SCI., 52:2664-2674, 2012. @ 2012 Society of Plastics Engineers, INTRODUCTION Polymeric membranes are widely used in the separation processes as they have acceptable film-forming capability, toughness, flexibility, and low costs. They show limited mechanical, chemical, and thermal resistance as [...]

Molecularly imprinting technique was combined with magnetic nanoparticles to synthesize molecularly imprinted polymer-encapsulated particles for selective removal and efficient separation of estrogenic compounds from water. The core-shell-structured particles were successfully prepared by a novel 2-h ultrasonication-assisted synthesis in a mixture of water and organic solvent using dual-layer surfactant-modified magnetic particles as core, the most physiologically active estrogenic compound (17β-estradiol) as template, and widely adapted methacrylic acid as functional monomer. Ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and magnetic separation were used to characterize the particles. High-performance liquid chromatography-tandem mass spectrometry was used for quantitative binding performance analysis at lownanogram per milliliter levels. The particles exhibited satisfactory recognition of 17β-estradiol in water. They possessed great potential for rapid, cost-effective, and efficient separation of estrogenic compounds from aqueous environment with specificity. POLYM. ENG. SCI., 52:1775-1783, 2012.[C] 2012 Society of Plastics Engineers, INTRODUCTION Low doses of endocrine disrupting compounds (EDCs), pharmaceuticals, and personal care products in water have been reported (1), (2). There is growing concern about the ecological and human health [...]

Low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), and polyvinyl chloride (PVC) (1:1:1:0.5) were solution blended by using a mixture of solvents consisting of xylene and tetrahydrofuran (THF) (70:30). [Si0.sub.2] nanoparticles were modified by cetyl trimethyl ammonium bromide (CTAB). Wood polymer composites (WPC) were prepared by using polymer mixture, polyethylene-co-glycidyl methacrylate (PE -co-GMA), wood flour, and modified [Si0.sub.2]. X- ray diffraction (XRD) studies showed that the intensity of the peaks of polymer mixture decreased due to incorporation of [Si0.sub.2]. The dispersion of [Si0.sub.2] nanoparticles and morphological characteristics were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The interaction between [Si0.sub.2] nanoparticles, PE-co-GMA, polymer mixture, and wood was studied by Fourier transform infra-red spectroscopy (FTIR). Tensile and flexural properties of the composites improved significantly due to the incorporation of [Si0.sub.2] nanoparticles. Thermal stability, hardness, flame retardancy, and water resistance capacity were also found to enhance. Maximum improvement in properties was observed by the inclusion of 3 phr modified [Si0.sub.2] in WPC. POLYM. ENG. SCI., 52:1516-1523, 2012. © 2012 Society of Plastics Engineers, INTRODUCTION Wood polymer composite (WPC) covers a wide range of area in composite field (1). These are eco friendly, low cost consuming, biodegradable, and renewable (2). The consumption of plastic [...]

Electrospun chitosan nanofiber mats have been obtained using chitosan solutions in a mixture of tri-fluoroacetic acid and dichloromethane. The relationship between processing parameters (solvent composition, polymer concentration in the solution, feeding rate, applied voltage, traveling distance between the needle, and the collector) and fiber morphology was studied. Taguchi's methodology was followed to determine which parameters have the strongest influence on mean fiber diameter and fiber homogeneity. Chitosan nanofibers obtained with this procedure were water soluble due to the protonation of amine side groups but were successfully neutralized by immersion in calcium carbonate solutions. It was established that fiber diameter is mainly determined by the solution concentration and the distance from the needle to the collector while other parameters have less influence. The set of parameters that produce the thinnest fibers were a concentration of 8 wt%, a TFA/DCM ratio of 80:20 (v/v%), a voltage of 30 kV, a flow rate of 6.0 mL/h, a gap distance of 10 cm, using a needle diameter of 0.5, allowing to produce randomly oriented mats with a mean fiber thickness of 66 nm. POLYM. ENG. SCI., 52:1293-1300, 2012. 2012 Society of Plastics Engineers, INTRODUCTION Biomaterials have been used in various scientific fields such as pharmacology (1), bioengineering (2), and electronics (3). Tissue engineering techniques require a sufficient number of cells with the right [...]

The crystallization behavior of low-density polyethylene (LDPE) embedded inside zinc oxide (ZnO) percolating network (LDPE/60 vol% ZnO) was investigated via differential scanning calorimetry (DSC), and compared with those of LDPE bulks (neat LDPE and LDPE/1.15 vol% ZnO). Results revealed that embedded LDPE pos-sessed by far shorter half-crystallization time at elevated crystallization temperatures than LDPE bulks, whereas at lower crystallization temperatures longer half-crystallization time was observed. Isothermal crys-tallization kinetics study revealed that the Avrami expo-nent of embedded LDPE varied in range of 1.8-2.0, indicating quasi-two-dimensional crystallization with heterogeneous nucleation, contrasting with about 3 for LDPE bulks. Moreover, crystallization activation energy of embedded LDPE was much larger than that of neat LDPE due to geometric confinement effect of ZnO network. POLYM. ENG. SCI., 52:1250-1257, 2012. [C] 2012 Society of Plastics Engineers, INTRODUCTION Crystallization of semicrystalline polymers in confined environments attracts increasing attentions recently due to scientific interests and potential applications in engineering sectors (1-3). As semicrystalline polymer chains are restrained in [...]

Thioglycolic acid (TGA)-capped CdTe nanoparticles (NPs) were synthesized in aqueous medium, and their application as fluorescence probes in the detection of adenine and guanine was studied. The TGA-capped CdTe NPs were characterized by transmission electron microscopy, X-ray diffraction spectrometry, spectrofluorometry, Fourier transform infrared, and ultraviolet-visible spectrometry. Based on the significant enhancement of fluorescence emission of these CdTe fluorescence probes in the presence of adenine or guanine, a quantitative analysis method for these purines was proposed. Experimental conditions that govern the extent of fluorescence enhancement were optimized. Under the optimal conditions, the relative fluorescence intensity versus adenine or guanine concentrations gave a linear response, permitting the dynamic range of 7.0 x [10.sup.-7]-1.0 x [10.sup.-4] mol/L and 6.0 X [10.sup.-7]-9.0 x [10.sup.-5] mol/L for adenine and guanine, respectively. The method has also been applied successfully to the detection of adenine and guanine in synthetic samples with satisfactory results. Key words: CdTe nanoparticles, fluorescence probe, adenine, guanine. Operant dans un milieu aqueux, on a effectue la synthese de nanoparticules (NP) de CdTe coiffees par d'acide thioglycolique (ATG) et on a etudie la possibilite de les utiliser comme sondes de fluorescence pour la detection de l'adenine et de la guanine. On a caracterise ces nanoparticules de CdTd coiffees par d'acide thioglycolique (ATG) par microscopie electronique de transmission, par spectrometrie de diffraction des rayons-X, par spectrofluorometrie, par spectrometrie infrarouge a transformation de Fourier et par spectrometrie ultraviolette-visible. Sur la base de l'augmentation significative de remission de fluorescence de ces sondes de fluorescence a base de CdTe en presence d'adenine ou de guanine, on a propose une methode d'analyse quantitative pour ces purines. On a optimise les conditions experimentales qui favorisent une augmentation de la fluorescence. Dans les conditions optimales, on observe une correlation lineaire entre l'intensite relative de la fluorescence en fonction des concentrations d'adenine ou de guanine et ceci etablit que les plages dynamiques sont respectivement de 7,0 x [10.sup.-7] a 1,0 x [10.sup.-4] mol/L et de 6,0 x [10.sup.-7] a 9,0 x [10.sup.-5] mol/L pour l'adenine et la guanine. La methode a ete appliquee avec succes a la detection de l'adenine et de la guanine dans des echantillons de synthese. Mots-cles : nanoparticules de CdTe, sonde de fluorescence, adenine, guanine. [Traduit par la Redaction], 1. Introduction Semiconductor nanoparticles (NPs) are nanostructured materials, (1) also known as zero-dimensional materials or nanocrystallites. (2) These smart NPs are composed of atoms from groups II-VI, III-V or IV-VI [...]

Gold nanoparticles (Au NPs) stabilized with six different thiolate-functionalized ionic liquids (TFILs) were synthesized in an organic solvent. The size and optical properties of the TFIL-stabilized Au NPs can be rationally controlled by altering the N-alkyl chain length and (or) the counteranion of the TFIL-stabilizing ligand. Au NPs were prepared from the reduction of a gold precursor (HAu[Cl.sub.4] or [[Au-C[equivalent to]C-t-Bu].sub.4]) employing NaB[H.sub.4] in the presence of the different disulfide precursors. A model, based on Israelachvili theory, is proposed to account for the dependence of NP size on the N-alkyl chain length and the counteranion of the surfactantlike TFIL stabilizers. Key words: gold nanoparticles, functionalized ionic liquids, gold(I) complexes, surface plasmon band, imidazolium salts. Des nanoparticules d'or (NPAu) stabilisees par six ioniques liquides fonctionnalises par un thiolate (ILFT) ont ete synthetisees dans un solvant organique. La taille et les proprietes optiques de ces NPAu stabilisees par des ILFT peuvent etre controlees rationnellement en modifiant la longueur de la chaine N-alkyle et (ou) le contre-anion du ILFT. Les NPAu ont ete preparees par reduction d'un precurseur d'or, HAu[Cl.sub.4] ou [[Au-C≍C-t-Bu].sub.4], a l'aide de NaBH4, en presence de chacun des six precurseurs de disulfure. Un modele, base sur la theorie de Israelachvili, est avance pour rendre compte de la relation entre la taille des NPAu et la longueur de la chaine N-alkyle et la taille du contre-anion du ILFT, qui agit comme stabilisant de la NP et surfactant. Mots-cles : nanoparticules d'or, liquides ioniques fonctionnels, complexe d'or(I), bande plasmon de surface, sels d'imidazolium., Introduction Gold nanoparticles (Au NPs) are subject to intensive research because of their application in optical sensing, (1) surface-enhanced Raman spectroscopy, (2) and catalysis. (3,4) Optical1 and catalytic (4) properties [...]

The effect of alumina nanoparticles on the viscosity and curing behavior of a bisphenol E cyanate ester monomer suspension was investigated by rheometry and differential scanning calorimetry. The viscosity was found to increase with solids content and was fit well by the Mooney equation. Cure experiments indicate that alumina particles catalyze the curing of the suspensions. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by nuclear magnetic resonance. POLYM. ENG. SCI., 51:1409-1417, 2011. © 2011 Society of Plastics Engineers, INTRODUCTION Bisphenol E cyanate ester (bis(4-cyanatophenyl)-l,l-ethane) or BECy is a low viscosity monomer with a reported viscosity of 0.09-0.12 Pa s [1]. As shown in Fig. 1 [2], BECy cures [...]

The aim of this paper is a comparison of the effectiveness of different macrocharacterization techniques for the prediction of the degree of dispersion and intercalation of bidimensional nanofillers in an amorphous thermoplastic matrix. Organically modified montmorillonites (omMMT) were used as bidimensional nanofillers, whereas amorphous polyethylene-terephthalate copolymer (PETg) was used as matrix. Wide angle x-ray diffraction analysis showed no relevant difference between the samples processed at different temperatures, all characterized by a predominantly intercalated structure. On the other hand, transmission electron microscopy (TEM) analysis showed the presence of some degree of exfoliation, as well as the presence of lamellar stacks of different thickness. The aspect ratio of lamellar stacks was estimated by means of rheological, mechanical, and gas permeability analysis. All techniques provided values which are in quite good agreement with TEM analysis. Furthermore, all techniques were able to capture the increase in the lamellar stack aspect ratio with decreasing processing temperature. POLYM. ENG. SCI., 51:1280-1285, 2011. ©2011 Society of Plastics Engineers, INTRODUCTION Poly(ethylene terephthalate) (PET) is a low-cost, commodity polymer that finds use in a wide variety of applications, such as fibers, bottles, films, and even engineering plastics for automobiles and [...]

Introduction During the last decades, noble-metal nanoparticles have attracted a great deal of interest by their unique optical, electronic, magnetic, and catalytic properties and intense research efforts are still devoted [...]

Silica nanosprings are found to have potential applications in sensing because of their large surface to volume ratio and the gallium nitride is a wide band gap semiconductor commonly used [...]

Catalytic performances of cobalt supported on silica nanosprings (Co/SiO2-NS) were evaluated and compared with conventional silica gel supported cobalt (Co/SiO2-gel) catalysts in the Fischer-Tropsch synthesis (FTS) of syngas to higher [...]