bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synergistic or additive corrosion inhibition of mild steel by a mixture of HEDP and metasilicate at pH 7 and 11
Authors: Mohammedi D. , Benmoussa A. , Fiaud C. , Sutter E. M. M. 
Published: November 2004

AbstractElectrochemical measurements (steady‐state current‐voltage curves and AC impedance) were coupled with mass‐loss measurements, SEM examinations, and EDSX analyses to investigate the inhibition of corrosion of a carbon steel by a mixture of phosphonic acid HEDP (acid 1, hydroxyethylene, 1‐1 diphosphonic) and sodium metasilicate pentahydrate Na2SiO3. 5H2O in an industrial hard water containing 3.10−3 M Ca2+ ions. At pH 7, HEDP and Ca2+ act in a synergistic manner, by formation of a HEDP and calcium containing layer. Addition of silicate at this pH value, allows to reach an efficiency of 94% due to an additive inhibition effect. At pH 11, metasilicate, HEDP, and Ca2+ ions reinforce the passive layer in a synergistic way. The mixture (1.7 · 10−5 M HEDP + 2.6 · 10‐3 M SiO2−3) in the Ca2+ containing electrolyte is shown to be able to inhibit efficaciously the corrosion of iron at room temperature, considering uniform corrosion at pH 7 or pitting corrosion at pH 11.
Distinguishing Linear from Star‐Branched Polystyrene Solutions with Fourier‐Transform Rheology
Authors: Neidhöfer Thorsten , Sioula Stella , Hadjichristidis Nikos , Wilhelm Manfred 
Published: November 2004

AbstractSummary: Fourier‐Transform rheology (FT rheology) was used to study the influence of the degree of branching on the nonlinear relaxation behaviour of polystyrene solutions. The results were compared with those obtained under oscillatory shear and step‐shear conditions. The different topologies could be distinguished using FT rheology where the other rheological measurements failed. Significant differences occurred under large amplitude oscillatory shear (LAOS) conditions as particularly reflected in the phase difference of the third harmonic, Φ3, which could be related to strain‐softening and strain‐hardening behaviour. Currently, this work is extended towards different topologies in polyolefins (e.g. long chain branched).Phase difference Φ3 as a function of the Deborah number De at γ0 = 2 for the polystyrene solutions measured at temperatures from 295 to 350.5 K.magnified imagePhase difference Φ3 as a function of the Deborah number De at γ0 = 2 for the polystyrene solutions measured at temperatures from 295 to 350.5 K.
Single‐Mode Microwave Ovens as New Reaction Devices: Accelerating the Living Polymerization of 2‐Ethyl‐2‐Oxazoline
Authors: Wiesbrock Frank , Hoogenboom Richard , Abeln Caroline H. , Schubert Ulrich S. 
Published: November 2004

AbstractSummary: The ring‐opening cationic polymerization of 2‐ethyl‐2‐oxazoline was performed in a single‐mode microwave reactor as the first example of a microwave‐assisted living polymerization. The observed increase in reaction rates by a factor of 350 (6 h → 1 min) in the range from 80 to 190 °C could be attributed solely to a temperature effect as was clearly shown by control experiments and the determined activation energy. Because of the homogenous microwave irradiation, the polymerization could be performed in bulk or with drastically reduced solvent ratios (green chemistry).Monomer conversion, represented by the ratio ln{[M0]/[Mt]}, plotted against time for six temperatures in the range from 80 to 180 °C, and polymerization reaction vials, showing an increase in yellow color for those reactions performed (well) above and below 140 °C, indicating side reactions.magnified imageMonomer conversion, represented by the ratio ln{[M0]/[Mt]}, plotted against time for six temperatures in the range from 80 to 180 °C, and polymerization reaction vials, showing an increase in yellow color for those reactions performed (well) above and below 140 °C, indicating side reactions.
Chain Transfer and Efficiency of End‐Group Introduction in Free Radical Polymerization of Methyl Methacrylate in the Presence of Poly(methyl methacrylate) Macromonomer
Authors: Miyake Kazuki , Zetterlund Per B. , Yamada Bunichiro 
Published: November 2004

AbstractSummary: Experimental and modeling studies of addition–fragmentation chain transfer (AFCT) during radical polymerization of methyl methacrylate in the presence of poly(methyl methacrylate) macromonomer with 2‐carbomethoxy‐2‐propenyl ω‐ends (PMMA‐CO2Me) at 60 °C are reported. The results revealed that AFCT involving PMMA‐CO2Me formed in situ during methyl methacrylate polymerization has a negligible effect on the molecular weight distribution.
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Cover Picture: Macromol. Rapid Commun. 22/2004
Authors: Mahajan Surbhi , Cho Byoung‐Ki , Allgaier Jürgen , Fetters Lewis J. , Coates Geoffrey W. , Wiesner Ulrich 
Published: November 2004

Cover: The cover shows the molecular architecture of the A block, poly(ethylene‐alt‐propylene), and the AB diblock, poly(ethylene‐alt‐propylene)‐block‐poly(ethylene oxide), leading to the final ABC triblock copolymer, poly(ethylene‐alt‐propylene)‐block‐poly‐(ethylene oxide)‐block‐poly(hexyl methacrylate). Oxygen containing segments are shown in red. The corresponding GPC chromatograms reveal narrow molecular weight distributions for all the species.Further details can be found in the Communication by S. Mahajan, B.‐K. Cho, J. Allgaier, L. J. Fetters, G. W. Coates, and U. Wiesner* on page 1889.
Synthesis of Hyperbranched Polysaccharide by Thermally Induced Cationic Polymerization of 1,6‐Anhydrohexopyranose
Authors: Satoh Toshifumi , Imai Tomoko , Kitajyo Yoshikazu , Maeda Takahiro , Narumi Atsushi , Kaga Harumi , Kaneko Noriaki , Kakuchi Toyoji 
Published: November 2004

AbstractThe thermally induced cationic polymerizations of 1,6‐anhydro‐β‐D‐glucopyranose (1a), 1,6‐anhydro‐β‐D‐mannopyranose (1b) and 1,6‐anhydro‐β‐D‐galactopyranose (1c) as a latent cyclic AB4‐type monomer were carried out using (S‐2‐butenyl)tetramethylenesulfonium hexafluoroantimonate (2) as an initiator. The solution polymerization in propylene carbonate proceeded without gelation to produce the water‐soluble hyperbranched polysaccharides (3a‐c) with controlled molecular weights and narrow polydispersities. The degree of branching (DB), estimated by the methylation analysis of 3a‐c, was in the range of 0.38 – 0.49. The thermally induced cationic polymerization of 1a‐c using 2 is a facile method leading to a hyperbranched polysaccharide with a high DB value.
New Monomers for Dental Application
Authors: Moszner Norbert 
Published: November 2004

AbstractThe currently used commercial restoratives composites and self‐etching enamel‐dentin adhesives usually contain various functionalised and cross‐linking methacrylates. New developments of polymeric composites for restorative filling materials are mainly focused on the reduction of the polymerization shrinkage and improvement of biocompatibility and wear resistance. This can be partially achieved by using new monomers, for example, cyclic monomers for the radical polymerisation such as bicyclic cyclopropyl‐acrylates or polycondensates generated by the hydrolytic condensation of triethoxypropylsilane dimethacrylates. In the presence of water and strongly acidic monomers, methacrylates undergo hydrolysis, which results in decrease of the performance of the adhesive. This problem can be overcome with new polymerizable acrylic phosphonic acids and cross‐linking bis(acrylamide)s, which show improved hydrolytic stability.
Poly(acrylamide) Grafts on Spherical Polymeric Sulfonamide Based Resin for Selective Removal of Mercury Ions from Aqueous Solutions
Authors: Şenkal Bahire Filiz , Yavuz Erdem , Bicak Niyazi 
Published: November 2004

AbstractPoly (acrylamide) was grafted from carboxylic acid groups onto cross linked poly (styrene) beads using a redox polymerization methodology. A beaded polymer with a poly(acrylamide) surface shell was prepared in three steps, starting from poly(styrene‐divinyl benzene) (PS‐DVB) (10% crosslinking) based beads with a particle size of 420‐590μm, according to the synthetic protocol; chlorosulfonation, sulfamidation with glycine and grafting using a concentrated aqueous acrylamide solution with cerium ammonium nitrate.The resulting polymer resin with 220 wt % of grafted poly (acrylamide) has been demonstrated to be an efficient mercury‐specific sorbent, able to remove Hg (II) from solutions at ppm levels. The mobility of the graft chains provides nearly homogenous reactions conditions and rapid mercury binding ability. The mercury sorption capacity under non‐buffered conditions is around 5.75 mmol/g. No interference arises from common metal ions such as Cd (II), Fe (II), Zn (II), and Pb (II).The sorbed mercury can be eluted by repeated treatment with hot acetic acid without hydrolysis of the amide groups.
Preparation of Polymer‐Supported Chiral 1,2‐Diamine as an Efficient Ligand for Asymmetric Hydrogenation Catalyst
Authors: Itsuno Shinichi , Takahashi Miyuki , Tsuji Atsushi 
Published: November 2004

AbstractAn enantiopure 1,2‐diamine having two phenolic hydroxy groups was synthesized, and attached to chloromethylated poly(styrene) through a benzyl ether linkage. The polymer‐supported Ru precatalysts were prepared from the polymeric chiral 1,2‐diamine and RuCl2/BINAP complex. In the presence of t‐BuOK the polymeric catalyst system worked well in asymmetric hydrogenation of aromatic ketones in a mixed solvent of 2‐propanol and DMF. The insoluble polymeric catalyst was readily separated from the reaction mixture and reused at least several times without loss of the catalytic activity.
Design and Application of Amphiphilic Polymeric Supports for Micellar Catalysis
Authors: Kotre Thomas , Zarka M. Tobias , Krause Jens O. , Buchmeiser Michael R. , Weberskirch Ralf , Nuyken Oskar 
Published: November 2004

AbstractIn this contribution, the synthesis and application of amphiphilic poly(2‐oxazoline)s with covalently bound transition metal catalysts for reactions in aqueous media is described. In the first example, bipyridine moieties were introduced via living ring‐opening polymerization of functionalized oxazoline monomers and the resulting block copolymers were used as macroligands for ATRP (atom transfer radical polymerization) using Cu(I)Br as active metal species. Furthermore, the fixation of a chiral biphosphane and its use for enantioselective hydrogenation of enamides is presented as well as the fixation of a ruthenium catalyst. The latter one is used for polymerization of diethyl dipropargylmalonate (DEDPM), and represents the first example of an alkyne polymerization using a ruthenium catalyst. In the case of the polymers stable latex particles were obtained
Surface‐Initiated Polymerization on Self‐Assembled Monolayers: Effect of Reaction Conditions
Authors: Schmelmer Ursula , Paul Anne , Küller Alexander , Jordan Rainer , Gölzhäuser Armin , Grunze Michael , Ulman Abraham 
Published: November 2004

AbstractSelf‐assembled monolayers of 4′‐nitro‐4‐mercaptobiphenyl were modified by electron beam irradiation and diazotization to create a surface‐bond asymmetric azo initiator for the surface‐initiated polymerization (SIP). The effect of different reaction conditions upon the thermally and photochemical initiated SIP was investigated.
Synthesis and Self Assembly of Hydrogen‐Bonded Supramolecular Polymers
Authors: Farnik Dominique , Kluger Christian , Kunz Michael J. , Machl Doris , Petraru Laura , Binder Wolfgang H. 
Published: November 2004

AbstractNew synthetic methodologies towards hydrogen bonded supramolecular polymers are described. Focus is directed on synthetic work towards telechelics with hydrogen bonds either as side chain moieties or as endgroups. Physical ordering effects related to polymers and particles are discussed citing own and related work in ∼60 references.
Pseudostationary Polymerization: Improving the Determination of the Rate Constant of Propagation
Authors: Zifferer Gerhard , Kornherr Andreas , Schnöll‐Bitai Irene , Olaj Oskar Friedrich 
Published: November 2004

AbstractPulsed‐laser initiated polymerization (PLP) leads to chain length distributions with characteristic extrapeaks. The low molecular weight side points of inflection LLPI are located near to (multiples) of a specific chain length L0 which is equal to the product of pulse separation t0 and propagation frequency kp[M], i.e. rate constant of propagation kp times monomer concentration [M], allowing a direct determination of kp. However, Poissonian broadening inherent in the polymerization process as well as Gaussian broadening due to axial dispersion caused by the size exclusion chromatographic (SEC) device leads to a shift of LLPI as compared to L0 – its extent depending on the experimental parameters chosen – which in turn causes an error up to 10–20% in the rate constants evaluated. Fortunately, comparison of the experimental peak width with some sort of theoretical peak width yields several types of correction factors and furthermore master‐correction functions which are able to reduce the remaining error on average by at least a factor of 10.
Morphology – Property Correlations of PP Materials by Means of Microhardness
Authors: Seidler Sabine , Koch Thomas 
Published: November 2004

AbstractThe present work deals with the influence of crystallization temperature, cooling rate and annealing conditions on microhardness, indentation modulus and creep behaviour of ethylene/propylene (E/P) random copolymers with 4, 6 and 8 mol% ethylene as well as α‐ and β‐spherulites in a homopolymer and an E/P random copolymer. The materials are unnucleated, the formation of β‐spherulites occurs sporadically. Additionally the indentation creep behaviour of α‐ and β‐nucleated PP is investigated.A nearly linear correlation between hardness as well as indentation modulus and crystallintity of the E/P copolymers can be proved. An increasing cooling rate leads to decreasing hardness and modulus values due to the hindered crystallization.For the investigation of the α‐ and β‐phases different crystallization and annealing temperatures are used. Independent of these conditions, microhardness and modulus determined by indentation testing are lower for the β‐phase in both materials. Increasing crystallization temperature and annealing lead to an increasing hardness and modulus in both phases. However, an effective annealing effect takes place only at short times and elevated temperatures above 100 °C. The increasing of microhardness and modulus is correlated with an increasing in lamellae thicknesses. Additionally, indentation creep experiments were carried out on nucleated materials that show the stronger creep tendency of the β‐phase PP and the stronger influence of annealing on this phase.
Microphotometric Detection of Particles/Inhomogeneities in Flowing Polymer Melts
Authors: Stephan Michael , Große Stephan , Stintz Michael , Blankschein Udo , Rudolph Andreas 
Published: November 2004

AbstractBy application of different unique microphotometric sensors it is possible to detect and quantify disturbing particles (gels, unmolten resins, black spots, additive agglomerates, bubbles) within a flowing polymer melt in realtime during extrusion processing. These particles result in disadvantageous optical and mechanical properties of a final polymer product. Sensors can be adapted inline and online to different extruders at various positions. This seems to give technical and economic benefit to quality control and process optimisation in polymer processing.
An Experimentally Fast and Straightforward Method for the Direct Determination of Axial Dispersion σAd as Occurring in Size Exclusion Chromatography
Authors: Schnöll‐Bitai Irene 
Published: November 2004

AbstractThe method for the direct determination of σad (the extent of axial dispersion) under normal working conditions makes use of the peak variance of Poisson distributions and narrow peaks, which can be determined from the points of inflection. For such distributions the experimentally measured peak variance is the sum of the pristine or true peak variance and that stemming from the broadening processes during SEC measurements. The advantage of this method is that commercially available narrow polymer standard can be used which is demonstrated for four series of polymer standards. Knowledge of σad finally enables the application of different correction procedures.
Injection Moulding of Parts with Microstructured Surfaces for Medical Applications
Authors: Gornik Christian 
Published: November 2004

Abstractm2M‐systems (micro‐to‐Macro) are parts with lateral dimensions of macroscopic scale and structures on the surface in the dimension of microns. The microstructure on the surface has a specific function depending on the intended purpose of the parts. With the use of m2M‐systems new methods of medical diagnostics are possible. Nowadays for the realisation of such parts mainly planar methods known from microelectronics and their standard materials silicon and glass are used. An alternative is to make m2M‐systems by injection moulding of plastics which lowers the manufacturing costs. In order to get an acceptable replication of the microstructure the use of special moulding techniques is necessary. The results of investigations in the variotherm moulding process and the requirements for the injection moulding machine are described in this paper.
New Capabilities of Rheology for Polymer Compound Industry
Authors: Locati Giancarlo , Valle Andrea 
Published: November 2004

AbstractRecent developments in testing equipment are enabling a better exploitation of rheology as a tool for polymer compound industry.After a short review of the novelties of recent equipment, some selected possibilities are shown in this paper, ranging from improved quality control of incoming and outcoming products, to recycling management, masterbatches characterization, and evaluation of dispersion effects on filled materials.
Modification of Recycled Polymer Blends with Activated Natural Zeolite
Authors: Djoumaliisky Strashimir , Zipper Peter 
Published: November 2004

AbstractThe growing interest in the natural zeolite is based on some specific peculiarities of its structure, which after dehydration enables adsorption processes of some polymer molecules and/or segments to take place on the zeolite surface. The main goal of the study is to investigate the effect of dehydrated zeolite on the flow behavior, mechanical properties and morphology of immiscible blends from unsorted polymer wastes. A tetra‐component blend consisting of 40 wt.% polypropylene (PP), 40 wt.% high‐density polyethylene (HDPE), 15 wt.% low‐density polyethylene (LDPE) and 5 wt.% polystyrene (PS), was studied as a model system of commingled plastic wastes. Compositions from recycled blend and dehydrated zeolite in a wide concentration range (from 0 to 20 wt.%) were prepared using a twin‐screw extruder Brabender DSE 35/17D in the temperature range from 140 to 190 °C. The compositions were characterized by capillary rheometry, differential scanning calorimetry (DSC), site‐resolved wide‐angle X‐ray scattering (WAXS) and mechanical tests. The results show a compatibilizing effect of dehydrated zeolite at low concentration levels (1‐2 wt.%) and open wide possibilities for utilization of dehydrated zeolite in the recycling of unsorted polymer wastes.
Influence of Talc and SEBS‐g‐MA on PP/SEBS‐g‐MA/Talc Composites under Gamma Irradiation Sterilization Conditions
Authors: Denac Matjaž , Musil Vojko , Ranogajec Franjo , Šmit Ivan 
Published: November 2004

AbstractAmong thermoplastics, polypropylene is outstanding with respect to its attractive combination of low cost, low weight, heat distortion temperature above 100°C, and extraordinary versatility in terms of properties and applications. With the appropriate modification, it is possible to improve the existing properties of the polypropylene, or even obtain the new ones. As a result of its originally superior properties, polypropylene is commonly used in medical purposes, where it has to undergo the process of sterilization beforehand. The sterilization of the polypropylene in medicine is most often being carried out with low dose of gamma irradiation, which can influence the changes of properties of both the polymeric matrix and modifiers. Therefore, the purpose of our research work was to determine the mechanical properties of unirradiated and gamma irradiated isotactic polypropylene (iPP) composites with talc filler and poly‐(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) block copolymer, grafted with maleic anhydride (SEBS‐g‐MA) as elastomeric modifier, as well as of corresponding binary blends. Unirradiated and gamma irradiated composites and blends were characterized by tensile measurements, measurements of notched impact strength and FTIR spectroscopy. The effects of composition and gamma irradiation on the properties of the iPP composites and blends are discussed, with emphasis on the study of the stabilizing effect of talc in irradiated iPP composites.
Phantom design method for high‐field MRI human systems
Authors: Yang Qing X. , Wang Jinghua , Collins Christopher M. , Smith Michael B. , Zhang Xiaoliang , Ugurbil Kamil , Chen Wei 
Published: November 2004

AbstractA phantom design method suitable for high‐field MRI based on the RF field wave characteristics of sample and experimental validations at 7.0 T and 3.0 T are presented. The RF field distribution in a phantom with a given RF coil system is primarily determined by the sample size relative to the wavelength inside the sample, and the ratio between the displacement and conduction currents. Experimental results demonstrate that the MR image intensity patterns associated with wave behavior in human samples at a given field strength can be reproduced with a phantom at the same or different field strengths once the dimension and penetration constant are scaled by the corresponding wavelength in the sample medium. Magn Reson Med 52:1016–1020, 2004. © 2004 Wiley‐Liss, Inc.
Localized 7Li MR spectroscopy: In vivo brain and serum concentrations in the rat
Authors: Pearce John M. , Lyon Melvin , Komoroski Richard A. 
Published: November 2004

AbstractThe brain concentration of lithium (Li) in treated rats was measured using a recently developed method based on in vivo 7Li PRESS localized MRS. Comparison was made to the corresponding serum concentration at two treatment durations. The brain and serum Li concentrations were highly correlated with each other, more so than found previously for humans. The brain and serum Li concentrations also correlated with dose. Both the brain Li concentration and the serum concentration at 16.1 days of treatment correlated with the corresponding measure at 6.6 days. After correction of the brain Li concentrations for reduced 7Li MRS visibility, the mean brain/serum Li ratio for rats was close to unity, unlike most previous values found for humans. However, in some individual cases the ratio deviated substantially from the mean, suggesting that serum Li is not always a reliable indicator of brain Li. Magn Reson Med 52:1087–1092, 2004. © 2004 Wiley‐Liss, Inc.