bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neue silikonkautschuke
Authors: Gruber H. , Mössl E. , Kazemi H. , Greber G. 
Published: April 2003

AbstractHydrophilic silicone rubbers have been prepared using allyl derivatives of glucose and sucrose resp. as unsaturated components in crosslinking of commercially avaliable RTV silicone components. Silicone rubbers with good tissue tolerance were obtained by covalent bonding of modified SiO2 fillers to the silicone matrix as well as by application of SiO2 fillers modified with anticoagulants.
Chain architecture and molecular self‐organization of polyurethanes: Perspectives for thermoplastic elastomers
Authors: Eisenbach C. D. , Heinemann T. , Ribbe A. , Stadler E. 
Published: April 2003

AbstractSegmented polyurethanes with a regular chain architecture exhibit very specific self‐organizing properties, often leading to multiphase systems with special phase structures. The study of a series of relatively stiff, monodisperse polyurethane model compounds of various molecularly engineered structures and also multiblock copolymers consisting of an alternating sequence of highly flexible polyether and the above polyurethane segment has shown that extended chain crystallization and chain folding of hard segments and thus the size, shape and ordering of the hard domains can be created and rearranged at will. The molecular design, which can also be applied to graft copolymers, predetermines the possibilities of supramolecular organization. These thermoplastic elastomers exhibit very special properties which correlate sysmatically with the supramolecular structure.
Einfluss des polymerrückgrats auf eigenschaften von thermoplastischen elastomeren
Authors: Schirle Maria , Beckmann Jörg , Stadler Reimund 
Published: April 2003

Abstract4‐Urazoyl benzoic acid groups were statistically attached to various hydrocarbon elestomers, polar elastomers and partially crystalline polymer via a polymer‐analogous reaction. Thermal analysis (DSC), infrared spectroscopy (FT‐IR), stress‐strain experiments and dynamic‐mechanical analysis were used to analyses whether these systems, analogous to functionalized polybutadienes, would form ordered supramolecular structures of the polar side‐groups that would lead to a thermoreversible crosslinking. While the structure formation is suppressed for elastomers with a large cross‐sectional area of the chain(e.g. butyl rubber) or polar side‐groups (e.g. polychloroprene), the mechanical properties can be controlled by balancing supermolecular structure formation and crystallization in the case of polyoctenamer.
Molecular motion, phase separation and internal surfaces in rubberelastic polymers
Authors: Spiess H. W. 
Published: April 2003

AbstractThe highly selective information provided by solid‐state NMR on molecular motions, phase separation and internal surfaces in elastomers is demonstrated by three examples: i. phase separation and interfacial regions in poly(styrene‐b‐methylphenylsiloxane) diblock copolymers, ii. packing effects, phase separation and internal surfaces of the hard segment aggregates in segmented model polyurethanes containing piperazine rings, and iii. interaction of polydimethylsiloxane elastomers with aerosil filler particles.
Preparation and characterization of heat, oil and fire resistant (HOFR) cable sheathing compounds from compatibilized polychloroprene‐ethylene‐propylene‐diene rubber blends
Authors: Kalidaha Amiya K. , De Prajna P. , Bhattacharyya Arabinda S. , Sen Achintya K. 
Published: April 2003

AbstractPreparation of heat, oil and fire resistant (HOFR) cable sheathing compounds is attempted by blending polychloroprene (PCP) and ethylene‐propylene‐diene terpolymer (EPDM) using dibutyl maleate grafted EPDM (EPDMgDBM) and chlorinated polyethylene (CPE) as compatibilizer. Cure rate incompatibility has been minimised by adding the curing agents in masterbatch form. Curing characteristics of the blends have been determined by Monsanto Rheometer and Brabender Plasticorder. Morphology of the blends and compatibility have been studied by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Thermal properties of the blends have been characterized by ageing studies.The optimized blends, after modification with suitable fillers and other ingredients, possess better properties than the control PCP‐compound and meet the specification BS 6899‐84.
Structural and rheological investigation of low density polyethylenes
Authors: Ondáš Miroslav , Špirk Eugen 
Published: April 2003

AbstractSome low density polyethylenes (LDPE) with different melt flow index (MFI) or produced by different producers have been examined in detail by solvent gradient fractionation, 13C NMR analysis, FTIR spectroscopy and melt rheological measurements. It was found that the distribution curves of the samples resemble Wesslau's logarithmic‐normal model. From branching analyses it can be concluded that the branching content in the analyzed LDPEs is independent from the molecular weight. Relations between viscosity curve parameters and molecular structure have been investigated. It has been found that the dependence of the first normal stress difference on the shear stress is influenced by polydispersity as well as by the character of samples branching.
An automated high pressure capillary rheometer with hydraulic drive
Authors: Schurz Josef , Prassl Josef , Ribitsch Volker 
Published: April 2003

AbstractA new capillary rheometer design is described, in which a hydraulic device is used to produce the pressure driving the sample fluid through capillaries. The device is fully automated and controlled by a PC unit. Various measuring modes can be preselected and are automatically executed. Some preliminary results with New tonian fluids and with polymer solutions show the functioning of the new rheometer.
Zinkacrylat und andere feste Monomere als Vernetzungsmittel für ungesättigte Polyester
Authors: Królikowski Wacław , Nowaczek Wiesława , Penczek Piotr , Rudnik Ewa 
Published: April 2003

AbstractDie Peroxid‐initiierte Copolymerisation eines ungesättigten Polyesters mnit Zinkacrylat, Diallylphthalat‐Prepolymer und einem Vinylesterharz wurde untersucht. Der Härtungsverlauf wurde anhand der Gelierungskurven und mitels Differentialkalorimetrie verfolgt. Die Prüfungen zeigten, daß Zinkacrylat die größte Reaktivität hat.
Copolymers of anionic polymerization of octanelactam with laurolactam. II. Kinetics of isothermal crystallization
Authors: Arvanitoyannis I. , Kehayoglou A. H. 
Published: April 2003

AbstractThe isothermal crystallization kinetics of the anionic copolyamides of ω‐octanelactam (OL) with ω‐laurolactam (LL) (nylon‐8/nylon‐12), covering a wide composition range (0/100 – 100/0 OL/LL, mol/mol), was established according to the Avrami equation by the use of differential scanning calorimetry. The crystallization parameters half‐time crystallization (t1/2), Avrami index (n), rate constant (k), and reduced crystallinity were determined for various crystallization temperatures. These parameter values are correlated to the composition of the copolyamides, the crystallization and supercooling temperature, and the results are discussed.Differences in kinetic parameter values between the homopolymers of this paper and those for the hydrolytic nylon‐8 and nylon‐12 reported in literature were observed and discussed.
Zur Optimierung der Synthese von Poly(p‐phenylen‐1,3,4‐oxadiazol) in Oleum
Authors: Leibnitz Eberhard 
Published: April 2003

AbstractDie Reproduzierbarkeit der Synthese von Poly(p‐phenylen‐1,3,4‐oxadiazolen) in Oleum Kann durch eine veränderte Monomerzugabetechnik, gemessen an der Standardabweichung der relativen Lösungsviskosität, um eine Größenordunung verbessert werden. Die Polykondensation verläft unter deutlich milderen Bedingungen in kürzeren Reaktionszeiten zu Polymeren mit höheren Molmassen als nach der bekannten Methode.Der Einfluß verschiedener Parameter auf die Reaktionsgeschwindigkeit und das Polykondensationsgleichgewicht wurde eingehend untersucht. Auf der Basis streulicht photometrischer und viskosimetrischer Messungen an Polymerlösungen in konzentrierter Schwefelsäure wurde eine [η]/Mw‐Bezeihung ermittelt.
Antibacterial activity of copolymers of trialkyl(4‐vinylbenzyl)ammonium chlorides with acrylonitrile
Authors: Senuma Masao , Iwakura Masahiro , Ebihara Shigeyoshi , Shimura Yukio , Kaeriyama Kyoji 
Published: April 2003

AbstractHomopolymers of cetyldimethyl(4‐vinylbenzyl)ammonium chloride (VB16), lauryl‐dimethyl(4‐vinylbenzyl)ammonium chloride (VB12), and trimethyl (4‐vinylbenzyl)ammonium chloride (VB1), and copolymers of these compounds with acrylonitrile were examined for antibacterial activity using B. subtilis, S. aureus, E. coli, and P. aeruginosa. All homopolymers and copolymers showed germicidal action to the bacterias, especially strong action to gram‐positive B. subtilis and S. aureus. The strength of the germicidal action of the quaternary ammonium branches was in the order: VB16 > VB12 ≫ VB1.
A new supertough epoxy formulation with high crosslinking density
Authors: Martuscelli E. , Musto P. , Ragosta G. , Scarinzi G. 
Published: April 2003

AbstractA highly crosslinked thermosetting epoxy resin was modified by a reactive blending process carried out in the presence of bisphenol‐A polycarbonate (PC). FTIR spectroscopy investigations demonstrated that the presence of PC in the blend decreases the reactants conversion after the curing and postcuring processes. Moreover, it was found that the fracture toughness of this blend system increases markedly by increasing the PC content in the blend. No evidence of phase separation of the minor component during the crosslinking reaction steps was observed.
Interpenetrierende Polymernetzwerke aus ungesättigten Polyesterharzen und Dian‐Dicyanat
Authors: Penczek Piotr , Mirkowska Bożenna 
Published: April 2003

AbstractInterpenetrierende Polymernetzwerke (IPN) wurden durch die gleichzeitige Vernetzung ungesättigter Polyesterharze und Dian‐Dicyanat erhalten. Die Copolymerisation von ungesättigtem Polyester mit Styrol erfolgte nach dem radikalischen Mechanismus, während das Dian‐Dicyanat cyclotrimerisierte, wodurch sich ein Polytriazin(Polycyanurant)‐ Netzwerk bildete. Die IPN zeichnen sich durch erhöhte Glastemperatur und mechanische Festigkeit im Vergleich zum entsprechenden ungesättigten Polyesterharz ohne Dian‐Dicyanat‐Zusatz aus.
Preparation and properties of silicon‐containing copolymers for near‐UV resists, II. Poly[(N‐(4‐hydroxyphenyl)maleimide)‐alt‐(p‐trimethylsilyl‐α‐methylstyrene)]
Authors: Chiang Wen‐Yen , Lu Jin‐Yuh 
Published: April 2003

AbstractPoly[(N‐(4‐hydroxyphenyl)maleimide)‐alt‐(p‐trimethylsilyl‐α‐methylstyrene)] (α‐PHTMMS) and several N‐(4‐hydroxyphenyl)maleimide ‐alt‐p‐α‐methylstyrene related copolymers were synthesized for novel positive near‐UV resists containing diazonaphthoquinone sulfonate (DNS). The chain‐stiffening effect of the maleimide group was responsible for high thermal resistance. Thus, a high glass transition temperature of 240°C and thermal decomposition temperature of 425°C were obtained. Lithographic positive images were obtained which resisted thermal deformation at 250°C. The prepared silicon‐containing resists were also used as the top imaging layer of a bilayer resist for microlithographic application.
On the polymerization of styrene in the presence of some benzanthrone dyes
Authors: Konstantinova Temenuschka , Bojadgieva Jordanka 
Published: April 2003

AbstractThe polymerization of styrene in the presence of some fluorescent dyes, benzanthrone derivatives, has been investigated. The dependence of the polymerization rate of styrene on the character of the dye was determined. It was found spectrophotometrically that 70 – 80% of the dye reacted in the polymerization, thus the coloured fluorescent polymers were obtained. They are resistant to wet treatment and decolouration by solvent. The incorporation of the dye into the polymer chain does not significantly affect the molecular weight and polydispersity of the coloured polymers.
The influence of sepiolite on the dynamic moduli and thermal transition of compatible and incompatible blends based on poly(vinylidene fluoride)
Authors: Herrero Consuelo R. , Morales Enrique , Acosta Jose Luis 
Published: April 2003

AbstractThis paper reports on a study of dynamic moduli and thermal transitions of poly(vinylidene fluoride) in compatible blends with poly(methylmethacrylate) and in non‐compatible blends with polystyrene. The effects of sepiolite on the compatibility of these blends have been studied.
Poly(butyl acrylate) inclusive polymerization in the presence of bacterial polyesters, 1. Synthesis and preliminary mechanical and morphological characterization
Authors: Avella M. , Immirzi B. , Malinconico M. , Martuscelli E. , Orsello G. , Pudia A. , Ragosta G. 
Published: April 2003

AbstractLinear polyesters of 3‐hydroxybutyric acid (PHB) and its copolymers with 3‐hydroxyvaleric acid (PHBV) are produced by the fermentation of glucose by the bacterium Alcaligenes Eutrophus1,2. Their large‐scale commerical development is severely limited, until recently, by the prohibitive cost, narrow processability window (Tdeg–Tm), and, above all, the low impact resistance around room temperature and below due to very high crystallinity and relatively high glass transition temperature.This paper reports on an attractive route to impact modification of PHBV by a reactive blending method. Interesting improvements are obtained by using 30 wt.‐% of acrylate rubber. Correlations are found between mechanical response and morphology of blends.
Solid‐state orientation studies on polypropylene disks, 1. Uniaxial compression with non‐lubricated press platens
Authors: Bruce G. D. , Weatherly G. C. , Vancso G. J. 
Published: April 2003

AbstractThe molecular orientation in isotactic polypropylene disks compressed uniaxially in the solid state using non‐lubricated press platens was studied by measuring optical birefringence and infrared dichroism. The orientation profile was inhomogeneous through the disk thickness and was dependent on the radial distance from the disk axis. The results indicate that, near the disk surface, the polymer chains in the crystalline regions are oriented parallel to the radial direction, while the chain direction becomes gradually perpendicular to the disk surface near the mid‐thickness at the disk. There is consequently a continuous rotation of the chain direction in the crystalline phase between these extremes, with the orientation factor going through zero. The formation of this orientation profile is explained by the observed fountain‐flow conditions during the compressive deformation. Mechanical failure of the specimens cut in the radial and in the tangential directions was usually initiated at the mid‐plane of the disks. This unusual behavior was attributed to the predominantly perpendicular orientation of the macromolecules in the polymer crystallites near the mid‐plane of the oriented disks.
Solid‐State orientation studies on polypropylene disks, 2. Uniaxial compression with lubricated press platens
Authors: Bruce G. D. , Snétivy D. , Weatherly G. C. , Vancso G. J. 
Published: April 2003

AbstractThe molecular orientation of isotactic polypropylene disks compressed uniaxially in the solid state using lubricated press platens was studied by measuring optical birefringence, infrared dichroism and wide‐angle x‐ray scattering. Differences in anisotropy obtained by optical birefringence and infrared dichroism were negligibly small throughout the disk at a low overall level of orientation. Pole figures obtained from WAXS measurements showed that the orientation texture developed during the deformation was essentially planar with polymer chains oriented perpendicularly to the compression direction.
New silicone rubbers, 1. Hydrophilic silicone rubbers
Authors: Mössl Eva , Gruber Heinrich , Greber Gerd 
Published: April 2003

Abstract3‐O‐Allylglucose (1), allylglucoside (2) and sucrose‐allylether‐mixtures (3), respectively, protected by trimethylsilyl (TMS)‐groups have been used as unsaturated components in crosslinking of commercially available RTV silicone components. The resulting hydrophobic silicone rubbers were converted into hydrophilic types with covalently bonded sugar residues by hydrolysis to split off the TMS‐groups. Silicone rubbers with glucose residues exhibited equilibrium water contents (EWC) from 2 to 9% dependent on the molar ratio of 1 and 2, respectively, to the Si‐vinyl component. The mixtures 3 can be used as crosslinking agent without additional Si‐vinyl component to give EWC's of more than 30%.
New silicone rubbers, 2. Biocompatible silicone rubbers
Authors: Kazemi‐Shirazi Helen , Gruber Heinrich , Greber Gerd 
Published: April 2003

AbstractBiokompatible silicone rubbers have been prepared using fillers based on two types of modified amorphous silica: (i) silica containing covalently bonded reactive H‐Si‐groups (1) obtained by reaction of silica with methyldichlorosilane, and (ii) silica with covalently immobilized antithrombogenic agent (5), prepared by reaction of 1 with divinylbenzene, graft copolymerization with acrylic acid and subsequent esterification with amylose sulfuric acid esters (2) as a heparinoid.Silicone rubbers (SR's) were obtained by hydrosilation curing of commercially available silicone components using 1 or 5 as fillers. In contrast to 5, 1 is incorporated covalently into the silicone network. Both SR types exhibited good mechanical properties as well as excellent tissue compatibility: contrary to SR's filled with nonmodified silica the cell growth of endothelian cells on the SR's with modified fillers was found to be almost identical to that on cell culture plates.
Zerstörungsfreie Prüfung von Polymeren mittels photothermischer Meßmethoden. 2. Photoakustische untersuchungen von Polyesterfärbungen in Abhängigkeit von der Farbstoffkonzentration und der Oberflächenrauheit
Authors: Eickmeier Achim , Schollmeyer Eckhard 
Published: April 2003

AbstractIm Bereich der textilen Analytik bereitet die Bestimmung der Farbstoffkonzentration dunkler und gesättigter Fäbungen große Schwierigkeiten. Deshalb wird die Einsatzmöglichkeit der photoakustischen Spektroskopie zur Charakterisierung von Fäbungen zn Konzentrationseichreihen systematisch untersucht. Die Meßergebnisse wurden mit einer modifizierten Kubelka‐Munk‐Funktion angepaßt, die über einen größeren Konzentrationsbereich linear verläft als bei der Reflexionsspektroskopie. Weiterhin wurde der Einfluß der Oberflächenstruktur auf das photoakustische Signal untersucht.
Kinetics analysis of the curing of a diepoxy‐diamine system
Authors: Mathieu Christophe , Seytre Gérard , Boiteux Gisèle , Fève Michel 
Published: April 2003

AbstractThe reaction between the diglycidylether of bisphenol A (DGEBA) and 4,9‐dioxa‐1,12‐dodecanediamine (DDDD) has been studied by means of isothermal and dynamic differential scanning calorimetry. The enthalpy of the reaction of an epoxy group with an amino‐hydrogen has been determined to be 112 ± 5 kJ/mol. A kinetic model has been validated. It involves two competitive mechanisms: one is catalysed by the hydroxy groups initially present on the epoxy chain or generated during the reaction (activation energy 77 ± 5 kJ/mol), the other is not catalysed with a higher activation energy (103 ± 3 kJ/mol).For each isothermal curing, the kinetics are not modified by gelation. Evaluated from the gel times, the overall activation energy of the reaction is equal to 62 ± 2 kJ/mol.
New flame‐retardant poly(pyromellitic imide aryl phosphoramide‐ester)s
Authors: Kannan Palaninathan , Kishore Kaushal 
Published: April 2003

AbstractFlame‐retardant poly(pyromellitic imide aryl phosphoramide‐ester)s were synthesized by interfacial polycondensation of N,N′‐bis(p‐hydroxyphenyl)pyromellitic diimide with aryl phosphoramidic dichlorides. The polymers were characterized by IR and 1H‐NMR spectroscopy. The molecular composition was confirmed by elemental analysis. The thermal stability and flammability of the polymers were studied by thermogravimetry and limiting oxygen index, respectively.
Graft copolymers having hydrophobic backbone and hydrophilic branches, 8. Effect of temperature on the dispersion copolymerization of poly(ethylene glycol) macromonomer with styrene
Authors: Riza Medyan , Capek Ignac , Kishida Akio , Akashi Mitsuru 
Published: April 2003

AbstractCopolymerization of poly(ethylene glycol) macromonomers with terminal meth‐acryloyl groups with styrene was carried out in the presence of 2,2′‐azobis(N,N′‐dimethyleneisobutyramidine) in ethanol/water mixture (4:1, v/v) at various temperatures. The overall activation energy for the dispersion copolymerization was obtained as 48 kJ/mol.
Compatibilization of poly(2,6‐dimethyl‐1,4‐phenylene ether)/poly(vinylidene difluoride) blends
Authors: Viersen Frits Jan , Colantuoni Paul , Mamalis Ilias 
Published: April 2003

AbstractStandard available PPE was modified to contain methacrylate‐functional groups. Radical copolymerization of these with methylmethacrylate (MMA) yielded a PPE/PMMA copolymer, suitable as compatibilizing agent in PPE/PVDF blends. Addition of PPE/PMMA copolymers (composition by weight 40/60) at just 5–10 wt.‐% levels gave a very good dispersion of the PVDF minor phase in a PPE/PS matrix. The most effective PPE/PMMA copolymer was found to be the one containing PPE‐pendent chains along PMMA. This copolymer can be made from PPE modified to contain only one methacrylate‐functional group per PPE chain. Adding 10 wt.‐% of this PPE/PMMA copolymer resulted in a blend with thermally stable morphology.
Der Einfluß des Photoinitiators auf die radikalische Härtung von Siliconacrylaten, 9
Authors: Müller Uwe , Vallejos Carlos 
Published: April 2003

AbstractDie photoinduzierte radikalische Vernetzung von Siliconacrylaten wurde mit verschiedenen Photoinitiatoren vom Benzoyltyp untersucht. Die Photovernetzung derartiger Produkte kann mit Hilfe eines radikalischen Kettenprozesses beschrieben werden. Aus kalorimetrischen Messungen folgt, daß Sauerstoff den Kettenprozeß inhibiert und terminiert, wobei dei Vernetzungsgeschwindigkeit und die Inhibierungszeit Funktionen des Luftdrucks, der Lichtintensität und der Quantenausbeute der Initiatrophotolyse sind.Der Vernetzungsprozeß kann nur beginnen, wenn der Sauerstoff in der Schicht verbraucht ist. Mit Hilfe des 1. Fickschen Diffusionsgesetzes kann gezeigt werden, daß der in das System eindiffundierende Sauerstoff auch den Grenzumsatz bestimmt.Obwohl Sauerstoff in der Schicht die Reaktionsgeschwindigkeit, die Inhibierungszeit und den Grenzumsatz bestimmt, wurde jedoch überraschenderweise festgestellt, daß Sauerstoff auf die Netzwerkdiche keinen Einfluß besitzt.Der negative Effekt des Sauerstoffs auf den Vernetzungsprozeß kann durch eine hohe Startgeschwindigkeit (Funktion der Lichtintensität, der Absorption und der Quantenausbeute der Initiatorphotolyse) reduziert werden.Mit Hilfe von zwei kinetischen Methoden wurde ermittelt, daß die Initiierungseffizienzen der verwendeten Initiatoren verschieden sind, wobei relative Abstufungen bestimmt werden konnten.