bluuebunny/crossref_metadata_2025_split huggingface dataset:
Über die Verzweigung des Polyvinylacetats. III. Bestimmung des Verzweigungsgrades und reaktionskinetischer Konstanten durch Messung der Mittelwerte des Polymerisationsgrades P̄w und P̄n als Funktion des Umsatzes
Authors: von Stein D. J. 
Published: April 2003

AbstractEine Serie von 11 Polyvinylacetaten wurde unter konstanten Reaktionsbedingungen bis zu verschiedenen Umsätzen polymerisiert. An diesen Präparaten wurden osmotische Messungen und Streulichtmessungen durchgeführt. Die Messungen liefern das Zahlen‐ und das Gewichtsmittel der Polymeren. Aus der Änderung der Mittelwerte mit steigendem Umsatz werden die Übertragungskonstante Cp zum Polymeren und die Wachstumskonstante kN der endständigen Doppelbindung berechnet. Die erhaltenen Zahlenwerte sind für 60°C: Cp = 1,8.10−4, kN/kW = 0,80.Unter Benutzung dieser Zahlenwerte wurde die Zahl der Verzweigungspunkte pro Polymermolekül als Funktion des Umsatzes berechnet.
Molekulargewicht von Polyformaldehyd bei der Polymerisation von Trioxan in der Schmelze
Authors: von Kučera Miloslav , Spousta Eduard 
Published: April 2003

AbstractDie Polymerisation von Trioxan in der Schmelze ist eine ionische Kettenreaktion, die an “lebenden” Kettenenden abläuft. Die Gültigkeit der TOBOLSKY‐Gleichung für die Abhängigkeit von P̄n vom Umsatz bei der Polymerisation von Trioxan wird bewiesen und der Wert der Übertragungskonstante für Wasser bei 85°C bestimmt.
Gamma‐ray induced polymerization of formaldehyde
Authors: Yamaoka Hitoshi , Hayashi Koichiro , Okamura Seizo 
Published: April 2003

AbstractIn gamma‐ray induced polymerization of formaldehyde, the effects of solvent and the copolymerization with vinyl monomers were studied. The rate of polymerization was of first order with respect to the dose rate; with respect to monomer concentration it was of second order in methylene chloride and toluene, but of first order in diethyl ether. From these results, the gamma‐ray induced polymerization of formaldehyde seems to proceed predominantly by an ionic mechanism in solutions. Results of copolymerization showed that the polymerization proceeds in methylene chloride and in toluene by a cationic, in diethyl ether by an anionic mechanism.
Hydrogen migration polymerization of N‐substituted acrylamides
Authors: Yokota Kenji , Shimizu Masatoshi , Yamashita Yuya , Ishii Yoshio 
Published: April 2003

AbstractThe modes of polymerization of N‐substituted acrylamides catalyzed by sodium tert‐butoxide at 105°C. were investigated by means of IR spectra. N‐cyclohexylacrylamide gave a vinyl polymer. All other monomers (N‐substituents were benzyl, p‐phenethyl, p‐anisyl, p‐tolyl, phenyl, and m‐chlorophenyl) gave hydrogen‐migrated polymers, i.e., poly‐N‐substituted‐β‐alanines.Thus electron‐releasing or ‐attracting effects of the N‐substituents, i.e., acidities of migrating amide‐hydrogens, might be responsible for the choice of type of polymerization.
Über oligomere siliciumverbindungen mit funktionellen Gruppen. 15. Mitt.. Über die Herstellung von siliciumorganischen p‐vinylphenylderivaten mit funktionellen gruppen
Authors: Greber Von Gerd , Reese Eckart 
Published: April 2003

AbstractEs wird die herstellung polymerisationsfähiger, siliciumorganischer p‐Vinylphenylderivate mit funktionellen Gruppen beschrieben.
Über oligomere siliciumverbindungen mit funktionellen gruppen. 16. Mitt.. Über die polymerisation von siliciumorganischen p‐vinylphenylderivaten mit funktionellen gruppen
Authors: Greber Von Gerd , Reese Eckart 
Published: April 2003

AbstractDie siliciumorganischen Styrolderivate der Formeln I und II

wurden homo‐bzw. mit verschiedenen Monomeren copolymerisiert und einige Copolymerisationsparameter sowie Q‐ und e‐Werte bestimmt. Im Vergleich zum unsubstituierten Styrol zeigen die Verbindungen der Formel I unabhängig von der Länge des Siloxanrestes die gleiche, die Verbindungen der Formel II dagegen eine gesteigerte Polymerisationsaktivität, die diskutiert wird. Die Polymerisation der Vinyl‐und Allylderivate (II, R = Vinyl und Allyl) führt zu löslichen, unverzweigten Makromolekülen mit seitenkettenständigen Vinyl‐Si‐ und Allyl‐Si‐Gruppen, da nur die Styroldoppelbindung unter den gewählten Bedingungen polymerisationsfähig ist.
Further studies on crystalline cationic poly(3‐methylbutene‐1)
Authors: Kennedy J. P. , Elliott J. J. , Groten B. 
Published: April 2003

AbstractCrystalline, cationically obtained poly(3‐methylbutene‐1) has been investigated. X‐ray and differential thermal analysis indicates the possible existence of three crystalline polymer modifications. The infrared spectra of crystalline and amorphous samples have been investigated.
Polymerization of conjugated diolefins by homogeneous aluminum alkyl‐titanium alkoxide catalyst systems. I. Cis‐1,4 isotactic poly (1,3‐pentadiene)
Authors: Natta G. , Porri L. , Carbonaro A. , Stoppa G. 
Published: April 2003

AbstractThe polymerization of 1,3‐pentadiene by soluble aluminum alkyl‐titanium alkoxide catalysts is reported. Both the cis and trans isomers of 1,3‐pentadiene are polymerized by these catalysts to polymers prevalently constituted of cis‐1,4 units. By fractionating the crude products obtained from the trans isomer, amorphous and crystalline fractions were isolated; the latter were found to have a cis‐1,4 isotactic structure on X‐ray examination. By fractionating the crude products obtained from the cis isomer, polymers having only a very weak crystallinity could be isolated. A characterization of the crystalline cis‐1,4 isotactic polypentadiene by X‐ray and IR examination is also reported.
The catalytic effect of ferric acetyl acetonate on the rates of dimerisation and trimerisation of 2,4‐tolylene‐diisocyanate
Authors: Davis A. 
Published: April 2003

AbstractThe initial rates of dimerisation and trimerisation of 2,4‐tolylene diisocyanate (TDI), catalysed by ferric acetyl acetonate (FeAA), are given by the expressions

and

Compared to the FeAA catalysed urethane reaction the processes of dimerisation and trimerisation are unimportant, a conclusion similar to that arrived at for the uncatalysed cure of a polyurethane.There is strong evidence that at the temperatures employed (25 to 78°C.), the catalytic effect is reduced as a result of thermal decomposition of FeAA. It would appear therefore that stability of FeAA is likely to be an important factor in the cure of a polyurethane.
Structural studies on human serum γ‐globulins and myeloma proteins. II. Cleavage of disulfide bonds of the globulins with sulfite and recombination of the fragments
Authors: Yonezawa D. , Migliore P. J. , Capetillo S. C. , Jirgensons B. 
Published: April 2003

AbstractThe disulfide bonds of human serum γ‐globulins were cleaved with sulfite in the presence of complex cupric ions. Sedimentation and viscosity measurements showed that the molecular weight of thus treated γ‐globulin (I) was the same as that of the untreated γ‐globulin in neutral or alkaline solutions. However, dissociation was observed in glycine‐HCl buffer of pH 2.3, and in N acetic acid. Analysis on Sephadex G‐100 yielded two fractions corresponding to PORTER's A and B chains. The ratio of A:B was near 72:28, and it was independent of the sulfite concentration and reaction time. Free SH groups could not be detected. Immunodiffusion experiments showed that both A and B fractions retained antigenic properties to anti‐7 S human γ‐globulin antisera. A and B were antigenically different, and B reacted well with anti‐BENCE‐JONES protein antisera. Similarity of B to BENCE‐JONES proteins was shown also in solubility at high temperatures and polyacrylamide gel electrophoresis. It was shown by sedimentation, viscosity, and optical rotatory dispersion analysis that I after dissociation in N acetic acid formed complexes by removal of the acid, which were very similar to I before acetic acid treatment. It was also shown that, when I was treated with mercaptoethanol, macromolecules were formed which were similar to original γ‐globulins in immunodiffusion and in molecular weight and rigidity. These facts suggest a possibility to reconstitute γ‐globulins (antibodies) from their separated chains.
Zur technik der fällungspunkt‐titration
Authors: Gruber Von Urs , Elias Hans‐Georg 
Published: April 2003

AbstractEs wird eine Apparatur für die Fällungspunkt‐Titration beschrieben und Einfluß und Bedeutung möglicher Fehler bei der Bestimmung des kritischen Fällungsmittelbruches φcrit untersucht. φcrit wird durch Extrapolation von log φ = f(log cP) auf eine Konzentration (cP) von 100% des Polymeren erhalten.Inkludiertes Lösungsmittel kann die Meßwerte stark beeinflussen. Eine zehnprozentige Abweichung der effektiven von der wahren Ausgangskonzentration erzeugt dagegen in φcrit einen Fehler von weniger als 0,5%. Die Lösedauer soll mindestens zwei Tage betragen. Zur Erzielung optimaler Werte soll das Lösungsmittel möglichst gut und das Fällungsmittel mäßig stark sein, bei gleichzeitig geringem Küvetteninhalt. Bei Einhaltung dieser Arbeitsbedingungen kann bei φcrit ein mittlerer Fehler des Mittels von ± 0,1% und ein mittlerer Fehler der Einzelmessung von ± 0,3% erreicht werden. Um diese Fehlergrenzen einzuhalten, soll der Temperaturfehler weniger als ± 0,15°C betragen.
Molecular weight measurement by vapor pressure osmometer
Authors: Kume Shouji , Kobayashi Haruo 
Published: April 2003

AbstractA description is given of number average molecular weight measurement by activity depression of polymer solution at 37°C.The detected temperature difference is elucidate to be time‐dependent, and extrapolated values of temperature difference give correct values.Three thousands of molecular weight for polybutadiene was given by using chloroform with three percents error of 95% confidence limit.
Glycidäther‐Reaktionen. I. Darstellung, konstitution und eigenschaften neuer glycidäther‐derivate des 4,4′‐dihydroxy‐1,1′‐dinaphthyls und des 2,2′‐dihydroxy‐1,1′‐dinaphthyls
Authors: Jedliński Von Z. , Tokarzewska M. 
Published: April 2003

AbstractDarstellung, Konstitution und Eigenschaften von drei neuen Diglycidäthern auf der Grundlage von Polyphenolen, Derivaten des α,α′‐ und β,β′‐Dihydroxydinaphthyls sowie β,β′‐Dihydroxydinaphthylmethans werden beschrieben. Durch Elementaranalyse, Molekulargewichtsbestimmung, Epoxydgruppengehalt und IR‐Spektrum wurde die Struktur der dargestellten Äther gesichert.
Cationic isomerization polymerization of 3,3‐dimethyl‐1‐butene
Authors: Kennedy J. P. , Elliott J. J. , Hudson B. E. 
Published: April 2003

AbstractThe cationic polymerization of 3,3‐dimethyl‐1‐butene (t‐butyl ethylene) has been investigated. Polymerizations were carried out with AlCl3 catalyst in ethyl chloride solvent in the temperature range −31 to −130°C. Trimers (viscous oils or soft gels) were obtained between −31 and −100°C. The composition and structure of these materials is complicated and remains obscure. Solid polymer was obtained only at −130°C. This material, whose degree of polymerization is ∼ 68, is a white amorphous powder and it melts between 55 and 66°C. It is soluble in most common solvents.Careful NMR and IR spectroscopic studies indicate that the repeat structure of this polymer is:
magnified image
Crystalline alternating ethylene‐butadiene copolymers
Authors: Natta G. , Zambelli A. , Pasquon I. , Ciampelli F. 
Published: April 2003

AbstractThe copolymerization of ethylene with butadiene at −25°C. in the presence of co‐ordinated anionic catalytic systems, prepared at −78°C. from a vanadium compound, organometallic compounds of aluminum and a weak LEWIS base, yields copolymers with particular crystalline structure.By fractionation of crude products, crystalline ethylene‐butadiene copolymers were obtained, the crystalline structure of which was attributed to a succession of ethylene units regularly alternating with trans‐buta‐1,4‐dienic units.
Metal alkyl catalysts for cationic polymerization of vinyl monomers
Authors: Saegusa Takeo , Imai Hirosuke , Furukawa Junji 
Published: April 2003

AbstractNew catalyst systems consisting of, e.g., metal alkyl—H2O—cocatalyst for the polymerizations of styrene, vinyl ether and α‐methylstyrene were found. Metal alkyls were Al(C2H5)3 or Zn(C2H5)2 and active chlorine compounds such as α‐chlorodimethyl ether, acetyl chloride or tert.‐butyl chloride were cocatalysts.A mechanism of cationic polymerization was proposed in which AlEt3 behaves as LEWIS acid and forms a carbonium ion complex with the cocatalyst. The function of water was assumed to convert Al(C2H5)3 into another LEWIS acid and the ternary systems of Al(C2H5)3—H2O—cocatalyst were regarded as LEWIS acid‐cocatalyst systems.In the polymerization of styrene with Al(C2H5)3—H2O—CH3COCl, the mechanism of cationic polymerization initiated by acetyl cation was established by the end group analysis.
Equilibrium milting temperature: Some experimental data with isotactic polypropylene, polybutene‐1, and polypentene‐1
Authors: Danusso Ferdinando , Gianotti Giuseppe 
Published: April 2003

AbstractExtrapolation of „kinetic”︁ melting temperatures of polymer samples crystallized at different temperatures should localize the „equilibrium”︁ melting temperature; however, before approaching this value, crystallization times become extremely long, and a valid criterion of extrapolation must be sought. At the moment, a linear extrapolation seems to be reasonable, at least for the attainment of first approximation results.Polypentene‐1, modification 1, appears to have an equilibrium melting temperature around 130°C.; polybutene‐1 modification 1 around 138°C., and modification 2 around 130°C. The determination for polypropylene is particularly uncertain, because of a remarkable influence of the thermal history of the crystallized samples. For this polymer the equilibrium value is surely above 182–183°C., but it is difficult to say whether it is immediately above this value or rather over 200°C.
Isotactic polybutene‐1: Modification 3 and its transformations
Authors: Danusso F. , Gianotti G. , Polizzotti G. 
Published: April 2003

AbstractModification 3 of isotactic polybutene‐1, prepared by crystallization from a solution at room temperature, was studied by dilatometric and X‐ray examinations at different temperatures. At high degrees of crystallinity, its specific volume is intermediate between that of modification 1 and 2. By rapid heating its melting can be observed at about 102°C., while by a sufficiently slow heating it can even be totally converted into modification 1 before melting, by a solid‐solid transformation. Modification 1 obtained in this way melts surprisingly low, at 109°C., probably because of morphological memory. During the melting of modification 3, or modification 1 originated by modification 3, crystallization of available liquid phase usually takes place, giving modification 2, which happens to be the most highly melting polymorph under these particular conditions.
The effect of substituents on the polymerisation of lactams
Authors: Cubbon R. C. P. 
Published: April 2003

AbstractSubstituents influence the polymerisation of lactams by their effects on the ring closure reaction in the equilibrium between cyclic monomer and polymer. The effects of substituents on the enthalpy of ring closure of caprolactam is discussed in terms of the change in gauche interactions and the configuration of the amide bond. The entropy of ring closure is also considered qualitatively. This simple theoretical approach gives reasonable agreement with the experimental results.
The conformational transition in partially esterified poly‐(methacrylic acid)
Authors: Mandel M. , Stadhouder M. G. 
Published: April 2003

AbstractThe conformational transition of poly‐(methacrylic acid), partially esterified with dimethyl sulfate, has been studied using potentiometric titration at constant temperature.It is found that the stability of the form existing at low values of dissociation (α) is not decreased by reducing the number of groups on the chain capable of establishing intramolecular hydrogen bonds. The transition is also shown to depend on the average charge per monomeric unit. This confirms the hypothesis that the stable form at low α‐values is a compact structure stabilized probably by VAN DER WAALS attractions between —CH3 groups.
Auftragung der mit einer säulenelutionsmethode gewonnenen integralen massenverteilungskurven von hochdruckpolyäthylenen nach den methoden von tung bzw. Wesslau
Authors: Berger Von R. , Langhammer G. 
Published: April 2003

AbstractDie Auftragungsmethoden für die integralen Massenverteilungskurven nach TUNG sowie WESSLAU werden an vier Lupolenen und zwei Mirathenen (Hochdruckpolyäthylene) untersucht. Im TUNG‐Diagramm ergeben sich keine Geraden. Im WESSLAU‐Diagramm erhält man bei der Auftragung über M eine gute Annäherung an Geraden, wenn man das M aus einer Kombination zweier von GUILLET u.a. vorgeschlagenen [η]‐M‐Beziehungen berechnet. Die aus dem WESSLAU‐Diagramm gewonnenen Werte für M̄n, M̄w und U werden mit den direkt aus den „konventionellen”︁ integralen Verteilungskurven berechneten verglichen. Es wird festgestellt, daß die U‐Werte nicht so hoch sind, wie oft in der Literatur angegeben.
Degradation of polytetramethylene oxide. I. Thermally‐induced
Authors: Davis A. , Golden J. H. 
Published: April 2003

AbstractThe thermal degradation of polytetramethylene oxide has been examined in detail. The polymer contained weak links which led to facile chain scission on heating. (50 to 150°C.). The activation energy of this degradation process in xylene solution is 13.3 Kcal/mol. The available evidence indicates that the weak links are hydroperoxide groups formed in the presence of air. These groups could be destroyed by heating in vacuum, the resultant degree of degradation of the polymer depending on the number of hydroperoxide groups present.Measurements of the intrinsic viscosity of polytetramethylene oxide, freed from weak links, showed that the polymer underwent random chain scission at elevated temperatures according to the equation:

The exponent, α, of the KUHN‐HOUWINK equation was thus determined to be 0.75 for the polymer in benzene at 20°C. Analysis of the molecular weight changes occurring during degradation at various temperatures showed that the chain scission process obeyed first order kinetics and could be expressed by the rate equation:

This result is compared with activation energies obtained by thermogravimetry in air and vacuum.
Oxyaluminum compound catalysts for the polymerizations of cyclic ethers and vinyl monomers
Authors: Imai Hirosuke , Saegusa Takeo , Ohsugi Shōji , Furukawa Junji 
Published: April 2003

AbstractPreparation of a species which was assumed to resemble partly the AlEt3—H2O system was tried by the reaction between oxyaluminum chloride and AlEt3. The product of this reaction as well as oxyaluminum halides were examined in the catalytic activity for the polymerization of three‐, four‐ and five‐membered cyclic ethers and of vinyl monomers such as styrene, α‐methylstyrene, and i‐butyl vinyl ether. In the reaction of AlOCl with AlEt3, most chlorine atoms were replaced by ethyl groups and a soluble product was formed which we called oxyaluminum ethyl, AlOEt. These oxyaluminum compounds, AlOCl, AlOBr, AlOI, and AlOEt, induced the polymerizations of vinyl monomers with or without t‐butyl chloride cocatalyst and a mechanism of cationic polymerization was proposed. The polymerizations of i‐butyl vinyl ether carried out in toluene with AlOCl, AlOBr or AlOEt catalysts gave crystalline isotactic polymers. The polymerizations of 3,3‐bis(chloromethyl)oxacyclobutane and tetrahydrofuran were also induced by oxyaluminum compound—alkylene oxide systems. By oxyaluminum catalysts and by the binary systems of oxyaluminum compound and metal alkyl, alkylene oxides such as propylene oxide and epichlorohydrin were polymerized to give a product containing fairly amount of acetone‐insoluble crystalline part.
Reaktionsfähige Hochpolymere mit Dichlor‐s‐triazin‐Gruppen
Authors: Manecke Von Georg , Rewicki Dieter 
Published: April 2003

AbstractAus 2,4,6‐Trichlor‐s‐triazin (Cyanurchlorid) und Poly‐p‐hydroxystyrol oder Poly‐p‐bzw. ‐m‐aminostyrol wurden Polymere mit Dichlor‐s‐triazin‐Gruppen erhalten. Die entsprechenden Monomeren (I—III) sowie das Methacrylsäurederivat V wurden dargestellt und deren Polymerisationsfähigkeit untersucht. —Reaktionen der synthetisierten Polymeren werden beschrieben.
Sulfobenzoates of cellulose derivatives
Authors: Lemmerling J. 
Published: April 2003

Abstractm‐ and p‐sulfobenzoates of cellulose derivatives can be prepared by reaction of m‐ or p‐halogenosulfonyl benzoic acid with cellulose derivatives in pyridine medium.The structure of the obtained products has been confirmed by infrared spectra. The degree of substitution (DS) on sulfobenzoates has been determined by potentiometric titration and microanalysis.
Syntheses of some polymers containing cyclopropane rings in the main chain. II
Authors: Shono Tatsuya , Morikawa Takeshi , Okayama Ryo‐Ichi , Oda Ryohei 
Published: April 2003

AbstractPolyurethanes, polyureas, polycarbodiimide, and polyamines containing cyclopropane ring in the main chains wre prepared, using 1,2‐cyclopropane diisocyanate, 1,2‐diaminocyclopropane, 1,2‐cyclopropan‐diacyclisocyanat, 1,2‐disaminomethyl‐cyclopropane, or 1,2‐bisiodomethyl‐cyclopropane as one component, Polyurethanes and polyureas were prepared by usual methods. Polycarbodiimide was synthesized according to the method of CAMPBELL, where 1‐ethyl‐3‐methyl‐3‐phospholene oxide was used as polymerization catalyst. Polyamines were obtained by applying the novel method which was reported by KLEBE. Some polymers and their films showed good technological properties.
Polymerization of propylene to syndiotactic polymer. Part. I: Valence of active vanadium in the catalytic systems
Authors: Natta G. , Zambelli A. , Lanzi G. , Pasquon I. , Mognaschi E. R. , Segre A. L. , Centola P. 
Published: April 2003

AbstractHomogeneous catalytic systems for the polymerization of propylene both to syndiotactic and amorphous polymers, based on soluble vanadium compounds and organometallic compounds of aluminium, were investigated by EPR analysis at different temperatures. It was shown that the vanadium in the catalytic complex has a valence state of 3.
Reactivity of α‐alkylacrylic esters. II. Copolymerization behaviours of methyl α‐alkylacrylates
Authors: Chikanishi Kunio , Tsuruta Teiji 
Published: April 2003

AbstractThe relative reactivities of α‐substituted methyl acrylates toward styrene radical decrease in the following order of the substituents C6H5 ≫ CH3 > C6H5CH2 > H ∼ C2H5 ∼ nC3H7 ∼ n‐C4H9 > i‐C4H9 > cyclo‐C6H11 > i‐C3H7 > sec‐C4H9. The order can mostly be explained in terms of a steric effect. A linear relationship between the relative reactivities and TAFT's steric parameters has been found with the exception of a few α‐substituents.
Effect of pressure on the radiation‐induced solid state polymerization of acrylamide
Authors: Tabata Y. , Suzuki T. 
Published: April 2003

AbstractThe effect of pressure on the radiation‐induced solid state polymerization of acrylamide has been studied in a pressure range of 1 to 5000 atm. over a temperature region of 28 to 70°C. Rates of polymerization and molecular weights have been measured.It was found that the rate of polymerization is suppressed by pressure at the lower temperatures; in the contrary, the rate is accelerated near the melting point.On the other hand, it was also found that the rate of polymerization is suppressed by pressure in an initial stage of polymerization, while it is accelerated in a later stage of polymerization at the same temperature.The number of polymer chains obtained is not affected by pressure; it depends on the irradiation dose only. These results indicate that the pressure has very little effect on the rate of initiation but that the propagation rate constant is profoundly affected by pressure.The effect of the pressure on the solid state polymerization of acrylamide is attributed to the pressure dependence on the activation enthalpy (ΔH ‡) and the activation entropy (ΔS‡) of the propagation step.