bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vinyl polymerization by metal complexes, 19. Formation of copper(II) chelates of vinylamine/vinyl alcohol copolymers
Authors: Kimura Keiichi , Inaki Yoshiaki , Takemoto Kiichi 
Published: April 2003

AbstractChelate formation of vinylamine/vinyl alcohol copolymers with copper(II) was studied both by the spectrophotometric and by titrimetric methods. For comparison, polyvinylamine/poly(vinyl alcohol) mixtures were also taken up for measurements. In the case of the copolymer systems, copper(II) ions were found to be coordinated exclusively by nitrogen atoms of the copolymer ligand. The complexation constants of the chelates were determined by applying the modified Bjerrum method, in neglect of the acid dissociation of hydroxy groups in the copolymers. It was found that the copolymer/Cu(II) chelates tend to be unstable with decreasing contents of NH2 groups in the copolymers. In the homopolymer mixture systems, copper(II) ions are not coordinated by the oxygen atoms of poly(vinyl alcohol), but only by the nitrogen atoms of polyvinylamine.
Studies on polymerizations initiated by syncatalytic systems based on aluminium organic compounds, 5. Copolymerization of isobutene and isoprene catalyzed by diethylaluminium chloride and chlorine
Authors: Cesca Sebastiano , Priola Aldo , Bruzzone Mario , Ferraris Giuseppe , Giusti Paolo 
Published: April 2003

AbstractAn extensive investigation of the main parameters regulating the copolymerization of isobutene and isoprene, initiated by the catalyst system diethylaluminium chloride + chlorine in methyl chloride, was carried out. The influence of the concentration of the catalyst components, of the monomers, of 1‐butene, and of the polymerization temperature on the yield, the molecular weight and the composition of the copolymer was studied. The reactivity ratio of isobutene with respect to isoprene is 2,5 ± 0,5 at −35°C. The activation energy M is −23,9 ± 3 kJ/mol and −18,0 ± 2 kJ/mol (−5,7 ± 0.7 and −4,3 ± 0,5 kcal/mol) for the copolymer with a mole fraction of 0,013 and 0,019, respectively, of isoprene, and −24,3 ± 2 kJ/mol (−5,8 ± 0,4 kcal/mol) for polyisobutylene. The results are compared with similar data obtained for the system diethylaluminium chloride + tert‐butyl chloride and diethylaluminium chloride + hydrogen chloride. The influence of water on the activity of the catalyst was investigated briefly and discussed. Some technological data obtained with typical copolymers are also reported.
Free volume concept and polymer solutions thermodynamics
Authors: Dayantis Jean 
Published: April 2003

AbstractAfter briefly recalling previous work on thermodynamics of polymer solutions, we tentatively present a van der Waals‐like relationship for the excess enthalpy of mixing for polymer solutions, applied recently by Bagley et al. to simple mixtures and we derive the corresponding value of χH, the enthalpic part of the Flory‐Huggins parameter χ.
Chemical structure of vinyl alcohol/acrylamide graft copolymers prepared by the cerium(IV) ion method
Authors: Staszewska Danuta 
Published: April 2003

AbstractGraft copolymerization of acrylamide onto poly(vinyl alcohol) (PVA) samples with different 1,2‐diol content was carried out by the Ce(IV) ion method. The poly(acrylamide) (PAAd) side chains were separated by oxidative degradation of the PVA backbone with nitric acid at which treatment the PAAd side chains reacted to poly(acrylic acid) (PAA) chains without a change of the degree of polymerization. The chemical structure of the graft copolymers was clarified on the basis of the number average molecular weights of the pure graft copolymer, of separated branches, and of the mother PVA molecules and the chemical composition of the graft copolymers. It was found that the number of branches per molecule was greater than one and increased with increasing content of 1,2‐diol structures in the PVA mother molecule. A number of grafted branches as high as 12 caused the graft copolymer to be insoluble in water.
Functional monomers and polymers, 24. Emission spectra of polymers containing nucleic acid bases
Authors: Inaki Yoshiaki , Renge Tsumoru , Kondo Koichi , Takemoto Kiichi 
Published: April 2003

AbstractThe emission and the ultraviolet spectroscopies were studied at 77 K in water/ethylene glycol or ethanol for polymers containing adenine, 6‐(methylamino)purine, and 6‐(dimethylamino)purine moieties, and for the corresponding dimeric and monomeric model compounds, in order to obtain more information about the nature and extent of the interactions between nucleic acid bases in the polymer chains. The emission spectra of the dimeric compounds and the polymers suggested the formation of excimers and the existence of strong interactions between the adenine rings of suitable compounds. These excimer emissions were not observed in the spectra measured in ethanol, and in water/ethylene glycol solutions at pH 2. The ultraviolet spectra suggested two kinds of base‐base interactions for plane in plane and coplanar arrangement.
Ethylene/propene copolymerization in the presence of the homogeneous catalyst system Ti(Oi‐C3H7)4/Al(C2H5)2F
Authors: Locatelli Paolo , Provasoli Augusto , Zambelli Adolfo 
Published: April 2003

AbstractThe behaviour of the homogeneous catalyst system Ti(Oi‐C3H7)4/Al(C2H5)2F in ethylene/propene copolymerization was studied.The copolymer structure is discussed in view of the stereoregulation mechanism previously proposed for vanadium‐based homogeneous catalyst systems.
Studies on functional micelles, 5. Solvent and salt effects on the micellar condensation of thioalanine S‐alkyl esters
Authors: Kawabata Yasuziro , Kinoshita Masayoshi 
Published: April 2003

AbstractThe condensation reaction of thioalanine S‐dodecyl ester (1c) was carried out in several organic solvents, or in their mixtures with water. In acetone, benzene, chloroform, or hexane, no cyclic dimer of alanine, 3,6‐dimethyl‐2,5‐piperazinedione (2) and in the water/organic solvent mixtures only low yields of 2 were obtained, contrary to the good yields which resulted in water alone. In the condensation reaction of thioalanine S‐octyl ester (1b) obvious salt effects were observed, especially with FeCl3.
Effect of solvents and initiators on the cationic copolymerization of 1,3‐dioxolane with 5‐methyl‐2,3‐dihydro‐2‐furanone
Authors: Yokoyama Yasuaki , Okada Masahiko , Sumitomo Hiroshi 
Published: April 2003

AbstractThe cationic copolymerization of 1,3‐dioxolane (1) with 5‐methyl‐2,3‐dihydro‐2‐furanone (2) which has two functional groups, a carbon‐carbon double bond and a lactone ring, was carried out with three triethyloxonium salts (Et3O+Y−, Y−: BF, FeCl and SbCl), with the boron trifluoride ethyl ether complex, and with tin tetrachloride in nitrobenzene, dichloromethane, and toluene at 0°C. On the basis of the NMR analysis of the microstructure of the copolymer, it was revealed that the growing species of 1 attacked exclusively the carbon‐carbon double bond of 2 in the cross‐propagation from 1 to 2, regardless of the solvents and initiators used, except when triethyloxonium hexachloroantimonate was used as initiator. With the latter initiator, the ring opening reaction of 2 by the attack of the growing species of 1 occurred competitively with the usual vinyl addition, although the latter mode of reaction was predominant. The ring opening reaction of 2 with this initiator is probably caused by some specific interaction of monomer 2 with the counter anion.
Synthesis of monomers expanding on polymerization. Synthesis and polymerization of 3‐methylene‐1,5,7,11‐tetraoxaspiro[5.5]undecane
Authors: Endo Takeshi , Bailey William J. 
Published: April 2003

AbstractA spiro ortho carbonate containing a double bond, 3‐methylene‐1,5,7,11‐tetraoxaspiro‐[5.5]undecane (2) was prepared from 2‐methylene‐1,3‐propanediol. The structure of the monomer was confirmed by its elemental analysis, IR and NMR spectra. The monomer was polymerized with Lewis acids such as boron trifluoride etherate and stannic chloride (tin tetrachloride) as catalysts. The IR and NMR spectra indicated that the polymer has the structure of an alternating copolymer containing ether and carbonate linkages with a pendant double bond (structure 8).Monomer 2 underwent expansion on polymerization.
Sequenzspezifische Cooligokondensation von Nucleinsäure‐Bausteinen mit Affinitäts‐Schutzgruppen, 1. Desoxyoligonucleotide mit 3′‐Ribouridin‐Terminus
Authors: Seliger Hartmut , Rössner Ernst , Aumann Gerd , Genrich Volker , Holupirek Manfred , Knäble Thomas , Philipp Manfred 
Published: April 2003

AbstractEs wird ein neues Verfahren zur Gewinnung von Oligonucleotid‐Fragmenten beschrieben, die zum Aufbau von Polynucleotiden eingesetzt werden können.Es beruht auf der chemischen Cooligokondensation von Nucleinsäurebausteinen der allgemeinen Formel XA, pB und pCY. Dabei sind A, B und C beliebige Nucleoside. X und Y sind Schutzgruppen, die der geschützten Oligonucleotidkette eine bestimmte Affinität verleihen (sog. „Affinitäts‐Schutzgruppen”︁). Es werden Beispiele besprochen, bei denen eine 3′‐terminale Uridineinheit als Affinitätsschutzgruppe dient. So wurde Thymidylsäure mit Derivaten der Ribouridylsäure cooligokondensiert, die beiden Typen von Produkten – (pdT)n und (pdT)nrU – durch Chromatografie auf Boratsäulen getrennt und anschließend die einzelnen Sequenzen durch DEAE‐Cellulose oder Papierchromatographie in reiner Form gewonnen. Die Cooligokondensation von Thymidylsäure mit O2′+ O3′‐(Diacetylribouridyl‐5′,3′‐yl)‐N‐(acetyl)desoxycytidin‐5′‐phosphat ergab Sequenzen (pdT)ndCrU. Weiterhin wurde die Dreikomponenten‐Cooligokondensation von 5′‐O‐[p‐Anisyldiphenylmethyl]thymidin mit Thymidylsaure und O2′,O3′‐Diacetylribouridylsäure untersucht. Unterschiede und Vorteile des Cooligokondensations‐Verfahrens gegeniiber der bisher üblichen schrittweisen Methode werden diskutiert.
Benzylierung von Polysacchariden in Gegenwart von Methylsulfinylmethanid
Authors: Keilich Gunda , Frank Norbert , Husemann Elfriede 
Published: April 2003

AbstractDie Perbenzylierung von Polysacchariden gelingt in Gegenwart von Methylsulfinyl‐methanid (1) mit Benzylchlorid in DMSO unter Stickstoff und Feuchtigkeitsausschluß. Während sich in einem Umsetzungsschritt Amylose, Pullulan, Dextran und Xylan vollständig substituieren lassen, werden Tribenzyläther von Laminaran, Glykogen und niedermolekularem Mannan erst nach der zweiten Benzylierung erhalten. Die Ausbeuten liegen zwischen 60 und 90%. Pustulan und Galaktomannan können unter diesen Reaktionsbedingungen nicht vollständig benzyliert werden.Die Benzylierung von hochmolekularem Mannan und Cellulose (in DMSO unlösliche und nicht quellbare Polyglykane) gelingt, wenn als Ausgangsmaterial die in DMSO löslichen Monoacetate verwendet und diese in Gegenwart eines Überschusses von 1 (4mol 1/mol OH‐Gruppe) mit Benzylchlorid unter analogen Bedingungen umgesetzt werden. Trisubstituierte Cellulose und Mannan erhält man in zwei Umsetzungsschritten. Die Ausbeuten liegen zwischen 30 und 35%.Die unterschiedlichen Ergebnisse bei der Benzylierung werden im Zusammenhang mit Löslichkeit, Polymerisationsgrad und Struktur der einzelnen Polysaccharide diskutiert.
The dibenzylmagnesium/tetrahydrofurfuryl alcohol system as an initiator of polymerizations of styrene and butadiene
Authors: Narita Tadashi , Kunitake Yuji , Tsuruta Teiji 
Published: April 2003

AbstractThe dibenzylmagnesium/tetrahydrofurfuryl alcohol system showed a very high reactivity as initiator for the anionic polymerization of styrene and butadiene, though the use of the magnesium alkyl alone could not induce the polymerization. A series of model reactions using 1,1‐diphenylethylene gave information on the structure and reactivity of the dibenzylmagnesium complex as initiator. It was concluded from the model reactions, together with UV spectroscopic data, that the initiating species, the benzyl anion, should be deliberated from the coordination‐agent‐separated ion pairs of the benzylmagnesium complex.
ESR study of the copolymerization of styrene with methyl methacrylate in a polymer matrix at high pressure
Authors: Borsig Eberhard , Klimová Marta , Szőcs Ferenc , Tin̆o Jozef 
Published: April 2003

AbstractThe relationships between the mole ratio of styrene monomer to methyl methacrylate monomer and the mole ratio of styrene terminated polymer radicals (“styrene radicals”) to methyl methacrylate terminated radicals (“methyl methacrylate radicals”) in the copolymerization initiated by benzoyl peroxide at the pressure of 6000 atm ( = 6.108 N/m2) in a polymer matrix was studied by ESR. The mole ratio of polymer radicals was calculated for varying proportions of styrene and methyl methacrylate at the pressure of 1 atm ( = 105 N/m2) and the results were compared with the ESR measurements. The components of the spectra were determined by simulating the spectra on a computer. Higher pressures substantially stabilize the styrene radicals even at a very low total amount of styrene monomer. The effect of pressure on the stability of individual radicals as well as the copolymerization parameters is discussed.
Copolymerization of acrylonitrile with ethyl methacrylate, 2
Authors: El‐Sabee Maher Z. , Shinouda Hakim G. , Morsi Mohamed A. , Ahmed Abdul R. , Mawazini Sheila 
Published: April 2003

AbstractThe copolymerization of acrylonitrile (AN) with ethyl methacrylate (EMA) was investigated in different solvents. The highest rate was observed in dimethylformamide and the lowest in benzene. The activation energy was determined in the temperature range of 60–80°C and was found to be 82 kJ/mol.The effects of temperature and monomer concentration on the intrinsic viscosity of the copolymers were investigated.
Compositional heterogeneity and molecular weight distribution of copolymer systems, 2. Kinetics of free‐radical grafting and heterogeneity of its product
Authors: Kotaka Tadao 
Published: April 2003

AbstractThe heterogeneity of graft copolymers was interpreted on the basis of the kinetics of free‐radical grafting under the conditions in which grafting was expected to be random. Besides some well‐known kinetic equations, a new equation relating the rate of graft‐chain production with the initiator, monomer, and prepolymer concentrations was derived. The theory was applied to analyze Cameron's data on the benzoyl peroxide initiated styrene grafting onto polybutadiene in benzene. It was found that the theory quantitatively describes the experimental results. Also an equation relating the graft fraction with the prepolymer and monomer concentrations under the conditions in which terminations were dominated by disproportionation was proposed.
Copolymères greffés: Poly(méthacrylate d'alkyl‐g‐oxyde d'éthylène), 1. Synthèse et caractérisation
Authors: Thierry Annette , Skoulios Antoine 
Published: April 2003

AbstractOn a montré qu'il est possible de synthétiser des copolymères greffés à greffons cristallisables présentant une bonne homogénéité en composition et en masse moléculaire. On a procédé par réaction de transestérification entre la fonction alcoolate de potassium terminale d'un polyoxyéthylène (lui‐même obtenu par polymérisation de l'oxiranne amorcée par du diphénylméthylpotassium) et les fonctions ester portées par un poly(méthacrylate de propyle) (ou de butyle). On a opéré en solution dans le toluène, à 110°C, dans un appareillage scellé sous vide.Pour caractériser les produits, on a utilisé conjointement l'ultracentrifugation, le fractionnement Kössler‐Polǎček, la résonance magnétique nucléaire, la pyrolyse éclair combinée avec la chromatographie en phase gazeuse, l'osmométrie et la diffusion de la lumière.
Coordination‐addition mechanism in the anionic polymerization of vinyl ketones initiated with alkylzinc
Authors: Tsuruta Teiji , Tsushima Rikio 
Published: April 2003

AbstractThe coordination‐addition mechanism in the polymerization of a vinyl ketone initiated with alkylzinc was elucidated by use of model compounds for the growing chain end and for the monomer. The formation of a 1:1 complex between the zinc compound and the vinyl ketone in hydrocarbon solvents was concluded from the UV spectra of the binary system. In tetrahydrofuran or dioxane little evidence was obtainable for complex formation. Cryoscopic data of the binary system in hydrocarbons and in cyclic ethers were found to be in agreement with the conclusion obtained from the UV data. The results of the kinetic studies of model reactions are interpreted in terms of a coordination‐addition mechanism, which was derived taking all the spectroscopic and cryoscopic data into consideration.
The color reaction between partially saponified poly(vinyl acetate) and iodine‐iodide in the presence of amylose
Authors: Hayashi Sadao , Takama Michihiro , Hojo Nobumasa 
Published: April 2003

AbstractThe color reaction between partially saponified poly(vinyl acetate), (P‐PVAc), which is dissolvable in water and iodine‐iodide was investigated in the presence of amylose. As the concentration of amylose increases, the absorbance at λmax = 488 nm of the red‐violet complex between P‐PVAc and iodine‐iodide decreases and, on the other hand, the absorbance at λmax = 625 nm of the blue complex between amylose and iodine‐iodide increases. The equation for the relationship between the decrease in the red‐violet complex and the increase in the blue complex was derived. On the basis of this equation, the molar absorption coefficient per iodine molecule at λmax = 625 nm for the blue complex of amylose with iodine‐iodide was found to be 3,68·104 l mol−1 cm−1 at 15°C.
Cationic polymerization of 4‐ethyl‐1,3‐dioxolane
Authors: Okada Masahiko , Mita Koji , Sumitomo Hiroshi 
Published: April 2003

AbstractThe bulk polymerization of 4‐ethyl‐1,3‐dioxolane, (1), was investigated at temperatures ranging from −48 to 0°C with boron trifluoride etherate and the perchloric acid/acetic anhydride binary system as initiators. At temperatures above − 20°C, liquid oligomers were obtained in poor yield, while at lower temperatures viscous polymer consisting of alternating sequences of oxy‐1‐ethylethylene and oxymethylene units with number average molecular weights of several thousands was produced. 1H NMR analysis of the acetal protons of the polymer on the basis of some model compounds disclosed that the bond cleavage of the monomer in the polymerization occurred nearly randomly at the two acetal C–‐O bonds. This polymerization involves a monomer‐polymer equilibrium. The thermodynamic parameters for the polymerization were determined from the temperature dependence of the equilibrium monomer concentrations: ΔH1c = −13,0±0,8 kJ mol−1 (= −3,1±0,2 kcal/mol) and ΔS1c = −59,4±3,8 J mol−1 K−1 (= −14,2±0,9 cal/(mol K)).4‐Isopropyl‐1,3‐dioxolane, (2), was found very reluctant to polymerize above − 78°C.
Herstellung radioaktiv markierter äthylen/propylen copolymerer. Berechnung der primärstruktur aus kinetischen daten
Authors: Exner Josef , Seeger Michael , Cantow Hans‐Joachim 
Published: April 2003

AbstractEine Synthese für an der α‐Methylgruppe mit Tritium markierten Äthylen/Propylen‐Co‐polymeren wurde ausgearbeitet. Deren Aktivität ist für die Messung der pyrolytischen Spaltprodukte in einem Durchfluß‐Zählrohr ausreichend. Die Sequenzlängenverteilung der mit löslichen Ziegler‐Natta‐Katalysatoren hergestellten Copolymeren wurde aus der Kinetik berechnet. Über Untersuchungen der thermischen Spaltungsmechanismen in solchen Copolymeren und die Pyrolyse zur Bestimmung der Sequenzlängenverteilung wird in Kürze berichtet.
Polymerisation von methacrylsäure‐methylester mit eisen(III)‐chlorid als initiator in sauren wäßrigen lösungen
Authors: Novaković Miroljub V. , Jovanović Slobodan M. 
Published: April 2003

AbstractEs wurde gezeigt, daß Eisen(III)‐chlorid in sauren wäßrigen Lösungen die Polymerisation von Methacrylsäure‐methylester bei Raumtemperatur starten kann. Der Einfluß der Eisen(III)‐chlorid Konzentration, der pH‐Werte der Lösungen, sowie der Anionenart und Anionenkonzentration auf die Inhibierungs‐Periode, den Umsatz und das Molekulargewicht des gebildeten Poly(methacrylsäure‐methylester)s wurde eingehend untersucht. Dabei wurde festgestellt, daß man die Polymerisation erfolgreich initiieren kann, wenn das Eisen in Lösung in Form von Fe(OH)2+‐ oder FeCl2+‐Ionen vorhanden ist. Für die Polymerisationsreaktion wurde das Reaktionsschema aufgestellt, daraus die Kinetik abgeleitet und auf Grund der erhaltenen Ergebnisse nachgeprüft.
Radical polymerization reactivities of methacrylic acid coordinated to cobalt(III) complexes
Authors: Osada Yoshihito 
Published: April 2003

AbstractRadical copolymerizations of methacrylic acid (MAA) coordinated to amminecobalt(III) complexes, methacrylatopentaamminecobalt(III) perchlorate (1) and cis‐dimethacrylatotetraamminecobalt(III) perchlorate (2) with MAA were carried out in an aqueous medium at pH 3 and at pH 7. It was found that 1 becomes incorporated into the macromolecules more easily at pH 7 than at pH 3. This may relate to the electrostatic interactions between the reaction species (monomer and growing radical). It was also found that only 1 can be homo‐polymerized at pH 3 although the product contains a certain amount of monomeric units of MAA. On the other hand, homo‐polymerization of 1 at pH 7 or that of 2 at pH 3 gave no polymeric product. In terms of the data of monomer reactivity ratios, Q‐e values and rates of copolymerization, reactivities of these metal complex monomers were discussed in connection with the effects of the transition metal complex attached to conjugated system of the methacrylate monomer.
Configurational effects of metal complexes attached to methacrylic acid in the process of radical polymerization
Authors: Osada Yoshihito 
Published: April 2003

AbstractMicrotacticities of the polymers obtained by the radical polymerization of methacrylic acid (MAA) coordinated to amminecobalt(III) complexes, methacrylatopentaamminecobalt(III) perchlorate (1) and cis‐dimethacrylatotetraamminecobalt(III) perchlorate (2) were studied. It was found that macromolecules obtained by the copolymerization of 1 with MAA at pH 3 have much more isotactic sequences. However, microtacticities of the polymers obtained by the copolymerization of 1 at pH 7 or that of 2 at pH 3 were slightly influenced by the incorporation of metal complex monomers. From these results as well as from Pddl/Pdl and Δεp values, it was found that the penultimate effects play an important rôle in the determination of the steric placement. It has also to be considered that the electrostatic interactions between the reacting species also play a certain rôle in the determination of the microstructures since the tacticties are greatly influenced by the ionized state of the reacting species.
Stabile Polykohlenstoffradikale, 1. Polyradikale mit orthoständigen Substituenten
Authors: Braun Dietrich , Euler Wolfgang 
Published: April 2003

AbstractKohlenstoffradikale stehen im allgemeinen im Gleichgewicht mit ihren Dimerisationsprodukten. Bei Polyradikalen führt dies durch intermolekulare Kombination zu vernetzten Polymeren. Durch sperrige Substituenten in Nachbarstellung zu den un gepaarten Elektronen läßt sich die Tendenz zu Vernetzungsreaktionen zurückdrängen. Durch eine Grignard‐Reaktion von p‐Chlorstyrol und anschließende Umsetzung mit geeigneten Carbonylverbindungen lassen sich sterisch gehinderte polymerisierbare Monomere erhalten. Folgende Verbindungen wurden dargestellt, charakterisiert, polymerisiert und polymeranalog in die entsprechenden Polyradikale überführt: α‐Phenyl‐α‐(o‐tolyl)‐4‐vinylbenzylalkohol (7), α,α‐Bis(2‐methoxyphenyl)‐4‐vinylbenzylalkohol (11), 1,3‐Diphenyl‐9‐(4‐vinylphenyl)‐9‐fluorenol (15) und 2,3,4,5‐Tetraphenyl‐1‐(4‐vinylphenyl)cyclopentadien‐1‐ol (17).