bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the determination of molecular weight distribution by the Spencer's method
Authors: Kamide Kenji , Ogawa Tsutomu , Nakayama Chozo 
Published: April 2003

AbstractIn order to examine the method of fractionation into summative fractions proposed by SPENCER, a complete mathematical fractionation was carried out by using an electronic computer according to the procedure of KAMIDE, OGAWA, and their coworkers. Various amounts of precipitates were separated from a 1.0% solution of a polymer having the most probable size distribution with the number‐average degree of polymerization (P)X̄ = 150. The solution theory by FLORY and HUGGINS was employed as the principle basis of the fractionation. The fractionation data obtained in this manner were analyzed according to the SPENCER'S method and the method revised by OKAMOTO to elucidate the integral P distribution in the initial polymer. The results were compared with the true distribution (i.e., the most probable distribution) and with the distribution evaluated from a simple successive precipitation method through use of the SCHULZ's procedure. It was found that the SPENCER's method has a tendency, more or less, to underestimate both the lower and higher regions of the molecular weight distribution. However, the SPENCER's method is sometimes preferable to the successive precipitational method to evaluate the P distribution. The OKAMOTO's method was found successful in a wide range of molecular weights.
ÜBer die polymerisation des trioxans mit thalliumtrichlorid und dessen gemische mit äthylmagnesiumbromid
Authors: Kabaivanov Von V. , Glavcev I. , Natov M. 
Published: April 2003

AbstractDie durch TlCl3 ausgelöste Polymerisation von Trioxan wurde untersucht. Ausbeute und spezifische Viskosität erreichen maximale Werte bei einer Katalysatorkonzentration von 2ċ10−4 Mol TlCl3/Mol Trioxan. Das innerhalb gewisser Grenzen im Monomeren enthaltene Wasser wirkt als Cokatalysator. Als besonders aktiv erwies sich der aus einem Gemisch von TlCl3 und C2H5MgBr (1:2) entstandene Katalysator. Für diesen Katalysator liegt die optimale Polymerisationstemperatur bei 75°C.
Über polymere acide kohlenwasserstoffe. Synthese und eigenschaften von polymeren des 9‐[2‐vinylfluorenylidenmethyl]‐fluorens
Authors: Förster Von H. J. , Manecke G. 
Published: April 2003

AbstractDie Synthese des 9‐[2‐Vinylfluorenylidenmethyl]‐fluorens aus 2‐Vinylfluoren und Bi‐phenylenvinylbromid wird beschrieben. Das erhaltene Monomere war sowohl radikalisch als auch kationisch polymerisierbar und ließ sich mit Styrol und Divinylbenzol zu vernetzten Copolymeren polymerisieren. Die Polymeren lassen sich mit Basen in tief rotviolett gefärbte polymere Carbanionen überführen, die mit Oxydationsmitteln zu polymeren Radikalen entladen werden können.
Darstellung und eigenschaften chelatbildender monomerer und polymerer sCHIFFscher basen vom salicylaldehyd und vom 2.5‐dihydroxyterephthalaldehyd (teil I)
Authors: Manecke Von Georg , Wille Werner E. 
Published: April 2003

AbstractMonomere SCHIFFsche Basen und Chelate des Salicylaldehyds mit verschiedenen Diaminoverbindungen wie Methylendiamin, Bis‐(2‐aminophenyl)‐disulfid und Bis‐(4‐aminophenyl)‐disulfid, Tetraaminoverbindungen wie 1.2.4.5‐Tetraaminobenzol und 3.3′.4.4′‐Tetraaminobiphenyl und Diaminodihydroxyverbindungen (mit einer jeweils zur Aminogruppe orthoständigen Hydroxylgruppe) wie 4.6‐Diaminoresorcin‐(1.3); 4.4′‐Diamino‐3.3′‐dihydroxy‐,3.3′‐Diamino‐4.4′‐dihydroxy‐ und 3.3′‐Diamino‐2.2′‐dihydroxybiphenyl; 4.4′‐Diamino‐3.3′‐dihydroxy‐ und 3.3′‐Diamino‐4.4′‐dihydroxydiphenylmethan wurden erstmals dargestellt. Durch Umsetzung des 2.5‐Dihydroxyterephthalaldehyds mit verschiedenen aliphatischen und aromatischen Diaminen und mit den oben aufgeführten Diaminodihydroxyverbindungen wurde eine Reihe von polymeren SCHIFFschen Basen dargestellt und deren Chelatbildungsfähigkeit am Beispiel der jeweiligen Nickelchelate untersucht. Durch Umsetzung des 2.5‐Dihydroxyterephthalaldehyds und seines Dioxims mit Metallsalzen wurden Koordinationspolymere erhalten.
Radical reactions initiated by chelate complexes of transition metals. V. Effect of the system bis‐(–)ephedrine copper(II)chelate/carbon tetrachloride on the degradation and/or crosslinking of polymers
Authors: Bartoň J. , Ďurďovič V. , Horanská V. 
Published: April 2003

AbstractThe reaction system bis‐(–)ephedrine copper(II)chelate/carbon tetrachloride was used as a source of trichloromethyl radicals for degradation and/or crosslinking of various polymers. It was found that this reaction system was little effective in degradation of polystyrene and polyisobutylene and/or crosslinking of polyethylene. The chain scission efficiency for polyisobutylene and polystyrene is of order 10−4 to 10−3 while no detectable quantity of gel was observed in the crosslinking of polyethylene. For the ratio of the rate constant of the reaction between trichloromethyl radicals and polystyrene, kPo1 H, and the rate constant of the reaction between trichloromethyl radicals and chelate, kChel H′ the value kPol H/kChel H = 0.18 was found. Thus trichloromethyl radicals react approximately 5 times more readily with hydrogen atoms of the chelate than with polystyrene. This result may account for the low efficiency of the system chelate/carbon tetrachloride in the degradation and/or crosslinking of polymers.
Fraktionierung von copolymeren aus styrol und p‐jodstyrol
Authors: Braun Von Dietrich , Chaudhari Dinkar 
Published: April 2003

AbstractCopolymere aus Styrol und bis zu 33 Mol‐% p‐Jodstyrol lassen sich in einer BAKER‐WILLIAMS‐Kolonne mit Benzol/Methanol nach dem Molekulargewicht fraktionieren. Die Copolymeren lassen sich polymeranalog in Polystyrole überführen.
Polymerisation des isobutylens durch zweikomponenten‐katalysatorsysteme, die aluminiumhalogenid als eine der komponenten enthalten
Authors: Lopour Von Petr , Marek Miroslav 
Published: April 2003

AbstractEs wurden hochaktive Initiatoren der Polymerisation des Isobutylens untersucht, die aus Aluminiumbromid oder ‐jodid in Kombination mit einigen FRIEDEL‐CRAFTS‐Halogeniden (TiCl4, SnCl4, BCl3 u. a.) bestehen. Dabei wurde festgestellt, daß bei der Initiierung dieser Polymerisation durch die genannten Zweikomponenten‐Katalysatorsysteme die durch die Reaktion ihrer Bestandteile entstehenden Mischhalogenide des Aluminiums eine bedeutende Rolle spielen. Die Beziehung zwischen der katalytischen Wirksamkeit der Zweikomponenten‐Katalysatoren und den Eigenschaften ihrer einzelnen Komponenten wurde geklärt.
Oxidative coupling polymerization of bisphenols
Authors: Yoshikawa Toshio , Kumanotani Ju 
Published: April 2003

AbstractThe oxidative coupling reactions of 4.4′‐isopropylidene‐bis‐(2‐methyl‐6‐tert‐butylphenol) or 4.4′‐isopropylidene‐bis‐(2‐tert‐butylphenol) with aqueous alkaline solution of potassium ferricyanide were found to give polymeric products (mol. wt. ca. 4500) which show self‐curing reaction by heating.By comparing their spectral data with those of their model compounds, it was found that they contain the cyclohexadienone (o‐quinol ether) structure which contributes to the self‐curing reaction.
Kinetic study of emulsion polymerization of vinyl chloride
Authors: Vidotto G. , Crosato‐Arnaldi A. , Talamini G. 
Published: April 2003

AbstractA kinetic study of vinyl chloride polymerization initiated with potassium persulphate at 50°C was carried out in water buffered to pH equal to 7 using sodium lauryl sulphate as emulsifier and with a ratio water to monomer equal to 2.8.Vinyl chloride was polymerized at emulsifier concentration both higher and lower than the critical micellar concentration (about 0.01 g/100 ml H2O).At emulsifier concentrations above the critical micellar concentration, kinetics of polymerizations begin with the same reaction rate, then, they differentiate showing a sharp decrease at conversions and times which are a function of emulsifier and initiator concentrations. After this decrease, the rate increases up to about 30% of conversion, then remains constant and finally, for conversions higher than 80%, decreases.The kinetic data of these emulsion polymerizations are in good agreement with the SMITH‐EWART theory, if one makes allowance for the polymerization occurring in water.
The radiation induced reactions of aqueous polyethylene oxide solutions. IV. Effect of additives as selective scavengers
Authors: Stafford J. W. 
Published: April 2003

AbstractIt was found that the effect of additives on the radiation induced reactions of aqueous polyethylene oxide solutions cannot be explained solely on the basis of competition between polymer and additive for hydrogen abstracting radicals. Polymer‐solvent and polymer‐additive interactions were found to be important. Some systems studied were best described in terms of the effect of additive on the radiation chemistry of water and the action of products of additive‐radical reactions on the polymer. Additives capable of influencing the ratio of intra to intermolecular crosslinking produced marked effects. The results indicate that polyethylene oxide is very reactive toward the hydroxyl radical, less so toward the hydrogen atom, and relatively inactive toward the solvated electron, although solvated electron scavengers increase the dose required to gel.
Anwendung der gelchromatographie auf cellulosenitrate
Authors: Meyerhoff Von G. 
Published: April 2003

AbstractEs wird über gelchromatographische Untersuchungen von Cellulosenitrat und Polymethylmethacrylat in Aceton als Lösungsmittel berichtet. Das günstigste Trennverhalten für die Fadenmoleküle sehr großen Durchmessers wurde mit hochvernetzten für Aceton gepackten Styrolgelen erzielt.Als universelle Trennparameter versagten die in Tetrahydrofuran häufig anwendbaren Kombinationen von [η] und M. Am besten stimmen noch die mittels Lichtstreuung gemessenen Trägheitsradien als Funktion des Elutionsvolumens für die beiden Polymeren überein.
Preparation and behavior of polymeric isothiuronium salts
Authors: Dykstra Thomas K. , Smith Donald A. 
Published: April 2003

AbstractMethacryloyloxyalkylisothiuronium salts were synthesized as precursors to polymers with pendant thiol groups. As indicated by potentiometric titration and polarography, thiol is generated from the monomers and their polymers by treatment with base. However, in some cases subsequent reactions consume the thiol formed. The rates at which thiol is generated and consumed are discussed in terms of chemical structure.
Bis‐trichloracétates des polyoxyéthylènes glycols. Utilisation pour la détermination précise de leur masse moléculaire moyenne en nombre et comme agent de synthèse
Authors: Galin Par Jean‐Claude , Galin Monique , Calme Paul 
Published: April 2003

AbstractDie Reaktion von Trichloracetylchlorid mit Polyglykolen verschiedener Molekulargewichte kann man in Substanz oder in Dimethylformamidlösung durchführen. Man kann auf diese Weise aus den Polyglykolen quantitativ die Bis‐trichloracetate herstellen, wobei keine Kettenspaltung eintritt. Aus dem Chlorgehalt dieser Polymeren erhält man genauere Werte für das Zahlenmittel des Polymerisationsgrades als mit anderen chemischen oder physikalischen Methoden.Die Initiierung der Polymerisation mit Hilfe des Donator‐Akzeptor‐Komplexes (DA) aus SO2 und Pyridin in Gegenwart von Bis‐trichloracetaten der Polyglykole ermöglicht es, Polyglykol/Polymethylmethacrylat‐Blockcopolymere zu synthetisieren.
Synthese von poly‐[m/p‐phenylen]‐4‐methyl‐1.2.4‐triazolen
Authors: Sundquist Von Jorma 
Published: April 2003

AbstractEinige Poly‐[m/p‐phenylen]‐N'‐methyl‐acylamidrazone wurden durch die Umsetzung von aromatischen Dihydraziden mit aromatischen N.N'‐Dimethyl‐bis‐imidchloriden bzw. N.N'‐Dimethyl‐bis‐iminoestern in Lösung hergestellt.Die Polyacrylamidrazone cyclisieren bei höheren Temperaturen im festen Zustand im Vakuum zu den entsprechenden Poly‐[m/p‐phenylen]‐4‐methyl‐1.2.4‐triazolen. Die Polymeren wurden mit inhärenten Viskositäten, IR‐Spektren, Thermoanalysen und Löslichkeiten charakterisiert. Poly‐[m/p‐phenylen]‐4‐methyl‐1.2.4‐triazole [inh. Viskosität bis 0,46] sind thermisch bis 350–400°C beständig.
Simulation of successive precipitational refractionation of macromolecules by electronic computer
Authors: Kamide Kenji , Ogawa Tsutomu , Nakayama Chozo 
Published: April 2003

AbstractAn attempt has been made to study the following refractionation method proposed by KAMIDE and his coworkers: The first fraction precipitated from a solution of a comparatively high initial concentration is divided by refractionation into several subfractions. The polymer‐lean phase obtained in the last refractionation stage is returned to that in the first fractionation step. As above described, the fractionation followed by the refractionation is repeated adequate times. Taking the FLORY‐HUGGINS theory as the basic principle, the hypothetical refractionations were performed by an electronic computer for a 1.0% solution of the polymer having the most probable distribution (the number‐average degree of polymerization X̄n = 150). The combination of the number of the fractions, i, with the number of the sub‐fractions per each fraction, j, as expressed by (i∼j), was chosen so as ij to be 15, such as (15∼1), (5∼3), (3∼5). The sub‐fractions showed a P distribution qualitatively similar to that obtained by a simple successive fractionation. The fractionation efficiency decreases in the order: (0∼15)0.1, (15∼1)1.0, (5∼3)1.0, (3∼5)1.0, (0∼15)1.0, where (0∼15) stands for the simple successive precipitation which yields 15 fractions as a total number of the fractions, and the suffix 0.1 or 1.0 refers to the initial concentration expressed by volume per cent of a dilute solution, from which the first fractions are separated. The (3∼5) and (5∼3) type refractionations were found to be also sufficiently effective with the exception of a few initial fractions to obtain fractions with X̄w/X̄n ≤ 1.1, where X̄w is the weight‐average P. The total numbers of separating steps necessary for these refractionation procedures are not so different from those of a simple successive fractionation.In addition, the method of KAMIDE et al. was compared with the SCHULZ's method by evaluating the cumulative weight P distribution of the initial polymer using the refractionation data (X̄w and the amount of the sub‐fractions). The method of SCHULZ underestimates both the smaller and larger P regions. On the other hand, the method of KAMIDE et al. slightly overestimates the smaller P region but gives the accurate distribution in the larger P region.
On the mechanism of polymerization of formaldehyde initiated by tertiary amines and phosphines. 3rd communication on macrozwitterions
Authors: Mathes N. , Jaacks V. 
Published: April 2003

AbstractTwo mechanisms are feasible in the anionic polymerization of virtually anhydrous formaldehyde initiated by uncharged LEWIS‐bases such as tertiary amines and phosphines:1. Direct initiation with formation of macrozwitterions the conventional mechanism in which an impurity such as water or methylene glycol acts as a cocatalyst. The investigations were carried out mainly by end group analysis. With triethyl amine as initiator the cocatalysis mechanism is the only or, at least, the predominant mechanism (at 20°C in dimethyl formamide). Quaternary ammonium ions – if any – are present in concentrations much below the concentrations of anionic chain ends. The latter were determined by termination with ethyl iodide and determination of the ethyl end groups formed in this termination reaction. Any quaternary ammonium end groups should be quite stable as indicated by the investigation of model compounds and by the lack of decomposition products in the polymer.In contrast, with triphenyl phosphine and with phosphorous acid tris(dimethylamide) as initiators the zwitterion mechanism seems to be correct and phosphorous is chemically incorporated in the polymers.
Gelchromatographische analyse der produkte der diels‐alder‐reaktion von chloropren
Authors: Čoupek Von J. , Bouchal K. 
Published: April 2003

AbstractDie DIEIS‐ALDER‐Reaktion und die thermische Polymerisation von Chloropren wurd en gelchromatographisch quantitativ verfolgt. Bei Anwendung eines Systems chromatographischer Säulen mit hoher Trennleistung wurde die Trennung der zyklischen Dimeren von Chloropren in Anwesenheit des Monomeren und Polymeren an einem Perlcopolymerisat Styrol/Divinylbenzol erreicht. Die gelchromatographisch erhaltene Temperaturabhängigkeit der Geschwindigkeitskonstante des Monomerenverbrauchs stimmt sehr gut mit den gaschromatographischen und dilatometrischen Angaben überein.
Optische rotationsdispersion und circulardichroismus von komplexen der amylose mit kupfer‐ und kobaltamminen. 5. Mitteilung
Authors: Heide Von , Bössler M. , Schulz Rolf C. 
Published: April 2003

AbstractSCHWEIZERs Reagens (Kupfertetramminhydroxid) bildet in verdünnter wäßriger Lösung mit Amylose einen Komplex, der mehrere induzierte COTTON‐Effekte aufweist. Aus den ORD‐Kurven ergibt sich für die Zusammensetzung des Komplexes ein Verhältnis von Cu:C6H10O5 = 1:1. Die Struktur dieses Komplexes ergibt sich aus den COTTON‐Effekten durch Vergleich mit niedermolekularen Modellverbindungen. Kupfertetramminsulfat bildet mit Amylose die gleichen Komplexe. Kupfersulfat hat keinen Einfluß auf die normale Rotationsdispersion von Amylose.Ammoniakalische Kobaltsalzlösungen bilden ebenfalls mit Amyloselösungen Komplexe, die induzierte COTTON‐Effekte aufweisen. Die Drehwerte ändern sich stark im Laufe einiger Stunden; es ist anzunehmen, daß sich ein Gleichgewicht aus verschiedenen Komplexen einstellt. Die Brutto‐Zusammensetzung dieser Kobalt‐Amylosekomplexe konnte nicht eindeutig bestimmt werden.
Thermal degradation of polyvinylpyridine and its copper chelates
Authors: Geuskens G. , Borsu M. , Hellinckx E. , David C. 
Published: April 2003

AbstractA fast initial drop of the molecular weight is observed when poly‐2‐vinylpyridine (2‐PVP) is heated at 250°C under vacuum. Such a behaviour is very similar to that of polystyrene; it must be attributed to the breaking of weak links or to a combination of random scission and intermolecular transfer. Chelation of 2‐PVP or 4‐PVP by Cu2⊕ions decreases markedly the stability of those polymers, and fast degradation occurs already at 100°C. The initiation of that process is due to a redox reaction.
A kinetic investigation of propylene oxide polymerization with diethylzine/alcohol catalyst system
Authors: Furukawa Junji , Kumata Yoshiyuki 
Published: April 2003

AbstractThe kinetic study on the polymerization of propylene oxide was carried out according to the continuous variation method as well as the independent one. In the former the catalyst fraction is varied in catalyst/monomer system, whose total amount is kept constant and in the latter the concentrations of monomer and catalyst are independently varied. It was found that the polymerization is proportional to [M]2[C] in the former, whereas to [M][C]1.7–2 in the latter. The mechanism is discussed in terms of the concept that the active catalyst site exists in a dimer form and two monomers are coordinated to the catalyst.
Oligomerization of styrene by trichloroacetyl chloride
Authors: Nishihara Koji 
Published: April 2003

AbstractThe thermal oligomerization of styrene at 60°C with trichloroacetyl chloride (TAC) was investigated. The initial rate of oligomerization can be described by the equation

The analysis of the oligomers showed that the main component of the oligomers was a styrene trimer of the structure magnified image
Radical polymerizations of vinyl monomer‐stannic chloride complexes
Authors: Yamada Bunichiro , Kusuki Yoshihiro , Otsu Takayuki 
Published: April 2003

AbstractThe reactivities of stannic chloride complexes with acrylonitrile, ethyl acrylate, and methyl methacrylate (1 : 1 molar ratio) were evaluated from the radical copolymerizations with vinyl chloride at 35–50°C. The vinyl chloride content in the resulting copolymers with acrylonitrile and ethyl acrylate were found to increase in the presence of stannic chloride. The reactivities of the complexes of these monomers were evaluated on the basis of the results of the copolymerizations in the presence of an excess stannic chloride. The Q and e values of these complexes were as follows: Acrylonitrile‐stannic chloride (1 : 1 molar ratio) complex, Q = 2.64, e = 2.22; ethyl acrylate‐stannic chloride (1 : 1 molar ratio) complex, Q = 3.58, e = 1.92.However, the vinyl chloride content in the copolymer with methyl methacrylate decreased with the addition of stannic chloride. The Q and e values of the complex (1 : 1 molar ratio) were estimated as Q = 2–4 and e = 0.4–1.0.
Applications of the two beam and the multiple beam interferometry techniques to polymer crystals
Authors: Patel G. N. , Patel R. D. 
Published: April 2003

AbstractTwo beam interference fringes over hedrites, sheaves, and spherulites of cellulose triacetate are obtained on crystals grown on carbon coated slides. The multiple beam interference fringes over the same crystals are obtained after silvering. The ratio of the fringes observed by the two beam to the multiple beam interferometry over the same crystal gave the refractive index of the crystal along the direction of the beam. Application of these techniques showed that the change of thickness of hedrites and sheaves due to increase in polymer concentration is the same. The hedrites of cellulose triacetate are diagonally thin and have a square depression at the centre. The surfaces of spherulites grown from solution are uneven.
Die bestimmung der molekulargewichtsverteilung von nichtkristallisierenden polymeren mit dem elektronenmikroskop. II. Zur quantitativen charakterisierung der schrägbedampfung
Authors: Barnikol Von I. , Barnikol W. K. R. , Jovanović N. , Schulz G. V. 
Published: April 2003

AbstractVerschiedene Methoden der Schrägbedampfung werden untersucht und hinsichtlich der „kompakten Höhe”︁ und der Rastergröße der Bedampfungsschicht charakterisiert. Als besonders geeignet erweist sich die direkte Verdampfung des Platins von einem Wolframdraht, wobei mit Hilfe eines bestimmten Blendensystems das Auftreten von Bedampfungs‐Scheinmolekülen verhindert werden kann.Polystyrolmoleküle scheiden sich auf der Unterlage (FormvarfilmPolyvinylformal
) im Form sehr flacher Teilchen ab, die mit guter Näherung als Kugelabschnitte zu berechnen sind. Bei der Auswertung der Aufnahmen ist das Auftreten von sogenannten Dekorationseffekten zu beachten, die zu zwei unterscheidbaren Schattenfeldern führen.
Kinetics and mechanism for the reaction between electrochemically produced naphthalene radical‐anions and ethylene and propylene oxides
Authors: Mengoli Giuliano , Vidotto Graziano , Furlanetto Ferdinando 
Published: April 2003

AbstractThe reaction between naphthalene radical‐anions produced through electrochemical reduction of naphthalene and ethylene and propylene oxides has been investigated in dimethylformamide at various temperatures using amperometric and polarographic techniques. The decay rate of naphthalene radical‐anions has been found to depend at the first power on their concentration and the concentration of ethylene and propylene oxides. The activation energies of the reactions are ⋍ 9.5 kcal/mole for ethylene oxide and ⋍ 11.5 kcal/mole for propylene oxide. As naphthalene radical‐anions oxidize completely to naphthalene, the interaction process is interpreted as an electronic transfer from radical‐anions to ethylene and propylene oxides.