bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on electrical and paramagnetic properties of poly(phenylene sulphide)
Authors: Kreja Ludwik , Rozpłoch Franciszek , Warszawski Andrzej 
Published: April 2003

AbstractElectrical and paramagnetic properties of poly(phenylene sulphide) synthesized by a direct method from benzene and sulphur were investigated. In darkness dc conductivity of the polymer in its pristine state is of the order 10−10 S/m. Upon doping with iodine it increases by 8 orders of magnitude. For undoped samples the n‐type conductivity and for those doped with iodine the p‐type conductivity was observed. On the basis of ESR experiments the number of spins and g‐value were determined, which for undoped polymer at room temperature are equal to 0.80 · 1017 spins/g and 2.0037, respectively. Next, the changes in spin concentration both for the iodine doped samples and these annealed within the temperature range 513 – 903 K were described. An attempt to discuss the ESR lineshape in a quantitative way was also made.
Synthesis and study of the chelating properties of 3‐carboxy‐4‐hydroxyacetophenone‐formaldehyde resins
Authors: Patel K. Surekha R. , Patel Hasmukh S. , Patel Shanti R. 
Published: April 2003

Abstract3‐Carboxy‐4‐hydroxyacetophenone (CHAP) was polycondensed with various proportions of formaldehyde using alcoholic alkali as catalyst. The resin samples, designated as CHAP‐F, have been characterized by elemental analyses and IR spectroscopy, by estimation of their number average molecular weights (M̄n), by measurement of intrinsic viscosity, and by TGA. Polymeric metal chelates of one CHAP‐F sample with Cu2+, Fe3+, Co2+, Ni2+, and UO22+ ions have been prepared and characterized.Ion‐exchanging properties of one CHAP‐F resin sample for Fe3+, Cu2+, and Ni2+ metal ions are studied by the application of the batch‐equilibration method.
Niedermolekulares poly(β‐hydroxybutyrat). Herstllung und anwendungen
Authors: Trathnigg Bernd , Weidmann Volker , Lafferty Robert M. , Korsatko Brigitta , Korsatko Werner 
Published: April 2003

AbstractNiedermolekulares Poly(β‐hydroxybutyrat) (PHB) kann durch kontrollierte Hydrolyse des auf biotechnologischem Wege hergestellten Polymeren erhalten werden. Die Geschwindigkeitskonstanten des Kettenabbaus wurden in verschiedenen 85prozentigen Säuren bei 90 und 100°C bestimmt. Aus den so erhaltenen PHB‐Fraktionen im Molmassenbereich von 3000 – 500000 wurden Matrixtabletten hergestellt. Es wird gezeigt, daß der Retardeffekt stark von der Molmasse des verwendeten Polymeren abhängt.
On the structure of styrene‐divinyl benzene copolymers as obtained by small‐angle X‐ray scattering
Authors: Włochowicz Andrzej , Sanetra Roman , Kolarz Bożena N. 
Published: April 2003

AbstractThe parameters of the supermolecular structure of styrene‐divinyl benzene copolymers with a degree of crosslinking equal to 5, 10, and 20% were examined. It was found that regions with different electron density occur in the copolymers.Mean sizes of heterogeneities, 1, thicknesses of transition layers E, and specific areas S/V were determined. It was found that as the degree of crosslinking increases the inhomogeneity of the copolymer structure becomes greater and the separation of the phases is more visible.
Elektrokinetische untersuchungen von chemiefasern
Authors: Pfeifer Stanisław , Włochowicz Andrzej 
Published: April 2003

AbstractElectrokinetische Parameter wie die elektroosmotische Stromstärke (Qc) und das elektrokinetische Potential (ζ) von Fasern hängen stark von Masse und Struktur der untersuchten proben ab. Anhand von Polyamid‐, Polyester‐ und Polyacrylnitrilfasern wurde der Einfluß dieser Parameter untersucht. Dabei zeigte sich (a), daß es nicht möglich ist, mit Hilfe der elektroosmotischen Methode die echten Werte des Zeta‐Potentials festzustellen und (b), daß für einen relativen Vergleich des Zeta‐Potentials verschiedener Fasern diese Einflüsse nicht bestimmt werden müssen.
Effect of various epoxy fortifiers on the reactivity in curing of epoxy resins
Authors: Patel Rasmika H. , Patel Ranjan G. 
Published: April 2003

AbstractDiglycidyl ether of ethylene glycol was prepared and used as a reactive diluent in the curing of an epoxy resin, based on diglycidyl ether of bisphenol A. Effect of different fortifiers on the curing reaction of the resin‐diluent system has been investigated using differential scanning calorimetry. The dynamic scans were analyzed using four different relations to evaluate the kinetic parameters, the activation energy and the order of the reaction. The reactions are found to follow first order kinetics with an activation energy in the range of 36 – 84 kJ mol‐1.
Organic solvent treatment of isotactic polypropylene films, 2. Temperature dependence of proton spin‐lattice and spin‐spin relaxation times of the sample treated with tetrachloroethylene
Authors: Tanaka Hiroshi 
Published: April 2003

AbstractThe structural properties of isotactic polypropylene films treated with tetrachloroethylene at high temperatures were characterized by proton spin‐lattice T1 and spin‐spin T2 relaxation times, loss in weight, crystallinity, molecular weight, and melting temperature, and heat of fusion. Two kinds of samples, a quenched and an annealed sample, were employed. There are a considerable loss in weight and large increases in crystallinity and in molecular weight when treated the sample at high temperatures especially in the quenched one. These morphological changes result in a shift of T1 minimum to high temperatures and a decrease in T2a. The effects of the solvent on the annealed sample are qualitatively the same for the quenched one but are relatively mild.
Viscosity‐index and polymer rheology. Comparison of concepts by means of experiments with some of the technically most important systems
Authors: Maderek E. , Wolf B. A. 
Published: April 2003

AbstractPoly(n‐decyl methacrylate), a statistical copolymer of ethylene and propylene, and a diblock copolymer of styrene and hydrogenated butadiene were studied as representatives of various kinds of viscosity‐index (VI) improvers. Essomarcol 52 and AF 1 from Schindler served as base‐oils, toluene and 1‐phenyl dodecane were also studied. By means of viscosity measurements in the temperature interval from 37.8 to 98.9°C up to a concentration of typically 1 wt.‐% polymer, the viscosity indices of the different systems and the corresponding intrinsic viscosities, Huggins coefficients, and activation energies of flow, E≠, were determined. The discussion of the obtained experimental material demonstrates that the VI of a base‐oil can be raised in two clearly distinguishable ways: (i) via an increase in the viscosity due to the mere presence of the polymer, without a change in E≠ and (ii), less general, via an additional reduction of E≠ as a consequence of thermodynamic interactions. Formulae are given from which these two contributions can be calculated.
Celluloseaustauscher mit glyoxal‐bis‐(2‐mercaptoanil) als ankergruppe für die abtrennung von silber, gold und quecksilber
Authors: Hofmann B. , Lieser K. H. 
Published: April 2003

AbstractDie Verteilungskoeffizienten von Ag+, Au3+ und Hg2+ and dem Celluloseaustauscher mit Glyoxal‐bis‐(2‐mercaptoanil) als Ankergruppe werden als Funktion des pH‐Wertes in 0,1 M NaNO3 als Grundlösung und unter Zusatz von NaCl, NH4NO3, Na2S2O3 und NaCN bestimmt. Ag+‐Ionen werden mit verhältnismäßig hohen Verteilungskoeffizienten gebunden, auch in Gegenwart von NH4NO3. Sogar in Gegenwart von Na2S2O3 liegen die Verteilungskoeffizienten noch in der Größenordnung von 102 ml/g. Au und Hg werden aus 0,1 M NaNO3 mit Verteilungskoeffizienten von etwa 5 · 103 bzw. etwa 103 ml/g gebunden, während in Gegenwart von 0,5 M NaCl und von NaCN die Verteilungskoeffizienten deutlich niedrigersind.
Biocide polymers, 19. Modification of carboxyl groups containing resins with 3(5)‐methylpyrazole
Authors: Hartmann Manfred , Wermann Kurt , Claußen Frank , Schwachula Gerhard , Feistel Lothar , Krauß Dieter 
Published: April 2003

AbstractPolymeric inhibitors of nitrification have been prepared by reversible attachment of 3(5)‐methylpyrazole to poly(acrylic acid‐co‐divinylbenzene) and poly(4‐vinylbenzoic acid‐co‐divinylbenzene) containing 86 mol‐% and 88 mol‐% carboxyl groups, respectively.Pyrazolide bonds between the bioactive agent and crosslinked copolymers were formed by means of aminolysis of reactive derivatives of the resins containing mixed anhydride groups or acid chloride groups. The modified resins had pendantly bound 3(5)‐methylpyrazole residues in the range of 7 to 36.4 wt.‐% and were subjected to hydrolysis in order to study the influence of crosslinking on the release rate of the active ingredient. The results obtained were discussed.
Coupling particle size distribution technique. A new ultracentrifuge technique for determination of the particle size distribution of extremely broad distributed dispersions
Authors: Mächtle Walter 
Published: April 2003

AbstractThe particle size distribution (PSD) of extremely broad distributed dispersions (diameter range 20 < D < 2000 nm) is not possible to be measured by analytical ultracentrifuge (AUC) using the standard technique, i.e. measuring turbidity τ at a single concentration c, because the specific turbidity τ/c varies too much between very small and very large particles. To solve this problem we have developed a new AUC technique, the so‐called Coupling‐PSD‐Technique. Here two different concentrations of the same dispersion are measured simultaneously by one single AUC run with two corresponding curves of light intensity I vs. time t being registered. At a low standard concentration cs, mainly the larger particles are detected, while at a concentration ch 5 to 30 times higher mainly the smaller particles are registered. Both I(t)‐curves are coupled mathematically and transformed into the requested broad distribution curve employing Stokes' law and Mie's light scattering theory for homogeneous isotropic spheres.We use an AUC together with an 8‐cells‐rotor and a multiplexer. Because very large and very small particles are to be measured simultaneously in one single run, we can no more apply a constant rotor speed N as before, but by means of a time program N(t) we always have to increase the rotor speed from 0 to 40000 rpm within one hour.
Block‐ und Propfcopolymere als Verträglichkeitsvermittler in Polymermischungen
Authors: Lausberg Dietrich , Mühlbach Klaus , Taubitz Christof 
Published: April 2003

AbstractZwei chemisch verschiedene Polymere sind im allgemeinen unverträglich, d. h. sie weisen eine hohe Oberflächenspannung und geringe Grenzflächenhaftung auf. Block‐und Pfropfcopolymere können diese unerwünschten Effekte stark verringern. Ein Konzept für Verträglichkeitsvermittler mit chemisch identischen und chemisch unterschiedlichen, aber thermodynamisch mischbaren Blöcken wird vorgestellt. Am System Poly[oxy(1,4‐phenylen)]/Poly(styrol‐co‐acrylnitril) (PPE/PSAN) werden alle möglichen Varianten — identisch‐identisch, identisch‐mischbar und mischbar‐mischbar — getestet. Die Ergebnisse werden diskutiert.
Estimation of polymer fractionation efficiency by comparison of theoretical models and experimental molecular mass distribution
Authors: Mencer Helena J. , Gomzi Zoran 
Published: April 2003

AbstractIn this paper the efficiency of a new modified column fractionation method was presented through the comparison of theoretical models and experimentally obtained molecular mass distribution. Five theoretical functions were used for fitting the experimental data: log‐normal, Tung, Schulz, polynomial, and Flory distribution function. The curve fittings were estimated by the mean square deviation. The mean square deviations in all the theoretical models were of the same order. The least values of mean square deviation and consequentely the best fitting of the gel permeation chromatography (GPC) distribution curve, which deals as a true distribution of the applied polymer sample, were achieved with polynomial and Flory model. These theoretical models were further chosen as a reference distribution function. The experimental fractionation data in two quite different solvent pairs were afterwards fitted to the chosen referent models. Fractionation data of the both applied solvent pairs have been in close agreement with Flory and polynomial model. This confirms the high efficiency of the proposed fractionation method.
Studies on the enhancement of separation characteristics of sulfonated poly(phenylene oxide)/polysulfone thin film composite membranes for reverse osmosis applications. I. Effect of chemical treatment
Authors: Agarwal A. K. , Huang R. Y. M. 
Published: April 2003

AbstractThe effect of chemical treatment on the reverse osmosis (RO) separation characteristics of sulfonated poly(phenylene oxide) (SPPO) thin film composite membranes was investigated. The effects of the concentrations of aqueous solutions of formaldehyde, sulfuric acid, hydrochloric acid, phosphoric acid, sodium hydroxide, and treatment time on the RO separation characteristics of the composite membranes with ion exchange capacity (IEC) of 2.14 and 2.50 meq/g in various combinations are reported in detail. The results indicate some enhancement in RO separation characteristics of the SPPO/polysulfone (PS) composite membrane under the best conditions of the chemical treatment.
Studies on the enhancement of separation characteristics of sulfonated poly(phenylene oxide)/polysulfone thin film composite membranes for reverse osmosis applications. II. Effects of nitromethane and the chemical treatment combined with gamma‐ray irradiation
Authors: Agarwal A. K. , Huang R. Y. M. 
Published: April 2003

AbstractThe enhancement effect of the addition of nitromethane into the coating solution of sulfonated sodium poly(phenylene oxide) (SPPONa) polymer for the synthesis of sulfonated poly(phenylene oxide)/polysulfone (SPPO/PS) thin film composite membranes on reverse osmosis (RO) separation characteristic was studied. The effect of gamma‐ray irradiation on the SPPO/PS thin film composite membranes was also evaluated when the membrane samples were in the wet and dry conditions. The composite membranes were also subjected to a chemical treatment combined with gamma‐ray irradiation in both wet and dry conditions in the hope of obtaining the maximum possible enhancement under each treatment. However, the experimental data of this combined treatment indicated the possibility of some degradation of the SPPO/PS composite membranes.
Modification of epoxy resins with acrylic rubbers containing a pendant epoxy group
Authors: Tomoi Masao , Yamazaki Hideo , Akada Hiroyuki , Kakiuchi Hiroshi 
Published: April 2003

AbstractNew acrylic rubbers with a pendant epoxy group were prepared by copolymerization of butyl acrylate (BA) with vinylbenzyl glycidyl ether (VBGE). The modification of an epoxy system (bisphenol‐A diglycidyl ether/p,p′‐diaminodiphenyl sulfone) with the acrylic rubbers was carried out in order to increase the toughness of the cured epoxy resin. The addition of 20 wt.‐% of the copolymer containing 74% of BA and 26% of VBGE units resulted in a 30% increase in the fracture toughness (KIC) of the cured resin at minimal expenses of strength and modulus of the resin. The modified epoxy resin had two‐phase morphology in which the rubber particles with average diameter of 2 μm are dispersed in the epoxy matrix. The copolymer without the pendant epoxy group, prepared from BA and vinylbenzyl methoxyethyl ether, was ineffective as a modifier, indicating that the reaction of the pendant epoxide with the epoxy matrix resulted in good interfacial adhesion between the rubber particles and the matrix, and in the increased toughness. The epoxide‐containing copolymers with 55 or 86% of BA units were also insufficient modifiers. The addition of the former yielded cured resins with homogeneous structure, whereas that of the latter resulted in macroscopic phase separation between the rubber and the epoxy resin.
Polyurethane ionomers: Effects of emulsification on properties of toluene diisocyanate based polyether polyurethane cationomers
Authors: Chan Wu‐Chung , Chen Show‐An 
Published: April 2003

AbstractToluene diisocyanate based polyether polyurethane cationomer solutions are prepared and then emulsified by adding water. Properties of films cast from the solutions and emulsions are studied using infrared spectroscopy, dynamic mechanical analysis, differential scanning calorimetry, wide‐angle X‐ray diffraction, and tensileelongation testing. It is found that the use of the asymmetric chain extender, N‐methyl‐diethanolamine, also leads to a polyurethane (PU) with detectable order in the hard domains as in the PU with symmetric chain extender such as 1,4‐butandiol. After quaternization with glycolic acid, the PU cationomers have increased elongation and tensile strength and modulus. These can be attributed to the proper Coulomb interaction between two neighboring hard segments. The emulsification of the PU ionomer solution results in an increased mixing between the soft segments and the hard segments with asymmetric 2,4‐urethane isomers originally located in the hard domains, and therefore make the hard domains containing a higher concentration of symmetric 2,6‐isomer. The hard domains then become more ordered. Such increased order and phase mixing leads to an increase of the three tensile properties. During the emulsification conductivity and viscosity variations show that water is firstly adsorbed on the surface of the hard segment microionic lattices and then enters into the disordered and ordered hard domains successively.
Nonlinear programming methods to determine surface free energy components of polymers using harmonic mean approximation
Authors: Erbil H. Yildirim , Meriç R. Alsan 
Published: April 2003

AbstractThe dispersion and polar surface free energy components, γ and γ, and the critical surface free energy, γc, of polymers were determined from contact angle data by the application of a nonlinear programming method using harmonic mean approximation.The surface free energy components of the probe liquids, γ and γ, which reflect the conditions of the maximized interaction parameter, Φ, were also simultaneously determined by this method.
Excimer formation in solution and molecular aggregation of polyethersulfone
Authors: Wu Zhongwen , Zhang Luifang , We Qingyang , Yosomiya Ryutoku 
Published: April 2003

AbstractFormation of intermolecular excimers in polyethersulfone (PES) dichloromethane solutions were observed at a PES concentration about 2.7 × 10−2 mol/l by the fluorescence analysis. External light energy irradiation enabled the formation of intramolecular excimers in the PES dichloromethane solution. These chains can gain an access to each other in parallel though the molecular chains are considerably rigid. The electron micrograph of the PES film, heat treated at 200°C for 72 hours, presented a diffraction micrograph, which suggests that the PES molecular aggregation is changed from a randomly coiled amorphous phase to an ordered one.
Poly(N‐vinylpyrrolidone‐co‐styrene)s: Extraordinary catalysts in two‐phase reactions
Authors: Kondo Shuji , Ozeki Masashi , Nakashima Nobuo , Suzuki Kenji , Tsuda Kazuichi 
Published: April 2003

AbstractPoly(N‐vinylpyrrolidone‐co‐styrene)s possess extaordinary activity as catalysts for several substitution reactions in organic‐aqueous two‐phase systems, although the monomeric analogue does not show this catalytic effect. The catalytic activity is affected remarkably by the composition of copolymer, indicating the importance of hydrophobic environment around the active site. It was also found that poly(N‐vinylpyrrolidone‐co‐styrene)s employed here extract potassium ions more effectively than the monomeric analogue and the extraction ability increases with increasing density of the pyrrolidone unit. It is reasonable therefore to assume that the catalytic activity is caused by both effects, cation extraction ability by the polymer and activation of anions by desolvation in hydrophobic region of polymers. Insoluble polymers, poly(N‐vinylpyrrolidone‐co‐styrene)s crosslinked by divinylbenzene also exhibit high activity as phase transfer catalysts.
Kurzmitteilung zum Mechanismus der Spannungsübertragung in eigenfaserverstärkten Kunststoffen
Authors: Wenig Werner , Schöller Thomas 
Published: April 2003

AbstractAn aus der orientierten Schmelze kristallisierten, eigenfaserverstärkten Polymerlegierungen aus isotaktischem Polypropylen (iPP) und isotaktischem Poly(1‐buten) (PB‐1) wurden mechanische Parameter (E‐Modul, Fließspannung) gemessen und mit aus äquatorialen Röntgenkleinwinkelstreukurven bestimmten lateralen Grenzschichtdicken korreliert. Die Kurvenverläufe von E‐Modul, Fließspannung und Grenzschichtdicke als Funktion der Komponentenzusammensetzung stimmen qualitativ überein. Es wird gezeigt, daß die Morphologie der Grenzschicht von besonderer Bedeutung für die Übertragung der Spannungen von der Matrix auf die Fasern ist.
Effect of thermal history on crystallization behavior of polyetheretherketone studied by differential scanning calorimetry
Authors: Wu Zhungwen , Zheng Yu Bin , Yu Hong Xe , Seki Miharu , Yosomiya Ryutoku 
Published: April 2003

AbstractThe crystallization behavior of polyetheretherketone (PEEK) was investigated by differential scanning calorimetry (DSC). The glass transition temperature of PEEK shifts to higher temperatures with an increase in crystallinity. Heat‐treated PEEK showed double peaks in their DSC curves, which is a characteristic phenomenon of PEEK. These double peaks were caused by the formation of incomplete crystal structures according to the conditions of heat‐treatment.
Styrene divinylbenzene copolymers. Influence of diluent mixture on matrix structure
Authors: Poinescu I. C. , Beldie C. 
Published: April 2003

AbstractIn order to prepare porous beads with good characteristics mixtures of diluents were used. The influence of the δ‐parameter values of the two diluents was investigated which constitute the mixture of diluents on the macroporous features.The influence of the mixtures of 2‐ethyl hexyl alcohol/polystyrene (M̄w = 172000), 2‐ethyl hexyl alcohol/toluene, and gasoline (bp 110–125°C)/polystyrene on the styrene‐divinylbenzene macroporous copolymer features was investigated. It was found that the specific surface areas or the porosities of the macroporous copolymers were very sensitive to the modifications of the δ‐parameter values and the monomer composition.
Ein modell zur quantitativen beschreibung der morphogenesis von PVC‐S, I. Modellierung der inneren morphologie — wissensstand
Authors: Weickert Günter , Klodt Rolf‐Dieter , Platzer Bernd , Weißenborn Klaus‐Dieter , Henschel Ines 
Published: April 2003

AbstractDie morphologischen Eigenschaften von PVC‐S‐Pulver (Teilchengrößenverteilung, Schüttdichte, Porosität u. a.) beeinflussen maßgeblich seine Verarbeitungseigenschaften. Das Ziel des ersten Teiles der vorliegenden Arbeit besteht in der kritischen Bewertung wesentlicher Ergebnisse des in der Fachliteratur publizierten Erkenntnisstandes zum PVC‐Kornbildungsprozeß. Einige Autoren untersuchen chemische und physikalische Details dieses Prozesses, während andere Autoren einfache mathematische Modelle zur Pulvercharakterisierung ableiten. Für den praktisch arbeitenden Ingenieur ist jedoch ein Mangel an Informationen zur Modellierung der Morphogenesis von PVC‐S nicht zu übersehen.Die PVC‐S‐Morphogenesis wird als 6‐Stufen‐Prozeß detailliert betrachtet, wobei bisherige Modellvorstellungen ergänzt werden.In den nächsten Teilen dieser Arbeit wird ein praktikables neues Modell zur Berechnung der Größe und Zahl der Teilchen von den Mikrodomänen bis zu den Agglomeraten in den Monomertropfen abgeleitet.