bluuebunny/crossref_metadata_2025_split huggingface dataset:
Graft polymerization of acrylonitrile onto chemically modified bleached jute fibers
Authors: Mohanty A. K. , Misra M. 
Published: April 2003

AbstractThe graft polymerization of acrylonitrile (AN) onto chemically modified bleached jute fibers has been studied using potassium peroxydisulfate‐ferrous ammonium sulfate redox initiating system. The effects of time of reaction, variation in concentration of monomer, peroxydisulfate, ferrous ammonium sulfate and sulfuric acid on graft yield have been studied. The effects of temperature, amount of jute fibers, some inorganic salts and organic solvents on graft yield have also been investigated. Grafted jute has been characterized by IR spectra. Grafting has improved the light fastness of jute dyed with Rhodamine B dye.
Lichtinduzierte Polymerisation, 4. Pfropfcopolymerisation von Methylmethacrylat auf Polyethylenoxid in Gegenwart von Chinolinderivaten
Authors: Braun Dietrich , Hettig‐Rupaner Claudia 
Published: April 2003

AbstractBei Verwendung von Polyethylenoxid (PEO) als polymerem Wasserstoffdonator werden bei der lichtinduzierten Polymerisation von Methylmethacrylat mit Chinolinderivaten Pfropfcopolymere erhalten. Die Abtrennung dieser Pfropfcopolymeren von dem ebenfalls entstehenden homopolymeren Polymethylmethacrylat (PMMA) und Resten an nicht umgesetztem PEO kann durch aufeinander folgende Extraktionen mit Ethyl‐acetat und Methanol erreicht werden. Damit ist eine Bestimmung von Pfropfausbeute, Pfropfungsgrad, Pfropferfolg und Pfropfhöhe möglich.
Zur Häurtung von Bisphenol‐A‐diglycidether mit Dicyandiamid in Gegenwart von Beschleuniger‐Addukten
Authors: Sanftenberg Heike , Fedtke Manfred 
Published: April 2003

AbstractEinkomponentige Epoxidharzsysteme mit effizienten Reaktionsbeschleunigern müssen lagerstabil sein. Daher wurden Versuche unternommen, Beschleuniger auf Basis von tertiären Aminen mit modifizierten Phenolnovolaken zu blockieren. Das Ausmaß der Blockierung ist sowohl von der Basizität der Amine, die mit der beschleunigenden Wirkung korreliert, als auch von der Acidität und dem strukturellen Aufbau der modifizierten Phenole abhängig. Die Bewertung der Härtungseigenschaften erfolgte über Gelzeitbestimmungen und Viskositätsmessungen.
Comparison of the crack growth method and the crack stress whitening zone method for the fracture toughness determination of phenolphthalein poly(ether ketone)
Authors: Han Yanchun , Yang Yuming , Li Binyao , Feng Zhiliu 
Published: April 2003

AbstractFracture toughness values of phenolphthalein poly(ether ketone) (PEK‐C) at 190°C were determined by two different methods, i.e. the conventional crack growth method and the crack stress whitening zone method, which show consistent results. This indicates that the crack stress whitening zone method can be used to determine the crack initiation of some polymers for which the blunting line concept is unsuitable.
Thermodynamic studies on some interpolymer interactions and stability of polycomplexes
Authors: Chatterjee S. K. , Nigam Shalini , Chhabra Mamta 
Published: April 2003

AbstractStability constant and related thermodynamic parameters (ΔH° and ΔS°) of a multicomponent intermacromolecular complex consisting of poly(acrylic acid‐coacrylamide), poly(methacrylic acid‐co‐acrylamide) and poly(N‐vinylpyrrolidone) have been determined using known methods. A distinct stepwise disintegration of the complex at different temperatures has been observed, and this could be correlated with the stability constant and thermodynamic parameters calculated at various temperatures.
Synthesis and characterization of cellulose/N‐methylolacrylamide/glycidyl methacrylate/methacrylic acid cation exchange resins
Authors: Abo‐Shosha M. H. , Ibrahim N. A. 
Published: April 2003

AbstractNew cation exchange resins based on cellulose/N‐methylolacrylamide (NMA)/glycidyl methacrylate (GMA)/methacrylic acid (MA) were prepared by polymerizing highly concentrated mixtures of NMA/GMA/MA in the presence of cellulose using a sodium persulfate/sodium sulfite redox system under different conditions including the concentrations of the redox system components, NMA and GMA as well as the polymerization temperature. Polymerization conditions were selected to synthesize three resins of different carboxy and nitrogen contents. Potentiometric titration showed that these resins were weakly basic cation exchangers of different strength. Water solubility and swellability as well as durability of these resins were examined.
Diffusion characteristics of vinyl chloride from PVC in slurry phase
Authors: Erbay Erol , Bilgiç Tülin 
Published: April 2003

AbstractThe porous nature of poly(vinyl chloride) (PVC) brings along the problem of residual vinyl chloride in the final product. Stripping techniques are developed to eliminate vinyl chloride to the desired levels. After a certain extent of monomer removal, the stripping rate of vinyl chloride is limited by diffusion. Therefore, the diffusion characteristics of vinyl chloride from PVC slurries was investigated. Stripping was carried out at the boiling point of water where the generated steam was used as a carrier substance. The boiling point of water was changed by elevating the pressures. The dependence of diffusion on concentration is put forward and the activation energy of diffusion was calculated.
Ein neues niedrigviskoses nichtreaktives verdünnungsmittel für epoxidharze
Authors: Večeřa Miroslav , Mleziva Josef 
Published: April 2003

AbstractFür manche Anwendungsgebiete liegt die Viskosität von Epoxidharzen zu hoch. Sie läßt sich jedoch durch den Zusatz von verschiedenen Verdünnern herabsetzen. Der Einfluß von 1,1‐Diphenylethan (DPE) auf die Viskosität und Reaktivität entsprechender Harzmischungen sowie auf die Eigenschaften gehärteter Proben wurde untersucht und mit anderen Verdünnungsmitteln verglichen. Epoxidsysteme mit DPE zeigten eine wirksame Erniedrigung der Viskosität, hohe chemische Beständigkeit und weitgehend unveränderte mechanische, thermische und elektrische Eigenschaften.
Interpenetrating polymer networks derived from epoxide‐amine adducts in either polymer network
Authors: Klee Joachim E. , Leube Walter , Mülhaupt Rolf 
Published: April 2003

AbstractA new type of interpenetrating polymer network was synthesized via photoinitiated free‐radical polymerization of α,ω‐methacryloyl terminated macromonomers prepared from epoxide‐amine‐adducts, followed by thermal addition polymerization of bisphenol‐A diglycidyl ether and 4,4′‐diaminodiphenylsulfone or 3(4),8(9)‐bis(aminomethyl)tricyclo[5.2.1.0.2,6]decane. The interpenetrating polymer networks are optically transparent and show only one glass transition temperature ranging from ‐10 to 130°C, as a function of the macromonomer/addition polymer mixing ratio. The presence of a single phase was confirmed by scanning electron microscopy (SEM).
Purification of soybean trypsin inhibitors by means of chromatographic methods
Authors: Bryjak Marek , Bryjak Jolanta 
Published: April 2003

AbstractThe paper presents comparative studies on chromatographic purification of soybean trypsin inhibitors (STI) applying various polymer matrices. Two types of copolymers were tested: a copolymer of butyl acrylate with ethylene glycol dimethacrylate, and a terpolymer of acrylonitrile and butyl acrylate crosslinked with divinylbenzene. The investigations revealed that a similar purification extent is achieved in affinity chromatography with trypsin attached to both copolymers and in ion exchange chromatography when the matrices are aminated with ethylene diamine. The purification phenomenon was not so high for both unmodified matrices, and quite negligible for matrices hydrophilized by end‐capping with tris(hydroxymethyl)aminomethane.
Polyurethanes and polyurethane cationomers bearing nitroaromatic groups and their photobehavior
Authors: Buruianǎ T. , Airinei A. , Buruianǎ E. C. , Robilǎ G. 
Published: April 2003

AbstractElastomer‐type polyether urethanes and polyether urethane cationomers with nitroaromatic groups were prepared and the effect of UV irradiation on their characteristics was evaluated comparatively with a model compound. The photobehavior by UV irradiation with a high‐pressure Hg lamp was studied in solution, following the change of absorption bands characteristic for nitro structures as a function of irradiation time. UV irradiation causes diminution of the intensity of characteristic UV absorption bands and a decrease of molecular weight.
Synthesis and copolymerization of vinyl cobalt(III)porphyrins
Authors: Anaç Olcay , Sezer Özkan , Daut Ayşe 
Published: April 2003

Abstract2‐Diazopropane and 1‐diazo‐1‐phenylethane were reacted with meso‐tetraphenyl‐porphin cobalt(III) bromide (Co(III)TPPBr), and the resulting vinyl Co(III)TPP derivatives were copolymerized with MMA to give alkyl Co(III)TPP complexes, covalently bound to macromolecules.
Poly(esterbenzoxazinone)s derived from 4,4′‐diaminodiphenylmethane‐3,3′‐dicarboxylic acid
Authors: Hamciuc Corneliu , Bruma Maria , Popescu Florin , Gaspar Mariana 
Published: April 2003

AbstractPoly(esterbenzoxazinone)s were prepared in two successive steps from 4,4′‐diaminodiphenylmethane‐3,3′‐dicarboxylic acid and aromatic diacid dichlorides which contained preformed ester groups, via polyamic acids as intermediates. The poly(esterbenzoxazinone)s are soluble only in concentrated sulfuric acid. They thermally decompose in a single step between 400 and 500°C.
Poly(phenylquinoxaline‐imide‐amide)s containing perfluoroisopropylidene units
Authors: Hamciuc Elena , Bruma Maria , Mercer Frank W. , Belomoina Nataliya M. , Simionescu Cristofor I. 
Published: April 2003

AbstractPoly(phenylquinoxaline‐imide‐amide)s have been synthesized by solution polycondensation of aromatic diamines containing preformed phenylquinoxaline units with diacid dichlorides incorporating preformed imide rings and perfluoroisopropylidene units. These polymers show high thermal stability; they decompose above 400°C and have glass transition temperatures in the 225–290°C range. Comparison of these compounds with related heterocyclic polymers leads to the conclusion that the decomposition of the former ones begins with the destruction of amide groups. Films prepared from polymer solutions showed good electrical insulating properties, comparable to those of a standard film (Film H). The highest quality of these poly(phenylquinoxaline‐imide‐amide)s is their remarkable solubility in polar aprotic solvents, which is very important for practical applications.
Removal of polymerization inhibitors from styrene based on adsorption
Authors: Matsas G. M. , Faliagas A. C. , Simitzis J. C. 
Published: April 2003

AbstractUse of adsorptive materials for the removal of polymerization inhibitors from styrene is studied. The adsorptive materials selected cover a wide range of properties and structure. The most important inhibitors that are used in laboratory and industrial scale were studied. The effectiveness of the adsorptive materials was assessed by determining the inhibitor uptake at equilibrium. It was found that activated carbons are the most effective adsorbents for the removal of inhibitors from styrene and that the factor most affecting adsorption is the polarity of the adsorbent and the adsorbate. The possible importance of removing the inhibitor before industrial‐scale polymerization is demonstrated.
Kinetic study and crosslink density in styrenebutadiene rubber compounds filled with boron‐amine‐modified silica
Authors: Elvira M. Rosario , Macías Antonio , Oteo José Luis , Royo Joaquín , Rubio Juan 
Published: April 2003

AbstractVulcanization kinetics and crosslink density of styrene‐butadiene rubber compounds have been studied with two vulcanization systems, an efficient (EV) and a conventional (CV) one. A surface‐modified silica with boron‐amine groups (SiOB(NH2)2) was employed as filler. Untreated and modified silica with two silanes (γ‐mercaptopropyl‐trimethoxysilane and γ‐aminopropyl‐triethoxysilane) have been used as reference.The best kinetic parameters, such as highest vulcanization rate, longest induction time and lowest activation energy, were obtained for the compound with boronaminated silica. The crosslink density, achieved with this compound, is similar to that with silane‐modified silica, probably because of the better surface distribution of boron‐amine groups on the silica. These facts lead to important technological improvements: better processing safety, faster vulcanization rate and improved physical properties.
Hyper‐crosslinked sorbents for hemoperfusion
Authors: Kolarz Bozena N. , Jermakowicz‐Bartkowiak Dorota 
Published: April 2003

AbstractPore structure changes of swelling sorbents, which were obtained from styrene and divinylbenzene (DVB) by additional crosslinking with α,α′‐dichloro‐p‐xylene in the presence of tin chloride catalyst and in dichloroethane solution, were examined. It was found that the amount of dichloroxylene influences the swelling decrease and the increase of sorption ability of sorbents for chemical compounds with low molecular weight. Hemocompatibility was imparted to the sorbent and it was useful for hemoperfusion when a small amount of sulfonyl groups (about 0.2 mmol/g) had been introduced.
Epoxidation of poly(cis‐1,4‐isoprene) microgels
Authors: Hallensleben Manfred L. , Schmidt Henning Rüdiger , Schuster Robert H. 
Published: April 2003

AbstractPoly(cis‐1,4‐isoprene) microgels and crosslinked natural rubber latex as well as noncrosslinked poly(cis‐1,4‐isoprene) were epoxidized by means of 3‐chloroperbenzoic acid and H2O2, respectively.Epoxidation of the latex leads to homogeneous functionalized polymer particles whereas the feature of the microgels which were obtained from the reaction in organic phase is a shell‐like profile of epoxidation. By variation the time of exposure of the microgels to the organic solvent prior to the epoxidation reaction, different profiles of epoxidation in the microspheres could be achieved.
Synthesis and properties of a cellulose exchanger with the crown ether diaminodibenzo‐17‐crown‐5 as anchor group
Authors: Beck E. W. , Lieser K. H. 
Published: April 2003

AbstractA new cellulose exchanger was synthesized from “o‐aminophenolcellulose” by diazotation and coupling with diaminodibenzo‐17‐crown‐5. The distribution coefficients for Ca2+, Sr2+, Ba2+, Na+ and K+ were determined in water/methanol mixtures as a function of the water content. Separation of Ca2+, Na+ and K+ and fractionation of the calcium isotopes 48Ca and 40Ca were investigated. The enrichment factor ε = 4.9 · 10−3 for 48Ca2+ is appreciably higher than that found for cation exchange resins with SO3H groups, but lower than that reported for certain cryptands.
Adhesion promotion for epoxy resin/copper and polyimide/copper joints by a two‐component coupling system of poly(4‐vinylimidazole) and cystamine
Authors: Dai Q. , Lu Y. 
Published: April 2003

AbstractA two‐component coupling agent layer on copper, produced by immersion of copper in poly(4‐vinylimidazole) solution and then in cystamine solution, showed better anticorrosive performance and higher adhesive strength for epoxy resin and polyimide than each single component even at high temperature.
The izod impact fracture behaviour of phenolphthalein poly(ether ketone)
Authors: Han Yanchun , Li Binyao , Yang Yuming , Feng Zhiliu , Wang Xuhui 
Published: April 2003

AbstractThe Izod impact fracture behaviour of notched specimens of phenolphthalein poly(ether ketone) (PEK‐C) has been studied over a temperature range from room temperature to 240°C by using an instrumented impact tester. The temperature dependence of the maximum load, total impact energy, initiation energy, propagation energy, ductility index (DI) and the relationships between these parameters and the relaxation processes have been investigated.
Cross‐linking reactions on polyamides by bis‐ and tris(maleimide)s
Authors: Kossmehl Gerhard , Nagel Hans‐Ingo , Pahl Andreas 
Published: April 2003

Abstract12 bis‐ and tris(maleimide)s were synthesized and characterized and their reactions with polyamides in the melt were examined. It was found that the double bonds of the maleimides react with terminal amino groups of the polyamides to form elastomeric networks. The chemical and physical properties of these elastomers were examined. Mixtures of bis‐ and tris(maleimide)s with amino‐terminated polyamides can be applied as hot melt adhesives with high tensile and shear strength, with high thermal stability and high chemical resistance.
Synthesis and characterization of liquid‐crystalline polyesters based on biphenyl‐4,4′‐diol
Authors: Haridas K. R. , Radhakrishnan Ganga 
Published: April 2003

AbstractThe syntheses of liquid‐crystalline polyesters of biphenyl‐4,4′‐diol and 1,4‐butanediol with adipic acid were carried out by varying the mole ratios of the two diols, keeping the total mole ratio of diacid to diols constant. Adipic acid was first converted into adipoyl dichloride, which was then reacted with the diol(s) in dimethylformamide. The resultant polyesters were characterized by means of 1H NMR and FT‐IR spectroscopy, elemental analysis, thermogravimetric analysis and gel permeation chromatography. The liquid‐crystalline behavior of the polyesters was studied by differential scanning calorimetry and hot‐stage polarization microscopy.
Differential scanning calorimetry and thermal gravimetric analysis of lignin blended with triglycidyl isocyanurate
Authors: De Chirico Aurelio , Audisio Guido , Provasoli Francesco , Schieroni Alberto Giacometti , Focher Bonaventura , Grossi Barbara 
Published: April 2003

AbstractThe thermal behaviour of lignin blended with triglycidyl isocyanurate (TGI) was investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) over a range of lignin contents from 0 to 85 wt.‐%.DSC thermograms of lignin/TGI blends show two exothermic peaks at about 250 and 355°C while TG analysis in nitrogen bears evidence of a single loss of weight at about 360°C. The first exotherm is suggested to correspond to the heat of bulk reaction between epoxy groups of TGI with phenolic hydroxy groups of lignin, and the second one to the heat of char formation of lignin. TG and infrared analyses suport this conclusion.
Hydrogels based on 3‐O‐acryloyl‐1,2;5,6‐di‐O‐iso‐propylidene‐α‐D(‐)‐glucofuranose
Authors: Koßmehl Gerhard , Volkheimer Jürgen , Schäfer Horst 
Published: April 2003

AbstractHydrogels (crosslinked polymers with a defined water content) based on 3‐O‐acryloyl‐1,2;5,6‐di‐O‐isopropylidene‐α‐D(‐)‐glucofuranose and 2‐hydroxyethyl methacrylate were prepared by radical copolymerization and acid hydrolysis of the isopropylidene protecting groups. The obtained hydrogel samples were examined for linear expansion to hydration, weight‐percent hydration, refractive index, extractables, percent transmission of visible light and oxygen permeability as typical properties for contact lens materials.
Poly(diaryl diazosulfide)s — synthesis and photolysis. Photopolymers, diazosulfides, interfacial polycondensation, photolysis
Authors: Nuyken O. , Lang A. , Staško A. , Wokaun A. 
Published: April 2003

AbstractPoly(diaryl diazosulfide)s were synthesized from aromatic bisdiazonium ions and benzene‐1,3‐dithiol via interfacial polycondensation. Number‐average molecular weights Mn in the range of 3400 to 11700 were determined by gel permeation chromatography (GPC).The new polymer class is distinguished by high photosensitivity and low thermostability. First order kinetics during photolysis of nearly all polymers and model compounds under investigation was observed by means of UV spectroscopy. Polymer degradation upon irradiation was verified by GPC measurements. Thermal decay was followed by differential scanning calorimetry (DSC).
Synthese schmelzspinnfähiger copolyoxadiazole für hochtemperaturbeständige faserstoffe
Authors: Strubl Rüdiger , Seyfarth Hans‐Eberhard , Taeger Eberhard 
Published: April 2003

AbstractPoly(p‐phenylen‐1,3,4‐oxadiazol) entsteht aus Terephthalsäure und Hydrazinsulfat in Oleum und kann aus Schwefelsäurelösung durch Naßspinnen zu Faserstoffen mit hervorragender Temperaturbeständigkeit und guten textilphysikalischen Eigenschaften verformt werden. Da das Polymere weder schmilzt noch in ülichen organischen Lösungsmitteln löslich ist, steht bisher kein ökonomisch und ökologisch günstiges Verarbeitungsverfahren zur Verfügung. Ziel der vorliegenden Untersuchungen war die Synthese schmelzspinnfähiger Copolyoxadiazole durch chemische Modifizierung. Dazu wurden Dicarbonsäuren als Comonomere eingesetzt, die die Beweglichkeit der Polymerketten erhöhen und die zwischenmolekulare Wechselwirkung beeinflussen.Die Cokondensation mit hinreichend stabilen Dicarbonsäuren erfolgte in Oleum order in einem Gemisch aus Amidosulfonsäure und Schwefelsäure. Völlig ohne Schwefelsäure entstehen Copolyoxadiazole aus Dihydraziden und Dichloriden auf dem Weg über die Polyhydrazide. Von den synthetisierten Copolyoxadizolen erwiesen sich solche als erweichungs‐ und schmelzfähig, die neben Terephthalsäure noch Isophthalsäure und ein oder zwei weitere Dicarbonsäuren enthalten. Gute Ergebnisse wurden mit 5‐Carboxypentyl‐N‐trimellitimid und anderen Dicarbonsäuren cyclischer Imide mit aliphatischen Segmenten erzielt. Eine zusätzliche Senkung der Erweichungs‐ und Schmelztemperatur gelang durch geringe Anteile an aliphatischen Dicarbonsäuren. Mit Bromterephthalsäure entstanden schmelzfähige Copolymere ohne aliphatische Kettensegmente. Die Erweichungs‐ und Schmelztemperaturen lagen zwischen 220 und 375°C. Die TG‐Analyse zeigte einen nur geringen Abfall der Thermostabilität im Vergleich zum Homopolymeren. Ausgewählte Copolyoxadiazole wurden in einer Kolbenspinneinrichtung verarbeitet. Die Fäden waren zum Teil spröde, andere flexibel und reckfähig.
Activation of the high pressure polymerisation of ethylene initiated with organic peroxides by means of organoaluminium compounds
Authors: Luft Gerhard , Batarseh Brigitte , Dorn Maximilian 
Published: April 2003

AbstractIn the course of this study, an activator system consisting of an aluminium trialkyl compound and a Lewis base was tested for its suitability for the radical polymerisation of ethylene at high pressure. The aim of reducing the initiator consumption and the polymerisation temperature was achieved with aluminium trialkyl alone without the use of a Lewis base.Among the aluminium trialkyl compounds examined, triethyl aluminium proved to be the most effective. This effectiveness is due to the increased rate of decomposition of the peroxide as a result of which a larger amount of free radicals becomes available thus increasing the rate of polymerisation. By using an addition of 50 mole ppm triethyl aluminium to 50 mole ppm tert‐butyl‐perpivalate in the ethylene feed it was possible to almost double the monomer conversion at a given polymerisation temperature and to reduce by half the consumption of peroxide initiator per kg polyethylene produced. Compared with the non‐activated polymerisation, the polymerisation temperature was reduced from 150°C to 125°C, the initiator consumption remaining the same. The costs of the triethyl aluminium activator are more than offset by the increased yield and the decrease in initiator consumption.