bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the determination of the molecular weight distribution of poly(dimethyl diallyl ammonium chloride) by ultracentrifugation
Authors: Timofejeva G. J. , Pavlova S. A. , Wandrey Ch. , Jaeger W. , Hahn M. , Linow K.‐J. , Görnitz E. 
Published: April 2003

AbstractMolecular weight distributions of poly(dimethyl diallyl ammonium chloride) were determined from sedimentation velocity measurements. After a presentation of the experimental basis for the evaluation of distribution curves, molecular weight distribution curves for different samples were discussed and compared with results of solution fractionations and kinetic‐mechanistic investigations.
Poly(methacryloyloxyalkylenoxybenz‐4‐′‐substituierte‐anilide)
Authors: Ruhmann R. , Rübner J. , Rodekirch G. , Zschuppe V. , Gnauck R. , Netopilik M. , Wolff D. 
Published: April 2003

AbstractSynthese und Eigenschaften einiger Poly(methacryloyloxyalkylenoxybenzoesäure‐4′‐subst.‐anilide) werden beschrieben. Das Ziel der Synthese, Polymere mit flüssigkristallinen Eigenschaften zu erhalten, wird insbesondere durch Copolymerisation mit anderen Methacrylaten erreicht.
Influence of cooling conditions on the structure and properties of high‐speed spun polypropylene fibres
Authors: Diačik I. , Diačik I. , Jambrich M. 
Published: April 2003

AbstractThe influence of blasting speed of cooling air on the structural parameters and physical properties of polypropylene fibres spun with take‐up speeds of 1000 to 5000 m/min is investigated and discussed.
Polyesterification of 1,3‐di(carboxymethoxy)benzene with tetraethylene glycol
Authors: El‐Safty M. A. , Shaaban A. E. , Moustafa H. Y. 
Published: April 2003

AbstractThe polyesterification of 1,3‐di(carboxymethoxy)benzene with tetraethylene glycol in both equimolar and nonequimolar ratios has been studied over the range of 120 to 160°C in the absence and in the presence of p‐toluenesulphonic acid as catalyst. The experimental results for uncatalyzed reactions agreed quite well with the kinetic equations proposed by Flory. The kinetic equations for acid catalyzed reactions, however, are in agreement with the kinetic equation proposed by Lin and Hsieh. The rate constants and activation energies for the uncatalyzed and acid catalyzed reactions were calculated.
Kinetical structural model for the network build‐up during the reaction of cyanic acid esters with glycidyl ethers. 2. Application of DCBA/DGEBA‐systems
Authors: Bauer J. , Bauer M. 
Published: April 2003

AbstractThe previously published kinetical structural model is applied to the network build‐up during the coreaction of 2,2‐bis(4‐cyanatophenyl) propane with 2,2‐bis(4‐glycidyloxyphenyl) propane in bulk. The relative rate constants of the main reactions, which act as the free parameters of the model, were identified for this case, and the good agreement between theory and experiment is shown.
Grafting of acrylamide onto guar gum with the redox system Cu2+/Na2S2O5
Authors: Bajpai U. D. N. , Jain A. , Bajpai A. K. 
Published: April 2003

AbstractThe grafting of acrylamide onto guar gum in aqueous medium initiated by the redox system Cu2+/Na2S2O5 in presence of oxygen has been studied at the temperature 35°C. The effect of the concentration of the components of the grafting system and of the reaction temperature has been determined. A plausible mechanism of the grafting process is suggested.
Biologisch abbaubare Polymere. 2. Mitt.: Zur Homo‐ und Copolymerisation von D,L‐Dilactid
Authors: Rafler G. , Dahlmann J. 
Published: April 2003

AbstractDie Ringöffnungspolymerisation des D,L‐Dialactids bzw. einer äquimolaren Dilactid/Digglycolid‐Mischung wurde in Gegenwart von Sn‐II‐octoat untersucht. Umsatz und Molmasse werden nicht nur durch die Kinetik der primären Ringöffnungsreaktion, sondern auch durch Intensität und Ausmaß von Folgereaktionen der reaktiven Gruppen des gebildeten Polyesters determiniert. Parallel zur Polymerbildung laufen inter‐ und intramolekulare Umesterungsreaktionen binnenständiger Estergruppen untereinander bzw. mit Endgruppen sowie irreversible Thermolysereaktionen ab.
Kinetics and mechanism of the emulsion polymerization of vinyl acetate by redox initiation
Authors: Badran A. S. , Shendy S. M. M. 
Published: April 2003

AbstractThe emulsion polymerization of vinyl acetate initiated by the redox system potassium persulfate‐salieylaldehyde sodium bisulfite with poly(vinyl alcohol) as emulsifier has been studied at different reaction conditions. The rate equation for the polymerization process is established and discussed.
Zur Verknüpfung von Siloxanen mit Epoxidharzen. 2
Authors: Schickert P. , Heller A. , Rühlmann K. 
Published: April 2003

AbstractDas Aushärtungsverhalten von Gemischen eines Methylphenylsiliconharzes und eines Phenolnovolak‐Epoxidharzes mit Al(acac)3 als Katalysator wurde anhand von Gelzeit‐ und DSC‐Messungen charakterisiert. Aus dem Zusammenhang zwischen Gelzeit, Härtungsbeginn, spezifischer Reaktionsenthalpie und der Zusammensetzung der Gemische wird geschlossen, daß zum Beginn der Härtung bevorzugt Reaktionen von Silanolgruppen mit Oxiran‐Resten, bei der weiteren Vernetzung jedoch in hohem Maße auch Umsetzungen von alkoholischen OH‐Gruppen mit Epoxid‐Resten ablaufen. Es werden Hinweise für die optimale Zusammensetzung von Silicon‐Epoxidharz‐Bindemitteln und für geeignete Verarbeitungstemperaturen gegeben.
Condensation polymers based on acenaphthene derivatives
Authors: Korhsak V. V. , Rusanov A. L. , Jedlinski Z. , Raubach H. , Palivoda A. , Bocharov S. S. , Bulycheva E. G. , Berlin A. I. , Shifrina Z. B. , Batirov I. , Shalikiani M. O. 
Published: April 2003

AbstractThe reactions involving acenaphthene and its derivaties resulting in the synthesis of various classes of mononmers, namely, bis(naphthalic anhydride)s, bis(acenaphthoquinone)s, bis(acenaphthylene)s, containing various bridging groups, are considered. The synthesized monomers have been shown to be applicable for the preparation of poly‐(naphthylimide)s, poly(naphthyoylenebenzimidazole)s, poly(quinoxaline)s, and poly(acenaphthylene)s combining good thermal characteristics and good processibility.
Phosphorus containing monomers, oligomers, and polymers from itaconic acid esters and dialkyl phosphites
Authors: Doseva V. N. , Borisov G. 
Published: April 2003

AbstractDialkyl esters of 2,3‐dialkoxycarbonyl propane‐phosphonic acid have been synthesized by addition of dialkyl phosphites to dialkyl esters of itaconic acid. The transesterification of these compounds with diols has been investigated with the aim to compare the reactivity of the two kinds of alkoxy groups. Unsaturated oligoesters have been synthesized by transesterification of dimethyl itaconate with ethylene glycol and diethylene glycol. Dimethyl phosphite has been added to their double bonds.
Phosphorus‐containing fire resistant polymers on the basis of cardotype bisphenols
Authors: Sh. Papava G. , Vinogradova S. V. , Kutateladze M. K. , Papava K. R. , Borisov G. , Verbanov S. 
Published: April 2003

AbstractAromatic homogeneous and mixed polyethers were synthesized on the basis of interaction of cardotype bisphenols, 4,4′‐difluorohenylsulfone and methyl‐bis(chloromethylphosphine) oxide. The presence of phosphorus atoms in the main polymer chain increases the fire resistance of these of polymers.
Kinetic and structural effects in matrix acceptor‐catalytic polyesterification
Authors: Ignatov V. N. , Vasnev V. A. , Perov A. B. , Vinogradova S. V. 
Published: April 2003

AbstractThe regularities of the acceptor‐catalytic copolyesterification in the presence of poly(4‐vinyl pyridine) and its low‐molecular analog γ‐picoline have been studied. The rate constant of the reaction is determined by the molecular mass of the polymer catalyst and by the concentration of the reagents.
Synthesis and investigation of the properties of aromatic polymers prepared by using samarium diiodide
Authors: Brandukova N. E. , Vygodski Ya. S. , Vinogradova S. V. , Raubach H. 
Published: April 2003

AbstractNew poly(α‐diketone)s were prepared by the reaction of aromatic dicarboxylic acid chlorides and samarium diiodide in tetrahydrofurane under mild conditions. The influence of the reaction conditions on the chemical structure and the properties of the resulting polymers has been studied. In a similar manne p‐fluorobenzoic acid chloride and samarium diiodide were used to obtain 4,4′‐difluorobenzil whose reaction of nucleophilic substitution with bisphenol A gave poly(ether‐α‐diketone)s.
Different unit structure of copolymers obtained by polycondensation of asymmetric monomers
Authors: Papava K. R. , Vasnev V. A. , Vinogradova S. V. , Markova G. D. 
Published: April 2003

AbstractThe influence of the reactivities of the functional groups of asymmetric and symmetric monomers and of the reaction conditions on the microstructure of the formed polyesters has been investigated. A quantitative estimation is presented for the different unit structure of the polycondensation interbipolyesters obtained from asymmetric monomers characterized by two types of isomers. The microstructure depends on the sequence of introduction of the comonomer units into the reaction system.
Polyaddition von Dian‐Diglycidylether mit Butin‐2‐diol‐1,4
Authors: Penczek P. , Szczepaniak B. , Rejdych J. 
Published: April 2003

AbstractDie Polyaddition von niedermolekularem Dian‐Epoxidharz mit Butin‐2‐diol‐1,4 wurde bei 80 bei 130°C mit Triethanolamin als Katalysator durchgeführt. Die Reaktion verläuft ähnlich der Polyaddition der Bisphenole mit Epoxidharz bei Harzüberschuß. Als Endprodukte entstehen Diepoxid‐Oligomere, die in der Kette CC Bindungen enthalten.
Formation of molecular‐weight distribution of alicyclic polyimides in one‐ and two‐phase polycondensation
Authors: Pavlova S. A. , Timofeeva G. I. , Zhubanov B. A. , Solomon V. A. , Yu. Sapozhnikova S. , Lyakh E. N. 
Published: April 2003

AbstractWith the methods of sedimentation, fractionation, and viscosimetry the influence of the reaction conditions on the molecular weight distribution of alicyclic polyimides is investigated. Under homogeneous conditions the most probable distribution occurs, whilst in the case of a two‐phase system the molecular weight distribution tends to narrow in comparison with the most probable one. The obtained data are in good agreement with the theory of the two‐phase polycondensation.
Mechanism of polycondensation of polyimides
Authors: Sazanov Yu. N. , Antonova T. A. , Stepanov N. G. , Blazo M. , Toth A. , Szekei T. 
Published: April 2003

AbstractUnder conditions of high temperature, polyimides and their prepolymers undergo a number of chemical transformations, the most part of which relate to reaction of polycondensation. New aspects of thermal cyclodehydration in the presence of heteroaromatic compounds used as stereospecific catalysts were studied. The mechanism of thermal decarboxylation and decarbonylation of polyimides under conditions of heating in inert and self‐generating atmosphere was ascertained. A study of the polycondensation processes leading to the formation of ordered domains in polyconjugated products of high temperature thermolysis was carried out. The principal parameters of the thermochemical transformation of the polyimide structure depending on the chemical nature of the polyimide unit were determined by means of the kinetics of the structural changes of the basic fragments of polyimide series. The role of nitrogen atoms in the formation of the turbo‐straticulate centres in the products of polyimide thermolysis is discussed.
Synthesis of new poly(phenylquinoxaline‐ester‐imide)s
Authors: Bruma M. , Sava I. , Hamciuc C. , Simionescu C. I. , Belomoina N. M. , Babich S. A. , Krongauz E. S. 
Published: April 2003

AbstractNew poly(phenylquinoxaline‐ester‐imide)s have been synthesized by solution polycondensation of certain dianhydrides containing performed ester groups with aromatic diamines incorporating phenyl‐substituted quinoxaline units. The thermal stability as well as the dielectric properties of these compounds are discussed and compared with those of related heterocyclic polymers.
The synthesis and investigation of thermostable soluble polybenzazoles
Authors: Izyneev A. A. , Varga J. , Mazurevskaya Sh. P. , Novak I. S. , Mazurevsky V. P. , Mognonov D. M. , Radnaeva L. D. 
Published: April 2003

AbstractThe poly(benzimidazole)s and poly(amidobenzimidazole)s produced on the base of different tetramines, diphenylate of dicarboxylic acids, and ε‐caprolactam or diamines are investigated. In the synthesis were used 3,3′‐diaminobenzidine or aromatic tetramines containing methylene, oxygen, or sulfon groups between the benzene cycles. The produced polymers are thermostable, soluble, and have high enough molecular weights.
Synthesis of new N,N′‐bisimides for thermostable polymers
Authors: Mognonov D. M. , Radnaeva L. D. , Varga J. , Tsyrennimaev V. Z. , Erzh B. V. , Izyneev A. A. , Golovach G. I. 
Published: April 2003

AbstractNew N,N′‐bisimides were synthesized by condensation of polynuclear aromatic diamines with maleic anhydride. The obtained N,N′‐bisimides are crystalline yellow‐coloured compounds, soluble in acetone, dioxan, amidic solvents, organic and inorganic acids. Their structure was identified by elemental analysis, NMR and IR spectroscopy. The N,N′‐bisimides were polycondensated with diamines in cresol solution to high polymers.
SAXS study of polyamide 6 swollen in methanol
Authors: Baldrian J. , Pleštil J. 
Published: April 2003

AbstractThe effect of the annealing temperature on the structure of unoriented polyamide 6 was studied by swelling in methanol and small‐angle X‐ray scattering. The observed values of mean‐square fluctuations of scattering density can be explained by using a model with an inhomogeneously swelling amorphous phase. An increase in the annealing temperature improves the internal structure of the lamellae and reduces coarseness of their surface. The concentration of polymer chains in the centre of the swollen amorphous interlayer strongly decreases.
Charakterisierung diolmodifizierter Epoxidnetzwerke mittels viskoelastischer Messungen
Authors: Wolff D. , Havránek A. , Schlothauer K. , Fedtke M. 
Published: April 2003

AbstractDie viskoelastischen Eigenschaften von diolmodifizierten Epoxidnetzwerken auf der Basis von Bisphenol‐A‐Diglyeidether wurden in Abhängigkeit von der Probenzusammensetzung für zwei verschiedene Beschleuniger, Magnesiumperchlorat und N,N‐Dimethylbenzylamin, untersucht und im Zusammenhang zur Netzwerkstruktur diskutiert.
Discrete strength spectrum of natural silk fibres
Authors: Tsoj B. , Karimov C. N. , Lukashov A. V. , Feofanov V. V. 
Published: April 2003

AbstractWith filaments of natural silk a discrete spectrum of tlie levels of strength was observed. These levels correspond to nine discrete length values of microtlefects, calculatecl by tlic formulas of failure mechanics. There is a clear correlation with the data of x‐ray measurements. The levels of strength are not affcctctl by temperaturc antl scale factor. From the results it coulcl be conclutled that tlie effect of sample size and of external actions on the filanieut consists in the redistributinii of the strength levels.
Synthesis of polyetherols with s‐triazine ring catalyzed by tetrabutylammonium hydroxide
Authors: Kucharski M. , Lubczak J. 
Published: April 2003

AbstractSome results of invesgitations of the synthesis of polytherols with s‐triazine ring by reaction of melamine with oxiranes using tetrabutylammonium hydroxide as catalyst are presented. The physico‐chemical properties of the products have been examined. By means of analytical methods, infrared and 1H‐NMR spectroscopy the structure of the compounds has been determined.
Permanganate/malonic acid initiated polymerization of acrylamide and methacrylamide
Authors: Behari K. , Gupta K. C. , Raja G. D. , Das P. 
Published: April 2003

AbstractThe kinetics of aqueous polymerization of acrylamide and methacrylamide using the redox pair potassium permanganate and malonic acid was studied. It was found that the order of the polymerization reaction is 0.5 with respect to permanganate and malonic acid, respectively, and 1.0 with respect to the concentration of the monomers. Polymer samples were prepared under different conditions, and their viscosity average molecular weights were determined. A plausible mechanism for the explanation of the experimental results is proposed.
Zu einigen Besonderheiten der Struktur von Kompositen aus Polyethylen und Polystyren
Authors: Bogdanov B. , Mihailov M. , Ilieva I. 
Published: April 2003

AbstractDie bei der Kristallisation von Mischungen aus Polyethylen und ataktischem Polystyren entstchenden Strukturen wurden im Lichtmikroskop untersucht. Charakteristische Unterschiede wurden gefunden, wenn die Polystyrenkomponente auf das Polyethylen aufgepfropft ist.
Further studies on the stability of polystyrene suspensions
Authors: Carrique F. , Salcedo J. , Cabrerizo M. A. , González‐Caballero F. , Delgado A. V. 
Published: April 2003

AbstractA device and method have been developed for the precise determination of the time evolution of the stability of suspensions. The technique is applied to the study of suspensions of well characterized spheres of polystyrene. The change with time of the light absorption properties of the studied systems were detected by computer control of the spectrophotometer employed. The experimental results, shown as stability of the suspensions as a function of KCl, CaCl2 and La(NO3)3 concentrations, are discussed in the light of the theoretically calculated curves of interaction energy between polystyrene spheres from DLVO theory. A very good agreement as represented by critical coagulation concentration is found between theory and experiment for the three electrolytes employed.
Concentration dependence of the sedimentation coefficient of poly(amidobenzimidazole)
Authors: Tarabukina E. B. , Slavina Z. N. , Frenkel S. Ya. 
Published: April 2003

AbstractThe concentration dependence of the sedimentation coefficient of poly(amidobenzimidazole) solutions in the neutralized form in DMAA and in the hydrochloride form in DMAA +0.3% LiCl has been investigated. With the aid of this dependence, the molecular weights Mks and the coefficients (1‐b) in the equation S0 = K = M1–b for these two systems were determined. The values of Mks obtained here agree with those obtained from sedimentation‐viscometric and sedimentation‐diffusion measurements. The macromolecules in both systems show different rigidities.
Poly(N‐vinyl pyrrolidone) as a template for the radical polymerization of 4‐vinyl pyridine
Authors: Awasthi Sanjay K. , Srivastava A. K. 
Published: April 2003

AbstractThe coefficient of interaction between poly(N‐vinyl pyrrolidone) and poly(4‐vinyl pyridine) is determined in solutions of the mixture of these two polymers in different solvents. The results show the complexation of the polymers. Maximum complexation occurred at molar ratio 1:1. The kinetics and mechanism of polymerization of 4‐vinyl pyridine in dimethylformamide with poly(N‐vinyl pyrrolidone) as a template is investigated.
Novolak phenol‐aldehyde oligomers as components for photoresists. Synthesis and modification
Authors: Dimitrov V. , Miloshev S. , Novakov P. 
Published: April 2003

AbstractThe paper presents a review of articles dealing with the synthesis and modification of novolak phenol‐aldehyde oligomers as components for the production of photoresists published in the period from 1976 till 1988. The catalysts and the reaction conditions of the synthesis of movolak oligomers using different phenols are discussed. The relationship between the initial components, reaction conditions and molecular weight characteristics of the obtained novolak oligomers is described. The modification of the novolak oligomers in order to improve their behaviour during alkaline development and etching is considered.
Influence of annealing on the dielectric properties of poly(vinylidene fluoride(0.98)‐co‐tetrafluoroethylene (0.02))
Authors: Wolak J. , Kulek J. 
Published: April 2003

AbstractMeasurements of dielectric properties and thermally stimulated discharge current were carried out for poly(vinylidene fluoride(0.98)‐co‐tetrafluoroethylene(0.02)) modified by polarization and annealing at high temperature. After polarization the polar β‐phase of PVDF appears. Annealing influences dielectric absorption connected with β‐α phase transformation. The increase of temperature sensitivity, monitored by dielectric measurements, in connection with decrease of tan δ forecasts the improvement of pyro‐ and piezoelectric properties.
Über die strahlenchemische Vernetzung von Halogenphenolnovolaken und Halogenphenolnovolak‐Bisazidgemischen
Authors: von Lampe I. , Wäsche M. , Lippitz A. , Lorkowski H.‐J. 
Published: April 2003

AbstractXPS‐Untersuchungen und die Bestimmung der Elektronenstrahlempfindlichkeit an Halogenphenolnovolak‐Resistschichten ergaben, daß ein Vernetzungsmechanismus über Halogeneliminierung abläuft. Durch Bisazidzusatz wird der Vernetzungseffekt erhöht. Die strahlenchemisch induzierte Halogeneliminierung der untersuchten 4‐Halogenphenolnovolake steigt in der Reihenfolge Fluor‐Chlor‐Brom‐Iod.
Infrared study of polyethylene membranes during the gas diffusion process
Authors: Bratu I. , Mercea P.‐V. 
Published: April 2003

AbstractThe structural modifications of a polyethylene membrane caused by simultaneous action of strain deformation and the diffusion of argon or argon plus dioxan vapours through the membrane were studied with polarized IR light. For the interpretation of the results it was assumed that the absorption of the radiation depends on the orientation of the macromolecular chains of the sample and on the nature of the gases which diffuse through the membrane.
Ionotropic gels of alginate polyelectrolyte. I. Potentiometric determination of the ionization constant of alginic acid polyelectrolyte in relation to sol‐gel transformation mechanism
Authors: Hassan Refat M. , Abd‐Alla Mohamed A. 
Published: April 2003

AbstractThe ionization constant of alginic acid as anion polyelectrolyte has been determined potentiometrically at a constant ionic strength of 1.0 mol dm−3. The experimental observations showed that alginic acid takes up 5.4 mequ. Na+/g at pH = 3.3 and the pK is 2.93 at 25°C. The mechanism of sol‐gel transformation in relation to the ionization constant is discussed.
Physical and chemical properties of acrylamide polymers and copolymers. Review
Authors: Myagchenkov V. A. , Kurenkov V. F. 
Published: April 2003

AbstractThe physical and chemical properties of acrylamide polymers and copolymers in aqueous, aqueous‐salt, and aqueous‐organic media are analysed. The main emphasis is given to the assessment of the effect of the medium quality on the conformation state of the macromolecules in the solution. Particular attention is directed to acrylamide polymers and copolymers with ionogenic groups, as these exhibit most interesting features of synthesis and a complex of solution properties.
The processing and structure of composites of isotactic polypropylene and atactic polystyrene with a high dispersion of the polystyrene component
Authors: Pluta M. , Milczarek P. , Włochowicz A. , Kryszewski M. 
Published: April 2003

AbstractHeterogenic polymeric systems of polypropylene and polystyrene with different morphology have been obtained by UV initiated polymerization of liquid styrene within polypropylene matrices of controlled molecular and supermolecular structure. The influence of styrene treatment and its polymerization in situ on the crystalline structure of the polypropylene matrix is determined, and the correlation between the initial structure of the matrix and the dispersion of the polystyrene component is shown.