bluuebunny/crossref_metadata_2025_split huggingface dataset:
The reaction of 1‐cyano‐1‐methylethyl radical with antidegradant ethoxyquin and its aminyl and nitroxide derivatives
Authors: Taimr Luděk , Šmelhausová Marcela , Prusíková Miluše 
Published: April 2003

Abstract6‐Ethoxy‐2,2,4‐trimethyl‐1,2‐dihydroquinoline (ethoxyquin, I) does not react with the model alkyl radical, 1‐cyano‐1‐methylethyl, in an inert atmosphere. On the other hand, its aminyl derivative (II) reacts readily with the model alkyl radical; the main product of this reaction is 6‐ethoxy‐8‐(1‐cyano‐1‐methylethyl)‐2,2,4‐trimethyl‐1,2‐dihydroquinoline (V), while 6‐ethoxy‐1‐(1‐cyano‐1‐methylethyl)‐2,2,4‐trimethyl‐1,2‐dihydroquinoline (VI) is formed as a by‐product. 6‐Ethoxy‐2,2,4‐trimethyl‐1,2‐dihydroquinoline‐N‐oxyl (III) also effectively deactivates the model alkyl radical to form 6‐ethoxy‐ 8‐(1‐cyano‐1‐methylethoxy)‐2,2,4‐trimethyl‐1,2‐dihydroquinoline (X).It follows from these results that I is an ineffective antidegradant in oxygen‐free atmosphere. However, at very low oxygen concentrations, I becomes capable of deactivating alkyl radicals. Together with its ability to deactivate alkylperoxide radicals, this explains the high antifatigue activity of I.In the presence of silica gel, V is readily cyclized to 8‐ethoxy‐1,2,3,4‐tetrahydro‐2‐imino‐1,1,4,4,6‐pentamethylpyrrolo[3,2,1‐ij]quinoline (VIII). VI undergoes thermal decomposition into its components, i.e., aminyl II and the model radical. Photodecomposition of X on silica gel yields 6‐ethoxy‐2,2,4‐trimethyl‐8‐quinolone (XIII).
Magnetic properties of metal layer deposited by reduction of polymer containing metal ions
Authors: Yosomiya Takatoshi , Sato Yoshihiro , Yosomiya Ryutoku 
Published: April 2003

AbstractMagnetic properties of metal layer deposited by reduction of polymer containing metal ions were investigated.Varying the ratio of the cobalt ion to the nickel ion in the polymer, the coercivity, the maximum flux density and the remanent flux density of the deposited metal layer were changed from 100 to 600 Oe, from 1 000 to 12 600 G and from 500 to 7 600 G, respectively. The X‐ray diffraction pattern of the metal layer with excellent magnetic properties gives distinct peaks corresponding to the (101) and (100) planes of the crystal of α‐Co.This suggests that such a deposited metal layer has the structure of highly crystalline metal layer.
Preparation and characterization of a mercaptan derivative of chitosan for the removal of mercury from brines
Authors: Argüelles‐Monal W. , Peniche‐Covas C. 
Published: April 2003

AbstractChitosan, [(1,4)‐2‐amino‐2‐deoxy‐β‐D‐glucan], was reacted consecutively with epichlorohydrin and thiourea. Subsequent hydrolysis of the isothiouronium salt yielded the mercaptan derivative of chitosan, which scavenges mercury ions from solution in the presence of a considerably high concentration of chloride ions.Sulfur contents varied with reacting conditions and reached values up to 7.3%. The derivative is insoluble due to partial crosslinking of chitosan during the reaction with epichlorohydrin and was characterized by IR spectroscopy, solid‐state 13C NMR, thermal analysis and pyrolysis‐mass spectrometry.
Phenomenological model for the unified studies of different physical properties of polymers
Authors: Dutta Tapati , Biswas Prabir Kumar 
Published: April 2003

AbstractA phenomenological model has been proposed to understand the development of strong anisotropy in physical properties of semicrystalline polymers on uniaxial drawing. The proposed model introduces temperature as an explicit parameter in the orientation function. The model contains two free parameters for each polymer which can be evaluated by fitting the experimental data on birefringence versus draw ratio at a particular temperature. The calculated values of elastic moduli, thermal conductivity and expansibility along and perpendicular to the drawing direction over the entire range of draw ratio and a wide range of temperature are in good agreement with experimental values.
Radical polymerization of mono‐ and di‐methacrylic esters containing bisphenol‐S
Authors: Liaw Der‐Jang , Teng Kuei‐Fei 
Published: April 2003

AbstractRadical polymerizations of mono‐ and di‐methacrylic esters containing bisphenol‐S (BPS‐M and BPS‐DM) were studied in terms of polymerization rate, solvent effect, copolymerization and kinetic measurements of photocrosslinking. The solvents were found to affect significantly the polymerization rate. Polar solvents such as DMSO and acetonitrile were found to slow down the polymerization rate. Copolymerization of BPS‐M(M1) with MMA(M2) was studied in acetone at 60°C. The monomer reactivity ratios were calculated to be r1 = 3.72 ± 0.01 and r2 = 0.80 ± 0.01 by the Fineman‐Ross method. The high reactivity of BPS‐M observed in this copolymerization system may be due to the “matrix effect”. Functional polymers containing methacrylate side‐groups were successfully modified and photocrosslinked by irradiation in the presence of benzoin isopropyl ether. The photocrosslinking process is found to be of second order kinetics.
Syntheses and reactions of photopolymers, I. New photosensitive azo monomers, photolysis, interfacial polycondensation, viscosity measurements, photodegradation
Authors: Nuyken Oskar , Dauth Jochen , Stebani Jürgen 
Published: April 2003

AbstractThe synthesis of new, unsymmetrically functionalized azo compounds and their incorporation into polymers is described. Their photochemical decomposition and thermal stability was studied by UV spectroscopy and differential scanning calorimetry (DSC), respectively. Chemical degradation was followed by viscosity measurements.
Thermal analysis of oxime‐blocked toluene diisocyanates
Authors: Kothandaraman Harimurthi , Thangavel Ramasamy 
Published: April 2003

AbstractOxime‐blocked toluene diisocyanates were synthesized and characterized by infrared spectra, nuclear magnetic resonance spectra, elemental analysis etc. Thermal analyses of blocked isocyanates were done by thermogravimetry. Solubility of blocked isocyanates in various polyols was tested. Formation of isocyanate on heating the blocked isocyanate was identified by gas chromatographic analysis.
Preparation of porous ion‐exchange membranes from sulfonated polyethylene/poly(styrene‐co‐divinylbenzene)
Authors: Bryjak Marek , Trochimczuk Witold M. 
Published: April 2003

AbstractIt was shown that the etching of styrene‐divinylbenzene copolymer from KESD‐2 type ion‐exchange membranes resulted in porous membranes. Modification of such membranes introduced both acidic or basic groups onto the pore surface. The ultrafiltration of bovine serum albumin through these membranes was mostly affected by coulombic interaction. Protein deposition on/in membrane was controlled by charge as well as hydrophilic properties of membranes. In addition, the effect of polystyrene crosslinking degree on the blend morphology was explained. The structure of polystyrene copolymer underwent the qualitative threshold when the crosslinking agent concentration reached the level of 2 wt.‐%.
Water‐soluble polyamides as potential drug carriers, VI. Synthesis of amine‐ and carboxyl‐functionalized carrier polymers by high‐temperature solution polymerization in polyphosphoric acid
Authors: Swarts Jannie C. , Neuse Eberhard W. , Perlwitz Axel G. , Stephanou Andreas , Lamprecht Gert J. 
Published: April 2003

AbstractHydrophilic polyamides containing amino or carboxyl groups in the repeat units suitable for drug binding are synthesized by polycondensation of aliphatic dicarboxylic acids, including succinic acid, iminodiacetic acid, and ethylenediaminetetraacetic acid (reacting as a difunctional monomer in these polymerizations), with diamines, such as diethylenetriamine, 1,2‐bis(3‐aminopropylamino)ethane, and the two hydrosolubilizing poly(ethylene oxide) derivatives, α,ω‐bis(2‐aminopropyl)poly(ethylene glycol) 800 (Jeffamine ED‐900) and α,ω‐bis(2‐aminopropyl)poly(ethylene glycol) 1900 (Jeffamine ED‐2001). The reactions are conducted in polyphosphoric acid medium at the optimal temperature range of 150–165°C. The product polymers, fractionated by aqueous‐phase dialysis in 12000–14000 molecular‐mass cut‐off membrane tubing, are isolated by freeze‐drying. Yield data, ranging from 1% to nearly 40% for the material so fractionated, indicate low propensity for polycondensation under these conditions for the volatile diethylenetriamine monomer, and only moderately better performance for the thermally labile Jeffamines, yet satisfactory polymerization behaviour for the bis(aminopropylamino)ethane. The microanalytically and spectroscopically characterized polyamides fulfil the biomedically important requirement of solubility in water; inherent viscosities in this medium are in the approximate range of 5–15 ml · g−1. The drug‐anchoring capabilities of these polymers will be the subject of forthcoming publications.
Determination of carbon black fillers in vulcanizates of natural rubber by metathesis degradation
Authors: Hummel Klaus , Kiattanavith Nilubol , Bernard Erich 
Published: April 2003

AbstractA method for the determination of carbon black fillers in peroxide vulcanizates or sulfur vulcanizates of natural rubber (NR, cis‐1,4‐polyisoprene) by metathesis degradation with 1‐octene was developed using the catalyst WCl6(C2H5)3Al2Cl3. The carbon black was separated from the reaction mixture by centrifuging and determined by weighing.In this connection, investigations were also performed with the catalyst WCl6C2H5Al2Cl3 which was less suitable for filler determination. The rate of degradation of crosslinked NR with (E)‐4‐octene was measured. Metathesis reactions of 2‐methyl‐2‐pentene (low‐molecular‐weight model compound of NR) with 7‐tetradecene showed the importance of double bond shift for the degradation of NR.
Radical terpolymerization of ethylene, methyl acrylate and vinyl acetate under high pressure. Physical properties of the polymers
Authors: Luft Gerhard , Stein Franz , Dorn Max 
Published: April 2003

AbstractPolymerization tests were carried out in a stirred autoclave designed for continuous operation in order to determine the influence of the reaction pressure and temperature and of the acrylic acid methyl ester and vinyl acetate comonomers on the ethylene‐acrylic acid methyl ester‐vinyl acetate terpolymer formed. Pressures between 1100 and 1900 bar and temperatures of 180 and 230°C were used. The average residence time was 40 seconds. Tertiary butyl perpivalate and tertiary butyl perethyl hexanoate in concentrations of 50 to 180 mol‐ppm in the ethylene feed were used as initiators. The characteristic properties of the polymers obtained were assessed by determining their composition, density, crystallinity, melting point, glass transition temperature, melt index, the average molecular weight, tensile strength and elongation at break.
Linear polythioesters, XXIII. Products of interfacial polycondensation of 4,4′‐dimercaptobiphenyl with acid dichlorides
Authors: Podkoscielny Wawrzyniec , Tarasiuk Bogdan 
Published: April 2003

AbstractNew polythioesters were obtained by interfacial polycondensation of 4,4′‐dimercaptobiphenyl with selected aliphatic and isomeric phthaloyl dichlorides.To determine the optimum polycondensation conditions, the influence of the following factors on reduced viscosity and yield were studied: type of organic phase, concentration of hydrogen chloride acceptor, type of catalyst, reaction temperature and rate of acid dichloride addition.A thorough examination was carried out only for the polycondensation of dithiol with isophthaloyl dichloride chosen as a model system. The structures of polythioesters were determined by elemental analysis, X‐ray and infrared spectra. The temperature of initial decomposition, the percentage of its mass loss, and temperature of the fastest decomposition process were determined from curves of differential and thermogravimetric analysis.Some physicochemical, mechanical and electrical properties were determined. The molecular weights were not measured because of the low solubility of the obtained polythioesters.
Cationic surface modification by polyelectrolytes: Polyelectrolyte complex formation at inorganic particle surfaces
Authors: Oertel Ulrich , Schwarz Simona , Buchhammer Heide‐Marie , Petzold Gudrun , Jacobasch Hans‐Jörg , Rätzsch Manfred 
Published: April 2003

AbstractThe surface charge of inorganic finely dispersed materials like diatom earth, perlite, glass or clay may be changed from negative to positive by the adsorption of cationic polyelectrolytes. Different materials exhibit equivalent electrokinetic surface properties with high amounts of the polycation adsorbed. Interfaces modified this way are able to adsorb anionic dye stuffs. Their adsorption capability for the dye stuff may be enhanced by addition of polyanions due to the formation of a nonstoichiometric polyelectrolyte complex (PEC) and therefore an increased number of cationic centres in the interface. Experimental results indicate that the zeta potential is correlated to the outer PEC layer whereby dye stuff adsorption measurements are sensitive for the more inner surface regions, too. Immediately after modification, materials modified with poly(diallyldimethylammonium chloride) and poly(maleic acid‐co‐α‐methylstyrene) have negative zeta potentials at high excess of added polyanion and a positive one after separation of the solid. This behaviour is attributed to the formation of a nonstoichiometric PEC with polycation in excess and reversible interaction with polyanion in the surrounding solution. Experimental results indicate that the surface may act as “solid‐like” polyelectrolyte in competition to the polyanion.
Photooxidative ageing of low density polyethylene. Kinetics determined by an electrical method
Authors: Jelčić Ž. , Mlinac‐Mišak M. , Jelenčić J. , Bravar M. 
Published: April 2003

AbstractThe efficiency of light stabilizers is investigated by electric methods in the initial stage of photooxidative ageing of low density polyethylene (LDPE). Three types of UV light stabilizers are tried to improve the UV stability of LDPE: a phosphite type (3,9‐bis‐[(2,4‐di‐tert‐butyl)phenoxy]‐2,4,8,10‐tetraoxa‐3,9‐diphosphaspiro[5.5]undecane) a benzophenone type [2‐hydroxy‐4‐octyloxy‐benzophenone] and a stabilizer based on chelate salt [2,2′‐thiobis(4‐tert‐octyl phenolato) (n‐butylamine) nickel (II)]. LDPE is very susceptible to ultraviolet light. UV light stabilizers improve the stability of low density polyethylene for electrical applications, especially the UV stabilizer based on chelate salt.
The interfacial polycondensation of tetrabromobisphenol‐A polycarbonate. I. Model reaction and mechanism studies
Authors: Gu Jen‐Tau , Luo Wei‐Chen , Wang Chun‐Shan 
Published: April 2003

Abstract2,2′,6,6′‐Tetrabromobisphenol‐A (TBBPA), a sterically hindered bisphenol, is known to give only low‐molecular‐weight polymers using the interfacial phosgenation process. The low reactivity is attributed to the bulkiness and electron‐withdrawing character of bromine substituents at the ortho positions. From the formation of carbamate products in model compound (2,4,6‐tribromophenyl chloroformate, TBPC) reactions with trialkylamines, the trialkylamine catalyst was found to act as a terminator by the degradation of the chloroformate‐trialkylamine complex. The generation of carbamate occurs through the decomposition of the acyl ammonium salt proceeding via nucleophilic displacement by Cl− at the carbon attached to the positive nitrogen center. The relative catalytic abilities of trialkylamines and pyridine derivatives were determined in the homogeneous (dichloromethane) and interfacial (dichloromethane/water) systems. From the results of model reactions with TBPC and sodium tribromophenolate, 4‐dimethylaminopyridine (DMAP) was found to be the best catalyst.
The effects of temperature and ionic strength on the cooperative binding of C.I. Basic red 18 with carboxymethyl cellulose
Authors: Pak Soo‐Min , Borsa Judit , Iijima Toshiro 
Published: April 2003

AbstractThe effects of temperature and ionic strength of a solution of C. I. Basic Red 18 on the cooperative interaction with carboxymethylcellulose were investigated by the dynamic dialysis method and the binding parameters were determined. The molecular model of the cooperative binding is presented.
Effect of some phosphorous compounds on the thermo‐oxidative stability of poly(ethylene terephthalate)
Authors: Karayannidis George , Sideridou Irini , Zamboulis Demetris , Stalidis George , Bikiaris Demetris , Wilmes Aloyse 
Published: April 2003

AbstractA series of poly(ethylene terephthalate) (PET) samples was prepared from dimethyl terephthalate and ethylene glycol. In each sample a phosphorous compound was added as heat stabilizer after the transesterification and before the polycondensation. These compounds were: phosphoric acid, tributyl phosphate, triphenyl phosphate, phenyl‐phosphonic acid, phenylphosphinic acid, and sodium phenylphosphinate. Firstly, their interference with the transesterification catalyst was examined. Their stabilization effect was estimated by DSC analysis in nitrogen and air. Various thermal criteria have been used, such as stabilization coefficient and induction period of oxidation. Under the conditions used for polymerization, the more efficient stabilizers were tributyl phosphate, phenylphosphonic and phenylphosphinic acid.
Composites from furfuryl alcohol and inorganic solids by cationic initiation, 3. Scanning electron microscopic investigations of solid poly(furfuryl alcohol)‐silica composites
Authors: Spange Stefan , Winkelmann Heinz , Martinez Ricardo 
Published: April 2003

AbstractComposites of poly(furfuryl alcohol) grafted onto silica, with different percentage of grafting, have been investigated by scanning electron microscopy, elemental analysis and UV/Vis‐reflectance spectroscopy. The size of the silica particles used for the coating procedure is not changed till a percentage of grafting to around 30%. A content of polymer higher than 35 wt.‐% enhances the bonding between the particles due to the crosslinking of poly(furfuryl alcohol) on the surface with those in solution leading to the agglomeration of the particles. A general model of cross‐linked poly(furfuryl alcohol)‐silica composites is suggested.
Electrical conductivity changes of polymers with conjugated double bonds induced by exposure to vapors and gases
Authors: Bischoff Gerlinde , Schmidt Werner F. 
Published: April 2003

AbstractExposure of polyacetylene, polypyrrole, poly(phenylacetylene), and poly‐p‐phenylene to oxidizing or reducing gases and vapors leads to changes of their electrical conductivity which can be explained by a three step model involving as a first step adsorption at the surface, as a second step diffusion into the bulk of the material and as a third step irreversible chemical changes due to reaction between the dopant and the polymer chain. These three regimes are sometimes well separated in time. During the adsorption regime, the conductivity change is reversible with respect to removal of the vapor atmosphere by evacuation.
Permeation‐fließanalyse an polymernetzwerken
Authors: Häusler Karl‐Georg , Kretzschmar Timo 
Published: April 2003

AbstractEs wurde eine Permeationsmeßzelle zur fließanalytischen Detektion des Permeationsstromes durch gequollene Polymernetzwerke entwickelt. Diese Apparatur ermöglicht es, den Permeationskoeffizienten P und den Diffusionskoeffizienten D an gequollenen Polymernetzwerken zu messen.Die eingesetzten Proben, 1,4‐cis‐Polybutadien (Buna cis 132) und Polysiloxan (Wacker SilGel 600), wurden β‐strahlenchemisch bzw. thermisch vernetzt und mittels Quellungsmessungen, Sol‐Gel‐Analyse sowie Messung des uniaxialen Kompressions‐modules Gccharakterisiert. Die Molmassen der unvernetzten Ausgangsprodukte wurden mit der Gelpermeationschromatographie (GPC) ermittelt.Die aus dem stationären Permeationsverlauf berechneten Permeationskoeffizienten und Diffusionskoeffizienten korrelieren linear bzw. exponentiell mit der Vernetzungs‐dichte bzw. dem Volumenquellungsgrad der Proben im Quellungsgleichgewicht.
Influence of crosslinking density of poly(butylacrylate) backbone on processibility of poly(vinylchloride) grafted onto poly(butylacrylate)
Authors: Zhang Xiaochun , Wang Luoli , Qian Baogong 
Published: April 2003

AbstractGraft copolymers of vinyl chloride onto poly(butylacrylate) with alternating amount of diallylphthalate crosslinker (PBA‐g‐VC) have been synthesized by suspension polymerization. Taking into account different crosslinking density of PBA, the processing behaviour of PBA‐g‐VC was studied with a Brabender Plasticorder and a viscoelastometer. The experimental results showed that, with increasing crosslinking density of PBA, the processing behaviour of PBA‐g‐VC improved initially, then reached an optimum and finally declined with further increase in crosslinking density of the backbone. Based on the results of viscoelastometer measurement, the mechanism of change of processibility of graft copolymer is discussed.
Vinyl ester resins, 3. Effect of ethyl methacrylate on thermal and mechanical properties
Authors: Choudhary Manjeet S. , Varma Indra K. 
Published: April 2003

AbstractThis paper describes the effect of ethyl methacrylate (EMA) on the thermal and mechanical properties of glass fibre‐reinforced laminates of vinyl ester resins derived from diglycidyl ether of bisphenol‐A and methacrylic acid. The thermal stability and the curing characteristic of the resins were investigated by thermogravimetric analysis and differential scanning calorimetry. The glass transition temperature of the laminates decreased with increase in EMA content. Dilution of vinyl ester resin with EMA resulted in a decrease in flexural strength and flexural modulus of the laminates.
α,ω‐Bis(2,3‐epoxypropyl)oligooxyethylene‐based crosslinked resins as solid‐liquid phase‐transfer catalysts
Authors: Dimonie Mihai , Teodorescu Mircea 
Published: April 2003

Abstractα,ω‐Diglycidyl‐oligoethylenoxides were prepared by reacting α,ω‐dihydroxy‐oligoethylenoxides with epichlorohydrin. They were then crosslinked with triethylenetetramine to form catalyst beads which were tested for their liquid‐solid phase‐transfer catalyst activity in the reaction of 1‐bromobutane with potassium phenoxide. Regardless of the oxyethylene chain length, the catalyst beads showed significant activity, which was relatively high for oligomers with a great number of oxyethylene repeating units.
The effects of radiation‐modified silica and monomeric diluents on the properties of dental composite resins
Authors: Hsiue G. H. , Chang H. L. 
Published: April 2003

Abstract2,2‐Bis[4‐(2‐hydroxy‐3‐methacryloyloxy‐propoxy)phenyl]propane (Bis‐GMA) was used as the main ingredient for a dental composite. The dental composite was prepared by mixing high viscosity Bis‐GMA with a low‐viscosity diluent monomer. Three monomers were used: triethylene glycol dimethacrylate (TEGDMA), trimethylol propane trimethacrylate (TMPTMA), and trimethylol propane triacrylate (TMPTA). The mixed components were allowed to polymerize under visible light. The degree of conversion was higher for the sample with lower viscosity. The silica which was used as filler in the dental composite was modified by using the radiation‐induced polymerization method in which methyl methacrylate (MMA) was grafted onto the silica gel. The higher the content of PMMA in the modified filler, the lower the hardness of the composite. Most properties of the samples are the same as those of a commercial product. The compressive strength is higher due to the strong filler‐matrix interface which is provided by 60Co γ‐ray radiation.
GPC investigation of polyimide‐siloxane copolymers. Calibration procedure
Authors: Szesztay M. , Ghadir M. 
Published: April 2003

AbstractGel permeation chromatography calibration of ultra‐styragel columns for additive polyimide‐siloxane copolymers was developed using peak assignments. The results show that polystyrene (PS) calibration can be used with good approximation for the samples of molar masses higher than 1000 g mol−1.