bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and characterization of self‐reinforced poly(propylene) composites: carded mat reinforcement
Authors: Bárány T. , Karger‐Kocsis J. , Czigány T. 
Published: November 2006

AbstractSelf‐reinforced poly(propylene) (PP) composites were produced by film‐stacking using carded mats of α‐isotactic PP fibers and films of β‐isotactic PP. Composite sheets were produced at various consolidation temperatures (T = 150–170°C) and constant holding time (t = 2 min). In a test series the holding time was varied (t = 2–20 min) by keeping the consolidation temperature constant. The consolidation degree of the sheets was studied on polished sections by light microscopy and quantified by density and peel test results. Specimens cut of the sheets were subjected to in‐plane static tensile and out‐of‐plane dynamic impact (instrumented falling weight impact, IFWI) tests. It was established that the best indicators for the consolidation degree are the density, tensile strength and specific perforation impact energy and between them linear correlations exists. Increasing the density of the composites resulted in increased tensile strength (due to lower void content and better fiber/matrix adhesion) and reduced perforation impact energy (due to hindered delamination between the constituent layers). Copyright © 2006 John Wiley & Sons, Ltd.
Poly(oxyalkylene) grafts to guar gum with applications in hydraulic fracturing fluids
Authors: Bahamdan Ahmad , Daly William H. 
Published: November 2006

AbstractHydraulic fracturing is routinely used in the oil and gas industry to improve or stimulate the recovery of hydrocarbons from underground formations. Highly viscous fluids are used to carry proppants into the fractures; guar gum derivatives are commonly used because they can be degraded readily for subsequent removal. In this study a new series of carboxymethylated guar gum derivatives, which are modified via the corresponding methyl esters with poly(oxyalkylene amines) to produce a series of poly(oxyalkylene‐g‐guar) derivatives with unique rheological properties are reported. Techniques for gelling the derivatives and for breaking the gels will be discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Development of electric control catheter and tweezers for thrombosis sample in blood vessels using piezoelectric polymeric fibers
Authors: Tajitsu Yoshiro 
Published: November 2006

AbstractPoly‐L‐lactic acid (PLLA) has recently attracted attention as a polymer which exhibits a high shear piezoelectric constant. In this study, it was possible to control the piezoelectric motion of the PLLA fiber by applying d.c. voltage and a.c. voltage similar to a piezoelectric actuator. Then, on the basis of the experimental results, an electric control catheter and tweezers, using PLLA fibers (PLLA fiber catheter/tweezers) was developed. In the demonstration, it was assumed that thrombosis in blood vessels occurred and it was attempted to remove the thrombosis from the affected area using the PLLA fiber catheter and tweezers. This very delicate operation was attempted under a microscope. Using the PLLA fiber catheter and tweezers, the affected area was excised. A video movie of the test demonstration was recorded using a CCD video camera. All stages proceeded well in this study. Copyright © 2006 John Wiley & Sons, Ltd.
Responsive micelles and vesicles based on polypeptide diblock copolymers
Authors: Chécot F. , Rodríguez‐Hernández J. , Gnanou Y. , Lecommandoux S. 
Published: November 2006

AbstractThe self‐assembly of well‐defined polypeptide‐based diblock copolymers into micelles and vesicles is presented. The stimuli‐responsive behavior of polypeptides to pH and ionic strength is used to produce stimuli‐responsive nanoparticles with a control size and shape. Results focusing on vesicles obtained from polypeptide‐based diblock copolymers that are particularly promising for biomedical application will be detailed by means of static and dynamic light scattering analysis, UV circular dichroism, NMR and small angle neutron scattering experiments. Also systems that are able to form vesicles with narrow size distributions at basic and acidic pH going through an intermediate state of single polymer chains are presented. These nanoparticles are particularly interesting for encapsulation and delivery purposes at a controlled pH. Finally, surface self‐assembly of micelles and vesicles will be shown as models for biological surfaces such as mucosal surfaces. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis of hydrogels by radiation‐induced cross‐linking of Pluronic® F127 in N2O‐saturated aqueous solution
Authors: Ulanski Piotr , Pawlowska Wioletta , Kadlubowski Slawomir , Henke Artur , Gottlieb Ronny , Arndt Karl‐Friedrich , Bromberg Lev , Hatton T. Alan , Rosiak Janusz M. 
Published: November 2006

AbstractPluronic F127, a tri‐block copolymer of poly(ethylene oxide) and poly(propylene oxide) of a nominal formula EO100‐PO65‐EO100, when subjected to the action of ionizing radiation in oxygen‐free, N2O‐saturated aqueous solution, undergoes predominantly cross‐linking by intermolecular recombination of polymer‐derived radicals. This manifests itself as an increase in average molecular weight and, at sufficiently high doses, as a formation of permanent hydrogel. Cross‐linking occurs with high yields. Side reactions include chain scission and traces of oxidation processes. Polymer concentration and temperature influence the yields of radiation‐induced reactions. This indicates that radiolysis mechanism depends on the spatial arrangement of Pluronic molecules, which can be organized into single chains, micelles, and physical gel. Macroscopic hydrogels of Pluronic are thermo‐sensitive (phase transition temperature behavior with the transition temperature, at the tested conditions, of ca. 27 °C). Pluronic gels are prone to oxidative degradation, both in an aqueous environment and in the dry state, especially at elevated temperatures. Copyright © 2006 John Wiley & Sons, Ltd.
PP/EPDM‐based thermoplastic dynamic vulcanizates with organoclay: morphology, mechanical and viscoelastic properties
Authors: Mirzazadeh H. , Katbab A. A. 
Published: November 2006

AbstractDynamically vulcanized nanocomposite thermoplastic vulcanizates (NC‐TPVs) based on ethylene‐propylene‐diene rubber (EPDM) and melt intercalated hybrid of poly(propylene) (PP)/maleic anhydride grafted poly(propylene) (PP‐g‐MA) with organo‐modified montmorillonite (org‐MMT) were prepared. X‐ray diffraction (XRD) analysis and scanning electron microscopy (SEM) examination have been performed to evaluate the extent of the intercalation, as well as to characterize the microstructure developed during dynamic vulcanization. The organocaly was better intercalated and dispersed in the PP matrix of the NC‐TPV samples at low clay contents. The NC‐TPV samples showed a matrix‐disperse type of morphology in which the crosslinked EPDM particles appeared in the form of agglomerates covered by a layer of nanocomposite PP (NC‐PP). The NC‐TPV samples exhibited higher elastic modulus compared with similar but unfilled TPV sample in spite of the lower crystallization degree for the former. The storage modulus (G′) of the molten NC‐TPV proved to be highly frequency dependent. This was assigned to the formation of a nanoclay network structure by the NC‐PP covered EPDM rubber particles. Copyright © 2006 John Wiley & Sons, Ltd.
Semi‐continuous emulsion copolymerization of vinyl acetate and butyl acrylate using a new protective colloid. Part 1. Effect of different emulsifiers
Authors: Sarac Ayfer , Yildirim Hüseyin 
Published: November 2006

AbstractVinyl acetate and butyl acrylate copolymers were synthesized in the presence of ammonium persulfate initiator, emulsifiers having different character such as non‐ionic and anionic+non‐ionic emulsifiers, and N‐methylol acrylamide as a new protective colloid in a classical glass reactor. The monomer ratio was chosen 85:15. In the case of mixture emulsifiers, the series of non‐ionic emulsifiers which have 10 to 40 moles ethoxylated nonyl phenol except 20 moles were combined with sodium dodecyl benzene sulfonate. The effects of the new colloidal stabilization agent, and different emulsifiers on the physicochemical properties of the copolymers were investigated at a constant temperature of 70°C by measuring conversion, viscosity, molecular weights, and molecular weight distribution, respectively, by using gravimetric method, Brookfield viscometer, viscometric method, and gel permeation chromatograpy. It was determined that the original copolymer latexes viscosities increased with the increased chain length for the two types of emulsifiers, in general. Similar changes were also found in viscosity average, number average and weight average molecular weights of the copolymers for the different types of emulsifiers. Copyright © 2006 John Wiley & Sons, Ltd.
Preparation of poly(vinyl pyrrolidone) grafted sulfonamide based polystyrene resin and its use for the removal of dye from water
Authors: Senkal Bahire Filiz , Yavuz Erdem 
Published: November 2006

AbstractPoly(vinyl pyrrolidone) was grafted onto crosslinked polystyrene beads through the 2‐chloroethyl sulfonamide (CSA) groups present in the resin using the atom transfer radical polymerization (ATRP) method. A beaded polymer with a poly(vinyl pyrrolidone) surface shell was prepared in three steps, starting from polystyrene‐divinylbenzene (10% crosslinking) based beads with a particle size of 420–590 μm, according to the synthetic protocol; chlorosulfonation, sulfamidation with 2‐chloroethylamine hydrochloride and grafting reaction of poly(vinyl pyrrolidone).The polymeric resin prepared with the described procedure with 72.66% of grafted poly(vinyl pyrrolidone) has also been demonstrated to be an efficient dye sorbent, able to remove dye from water even at ppm levels. The dye sorption capacity under non‐buffered conditions is around 0.65 g dye/g resin. Copyright © 2006 John Wiley & Sons, Ltd.
Wood flour filled PP composites: adhesion, deformation, failure
Authors: Dányádi Lívia , Renner Károly , Szabó Zoltán , Nagy Gábor , Móczó János , Pukánszky Béla 
Published: November 2006

AbstractPoly(propylene) (PP) wood composites were prepared in a wide composition range from 0 to 70 wt% wood content. Matrix/wood adhesion was improved by the introduction of two maleinated polypropylenes (MAPPs) with different molecular weights and functionality. MAPP/wood ratio changed from 0 to 0.25 in 0.05 steps. Mechanical properties of the composites were characterized by tensile testing, while their fracture resistance was determined with instrumented impact measurements. Micromechanical deformation processes were followed by acoustic emission and volume strain measurements, which were supported by scanning electron microscopy done on the broken surface of fractured samples. The results show that stiffness increases with wood content and it does not depend very much either on the type or the amount of the functionalized polymer used. However, ultimate tensile properties are strongly influenced by the amount and properties of MAPP; larger molecular weight and smaller functionality are more advantageous both for strength and impact resistance. The optimum MAPP/wood ratio was found to be around 0.05 in accordance with some literature data. Because of their large size, wood particles debond very easily from the matrix leading to volume increase and catastrophic failure at small deformations. When adhesion is improved by the introduction of MAPP, large wood particles fracture thus also contributing to the failure of the composite. At large wood content considerable aggregation of the particles may take place leading to inferior strength. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis and swelling behavior of poly(2‐dimethylaminoethyl methacrylate‐co‐N‐hydroxymethyl acrylamide) hydrogels
Authors: Gürdağ Gülten , Çavuş Selva 
Published: November 2006

AbstractCrosslinked poly(2‐(N,N‐dimethylamino)ethyl methacrylate‐co‐N‐hydroxymethyl acrylamide) poly(DMAEMA‐co‐NHMAAM) copolymers were synthesized using ammonium persulfate (APS)/N,N,N′,N′‐tetramethyl ethylenediamine (TEMED) as initiator/accelerator system in the presence of tetraethyleneglycol diacrylate (TEGDA) as crosslinker in water at 60°C. The effects of comonomer composition in the feed, pH of the swelling medium, and the temperature on the equilibrium swelling (ES) values of hydrogels were investigated. While the initial total monomer concentration was kept constant at 0.5 or 1 mol/l, the contents of APS and TEGDA in the feed were 1 mol% of the total monomers. ES values of DMAEMA‐NHMAAM gels increased with the increase in DMAEMA content in the feed. Although DMAEMA‐NHMAAM hydrogels containing up to 30 mol% were transparent in appearance, the presence of 40% DMAEMA in the copolymer worsened its transparency. ES values of the copolymer gels with high DMAEMA contents increased with both temperature and the pH of swelling medium. Copyright © 2006 John Wiley & Sons, Ltd.
Langhans giant cells from M. tuberculosis‐induced human granulomas cannot mediate mycobacterial uptake
Authors: Lay G , Poquet Y , Salek‐Peyron P , Puissegur M‐P , Botanch C , Bon H , Levillain F , Duteyrat J‐L , Emile J‐F , Altare F 
Published: November 2006

AbstractTuberculosis is characterized by a tight interplay between Mycobacterium tuberculosis (M. tb) and host cells within granulomas. These cellular aggregates restrain M. tb spreading but do not kill all bacilli, which persist for years. A more detailed investigation of the interaction between M. tb and granuloma cells is needed to improve our understanding of this persistence and to explain the physiopathology of tuberculosis. In the present study, a recently developed in vitro human model of tuberculous granulomas has been used to analyse the modulation of granuloma cell differentiation by M. tb, in comparison to poorly virulent mycobacteria, which do not persist. It is reported that whilst all mycobacteria species induce granuloma formation, only M. tb triggers the differentiation of granuloma macrophages into very large multinucleated giant cells (MGCs) that are unable to mediate any bacterial uptake. This loss of function is not due to cell quiescence, as MGCs still display NADPH oxidase activity, but it correlates with decreased expression of phagocytosis receptors. This phenomenon is specific for the virulent species of M. tuberculosis complex, as poorly virulent species only induce the formation of small multinucleated cells (MCs) with conserved mycobacterial uptake ability, which never reach the MGC differentiation stage. The phenotype of MGCs thus strongly resembles mature dendritic cells with a loss of microbial uptake ability, despite conserved antigen presentation. In M. tb‐induced granulomas, MGCs thus seem to be devoted to the destruction of bacilli that have been ingested in previous differentiation stages, ie in macrophages and MCs. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Gallbladder disease in the general population: association with cardiovascular morbidity and therapy
Authors: González‐Pérez BPharm Antonio , García Rodríguez Luis A. 
Published: November 2006

AbstractPurposeBoth gallbladder (GB) and cardiovascular disease are very common diagnoses that carry substantial economic costs. Prior studies suggest that personal history of ischaemic heart disease (IHD) could determine the occurrence of GB disease. Additionally the use of thiazide diuretics may also be a risk factor for this condition. We aimed to evaluate different cardiovascular conditions and related drugs that could be associated with GB disease.MethodsWe identified all incident cases of gallbladder disease occurring during 1996 among patients aged 20–79 years old registered in the General Practitioner Research Database. We performed a nested case control analysis using 2353 cases and 10 000 controls frequency matched to the cases by age and sex.ResultsAfter adjusting for potential confounders IHD was associated with a small increased risk of GB disease (1.29, 95%CI:1.08–1.55). When only cases requiring cholecystectomy were considered in the analysis, the resulting estimate was 1.06 (95%CI:0.83–1.35). Users of thiazide diuretics presented an OR of 1.36 (95%CI:1.08–1.71). Other antihypertensive drugs were not associated with GB disease.ConclusionsOur results confirm the small increased risk of GB disease associated with thiazide diuretics. On the other hand, our data do not support a major association between IHD and GB disease. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis and characterization of novel poly(γ‐benzyl‐L‐glutamate) derivatives tailored for the preparation of nanoparticles of pharmaceutical interest
Authors: Barbosa Ma Elisa Martínez , Montembault Véronique , Cammas‐Marion Sandrine , Ponchel Gilles , Fontaine Laurent 
Published: November 2006

AbstractFour poly(γ‐benzyl‐L‐glutamate) (PBLG) derivatives bearing at one end specific groups were synthesized by ring‐opening polymerization of the corresponding γ‐benzyl‐L‐glutamate N‐carboxyanhydride using different amine‐terminated initiators. These moieties were chosen to introduce, on demand, specific functionalities in nanoparticles of pharmaceutical interest. The PBLG and PBLG derivatives were characterized by 1H NMR, viscosimetry, Fourier transform infrared spectroscopy and differential scanning calorimetry. Nanoparticles smaller than 100 nm in diameter could be easily prepared from these PBLG derivatives by slight modification of a known nanoprecipitation technique. Copyright © 2006 Society of Chemical Industry
Nonisothermal crystallization behavior of a luminescent conjugated polymer, poly(9,9‐dihexylfluorene‐alt‐2,5‐didodecyloxybenzene)
Authors: Yang Gui‐Zhong , Chen Xiaolei , Xu Yan , Li Chun‐Zhong , Wu Peiyi , Liu Tianxi 
Published: November 2006

AbstractThe nonisothermal crystallization kinetics of poly(9,9‐dihexylfluorene‐alt‐2,5‐didodecyloxybenzene) (PF6OC12) from the melt were investigated using differential scanning calorimetry under different cooling rates. Several analysis methods were used to describe the nonisothermal crystallization behavior of PF6OC12. It was found that the modified Avrami method by Jeziorny was only valid for describing the early stage of crystallization but was not able to describe the later stage of PF6OC12 crystallization. Also, the Ozawa method failed to describe the nonisothermal crystallization behavior of PF6OC12. However, the method developed by combining the Avrami and Ozawa equations could successfully describe the nonisothermal crystallization kinetics of PF6OC12. According to the Kissinger method, the activation energy was determined to be 114.9 kJ mol−1 for the nonisothermal melt crystallization of PF6OC12. Copyright © 2006 Society of Chemical Industry
Magnetic behavior of polycarbosilazane FeII, FeIII and mixed‐valence FeII–III chloride metallopolymers
Authors: Ali Hamam Yaqoub , El Ghanem Hasan Moh'd , Mahmoud Arafa Issam , Said Moh'd Rida , aljarayish Ibrahim Abo 
Published: November 2006

AbstractFeII, FeIII and mixed‐valence FeII–III chlorides were reacted with poly[N,N′‐bis(dimethylsilyl)ethylenedi‐ amine], [Si(CH3)2NHCH2CH2NH]n, to form the corresponding Fe‐polycarbosilazane macromolecular complexes. The average chain–chain spacing in these materials was estimated from X‐ray diffraction data and found to be 6.94, 7.29, 7.30 and 7.45 Å in metal‐free and FeII, FeIII and FeII–III‐containing polycarbosilazanes, respectively. This demonstrates that FeII, FeIII and FeII–III chlorides are encapsulated between the polycarbosilazane chains. The chain–chain expansions in the divalent FeII and trivalent FeIII chloride macromolecular complexes are comparable, but less than that in the FeII–III chloride analog, which suggests that different chain–chain packings exist in the mixed‐valence macromolecular complex. The magnetic properties of the resulting complexes were investigated by measuring the magnetization in magnetic fields up to 8 kOe and in the temperature range from liquid nitrogen temperature to room temperature. Copyright © 2007 Society of Chemical Industry
Thermomechanical properties and crystallization behavior of layered double hydroxide/poly(ethylene terephthalate) nanocomposites prepared by in‐situ polymerization
Authors: Lee Wan Duk , Im Seung Soon 
Published: November 2006

AbstractThermomechanical properties and crystallization behavior of poly(ethylene terephthalate) (PET) nanocomposites containing layered double hydroxide (LDH) were investigated. To enhance the compatibility between PET matrix and LDH, dimethyl 5‐sulfoisophthalate (DMSI) anion intercalated LDH (LDH‐DMSI) was synthesized by coprecipitation method, and its structure was confirmed by Fourier transform infrared (FTIR) spectrometer and X‐ray diffraction (XRD) measurements. Then, PET nanocomposites with LDH‐DMSI content of 0, 0.5, 1.0, and 2.0 wt% were prepared by in‐situ polymerization. The dispersion morphologies were observed by transmission electron microscopy (TEM) and XRD, showing that LDH‐DMSI was exfoliated in PET matrix. Thermal and mechanical properties, such as thermal stability, tensile modulus, and tensile yield strength of nanocomposites, were enhanced by exfoliated LDH‐DMSI nanolayers. However, elongation at break was drastically decreased with LDH loading owing to the increased stiffness and microvoids. The effect of exfoliated nanolayers, which acted as a nucleating agent confirmed by differential scanning calorimeter (DSC), on the microstructural parameters during isothermal crystallization, was analyzed by synchrotron small‐angle X‐ray scattering (SAXS). It is believed that nanocomposites could be crystallized more easily owing to the increased nucleation sites, which lead to the decrease of average amorphous region size and the long period with the increase of LDH‐DMSI content. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 28–40, 2007
Highly Efficient VOC Decomposition Using a Complex System (OH Radical, Ozone‐UV, and TiO2)
Authors: Kogoma Masuhiro , Miki Yuji , Tanaka Kunihito , Takahashi Kazuo 
Published: November 2006

AbstractSummary: Toluene decomposition is examined using a corona discharge, a UV lamp, and a TiO2 catalyst complex system. The toluene decomposition reaction occurs only with OH and O (1D) radicals. High decomposition ratios are obtained: 98% for the toluene/H2O/O2‐corona/UV system and 70% for the toluene/H2O/air‐corona/UV system. Moreover, if the TiO2 catalyst is combined with the corona‐UV system for 1 000 ppm of toluene, this value increases to 78% (0.31 Wh · m−3 · ppm−1), which is higher than that obtained in a normal corona discharge system.Relationship of the decomposition ratio with the UV irradiation in air and O2 as a function of toluene concentration.imageRelationship of the decomposition ratio with the UV irradiation in air and O2 as a function of toluene concentration.