bluuebunny/crossref_metadata_2025_split huggingface dataset:
Versuche zur pfropfung von polystyrol auf rußoberflächen
Authors: Braun Dietrich , Kamprath Axel 
Published: April 2003

AbstractSchlagfeste Polystyrole auf der Basis von Polybutadienkautschuk als Elastomerkomponente besitzen im Vergleich zu Standard‐Polystyrolen eine deutlich reduzierte Witterungsbeständigkeit. Einer wirkungsvollen Stabilisierung dieser Werkstoffe mit feinverteiltem Ruß steht die Tatsache entgegen, daß infolge einer mangelnden Ruß‐Polymer‐Verträglichkeit das Pigment eine Kerbwirkung zeigt, die den Hauptvorteil des schlagfesten Polystyrols — seine hervorragende Zähigkeit — deutlich vermindert. In dieser Arbeit wird über Versuche berichtet, durch Aufpfropfen von Polystyrolketten auf die Rußoberflache eine Verbesserung der Ruß‐Polymer‐Verträglichkeit und damit der technologischen Eigenschaften zu erreichen.
Incidence of heterogeneity due to polymer incompatibility on the reaction between telechelic prepolymers and on the mechanical properties of the multiblock copolymers formed
Authors: Chaumont Philippe , Beinert Gérard , Prud'Homme Christian , Herz Jean 
Published: April 2003

AbstractThe polycondensation reaction between telechelic poly(dimethylsiloxanes) and α,ω‐difunctional polystyrenes (or substituted polystyrenes) in toluene solution is very fast, in spite of the heterogeneous nature of the reaction medium. In the first part of the article is reported a qualitative approach of the condensation reaction in relation to the microscopic structure of the reaction medium. The second part is devoted to an investigation of the mechanical and thermomechanical behaviour of the multiblock copolymers which results from intramolecular phase separation.
Dielectric behaviour of styrene‐methyl methacrylate copolymer foams at microwave frequencies
Authors: Bandyopadhyay Pranab C. , Banthia Ajit K. , Chaki Tapan K. 
Published: April 2003

AbstractAmbient dielectric effects were studied by the short‐circuited waveguide method at 9.375 GHz microwave frequency in foams from copolymers of styrene and methyl methacrylate of varying compositions, generated under identical conditions of solvent‐nonsolvent ratio, impregnation time and steaming period. The results were correlated with foam‐density, porosity and composition and were interpreted in terms of dipole‐dipole interactions and the applicability of Wiener's inequalities, logarithmic law of Lichtenecker and Rother with an empirical factor of 0.64 in the index based on the additive law of mixtures and the Böttcher‐Bruggeman's relation. Scanning electron micrography on copper‐coated fractured surfaces of the samples was done in order to examine the degree of foamability, cell‐size distribution and the mechanism of failure. Microhardness, compressive and flexural strength were also measured. Loss characteristics were similarly ascribed to copolymer foamability and dipoleorientability. A prudent choice in the monomer reactivity ratio might therefore yield an optimum reinforcement and a proper dielectric requirement suitable for electronic and radar device constructions.
Viskosimetrische bestimmung des polymerisationsgrades von oxycellulose mit hilfe der EWNN‐methode
Authors: Blaha Jan , Černý Pavel , Jahn Karel 
Published: April 2003

AbstractFür die Bestimmung der Grenzviskositatszahl [η] von nitroso‐oxydierter Cellulose in verdünnter Losung wurde die EWNN Methode (alkalische Lösung eines Eisen‐Weinsäure‐Natrium‐Komplexes) angewandt. Die bisher bekannten Berechnungsmethoden von [η] mit Hilfe der Polynome für verschiedene Arten von Polymeren, verschiedene Lösungsmittel und Meßsysteme sowie auch für reine Cellulose erwiesen sich als unbrauchbar. Es wurde eine empirische Berechnungsformel in expliziter Form

mit A1 = −2,348, A2 = 3,584 und A3 = 0,006 (ηsp: spezifische Viskosität, c: Konzentration g/100 ml) vorgeschlagen, die die Berechnung von [η] bei Oxycellulose aus einer bei einer einzigen Konzentration der Probe durchgeführten Messung ermöglicht. Für die Berechnung eines Mittelwertes für den Polymerisationsgrad nach der Staudinger‐Mark‐Houwink‐Gleichung war es möglich, die für nichtoxydierte Cellulose geltende Konstante zu verwenden.
Mechanisms of degradation of cotton and effects of mercerization‐stretching upon the course of these mechanisms, part VII. Characterization of microstructural differences between scoured cotton and slack mercerized‐stretched cottons
Authors: Hebeish A. , Waly A. , Abou‐Zeid N. Y. , Ibrahim N. A. , El‐Rafie M. H. , El‐Aref A. T. , Bayazeed A. 
Published: April 2003

AbstractConditions were established to introduce almost equal and reproduciple amounts of diethylaminoethyl (DEAE) substituents into the molecular structure of scoured cotton (substrate I), slack mercerized cotton (substrate II), slack mercerized‐stretched (94%, substrate III), and slack mercerized‐stretched (103%, substrate IV) cotton. Similarities between the original structures of these substrates before and after the chemical modification were assessed by X‐ray analysis. Comparison between the DEAE cottons and the corresponding unmodified cottons upon acid hydrolysis with respect to moisture regain, loss in weight and degree of polymerization was also made. Chemical analysis was used to study the compositions and structures of the hydrolyzates (i.e., hydrocelluloses and solublized fractions) resulting from hydrolysis of the modified cottons with 2.5 N HCl under reflux for different lengths of time. Studies of rates of hydrolysis of the cellulose, rates of removal of substituted glucoses and rates of removal of individual types of substituted glucose units were considered as means to provide information regarding: (a) distribution of DEAE substitutents throughout the structure of cellulose, (b) nature of accessible regions where the DEAE substituents are developed, and (c) selective availability of the hydroxyl groups at C‐2, C‐3 and C‐6 of the D‐glucopyranosyl units in the cellulose elementary fibril.
Effect of copolymers modifying PVC on its physical and mechanical properties and its UV‐radiation resistance. III. Changes in thermal stability of PVC films modified by MMA/MA, VC/VAC, MBS or ABS induced by UV‐irradiation
Authors: Kamińska A. , Kaczmarek H. 
Published: April 2003

AbstractThe influence of UV‐radiation on thermal stability of PVC films, depending on the type and quantity of modifying copolymers, was studied. It was found that UV radiation can induce various changes in thermal stability of PVC decreasing its dehydrochlorination temperature T01 while increasing temperature of decomposition T02.Particularly distinct changes in sampels containing VC/VAC indicate that even 1% of this copolymer accelerates the photodehydrochlorination and the processes which decrease the temperature of decomposition of PVC.Smaller changes than in pure PVC in thermal parameters in samples containing ABS after irradiation show that this copolymer increases the PVC resistance to UV radiation.Films containing MBS, ABS, MMA/MA reveal the largest changes in T01 after irradiation in the case of a content of 1% of these copolymers in the samples. In the case of bigger quantity (3 to 10%) the changes are smaller and may even diversify their direction. These copolymers, contrary to VC/VAC, make PVC films a little turbid indicating the limited compatibility of both components. Hence, the conclution is that the structure of a film, depending on compatibility of components and changing with their differing concentration, has decisive influence on the thermal and photochemical processes.
Pyrolysis field desorption mass spectrometry of polymers. III. Aliphatic polyamides
Authors: Bahr U. , Lüderwald I. , Müller R. , Schulten H.‐R. 
Published: April 2003

AbstractPyrolysis field desorption mass spectrometry has been performed from various polyamides such as nylon 6, 8, 12, and nylon 66. The pyrolytic behaviour of these compounds depends strongly on the solvent and the temperature program employed. Using formic acid as solvent strong thermal fragmentation is observed, while with 1,1,1,3,3,3‐hexafluoro‐2‐propanol almost exclusively molecular ions or cationized molecules of the monomer building block M are produced. With increasing temperature larger clusters of polymeric subunits (Mn + Na)+ are generated, but thermal fragmentation on the emitter surface also increases. The cationized molecules dominate all spectra. They are found from M3 to M5 or M15 depending on the chain length of the polymer subunit. With increasing temperature, the base peak of the spectrum is shifted to the higher mass end and small signals up to m/z 2000 and above are recorded. Thermal products are mainly formed by water elimination (−18 mu), loss of the acid amide group (−44 mu) after rearrangement and from longer polyamides by loss of the methylene groups (− 42 or 56 mu) by cis‐elimination.These thermal fragmentations of the polymeric substances on the emitter surface can be controlled by appropriate emitter heating and correlate directly with the common chemical knowledge of these materials in the liquid or solid phase. Together with the options of integrating recording, high mass resolution and direct isotope determination, the combination of pyrolysis and field desorption mass spectrometry offers a unique tool for characterization of building blocks and high mass sequences in synthetic polymers.
Lattice expansion of the core‐fibrils in polypropylene‐poly(1‐butene) blends
Authors: Wenig Werner 
Published: April 2003

AbstractLattice parameters of the core‐fibrils in annealed polypropylene/poly(1‐butene) blends, crystallized from the oriented melt, have been measured.The unit‐cell parameters for pure PP and PB‐1 agree well with literature values, while in the blends a lattice expansion is measured: the lattice spacings of both components increase with decreasing concentration of the respective second component.
Polymerization of lactams, 67. Modification of polyamide 6 with poly(oxyethylene) and its derivatives, part I
Authors: Cupák František , Kubánek Vladimír , Kondelíaková Jaroslava , Týfová Ilse 
Published: April 2003

AbstractThe polymerization of 6‐caprolactam by various mechanisms was investigated in the presence of poly(oxyethylene) (POE) of moleculare mass 1000 and 3000 terminated with hydroxyl or methoxy groups. Whereas the rate of hydrolytic polymerization (6‐aminocaproic acid as initiator) is not affected by addition of POE, the acidolytic polymerization (initiator: lauric acid) and spontaneous polymerization (without initiator intentionally added) are pronouncedly accelerated. The equilibrium content of polymer decreases with the increasing of POE concentration in initial reaction mixture in all mechanisms. A block copolymer probably results; the content of chemically bound POE is highest in the acidolytic polymerization and lowest in the hydrolytic polymerization.
Reaktive Träger mit Maleinimidgruppen zur Immobilisierung von Enzymen, 2
Authors: Manecke Georg , Middeke Hermann‐Josef 
Published: April 2003

AbstractVernetzte Copolymere aus Acrylnitril oder aus Acrylnitril und Acrylsäure wurden mit N‐Methylolmaleinimid zu maleinimidgruppenhaltigen reaktiven Trägern umgesetzt. Enzyme mit SH‐Gruppen oder solche, in die in einer Thiolierungsreaktion SH‐Gruppen eingeführt worden waren, konnten an diesen Trägern erfolgreich immobilisiert werden.
Compatibility of poly(vinyl chloride) and polyurethane blends
Authors: Shen C. H. , Wang Y. Y. 
Published: April 2003

AbstractThe compatibility and the mechanical properties of the blends of polyurethane (PU) elastomer and poly(vinyl chloride) (PVC) were studied. The results showed partial compatibility between PU and PVC. When the portion of PVC in blends exceeded 75%, the compatibility decreased. On the other hand, increasing the molecular weight of the glycol in PU improved the compatibility. The elongation decreased and the Young's modulus increased as the proportion of the weight of PVC in blends was increased. The tensile strength reached a minimum when PU/PVC was 50/50.
Functional metal‐porphyrazine derivatives and their polymers, 10. Secondary fuel cells based on oxygen reduction on platinum electrode modified by polymers and metal‐phthalocyanines
Authors: Hirabaru Okikazu , Nakase Tomohiro , Hanabusa Kenji , Shirai Hirofusa , Takemoto Kiichi , Hojo Nobumasa 
Published: April 2003

AbstractSecondary fuel cells based on oxygen reduction of platinum electrode modified by polymers and metal‐phthalocyanine (Mt = Fe(III), Co(II), Ni(II), and Cu(II)) were studied. The discharge curves for the platinum electrode modified by poly(2‐vinylpyridine) (or polystyrene) and Co‐phthalocyanine in 30% KOH aqueous solution, for a 30 min charge at 500 μA, followed by a 100 μA discharge showed a stable plateau at about −0.24 V SCE (Saturated Calomel Electrode). The open circuit voltage (vs. Zn) of the cell was 1.2 V, and the discharge capacity was of 46 A · h/kg. For this battery there was no significant decay in its characteristics after more than 30 charge‐discharge cycles. In Mt‐phthalocyanines, the values decreased in the order of Co(II) > Fe(III) > > Cu(II) > Ni(II). From a cyclic voltammogram for the electrode modified by the polymer and Co‐Pc, the cathodic reactions were discussed.
Graft copolymerization of styrene, methylmethacrylate, and acrylonitrile onto jute fibres
Authors: Abou‐Zeid N. Y. , Higazy A. , Hebeish A. 
Published: April 2003

AbstractThe contribution of jute constituents, namely, water soluble matters, waxes, pectins, lignin, hemicelluloses, and α‐cellulose in the graft copolymerization reaction of jute fabric with some vinyl monomers was investigated. Styrene, methylmethacrylate, and acrylonitrile were used as the monomers and Fe2+/H2O2 redox system as initiator. The graft copolymerization reaction was carried out at 80°C using different concentrations of monomer and initiator for different lengths of time. The water soluble matters, pectins, and lignin were found to accelerate the graft copolymerization reaction during the initial stages of the reaction and in the meantime impede termination during the latter stages of the reaction. Generally, the magnitude of grafting is governed by nature of the substrate, nature of the monomer, and the conditions of the polymerization reaction. Grafting decreases the moisture regain of jute and substrates derived thereof irrespective of the monomer used within the range studied. Also, grafting decreases the tensile strength and imparts rot‐proofing properties to the substrates examined.
Porous bead aliphatic‐aromatic methacrylate copolymers, II. The estimation of the structure of methyl methacrylate—di(methacryloyloxymethyl)naphthalene copolymers by means of scanning electron microscopy
Authors: Wójcik Anna B. 
Published: April 2003

AbstractScanning electron microscopy was used to obtain complementary data concerning the surface and inner structure of porous aliphatic‐aromatic methacrylate copolymers. Depending on the amount of a porogenic (toluene and dodecane) or crosslinking agent, the suspension copolymerization of methyl methacrylate and di(methacryloyloxymethyl)naphthalene (DMN) leads to either porous polymers with measurable surface areas or gel type polymers with no measurable surface areas. Porous polymers are visualized as one or two level organization of microglobules within the beads whereas gel type polymers exhibit no pores or microglobules neither in the surface layer nor in the bead interior.
Reactive polymers, 47. Sorption properties of the reaction product of macroporous poly (glycidyl methacrylate‐co‐ethylene dimethacrylate) with 8‐aminoquinoline
Authors: Švec F. , Jehličková A. 
Published: April 2003

AbstractThe sorption of Fe(III), Al(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Au(III), Pd(II), Pt(IV), and Hg(II) ions on a sorbent prepared by reacting the copolymer of glycidyl methacrylate and ethylene dimethacrylate with 8‐aminoquinoline was investigated. Gold and palladium are strongly absorbed in hydrochloric acid. Results of static and dynamic tests indicate the possibility of separation of Au(III) and Pd(II) from Pt(IV) and from the other metal ions investigated in the study. The sorption of Hg(II) by the polymer increases in nitric acid.
A contribution to the study of the polymer‐filler interface in polyester and surface treated sepiolite composites
Authors: Linares Amelia , Acosta Jose Luis 
Published: April 2003

AbstractThe acetalation and esterification of the sepiolites with different acids and aldehydes have been carried out in order to study the interface phenomena through their technological properties. Also, a complete study of the characterization of all the organic minerals obtained has been done. It must be pointed out the strengthening effect which is produced when some of the organic minerals obtained are present in polyester compounds.
Study of the structure and properties of phosphorinated segmented polyurethanes
Authors: Vilenskyj V. A. , Kercha Y. Y. , Lipatov Y. S. , Goncharova L. B. , Grecov A. P. , Shapoval R. L. 
Published: April 2003

AbstractThe effect of an expanded set of physical bonds in rigid polyurethane segments has been studied by X‐ray measurements, thermography, thermomechanics, etc. It has been shown that, by varying the nature and structure of quaternizing agent, the structure and properties of the segmented polyurethanes can be purposefully varied. Heat treatment (annealing) of polyurethanes, and polyurethane‐ionomer samples has proved that the growth of hard domains is first of all due to the rigid segments associating with hard domains already existing.
Studium der alkalischen hydrolyse der ester‐bindungen in einem acrylsäureethylester‐acrylnitril‐divinylbenzol‐perlcopolymeren
Authors: Matějíaček Alois , Seidl Josef , Krejcar Emil , Matyáš Josef 
Published: April 2003

AbstractAufgrund der Resultate früherer Arbeiten wurde die mathematische Auswertung der bei der alkalischen Hydrolyse der Ester‐Bindungen von Acrylsäureethylester‐Acrylnitril‐Divinylbenzol‐Perlcopolymeren erhaltenen Zeit‐Umsatz‐Kurven durchgeführt. Der Einfluß der Reaktionstemperatur, des molaren Verhältnisses zwischen den Bestandteilen des reagierenden Systems, der Perlgröße des Copolymeren und seiner Vernetzungsdichte wurde mit Hilfe der Reaktionskonstanten und der Diffusionskoeffizienten verfolgt.
Characterization of nylon 6 fibers grafted by acrylic monomers
Authors: Mukherjee A. K. , Goel H. R. 
Published: April 2003

AbstractSamples of nylon 6 fibers grafted with the acrylic monomers methyl methacrylate (MMA), ethyl methacrylate (EMA), and n‐butyl methacrylate (n‐BMA) with various graft levels were investigated by infrared, X‐ray and scanning electron microscopic studies and the changes due to grafting with respect to the parent nylon 6 fibers were studied.The IR spectra of grafted nylon 6 samples show that there is a little change in the peak heights by grafting of nylon 6 with various monomers. The characteristic peaks of parent nylon are, more or less, maintained in the case of grafted samples. A peak at 1730 cm−1 of the ester group was noted which confirms that the polymer has been grafted with the monomer.X‐ray diffraction data on the grafted samples show some remarkable variations with the degree of grafting, depending upon the nature of the graft monomer. The percentage of crystallinity varies with the degree of grafting. In the initial stages of grafting it shows a decrease in the case of PMMA graft and an increase in the case of PEMA and Pn‐BMA graft. At higher degrees of grafting (above 50% graft add‐on) the percentage of crystallinity decreases in all the three cases. Orientation index has been found to increase in the initial stages of grafting in the case of EMA and n‐BMA grafted nylon 6 and it decreases later on, whereas in the case of MMA graft it decreases continuously even at low graft level.The studies of surface characteristics for the parent and grafted samples show that spectacular changes on the surface of the various samples have taken place. With the increase in the graft level the diameter of the fiber increases and also the voids and cracks appear on the surface.
Wasserlösliche kationisch modifizierte copolymere mit acrylamid
Authors: Okay Oguz , Schindlbauer Hellmuth 
Published: April 2003

AbstractDie Copolymerisation von Acrylamid mit N‐[3‐(N′‐Diethyl‐N′‐methyl)ammoniumn‐propyl]‐maleinimid‐methylsulfat in Aceton/Wasser‐Gemischen mit Persulfat‐Initiator führt zu pulverförmigen kationischen Polymeren mit hoher Molmasse, die leicht wasserlöslich sind und sehr gute Ausflockungseigenschaften zeigen. Das Copolymere weist praktisch die gleiche Zusammensetzung auf wie das eingesetzte Monomerengemisch. Sowohl die Ausbeute als auch die Molmasse des Copolymeren steigen mit zunehmender Acetonmenge (bis ca. 52 Vol.‐%) im Lösungsmittelgemisch an.
Chemische wechselwirkung in schmelzdispersionen von polyethylenterephthalat und polypropylen
Authors: Georgiev Yanko , Stojanov Stojan , Dimov Kiril 
Published: April 2003

AbstractDie durch Thermobehandlung von Schmelzdispersionen erhaltenen zusammengesetzten Polymerlegierungen aus Polyethylenterephthalat (PETP) und Polypropylen (PP) wurden mit Hilfe der Thermischen Differentialanalyse und durch die Löslichkeit in spezifischen Lösungsmitteln untersucht. Der beobachtete exotherme Peak im Bereich 220–240°C wird auf eine Reaktion zwischen beiden Polymerkomponenten zurückgeführt, wobei die Reaktion durch thermoxidative Zersetzung des Polypropylens aktiviert wird. Es wird festgestellt, daß PP‐ und PETP‐Thermostabilisatoren die chemische Reaktion beider Polymerer in den Schmelzdispersionen inhibieren.
Some kinetic features of the initial stage of acid‐catalyzed polycondensation of furfuryl alcohol and formaldehyde, II
Authors: László‐Hedvig Z. , Szesztay M. , Pupek I. , Tüdős F. 
Published: April 2003

AbstractThe initial stage of the phosphoric acid catalyzed autocondensation of furfuryl alcohol (FA) was studied in comparison with the FA‐formaldehyde (F) system with special respect to formation and consumption reactions of dimers under different reaction conditions. A GPC method using simultaneously refractive index and UV absorption detectors with filters of different wavelength was developed to follow the concentration change of dimers.
Crystal nucleation in polypropylene injection‐moulding resins containing fibrous fillers
Authors: Campbell D. , White J. R. 
Published: April 2003

AbstractInjection mouldings contain residual stress and molecular orientation and both are influential in determining properties. When a fibrous filler is present the magnitude and distribution of residual stress and molecular orientation are modified and, with semi crystalline polymer matrices, the crystal morphology is also modified. This subject has been studied recently by Misra et al.1 and their views are discussed here. We propose that some of the effects they attribute to residual stress are better explained with reference to molecular orientation.
Beiträge zur galvanisierung von polymeren, 10. Metallisierung von copolymeren aus acrylnitril und butadien nach vorbehandlung mit ozon
Authors: Springer Jürgen , Förster Frank , Uzman Mehmet 
Published: April 2003

AbstractCopolymere aus Acrylnitril und Butadien lassen sich haftfest metallisieren. Die Dauer der Ozonbehandlung hat nur geringen Einfluß auf die Polymer‐Metall‐Haftung. Die Haftfestigkeit nimmt mit dem Nitrilgehalt unde der Molmasse des Polymeren zu. Bei Kohäsionsbruch im Polymeren sind Werte bis etwa 150 N/25 mm gemessen worden. Die höchsten Haftfestigkeiten wurden an Proben gemessen, deren kritische Oberflächenspannung etwa der der chemisch abgeschiedenen Nickelschicht entspricht. Kavernen, die eine mechanische Verankerung des Metalls ermöglichen würden, sind nicht beobachtet worden.