bluuebunny/crossref_metadata_2025_split huggingface dataset:
Luminescent polyvinylpyrrolidone/ZnO hybrid nanofibers membrane prepared by electrospinning
Authors: Lu Xiaofeng , Zhang Wanjin , Zhao Qidong , Wang Lifeng , Wang Ce 
Published: August 2014

AbstractPolyvinylpyrrolidone (PVP)/ZnO composite nanofibers were successfully prepared by a facile method called electrospinning technique. The synthetic strategy involved two steps: (1) Preparation of ZnO sol in ethanol solution. PVP molecules then added into the above sol and achieved the appropriate rheology for electrospinning; (2) Electrospun the above solution to obtain fibers of PVP/ZnO composites. Scanning electron microscopic (SEM) analysis of the composite nanofibers revealed network structures like a spider’s web. Transmission electron microscopy (TEM) showed small nanoparticles of the ZnO component with an average particle size in the range of 3 - 4 nm and a good dispersion. X-Ray diffraction results showed that a pure wurtzite phase was obtained in PVP fibers. XPS spectra proved that the Zn and O elements existed in PVP/ZnO composite nanofibers. FTIR and UV-vis spectroscopy were used to characterize the structure of PVP/ZnO composite nanofibers. The photoluminescence properties of the PVP/ZnO composite nanofibers were also investigated.
Mesomorphic Phase Behavior in Comb-like Polymer- Surfactant Complex
Authors: Akiba Isamu , Masunaga Hiroyasu , Murata Shouichi , Sasaki Kanako 
Published: August 2014

AbstractIt was found that a comb-like complex consisting of poly[2-(N,Ndimethylamino) ethyl acrylate] (PDAEA) and p-dodecylbenzene sulfonic acid (DBSA) formed mesomorphically ordered lamellar phase at room temperature where PDAEA and DBSA are in molten state. The lamellar phase shows optical anisotropy, although the individual components are always isotropic. In addition it is found that the optical anisotropy of the PDAEA-DBSA complex completely disappears with accompanying order-disorder transition of the lamellar morphology with elevating temperature.
Fluorescence Study of Fılm Formatıon From Hard/ Soft Latex Blends
Authors: Uğur Şaziye , Holl Yves 
Published: August 2014

AbstractThe effects of blend composition on film formation is studied using the SSF and UV-visible (UVV) techniques. Latex blend films were prepared from mixtures of two types of particles in dispersion, one composed of a high-Tg (hard) pyrene (P) labeled polystyrene (PS) latex; the other a low-Tg (soft) poly(n-butyl acrylate) (BuA1). Twelve different blend films were prepared in various hard/soft latex compositions at room temperature and annealed at elevated temperatures above glass transition temperature (Tg) of polystyerene for 10 min. Fluorescence intensity (IP) from P was measured after each annealing step to monitor the stages of film formation. The evolution of transparency of latex films was monitored using photon transmission intensity, Itr. Film morphologies were examined by atomic force microscopy (AFM). The results showed that as the amount of hard component in the blend is decreased, a significant change occured in both IP and Itr curves at a certain critical weight fraction (50%wt) of PS hard latex. Above this fraction two distinct film formation stages, which are named as void closure and interdiffusion were seen in fluorescence data. However, below 50%wt PS no film formation stages were observed. Below this fraction, Itr data showed that phase separation process occurs between PS and BuA1 polymers. These results were also confirmed by AFM pictures. Film formation stages for 50-100%wt range of PS were modeled and related activation energies were calculated. There was no observable change in activation energies confirming that film formation behavior is not affected by varying the blend composition.
Synthesis of cationic flocculants based on acrylamide and [2-(acryloyloxy)ethyl]trimethylammonium chloride copolymers by semicontinuous inverse microemulsion polymerization. Part II: influence of initiator addition conditions, initial temperature, pH and comonomer concentration on flocculating performance
Authors: Sasia Pedro M. , Ochoa G. José R. , Río Francisca , Díaz de Apodaca Elena , Nieto Javier , Torrecilla Jesús , Katime Issa , Escudero Francisco J. 
Published: August 2014

AbstractThe influence of initiator concentration, specific flow rate of initiator addition (Qsp), initial copolymerization temperature (Ti), aqueous phase pH and total comonomer concentration (TCC) on flocculating performance of latex particles of acrylamide and [2- (acryloyloxy)ethyl]trimethylammonium chloride copolymers with a cationic charge density of 40%, obtained by inverse microemulsion copolymerization by using a surfactant blend of Arlacel 83 and Softanol 90 as emulsifier and Rolling M-245, a mixture of n-decane and n-tetradecane in about 40/60 weight ratio, as oil phase, has been studied for high TCC, ranging from 28 to 34.5% (w/w). Comonomer inverse microemulsion copolymerizations were carried out in the semicontinuous mode by adding continuously an aqueous solution of sodium metabisulfite as initiator into stirred inverse comonomer microemulsions. Initiator concentration has a strong influence on viscosity, viscometric structuring degree (VSI) and average weight molar mass (Mw) of copolymers in the range from 5 to 25 g/L. Both viscosity and Mw decrease with increasing initiator concentration. Best flocculating performance is obtained from 10 to 20 g/L, values at which VSI shows a minimum. Under the experimental conditions used, Qsp (153 to 310 mL/h/kg of comonomer), Ti (25 to 35ºC) and aqueous phase pH (2.5 to 4.5) have almost no influence on both viscosity and VSI and, hence, on flocculating performance. On the contrary, TCC has a slight influence on copolymer viscosity but a strong one on VSI which increases dramatically with TCC, being the worst flocculating performance obtained at the highest TCC studied (34.5% (w/w)). Flocculating performance results are explained in terms of copolymer structuring degree and collapsed state of copolymer chains inside latex particles as well as in terms of the composition drift with conversion.
Composition distribution of poly(propylene-g-styrene) synthesized by solid-state grafting of styrene onto spherical polypropylene reactor granules
Authors: Deng Qing-tian , Fu Zhi-sheng , Zhang Le-tian , Xun Jun-ting , Fan Zhi-qiang 
Published: August 2014

AbstractAn iPP-g-St graft copolymer synthesized by free-radical initiated solidstate grafting polymerization of styrene in nascent spherical iPP granules was effectively fractionated by temperature gradient extraction fractionation (TGEF) into fractions of different styrene content. The fractions were characterized by FTIR, 1H-NMR, DSC, PLM and WAXD. The fraction extracted at room temperature (25 0C) is homopolymer of styrene, and the fractions collected at 70, 90, and 105 0C are iPP-g-St graft copolymer with decreasing degree of grafting. All the fractions of the grafting product contain a certain amount of styrene, meaning that almost all the iPP chains in the granules are accessible to the grafting monomer. The internal morphology of the iPP granules is highly porous, which enables the grafting monomer and the radicals to reach at each iPP chain during the polymerization. As styrene content of the iPP-g-St fraction increases, its crystallinity decreases, the size of iPP lamella decreases, and the crystalline morphology becomes more irregular.
Effect of degree of substitution on the mechanical and thermomechanical properties of lauroyl cellulose ester films
Authors: Joly Nicolas , Martin Patrick , Liénard Luc , Rutot Delphine , Stassin Fabrice , Granet Robert , Krausz Pierre , Cavrot Jean-Paul 
Published: August 2014

AbstractCellulose-based plastic films were prepared in homogeneous media with a range of lauroyl fatty acid attachments by ester formation, expressed as the degree of substitution (DS). The esters were cast to form films and their mechanical properties studied. This study showed a surprising relationship between DS and elastic modulus as well as DS and tensile strength, where a peak was observed at DS 2.4. The unexpected variation of static elastic modulus (E) was confirmed by dynamic mechanical analysis (DMA) and this trend was also observed for glass transition temperature (Tg). These results are discussed in relation to sample cohesion.
Poly(styrene/α-tertbutoxy-ω-vinylbenzyl-polyglycidol) micro spheres for the preparation of novel photonic crystals
Authors: Basinska Teresa , Kergoat Loïg , Mangeney Claire , Chehimi Mohamed M. , Slomkowski Stanislaw 
Published: August 2014

AbstractWe report on the preparation of a novel photonic crystal assembled from poly(styrene/α-tertbutoxy-ω-vinylbenzyl-polyglycidol) microspheres. The latex particles were fully characterized in terms of size (271 nm, Dw/Dn=1.004), electrophoretic mobility (-3.79x10-8 m2V-1s-1) and surface chemical composition (evidence for a PGL-rich particle surface). They were then assembled into 3D colloidal crystal showing an optical stop band in the visible region. The λmax for the Bragg diffraction peak is 570 nm. As the particles under study are highly hydrophilic and biocompatible, this work opens up new opportunities for the design of photonic crystal-based biosensing devices.
Synthesis and cellular uptake of superparamagnetic dextran-nanoparticles with porphyrinic motifs grafted by esterification
Authors: Lucas Romain , Granet Robert , Sol Vincent , Le Morvan Caroline , Policar Clotilde , Rivière Eric , Krausz Pierre 
Published: August 2014

AbstractThis paper describes new superparamagnetic nanoparticles bearing dextran-grafted porphyrins with effective cellular uptake properties. They average 110 nm in diameter and are composed of a 5 nm iron oxide core coated with protoporphyrin-grafted dextrans. These particles show good magnetic properties, are avidly incorporated into cultured cancer cell lines, and thus present a great potential for cellular imaging and photodynamic therapy applications.
Self-Assembly of Methacrylic Nanostructured Copolymers Containing Polyhedral Oligomeric Silsesquioxanes
Authors: Molina D. , Levi M. , Turri S. , Penso M. 
Published: August 2014

AbstractTwo hybrid copolymer series obtained by free-radical copolymerization of methacrylcyclohexyl Polyhedral oligomeric silsesquioxane (POSS) with butyl methacrylate or 2-ethylhexylmethacrylate were characterized by 1H-NMR spectroscopy, gel permeation chromatography (GPC), X-rays Diffraction (XRD), differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA). Reactivity ratios were calculated by low yield composition data suggesting the formation of random copolymers with low probability of poly-POSS sequences. XRD studies showed the crystallization behaviour of the inorganic phase independently on the POSS content; however sample processing by solvent casting effectively hindered the copolymer self-assembling ability. DSC suggests the formation of polyphasic structures with Tg increasing with POSS content, and with endothermal peaks occurring at higher temperature. Finally TGA shows an improved thermal stability of hybrid copolymers with char yield correlated to the level of inorganic phase.
Non-isothermal crystallization kinetics of Poly(phenylene sulfide)/hyperbrtanched Poly(phenylene sulfide) blends
Authors: Yan Bo , Chen Yanmo , Zhu Meifang , Liu Ting 
Published: August 2014

AbstractThe non-isothermal crystallization behaviour of poly(phenylene sulfide) (PPS) in blends with hyperbranched poly(phenylene sulfide) (HPPS) was studied by means of differential scanning calorimetry (DSC). It was observed that the PPS crystallization temperature was found to decrease upon addition of the HPPS. It suggested that the crystallizability was reduced. The Ozawa equation was valid not only for neat PPS, but also for the blends. A notable reduction in Avrami exponents for the PPS/HPPS blend systems suggested that the nucleated process leads to rodshaped growth with thermal nucleation. The cooling crystallization function, which represents the rate of non-isothermal crystallization, was found to decrease with increase in HPPS content. The Ea value increases with the increase in HPPS content. Our results indicated that crystallization of the PPS was hampered by content of hyperbranched poly(phenylene sulfide).
Infinite dilution diffusion coefficients of organic solvents in nascent polyethylene particles by inverse gas chromatography measurements
Authors: Yan Xiaowei , Wang Jingdai , Shan Yibin , Yang Yongrong , He Chao 
Published: August 2014

AbstractDiffusion coefficients of four organic solvents: dichloromethane, trichloromethane, tetrachloromethane and n-hexane in polyethylene particles at infinite dilution were determined by use of inverse gas chromatography (IGC). The polymer particles were used as supplied by the producer to pack the chromatographic columns. This allowed a direct measurement of the interested properties in a particle with the same morphology obtained at the reactor outlet. The particle morphology was investigated and classical mathematical model for chromatographic process was adopted based upon the analysis of particle microstructure. It was found that the limitation step for mass transfer was in the polymer matrix rather than in macropores, and when interpreted in terms of diffusion coefficients for spherical particles, the measured diffusion coefficients compared favourably with predicted values from literature relationships and free volume theory.
Synthesis and characterization of methoxy poly(ethylene glycol)-b-poly(DL-lactide-co-glycolide-co-ε-caprolactone) di block copolymers: Effects of block lengths and compositions
Authors: Baimark Yodthong , Srisa-ard Mangkorn , Threeprom Jirasak , Molloy Robert , Punyodom Winita 
Published: August 2014

AbstractMethoxy poly(ethylene glycol)-b-poly(D,L-lactide-co-glycolide-co-ε- caprolactone) diblock copolymers, designated as MPEG-b-PDLLGCL, with different MPEG block lengths and DLL:G:CL ratios were synthesized via ring-opening polymerization in bulk using MPEG and stannous octoate as the initiating system. The diblock copolymers were characterized using a combination of FT-IR, 1HNMR, GPC and DSC. The percentage yields of the diblock copolymers were in excess of 90%. 1H-NMR analysis confirmed that the PDLLGCL blocks contained at least some random character. From their DSC curves, the diblock copolymers were amorphous in morphology. Their glass transition temperatures decreased as the MPEG block length increased and as G and CL units were incorporated.
Synthesis and bharacterization of poly(vinyl alcohol)-boric acid beads from PVA with several hydrolysis degrees
Authors: Melo Adriana de , Borges Daniel L. G. , Debacher Nito A. , Curtius Adilson J. 
Published: August 2014

AbstractThis work describes the synthesis and characterization of poly(vinyl alcohol)-boric acid (PVA-BA) sphere-like beads. The PVA-BA beads were prepared by the dropwise addition of PVA aqueous solutions to a boric acid solution under constant stirring and controlled temperature. Different temperatures for bead formation as well as PVA with several hydrolysis degrees were used and tested. PVA with several hydrolysis degrees were characterized regarding molecular mass and intrinsic viscosity, while characterization of PVA-BA beads was carried out using thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results obtained with TGA have shown that structural changes occurs in PVA following the reaction with boric acid and that the spheres formed are thermally stable, whereas SEM analysis demonstrated that symmetric sphere-like beads were formed, with considerable porosity, which are requisite for solid supports when applied to effluent treatment. Trace element extraction tests were carried out using inductively coupled plasma mass spectrometry (ICP-MS). Without the addition of a chelating agent, no significant extraction occurred from acidic solutions, while after the addition of ethylenediaminetetracetate, less than 10% of the trace element content was extracted from the aqueous phase by the PVA-BA beads. However, after the addition of ammonium O,O-diethyldithiophosphate (DDTP), over 10% of As, Co, Cr, Fe, Sr and Zn, 40% of Cd and 70% of Pb were extracted from acidic solutions, even without any further optimization. The results have shown that the synthesized PVA-BA beads are potential alternatives for trace element extraction in effluent treatment.
Study of the effect on conductivity and its uniform distribution in injection molded composite polymer bipolar plate
Authors: Shia-Chung Chen , Ming-Yi Shih , Yi-Chang Lin 
Published: August 2014

AbstractIn this study, PPS blended with as high as 50 wt% carbon fiber were injection molded. Effects of molding conditions as well as the melt flow condition parallel and perpendicular to fluid channel on the surface conductivity was investigated. It was found that mold temperature affects the surface conductivity of molded parts significantly. Using a variable mold temperature control system based on electromagnetic induction heating, the conductivity of the molded part increase by about 152% when the peak mold temperature increases from 120 °C to 210 °C. The channel layout also helps the fiber to orient more randomly leading to an increase in the conductivity. The channel design parallel to melt flow increases the conductivity by 152% and when it is perpendicular to melt flow, the conductivity increases by 95%. Channel layout perpendicular to melt flow direction provides more influence on the fiber reorientation than that of the parallel design.
Flexible Fluid Pump Using Magnetic Composite Gels
Authors: Mitsumata Tetsu , Horikoshi Yuki , Takimoto Jun-Ichi 
Published: August 2014

AbstractA flexible fluid pump made of magnetic composite gels has been developed. The magnetic composite gel was sodium alginate or poly(vinyl alcohol) gel in which barium ferrite particles were dispersed. The pump consisted of a magnetic gel-rotor and a driving magnet. The rotor demonstrated the rotational motion in response to a rotational magnetic field generated by the driving magnet. The gel-rotor had the shape of a screw so as to deliver water efficiently. The diameter of the rotor was varied from 3.8 to 5.5 mm and the diameter of the tube for delivering water was kept as 6 mm. Flow rates pumped by the rotor increased with increasing the diameter, length, and rotation speeds of the rotor. The maximum flow rate of 34 ml/min was achieved when the rotation speeds was 5000 rpm. The rotor with a diameter of 300 μm was also successfully synthesized, however the rotor did not deliver water in a microtube with a diameter of 500 μm. Processing of the gel-rotor, and the efficiency of the water delivery are presented.
Simple Derivation of the First Cumulant for the Rouse Chain
Authors: Lisy Vladimir , Brutovsky Branislav , Tothova Jana 
Published: August 2014

AbstractA simple analytic expression for the first cumulant of the dynamic structure factor of a polymer coil in the Rouse model is derived. The obtained formula is exact within the usual assumption of the continuum distribution of beads along the chain. It reflects the contributions to the scattering of light or neutrons from both the internal motion of the polymer and its diffusion, and is valid in the whole region of the wave-vector change at the scattering.
Stability and particle size of polypyrrole dispersion using sodium dodecylbenzenesulfonate as surfactant
Authors: Xing Shuangxi , Zhao Guoku 
Published: August 2014

AbstractPolypyrrole (PPy) dispersion was prepared using FeCl3·6H2O as oxidant in the presence of sodium dodecylbenzenesulfonate (SDBS) as surfactant. The formation of the micelles and the electrostatic interaction between PPy and SDBS were considered the driving forces for the formation and stability of the dispersion. UV/Vis/NIR, FTIR spectra and SEM images were studied to confirm the structure and morphology of the PPy dispersion, respectively. Polymerization of pyrrole under different preparation conditions including the concentration of the surfactant, the pyrrole monomer and the oxidant and also the addition of acid were carried out in order to investigate their effects on the stability and average particle size of the dispersions. The conductivity of the resulting PPy particles was measured and a comparison between the PPy and polyaniline dispersion formed with SDBS as surfactant was also given.
Fracture toughness of controlled-rheology polypropylenes
Authors: Salazar Alicia , Rodríguez Susana , Navarro José Manuel , Ureña Alejandro , Rodríguez Jesús 
Published: August 2014

AbstractThe rheological, thermal, tensile and fracture properties of controlledrheology polypropylene processed via organic peroxides have been evaluated. Different concentrations of di-tert-butylperoxide (DTBP) were used in this work. Both melt flow index and the crystallinity index increased slightly with the peroxide content while the melting temperature tend to decrease. This was attributed to the decrease in the molecular weight which mainly affects the amorphous region, especially the entanglement density of this semycrystalline polymer. As a consequence, the tensile stress and strain at break reduced as the peroxide content increased. The elastic-plastic response of the different polypropylenes at room temperature promotes the use of J-integral to determine the fracture toughness. A multiple specimens method was utilized. The crack initiation resistance and the crack propagation resistance were influenced by the molecular weight, decreasing as the peroxide content increased. The micromechanisms of failure were analyzed via scanning electron microscopy.
Electrical performance and stability of polypyrrole coated PET fibres
Authors: Varesano Alessio , Ferrer Anna Ibarzabal , Tonin Claudio 
Published: August 2014

AbstractPET non-wovens were treated with intrinsically electro-conducting polypyrrole (PPy) produced by chemical oxidative in situ polymerization from pyrrole aqueous solution, using Fe3+ or S2O82- as oxidant, and different dopants. The resulting materials have different electrical performances and thermal properties depending on the thickness of the PPy coating, the amount and the type of dopant embedded into the polymer layer, the type of oxidant used and the pH of the polymerization bath. Samples were maintained at different temperatures and humidity with the aim of gathering information about the electrical performance stability in different environmental conditions. Generally, PPy shows conductivity decay when maintained at high temperature, whereas the conductivity slightly decreases when stored for a long time at cold or room temperature. Moreover, the PPy coating enhances the resistance to heat of the PET fibres (i.e. increase in melting temperature).
Effects of chemical structure and plasma treatment on the surface properties of polysulfones
Authors: Ioan Silvia , Filimon Anca , Avram Ecaterina , Ioanid Ghiocel 
Published: August 2014

AbstractThe correlation between surface tension parameters and the chemical composition of polysulfone, chloromethylated polysulfone and quaternized polysulfone membranes, before and after plasma treatment, was investigated. Calculations are based on the geometric mean approach of Owens, Wendt, Rabel and Kälble, as well as on the theoretical methods involving quantitative structureproperty relationships on the basis of the group contribution techniques. The chemical modifications of polysulfone membranes and the low pressure plasma treatment affect the contact angle corresponding to different liquids. Consequently, the total surface tension and the polar component increase with the substitution degree of chloromethylated polysulfone and with the quaternization degree of the ammonium groups, in quaternized polysulfone samples. The plasma treatment modifies the surface energy of the samples, increasing their surface polarity and wettability. Surface wettability trends were also studied by means of the free energy of hydration between compounds and water.