bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poly(ester‐ether) fibres
Authors: Varma D. S. , Maheswari A. , Gupta V. , Varma I. K. 
Published: April 2003

AbstractEster‐ether copolymers were prepared by melt condensation reaction using dimethyl terephthalate (DMT) and different quantities of ethylene glycol (EG) and poly(ethylene glycol) (PEG) (MW 400) in the initial monomer feed. Five copolymer samples were prepared by varying the contents of PEG on the basis of EG from 0.5 to 2.5 mol‐%. The polymer samples were characterized by determination of melting points (mp) and intrinsic viscosities. The mp decreased from 258°C to 248°C on increasing the poly(ethylene oxide) segments in the backbone.Thermal stability of the copolymers also decreased by the introduction of PEG units in the backbone. The polymers were melt spun into fibres. With the increase of PEG in the copolymer fibres a decrease in tensile strength and initial modulus was observed while the elongation increased. The dye uptake and moisture regain of the copolyester fibres was considerably enhanced in comparison of poly(ethylene glycol terephthalate) (PET) fibres.
Reactive polymers, XXX. The synthesis of 2‐hydroxypropylene dimethacrylate in a mixture with glycidyl methacrylate and their copolymerization to a macroporous product
Authors: Švec F. , Labský J. , Lányová L. , Hradil J. , Pokorný S. , Kálal J. 
Published: April 2003

AbstractA method has been developed for direct preparation of a polymerization mixture containing a monovinylic monomer (glycidyl methacrylate, GMA) and a crosslinking agent (2‐hydroxypropylene dimethacrylate) by reacting methacrylic acid with GMA in excess. Procedures are described for obtaining a polymerization mixture of required composition, and kinetic parameters of the reaction are determined. The mixtures thus obtained are used to demonstrate the possibility of preparing macroporous hydrophilic polymers in the spherical form with defined properties.
Radiation grafting of poly(ethylene terephthalate)(PET) fibre, I. Grafting with vinyl acetate
Authors: Faterpeker S. A. , Potnis S. P. 
Published: April 2003

AbstractPoly(ethylene terephthalate)(PET)fibre has been grafted with vinylacetate in presence of methanol and 1,2‐dichloroethane by a one step simultaneous swelling and irradiation technique using gamma radiation from Cobalt 60. 30% graft was obtained at an irradiation dose of 2.5 Mrad. Higher percentage graft could be obtained at higher doses. CuSO4solution in water was used as homopolymerization inhibitor. 5 · 10−4mol CuSO4per litre of vinyl acetate was found to be optimum and showed no inhibition period. The percentage of graft was directly proportional to the dose. Tensile strength and percentage elongation increased with graft up to a level of 22.0% and then decreased sharply.
Morphologie von kautschukmodifiziertem Polystyrol auf basis von Styrol‐Butadien‐Dreiblockcopolymeren
Authors: Echte Adolf , Gausepohl Hermann , Lütje Hans 
Published: April 2003

AbstractMischungen aus Polystyrol und Styrol‐Butadien‐Zweiblockcopolymeren führen bekanntermaßen zu einem Zweiphasensystem mit definierter morphologischer Struktur. Entsprechend dem Phasenvolumenverhältnis von Styrol zu Butadien im Kautschuk enstehen Zellen‐, Labyrinth‐ und Kapselteilchen sowie inverse Zylinder‐ und Kugelstrukturen.Untersuchungen dieser Art wurden auf Styrol‐Butadien‐Styrol‐ und Butadien‐Styrol‐Butadien‐Dreiblockcopolymere ausgedehnt. Unter bestimmten Bedingungen bilden diese Sequenzpolymeren Überstrukturen, die nach ihrem Erscheinungsbild Kugelhaufen, Fadenhaufen bzw. Mehrschalenteilchen genannt wurden. Voraussetzung für die Bildung dieser Strukturen ist es, daß die außenliegenden Blöcke zwei verschiedenen Domänen angehören und das mittlere Segment der kohärenten Phase zuzurechnen ist.
Lichtbeständige Polyurethane für integralschäume und Elastomere
Authors: Horacek Heinrich , Volkert Otto 
Published: April 2003

AbstractIntegralschaumstoffe und Elastomere aus Polyurethan auf Basis aromatischer Isocyanate sind zwar gut witterungsbeständig, jedoch vergilben sie bei Lichteinwirkung. Deshalb werden sie in der Regel dunkel eingefärbt oder lackiert. Durch Zugabe von UV‐Stabilisatoren und Reduktionsmitteln wird die Vergilbung nur verzögert. Um den aufwendigen Lackierprozeß zu umgehen, wurden lichtstabile Integralschäume entwickelt. Als Isocyanate wurden dabei aliphatische Isocyanate verwendet. Die Entwicklung spezieller Katalysatoren ermöglichte es, ähnliche Verarbeitungseigenschaften wie bei Verwendung von klassischen, aromatischen Isocyanaten einzustellen. Die so zugänglichen, farbigen Integralschäume erfüllen sowohl in ihren mechanischen Eigenschaften als auch in der Lichtbeständigkeit die vom Markt her gestellten Anforderungen.
Synthese von chelatbildenden ionenaustauschern auf der basis von Polystyrol
Authors: Griesbach M. , Lieser K. H. 
Published: April 2003

AbstractDie Synthese von selektiven Chelataustauschern auf der Basis von Polystyrol wird beschrieben. Die Verbindungen werden gewonnen durch Nitrierung von Polystyrol, Reduktion, Diazotierung und Kupplung mit Chelatbildnern, insbesondere mit Phenolderivaten und aromatischen Aminen.
Properties and structure of interpenetrating polymer networks, 1. Poly(methacrylic acid‐co‐divinylbenzene)‐poly(styrene‐co‐divinylbenzene) system in the dry state
Authors: Kolarz Bożena N. 
Published: April 2003

AbstractOn the basis of some properties of poly(methacrylic acid‐co‐divinylbenzene)‐poly‐(styrene‐co‐divinylbenzene) system poly(MA‐co‐DVB)‐poly(St‐co‐DVB)) in the dry state, i.e., its porosity, pore volume, and microscopic observations, a model of the interpenetrating polymer network (IPN) has been proposed. It has been found that the supramolecular structure of IPNs is determined by the secondary and tertiary structures of poly(St‐co‐DVB) (network 1). It was found to be macroscopically inhomogeneous, thus the IPNs were composed of network 1 domains formed through the aggregation of microgels, microspheres, and linear polymer chains linking them, and of poly(MA‐co‐DVB) domains (network 2) formed from microgel regions linked with long chains of poly(methacrylic acid). Between those two domains interpentration regions exist that are characterized by mutual entanglement of polymer chains.
Properties and structure of interpenetrating polymer networks, 2. Poly(methacrylic acid‐co‐divinylbenzene)‐poly(styrene‐co‐divinylbenzene) system in the swollen state
Authors: Kolarz Bożena N. 
Published: April 2003

AbstractThe swelling properties of the interpenetrating polymer networks (IPN), namely, poly(methacrylic acid‐co‐divinylbenzene)‐poly(styrene‐co‐divinylbenzene) (poly(MA‐co‐DVB)‐poly(St‐co‐DVB)) in a series of organic solvents, i.e., acetone, xylene, heptane, methacrylic acid, and water, have been studied. It has been found that the system, in spite of its inhomogeneous supramolecular structure, exhibits a uniform swelling in the solvents having solubility parameters approaching these for both networks as, for example, in acetone. Because of the limited possibility of hydrogen bond formation between carboxyl groups, and the relative ease of bonding of the small acetone molecules, the H+ form of the IPN has been found to be more solvated than the Na+ one.These determinations allow to calculate the concentration of elastically active network chains (EANC), the crosslinking density increment factor of the IPN in relation to the concentration of EANC in the matrix, and the volume fractions of the interpenetration regions, which for the particular IPNs were found to be from 0.06 to 0.17. The interpenetration range could also be estimated from the specific volume contraction of the gel, and from the difference in the volume fraction of these copolymers in the gel of both networks. The hydration of poly(MA‐co‐DVB) was found to depend on the supramolecular structure of the IPN, and on the degree of dissociation of the carboxyl groups especially; it follows that the Na+ form is more highly hydrated than the H+ one.
Synthesis and thermal stability of phenol‐1,2‐dichloroethane resins
Authors: Patel R. , Patel J. , Patel V. S. , Patel K. C. 
Published: April 2003

AbstractPhenol and cresols have been reacted with 1,2‐dichloroethane using anhydrous aluminium chloride as catalyst. The resin samples thus obtained have been characterized by IR spectra and number average molecular weight (M̄n) by vapour pressure osmometry (VPO). The thermal properties have been studied by differential thermal analysis (DTA), thermogravimetry (TG) and differential scanning calorimetry (DSC).Kinetic parameters for the decomposition reaction are determined by Chatterjee and Reich methods. Thermal stability is found to be dependent upon the position of methyl group on aromatic nuclei.
Two‐component blends of poly(vinyl chloride) with some vinyl chloride copolymers I. Rheological characteristics of melts
Authors: Kozłowski Marek , Łaskawski Włodzimierz 
Published: April 2003

AbstractThe rheological characteristics of PVC blends with vinyl chloride‐vinyl acetate and vinyl chloride‐propylene copolymers are presented. The results were obtained using capillary rheometry, plastography, extrusiometry, and by measuring the Archimedes spiral length. It was found that the processing properties of modified PVC were improved with increasing content of both modifying copolymers in the blends, especially those with lower molecular weights. The systems containing vinyl chloride‐propylene copolymers, besides their better rheological characteristics, exhibited improved dynamical thermal stability.
Two‐component blends of poly(vinyl chloride) with some vinyl chloride copolymers II. Physicochemical, mechanical and thermal properties of the blends
Authors: Kozłowski Marek , Łaskawski Włodzimierz 
Published: April 2003

AbstractPoly(vinyl chloride) blends with vinyl chloride‐vinyl acetate and vinyl chloride‐propylene copolymers were found to have better processing properties than PVC homopolymers. The functional properties of these blends were determined from physico‐chemical, mechanical, and thermal investigations. Swelling in benzene and deformation under compression was found to increase with the copolymer content in the blends, but their softening point decreased at the same time. These changes were especially pronounced for lower‐molecular weight copolymers which indicates loosening of the blend structure. The mechanical properties of the blends, except for some decrease in the impact strength for the compositions containing lower molecular weight copolymers, were found to be near those for unmodified PVC.
Two‐component blends of poly(vinyl chloride) with some vinyl chloride copolymers III. Estimation of their compatibility
Authors: Kosłowski Marek , Łaskawski Włodzimierz 
Published: April 2003

AbstractCompatibility studies on blends of poly(vinyl chloride) with vinyl chloride‐vinyl acetate and vinyl chloride‐propylene copolymers in the solution and condensed states are presented. The compatibility ranges were determined from the determinations of the dynamic viscosity of their solutions in cyclohexanone. The weakest interactions were found for polymers mixed in a 1 : 1 weight ratio. The glass transition temperature determinations for particular blends as well as microscopic observations suggest that the studied systems are homogeneous ones. This notion confirms our earlier results obtained by physicochemical, mechanical, thermal, and rheological investigations.
On the photolysis of hydroxy alkylphenones and o‐substituted derivatives. Laser flash photolysis and photocuring studies
Authors: Eichler J. , Herz C. P. , Schnabel W. 
Published: April 2003

Abstract1‐Phenyl‐2‐acetoxy‐2‐methyl‐propanone‐1 (III) and 1‐phenyl‐2‐methoxy‐2‐methyl‐propanone‐1 (IV) were irradiated at room temperature with 15 or 25 ns flashes of 265 nm or 347 nm light in Ar‐saturated cyclohexane or benzene solution. Transient absorptions and emissions were recorded as a function of time between 300 and 550 nm. Triplet lifetimes of III in cyclohexane and benzene and of IV in p‐dioxane were determined as ca. 2 μs. In contrast to the photolysis of 1‐phenyl‐2‐hydroxy‐2‐methyl‐propanone‐1 (compound I) and of 1‐[4‐(2‐propyl)‐phenyl]‐2‐hydroxy‐2‐methyl‐propanone‐1 (compound II), α‐cleavage occurs upon UV irradiation of III and IV to a minor or negligible extent.Triplets of III were found to react effectively with N‐methyldiethanol amine, but a reaction with cyclohexane did not become noticeable. They react with O2 with k(T + O2) = 1.6 · 109 l/mol s.Triplets of IV react with cyclohexane with k(T + CH) = 8.6 · 105 l/mol s and with O2 with k(T + O2) = 1.1 · 109 l/mol s. They are inert towards p‐dioxane.Photocuring of a transparent acrylate coating system yielded the following results on the basis of pendulum hardness measurements: I and II exhibit excellent initiator effectivity, III and IV are not capable of initiating curing if applied without coinitiator, e.g. N‐methyldiethanol amine. In the presence of the latter III and IV exhibit satisfactory curing capability.In conclusion: the high curing effectivity of I and II is due to the high yield and the high rate of α‐cleavage. III and IV do not undergo α‐cleavage and therefore do not initiate curing. The curing capability of III and IV in the presence of a coinitiator is due to the formation of ketyl radicals by a hydrogen transfer mechanism.
Chemical modification of cotton through reaction with alkoxy adducts of acrylamide and hexahydro‐1,3,5‐triacryloyl‐s‐triazine in nonaqueous medium
Authors: Hebeish A. , Abou‐Zeid N. Y. , Anwar W. 
Published: April 2003

Abstract(β‐Alkoxypropionamide as well as hexahydro‐1,3,5‐x(β‐alkoxypropionyl)‐y(acryloyl)‐s‐triazine in nonaqueous medium were prepared. The products so obtained were reacted with cotton cellulose in nonaqueous medium under a variety of conditions. It was postulated that β‐methoxypropionamide reacted with cotton cellulose in presence of an acid catalyst via a substitution reaction. Reaction of hexahydro‐1,3,5‐mono(β‐alkoxypropionyl)‐diacryloyl‐s‐triazine with cotton cellulose also proceeded mainly through a substitution reaction. Addition and/or polymerization reaction, which entailed saturation of the double bonds of the acryloyl groups, occurred when the chemical modification of cotton was carried out at high temperature (above 130°C) for more than 10 minutes using higher concentrations of hexahydro‐1,3,5‐mono(β‐alkoxypropionyl)diacryloyl‐s‐triazine (8% or more)).
Mercury sorbents with thiol and quaternary ammonium groups
Authors: Beneš M. J. , Štamberg J. , Očenáašek M. , Matějka Z. 
Published: April 2003

AbstractMacroporous bifunctional mercury adsorbents containing different portions of thiol and quaternary ammonium groups were prepared by nucleophilic attack of potassium ethylxanthogenate to the crosslinked poly[(vinylbenzyl)trimethylammonium chloride] (type I styrene anion exchanger). Both the active groups complemented each other raising selectivity at high dilutions, capacity in the presence of excessive alkali chlorides and regeneration ability in repeated cycles.
The determination of β‐ketoamide structures in poly(2‐pyrrolidone)
Authors: Stehlíaček Jaroslav , Roda Jan , Votrubcová Zdeňka , Pokorný Svatopluk 
Published: April 2003

AbstractKetoamide and ketoimide units incorporated in poly(2‐pyrrolidone) as a result of side reactions in the anionic polymerization may be quantitatively determined as 1,7‐dibenzamido‐heptane‐4‐one (IIa) after the total acid hydrolysis of the polymer and benzoylation of the hydrolyzate. Conditions were found for the quantitative analysis of these structures using liquid chromatography.
Macronet isoporous styrene copolymers: Unusual structure and properties
Authors: Davankov V. A. , Tsyurupa M. P. 
Published: April 2003

AbstractA systematic study of properties of macronet isoporous polymers of styrene offers the following model for their structure: A homogeneous loose highly crosslinked molecular network shrunk in the dry state and relaxed in the swollen one. This model allows to explain the considerable elasticity (changes in volume) exhibited by densely crosslinked polymers, their swelling in poorly solvating media, the increasing degree of swelling with increasing degree of crosslinking of the network, and the marked porosity.
Pfropfung azogruppenhaltiger Polycarbonate, 2
Authors: Nuyken Oskar , Gerum Johannes , Kerber Robert 
Published: April 2003

AbstractAzogruppen enthaltende Polycarbonate wurden als Initiatoren zur Herstellung von Pfropfcopolymeren aus unterschiedlichen Vinylmonomeren eingesetzt. Die Zusammensetzung der Pfropfcopolymeren wurde gravimetrisch sowie durch Elementaranalyse, IR‐ und 1H NMR‐Spektroskopie bestimmt. Die Länge der Seitenketten wurde nach Hydrolyse des Polycarbonatrückgrates gemessen.
Comparative adsorption studies using a polyacrylamide and a polysaccharide type polymer in oilfield oriented model systems simulating enhanced oil recovery conditions
Authors: Klein Joachim , Westerkamp Aloys 
Published: April 2003

AbstractIn order to get direct information about polymer retention in Enhanced Oil Recovery and a more detailed picture about the influence of polymer retention in the mode of action of polymers as mobility reducing agents, static adsorption measurements have been carried out in a practice‐oriented model system.Valentin‐Busch‐Quarz was found to be a suitable model adsorbent, and polyacrylamides as well as a biologically synthesized polysaccharide were used as adsorbing agents. Adsorption isothermes of these polymers have been determined as a function of ionic strength, temperature of adsorption, and molecular weight. Performance of the adsorption‐ and desorption measurements required a new analytical technique employing a gel permeation chromatograph. The following results were found:Polyacrylamides are adsorbed irreversibly and the saturation amount of adsorption increases with increasing molecular weight, increasing ionic strength, and decreasing temperature. The adsorption of the polysaccharide is reversible to some degree, the amount of saturation again increasing with increasing ionic strength and decreasing temperature. With salt concentration below 15 g · dm−3 no polysaccaride is being adsorbed.
Lösungseigenschaften eines Segmentpolyurethans auf Polycaprolactonbasis
Authors: Šimek Lubomír , Hrnčiřík Josef , Mládek Milan 
Published: April 2003

AbstractDas Verhalten von verdünnten Lösungen eines Polycaprolacton‐Polyurethans wird hinsichtlich viskosimetrischer Messungen, Fraktionierung, Molekülgrößenverteilung und Bestimmung einiger thermodynamischer Parameter beschrieben.
Untersuchung der negativen thermischen Ausdehnung von verstrecktem Polyethylen
Authors: Wolf Frank‐Peter , Karl Veit‐Holger 
Published: April 2003

AbstractDer linear thermische Ausdehungskoeffizient α von Polyethylen hoher Dichte wurde für Temperaturen von etwa −15 bis +50°C bestimmt. Bei isotropen Proben erhält man für T0 = 20°C Werte um 120 · 10−6 K−1, die sich je nach Kristallisationsgrad aus den Ausdehnungskoeffizienten αam = 230 · 10−6 K−1 der amorphen und α;kr = 90 · 10−6 K−1 der kristallinen Phase ergeben. Proben mit Verstreckungsgraden λ = 8 bis 16 haben in Faserrichtung α = −24 · 10−6 K−1, während man für Kristallite in Richtung der c‐Achse αc = −12 · 10−6 K−1 findet. Ausgehend von einem Zweiphasen‐Modell erhält man für die orientierte amorphe Phase etwa αam = −52 · 10−6 K−1. Dies wird auf entropieelastisches Verhalten der gespannten tie‐molecules zurückgeführt. Dagegen ist die Volumenausdehnung für verstreckte und isotrope Proben etwa gleich.
Synthese und Eigenschaften eines Celluloseaustauschers mit Diaminodibenzo‐18‐Krone‐6 als Ankergruppe
Authors: Djamali M. G. , Burba P. , Lieser K. H. 
Published: April 2003

AbstractDer Austauscher wird durch Umestzung von Cellulose mit 4‐(β‐Sulfatoethylsulfonyl)‐2‐aminophenol, Diazotierung und Kupplung des Reaktionsproduktes mit Diaminodibenzo‐18‐Krone‐6 hergestellt. Der Gehalt an Ankergruppen beträt 0,25 mmol/g. Die Einstellung des Austauschgleichgewichtes mit Alkali‐ und Erdalkaliiodiden erfolgt in zwei Teilschritten von etwa 15 s und etwa 7 min Halbwertszeit. Die Logarithmen der Verteilungskoeffizienten Kd für Ki, NaI, CaI2, BaI2 und ZnI2 liegen in Methanol zwischen log Kd = 1,0 und log Kd = 1,5 (Kd in ml/g). Sie negmen mit dem Wassergehalt des Methanols deutlich ab.
Interpolymer anion exchange membranes, I. Properties of weak base membranes based on polyethylene modified by styrene and divinylbenzene in the presence of diluents
Authors: Poźniak Gryzelda , Trochimczuk Witold 
Published: April 2003

AbstractWeak base anion exchange membranes with diethylamine groups have been prepared on the basis of low‐density polyethylene modified by styrene and divinylbenzene in the presence of iso‐octane or toluene as inert diluents. The effect of the kind and amount of the inert diluent used during interpolymerization on properties of thus obtained membranes has been studied. The membranes were found to have similar anion exchange capacity, but their diffusion propeties toward strong mineral acids have been found to depend on the inhomogeneity of styrene‐divinylbenzene copolymer gel as well as the mode of its distribution in the amorphous phase of polyethylene.
Hochfeld‐13C‐kernresonanz an acrylnitril/vinylchlorid‐copolymeren
Authors: König Joachim , Wendisch Detlef 
Published: April 2003

AbstractCopolymers of acrylonitrile and vinylchloride (molar ratio ACN : VC = 44.5 : 55.5) were synthesized by continuous emulsion polymerization. Their sequence distribution was studied by 13C‐NMR‐spectra at 90.52 MHz. Three different methylene carbon regions were attributed to diads of the type VCVC,VCACN and ACNACN. The experimentally determined diad distribution was in good agreement with the calculated diad distribution, using reactivity ratios of rACN = 3.6 and rVC = 0.05.
Resacetophenone‐formaldehyde resins, I. Metal chelates
Authors: Parmar J. S. , Patel M. R. , Patel M. M. 
Published: April 2003

AbstractSynthesis and properties of a resacetophenone‐formaldehyde resin are described. The number average molecular weight of the resin determined by vapour pressure osmometry and nonaqueous conductometric titration is 2500 and 2200 g/mol, respectively.Cu(II), Ni(II) and Co(II) chelates of the resin were prepared. The elemental analysis of chelates indicated a metal to ligand ratio 1:2. From the diffuse reflectance spectra of the chelates it could be concluded that Ni(II) and Co(II) chelates have a tetrahedral structure while Cu(II) chelate has a square planar structure. Infrared spectral studies showed that the metals are co‐ordinated through the oxygen of the carbonyl and phenolic groups. The presence of methylene bridges was also indicated from IR spectral studies. The thermal properties of the resin and its metal chelates are discussed.
A simulation model for the determination of Flory's branching coefficient in infinite network systems
Authors: Madhavan N. S. , Nair C. G. Sukumaran , Swaminathan V. 
Published: April 2003

AbstractThe object of this paper is to present the features of a simulation model for the evaluation of the branching coefficient of complex polymer networks. A generalized computer program, developed for this purpose, has yielded values which are in good agreement with those obtained from the well‐known theoretical equations for the simpler 3,2,1/2,1 system.
Urea‐formaldehyde resins 4. Formation of condensation products during resin preparation
Authors: Kumlin Kjell , Simonson Rune 
Published: April 2003

AbstractThe formation of diurea compounds containing methylene and dimethylene ether bridges, respectively, as well as the formation of more highly condensed compounds during the preparation of urea‐formaldehyde resins under different conditions have been investigated. The quantitative determination of each individual diurea compound was carried out by means of liquid chromatography. Identification of diurea compounds with a dimethylene ether bridge was made by 1H‐NMR spectroscopy.