bluuebunny/crossref_metadata_2025 huggingface dataset:
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

The 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

A 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

Es 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

Die 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

The 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

The 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

The 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

The 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

On 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

The 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

The 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

The 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

Eine 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

Es 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

Radical 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

Microtacticities 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

Kohlenstoffradikale 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).
Zur Fraktionierung von Polymeren mit entmischenden Flüssigkeiten
Authors: Kuhn Rainer
Published: April 2003

Man kann chemisch verschiedene Polymere aus homogener Lösung in einem geeigneten Mischlösungsmittel quantitativ voneinander trennen, wenn die Lösungsmittel bei hohen Temperaturen mischbar sind, aber durch Temperatureniedrigung entmischen.

Die neuartige Fraktioniermethode wird mit Hilfe der Löslichkeitsparameter von Polymeren und Lösungsmittelgemischen und an einigen Beispielen mit Hilfe der zweiten Virialkoeffizienten beschrieben.

Die Nützlichkeit der Fraktionierung wird gezeigt anhand der in einem einzigen Fraktionierschritt durchgeführten Trennung von ca. 30 verschiedenen Mischungen von Polymeren und Copolymeren inklusive Pfropfcopolymeren nach ihrer chemischen Zusammensetzung. Die Fraktionierung mit entmischenden Flüssigkeiten ist besonders in solchen Fällen nützlich, bei denen andere Fraktioniermethoden, z. B. die Fällungsfraktionierung, keine befriedigenden Ergebnisse liefern.

Mit der beschriebenen Fraktioniermethode ist es in speziellen Fällen möglich, dreichemisch verschiedene Polymere oder Oligomere quantitativ voneinander zu trennen.
Polyelektrolyte durch assoziat‐bildung von amylose mit azo‐farbstoffen
Authors: Schulz Rolf C. , Trisnadi Julia A.
Published: April 2003

Die Wechselwirkung bestimmter Azofarbstoffe mit Amylose in wäßriger Lösung führt zu starken Änderungen der optischen Drehung (induzierte Cotton‐Effekte) und zu einem Anstieg der spezifischen Viskosität. Amylose verhält sich in Gegenwart von z. B. Kongorot (1) oder Diaminechtrot (2) wie ein Polyelektrolyt. Diese Erscheinungen werden mit der Bildung räumlich geordneter Assoziate zwischen Amylose und Farbstoff‐Molekülen erklärt. Andere Farbstoffe (z. B. Azoblau (3) und Calcon (4)) haben weder Einfluß auf die Viskosität noch auf die chiroptischen Eigenschaften. Offensichtlich fehlen in diesen Fällen die erforderlichen strukturellen Voraussetzungen für die Bildung von Assoziaten. Farbstoffe, die bei Amylose Cotton‐Effekte induzieren und die Viskosität verändern, bilden mit Polyvinylalkohol thermoreversible Gele.
Further evaluation of sequences in methyl methacrylate/methacrylic acid copolymers by 1H‐NMR in different solvents and 13C‐NMR
Authors: Johnsen Andreas , Klesper Ernst , Wirthlin Toni
Published: April 2003

The assignment of configurational pentads‐compositional triads in the 13C‐NMR spectra of atactic methyl methacrylate‐methacrylic acid (MMA‐MAA) copolymers is studied. Based on the known chemical shifts of the pentad‐triad sequences in syndiotactic and isotactic MMA‐MAA copolymers, as well as in atactic PMMA and atactic PMAA, chemical shift increments are derived which allow the postulation of the chemical shifts of the remaining pentad‐triad sequences. The postulated assignment of these sequences is verified by comparison of experimental 13C‐NMR peak intensities of three different types of atactic MMA‐MAA copolymers with calculated peak intensities. Because the experimental peak intensities are composed of more than one pentad‐triad resonance which strongly overlap, and can therefore be measured only as a sum, the three MMA‐MAA copolymers are chosen to possess widely differing compositional statistics at the same P(A). The calculated peak intensities are based on the copolymerization theory for the first type copolymer, which was obtained by radical‐initiated copolymerization. For the second type copolymer, derived by half‐esterification of poly(methacrylic anhydride) with methanol, the compositional‐configurational triad peak intensities are first determined by 1H‐NMR spectra using three different solvents. Some features of the statistics of this type of polymer analogous reaction are set forth, and the opening of the anhydride ring is found to be random. This fact allows the accurate calculation of the probabilities of the pentad‐triad sequences. For the third type copolymer, derived by hydrolysis of atactic PMMA in pyridine/water, a blocklike compositional triad distribution was found, which is—as opposed to the second type copolymer—statistically correlated with the configurational sequences. Only an approximate calculation of the probabilities of the pentad‐triad sequences was carried out. For all three types of copolymers a reasonable agreement between experimental and calculated pentad‐triad peak intensities was found.
Crystallization during polymerization of L‐alanine N‐carboxy anhydride initiated by diamines
Authors: Kōmoto Tadashi , Khair B. M. Abo‐El , Maeda Katsura , Oya Masanao , Kawai Tohru
Published: April 2003

Polymerization of L‐alanine N‐carboxy anhydride (4‐methyl‐2,5‐dioxo‐1‐oxa‐3‐azacyclopentane) was carried out in acetonitrile using hexamethylene diamine (HM), ethylene diamine (ED) and bis(4‐aminophenyl) ether (AP) as initiators, in order to investigate the effect of diamines on the crystallization mechanism during polymerization in comparison with that for butylamine already reported.

The resultant polymers obtained here had wider molecular weight distributions than those obtained with butylamine, indicating the occlusion of some active growing chain ends into the precipitate during polymerization. The relative width of the molecular weight distribution of the polymers formed in the later stages of the polymerization was larger in the following order as compared among the initiators: HM<ED<AP. The oligomer chains formed in the beginning of the polymerization crystallized into the antiparallel β‐structure and thereafter the β‐helical chains grew from the active sites of the β‐chains. However, it is likely that, in the later stages of the polymerization, the α‐helical chains grew from one of the amino groups of a diamine molecule but most of the other amino groups were inactive, since the ends of the β‐chains were occluded into the precipitate due to the antiparallel nature of the β‐chains precipitated. The morphologies of the resultant polymer crystals were in good agreement with the results obtained from the intrinsic viscosities (molecular weights), conformations, and structures.
Heterogeneous polymerization of L‐alanine N‐carboxy anhydride initiated by amines having primary and tertiary amino groups
Authors: Khair B. M. Abo‐El , Kōmoto Tadashi , Kawai Tohru
Published: April 2003

Various amines such as aniline (A), N,N‐diethyl‐1,3‐propanediamine (DPD), and pamino‐N,N‐diethylaniline (ADA), were used as initiators in the heterogeneous polymerization of L‐alanine N‐carboxy anhydride (L‐alanine NCA), (4‐methyl‐2,5‐dioxo‐1‐oxa‐3‐azacyclopentane). When ADA is used as initiator, the initiation reaction proceeds via normal amine initiation as for primary monoamines. On the other hand, in the polymerization initiated by DPD, the initiation reaction takes place from both the primary and tertiary amino groups of the initiator. In all systems, the propagation proceeds by nucleophilic attack of the amino groups of the growing chains on the C(5) of the L‐alanine NCA ring.

The resultant polymers obtained in the case of the initiators A or ADA had wider molecular weight distributions than those from DPD‐initiated polymerization. Oligomers and polymers obtained using DPD as initiator were in the form of β‐and α‐conformations, respectively. However, mixtures of both β‐structure and α‐helix were formed in the polymerization initiated by A or ADA. It is suggested that the number of the growing chain ends occluded in the precipitate is increasing in the following order with respect to the initiator used: DPD<A≈ADA. The morphologies of the resultant polymer crystals were in good agreement with the results from IR and X‐ray analysis.
13C NMR chemical shifts and stereochemical structures in poly(vinyl chloride)
Authors: Ando Isao , Kato Yoshiharu , Nishioka Atsuo
Published: April 2003

The 13C NMR chemical shifts of triad and tetrad configurations in poly(vinyl chloride) have been calculated by the average excitation energy approximation using the CNDO/2 MO method. On the basis of these calculations, both Inoue's and Carman's assignments for the observations of the triad and tetrad configurations have been examined and the partial discrepancy between them ascribed to the solvent effect. Further, the tacticity dependences of the calculated chemical shifts for triad and tetrad configurations are discussed.
Acrylsäure‐popcornpolymere, 2. Oberflächenstruktur der glasigen und der popcorn‐polymeren
Authors: Breitenbach Johann Wolfgang , Kauffmann Harald Friedrich , Zwilling Gunther
Published: April 2003

Durch Rasterelektronenmikroskopie werden die charakteristischen Unterschiede der Oberflächenstruktur der durch Polymerisation von Acrylsäure in Substanz und in Mischung mit Wasser erhaltenen Polymertypen—opak, glasig, Popcorn—gezeigt. Diese Unterschiede stehen in Beziehung zum Bildungsmechanismus der Polymeren.
Sedimentation measurements on polystyrene solutions in cyclohexane below the Flory theta temperature
Authors: Pouyet Geneviève , Candau Françoise , Dayantis Jean
Published: April 2003

Sedimentation measurements have been performed, at different temperatures below the Flory Θ temperature (a) on a series of monodisperse polystyrene samples in cyclohexane solution ranging in molecular weights from 8,5·104 to 1,1·106 and (b) on mixtures of the above samples. For the monodisperse polystyrene solutions it is found that the chain dimensions at the critical temperature are smaller than the unperturbed dimensions. For the solutions of the mixtures, the qualitative properties of the Johnston‐Ogston effect were studied. Furthermore, the measurement of the concentrations of each sample in the mixtures (neglecting the effect of the Johnston‐Ogston effect on the area of the peaks) has shown that the slow species is driven by the fast species, as the latter precipitates.
Cationic polymerization of p‐fluoro‐α‐methylstyrene
Authors: Orhan Erdal H. , Akovali Güneri , Baysal Bahattin M.
Published: April 2003

Boron trifluoride diethyl etherate‐initiated polymerization of p‐fluoro‐α‐methylstyrene at −78°C in toluene, toluene/mixture of hexane isomers and toluene/hexane was carried out. Determination of the limiting viscosity numbers and molecular weights of some of the polymeric samples led to the evaluation of the Mark‐Houwink constants for poly[1‐(4‐fluorophenyl)‐1‐methylethylene] at 25°C in benzene. Polymerization in 1,2‐dichloroethane at −15°C showed varying rates in the absence of added water. When the molar ratio of added water to the catalyst was 2,5 reproducible rates were observed. The IR spectrum of low‐moleular weight polymers (obtained at −15°C) contained bands corresponding to unsymmetrically disubstituted end‐groups containing double bonds.
Polymerization of mesomorphic monomers, 2. Bulk polymerization of 4‐(2‐vinyloxyethoxy)benzoic acid
Authors: Tanaka Yoshio , Hitotsuyanagi Mikio , Shimura Yukio , Okada Akira , Sakuraba Hidetaka , Sakata Tokuji
Published: April 2003

A new thermotropic liquid crystalline vinyl ether, 4‐(2‐vinyloxyethoxy)benzoic acid (1a), was obtained by hydrolysis of the corresponding methyl ester 1b. The radical bulk polymerization of this acid was carried out at 130–195°C in the solid, the mesomorphic, and the isotropic liquid phases with 2,2′‐azoisobutyronitrile to study the effect of monomer ordering on polymerization rate and polymer properties. No significant effect on the rate of polymerization and the intrinsic viscosity of the products appeared to be associated with the existence of the mesomorphic phases. The rate increased with increasing temperature, i.e., decreasing ordering or enhanced mobility of the monomer. The intrinsic viscosity was 0,06–0,10 dl g−1 in N,N‐dimethylformamide at 30°C. High crystalline polymers were obtained in the solid and the mesomorphic phases, whereas the polymer formed in the isotropic liquid phase was a less crystalline solid.
Studies on chitin, 2. Effect of deacetylation on solubility
Authors: Sannan Takanori , Kurita Keisuke , Iwakura Yoshio
Published: April 2003

A reproducible method for obtaining water‐soluble chitin and a relationship between solubility and degree of deacetylation of chitin were studied. It was found that the regenerated chitin isolated at low temperature from an alkali chitin solution left at 25°C for 48 to 77h showed very good solubility in water at 0°C. The degree of deacetylation of an alkaline treated chitin was determined by titration with hydrochloric acid. It increased rapidly to about 75% as the alkaline treatment time increased and began to level off to about 90% and only the regenerated chitin samples with around 50% of deacetylation were found to be soluble in water. The X‐ray diffraction diagrams showed that these were amorphous, although both chitin with lower degree of deacetylation and chitosan had crystallinity. The improved solubility of chitin with about 50% of deacetylation would be attributed to the partial deacetylation which probably brought about the destruction of secondary structure and also the increase of the hydrophilic property on account of the increased number of amino groups.
Interaction between dyes and polyelectrolytes, 2. Structural effect of polyanions on the methylene blue binding
Authors: Shirai Masamitsu , Nagatsuka Tatsuki , Tanaka Makoto
Published: April 2003

The structural effect of polyanions on the binding type of methylene blue (1) was investigated spectrophotometrically. 1 was bound to poly(potassium styrenesulfonate) (PSS) and poly(sodium 4‐vinylphenylsulfate) (SVS) in the dimeric or slightly aggregated form and to poly(sodium vinylsulfonate) (SVF) and poly(potassium vinyl sulfate) (PVS) in the highly aggregated (polymeric) form. It was found that the flexibility of polyanions plays an important rǒle in the aggregation of bound 1 and that the difference between SO and OSO as binding site is not a significant factor.
Organozinc catalyst systems for the copolymerization of carbon dioxide with propylene oxide
Authors: Kuran Witold , Pasynkiewicz Stanisław , Skupińska Jadwiga
Published: April 2003

A series of new catalytic systems: (C2H5)2Zn/polyhydric phenols was prepared and their activity in the alternating copolymerization of carbon dioxide with propylene oxide (epoxypropane) was studied. On the basis of the results obtained, the structure of organozinc compounds formed in these systems and also in others described in the literature is proposed and discussed. It is shown that the presence of an internal coordinative bond in the catalyst molecule is responsible for its activity in copolymerization.
Synthèse et caractérisation de copolymères triséquencés de différents méthacrylates d'alkyle
Authors: Seow Pin Kwong , Lingelser Jean‐Paul , Gallot Yves
Published: April 2003

Triblock copolymers of different alkyl methacrylates with side chains containing 1 to 12 carbon atoms were synthesized by anionic polymerization in tetrahydrofuran with diphenylmethyl sodium or naphthalene sodium (sodium dihydronaphthylide) as initiators. The polymer samples were fractionated by means of solvent/non‐solvent systems. Gel permeation chromatography (GPC), light scattering, osmometry, and elemental analysis were used to characterize the fractions. The copolymers were found to be free of homopolymers and the polydispersity of molecular weight of the fractions to be very low.
Präzisionsmessungen zur bestimmung spezifischer volumsgrößen von makromolekülen in einem vielkomponentensystem, im besonderen von lysozym und papain in wäßrigen saccharoselösungen
Authors: Schausberger Alois , Pilz Ingrid
Published: April 2003

A method was developed, which makes it possible to evaluate in a liquid multicomponent‐system the value of specific volumes of a component, by variation of the density of the solution caused by the variation of the concentration of this component.

In particular, in the system H2O‐protein‐sucrose the dependence of the partial specific volume of lysozyme and papain was studied on the concentration of proteins in the range of 0 to 10 wt.‐% and on the concentration of sucrose in the range of 0 to 50 wt.‐%.

For both proteins no dependence of the partial specific volume of the protein on the concentration of the protein, but an increase of the partial specific volume with increasing concentration of sucrose could be observed.
Photosensitized polymerization of octyl methacrylate under high pressure
Authors: Yokawa Masaru , Yoshida Junichi , Ogo Yoshiaki
Published: April 2003

By use of the rotating sector technique under high pressure, the changes of the rate constants of propagation and termination in the polymerization of octyl methacrylate, Photosensitized with 1,1′‐azocyclohexane‐1,1′‐dicarbonitrile, were studied at 30°C over a pressure range of 1 to 1000 bar at 250 bar pressure intervals. The effects of pressure on the individual rate constants were determined and the activation volumes of propagation and termination were obtained as −24,7 and 20,8 cm3 mol−1, respectively. The overall activation volume was −19,2 cm3 mol−1. The effects were compared with the results for methyl and butyl methacrylate polymerizations. The increase in the size of the ester groups brought about a diminution in the value of the activation volume for the propagation reaction. The effect of pressure on the termination mechanism was discussed from the view point of the viscosity effect on the diffusion‐controlled termination.
Darstellung von Austauschern mit Kryptanden als Ankergruppen
Authors: Blasius Ewald , Maurer Paul‐Gerhard
Published: April 2003

Four exchangers (8, 9, 16, and 17) with cryptate forming anchor‐groups were prepared and their properties were studied. They were synthesized by the reaction of the cryptate formers 6 and 7 with chloromethylated polystyrene or by condensation of the cryptate formers 14 and 15 with formaldehyde or with formaldehyde/phenol. The exchangers were found to be very resistant towards heat and chemical attack. Their capacities for alkali salts amount to 1,0–1,3 mmol per gram of the air‐dried resin.
Vernetzte polymere mit spaltbaren netzbrücken, 4. Untersuchungen zur netzstruktur von copolymeren aus 1,2‐bis(4‐vinylphenyl)‐1,2‐äthandiol und styrol
Authors: Braun Dietrich , Brendlein Wolfgang , Paudjojo Lusiawati
Published: April 2003

Cross‐linked copolymers from styrene and 1,2‐bis(4‐vinylphenyl)‐1,2‐ethanediol (1) were synthesized. The concentration of the pendent vinyl groups linked to the polymer was determined by means of IR‐spectroscopy as a function of the initial composition, of the total monomer concentration, and of the yield. The values were compared with previously elaborated theoretical calculations. Differences between experiment and theory are presumably due to an inhomogeneous distribution of the pendent vinyl groups in the polymerization system. Measurements of swelling with crosslinked copolymers from styrene and 1 showed, that the specific gel bed volume can be well correlated with the theoretically calculated concentration of cross‐links, if the total monomer concentration and the fraction of cross‐linking component are kept below certain maximum values and if the yield does not exceed 80% significantly.
Polymerizable amphiphiles, 1. Synthesis and proton magnetic resonance studies of [3‐(4‐vinylphenyl)propyl]‐β‐D‐glucopyranoside
Authors: Chung Daniel C. , Kostelnik Robert J. , Elias Hans‐Georg
Published: April 2003

The title compound 2 was synthesized and its micellization in water investigated by proton magnetic resonance at 260 MHz. Chemical shift changes with concentration were observed, the largest change being for the aromatic protons indicating ordered phenylene rings in the micelles. The critical micelle concentration of this compound in D2O at 37°C was found to be approximately 0,010g/cm3.
New catalysts for the oxidative polymerization of 2,6‐dimethylphenol, 1. Copper complex of toluene‐3,4‐dithiol
Authors: Kaneko Masao
Published: April 2003

It was found that a copper complex of toluene‐3,4‐dithiol (Cu‐TDT) catalyzes the oxidative polymerization of 2,6‐dimethylphenol (1), and the catalytic behavior was studied. The activity of the Cu‐TDT is higher than that of the known copper(II)‐pyridine complex. The higher the pyridine content in the solvent mixture pyridine/o‐dichlorobenzene, the higher is the activity of Cu‐TDT. Cu‐TDT loses its activity gradually in pyridine solution, however, about 40% of its activity remains even after 150h. The reasons for the high activity are discussed.
Radical copolymerization of cyclic acetals derived from acrolein, 2. Alternating copolymerization
Authors: Acosta José Luis , Mateo José Luis , Sastre Roberto
Published: April 2003

Copolymerizations of 2‐vinyl‐l,3‐dioxane (1a), 5,5‐bis(hydroxymethyl)‐2‐vinyl‐1,3‐dioxane (1b), and 5,5‐dimethyl‐2‐vinyl‐1,3‐dioxane (1c) with maleic anhydride (MA) and N‐vinyl‐2‐pyrrolidone (NVP) were investigated. Copolymerization of the cyclic acetals 1 with MA yielded copolymers with perfectly alternating sequences independent of the initial monomer feed composition. Terpolymerization of 1a, MA, and styrene, also despite of monomer composition, yielded terpolymers with a molar composition of 50% in MA which confirms the participation of transfer complexes in these copolymerizations. The composition of the 1/NVP copolymers (mole fraction) F1(NVP) ≈ 0,6–0,8 also varied little with the feed. The copolymerization rates passed through a maximum when the monomer mixture contained a mole fraction f1 (NVP) of ca. 0,7.
Study of the mechanism of propagation and transfer reactions in the polymerization of olefins by Ziegler‐Natta catalysts, 3. Determination of the rate constants of chain transfer with an organo‐alumimium cocatalyst
Authors: Bukatov Gennadii D. , Chumaevskii Nikolai B. , Zakharov Vladimir A. , Kuznetsova Galina I. , Yermakov Yurii I.
Published: April 2003

By quenching polymerization with tritium‐labelled methanol the total number of the metal‐polymer bonds in the polymerization of ethylene and propylene by Ziegler‐Natta catalysts was determined. Using the propagation rate constants determined by quenching polymerization with 14CO the rate constants of chain transfer with AlEt3 and Al(i‐Bu)3 and the activation energy of chain transfer with AlEt3 were calculated.
Réactions primaires de dégradation oxydante au cours de l'autoxydation du poly(oxytétraméthylène) à 25°C, 1. Caractérisation de la production d'éthylène
Authors: Thomassin Claude , Marchal Jean
Published: April 2003

Autoxidation of poly(oxytetramethylene) at 25°C was studied by means of radiation induced initiation of chloroformic solutions of the polymer. It includes primary oxidative degradation reactions characterized by main chain scissions and subsequent formation of ethylene, formate groups, and hemiformal groups.
Application of spin trapping technique to radical polymerization, 11. Initiation and propagation mechanisms for alternating copolymerization of styrene with maleic anhydride
Authors: Sato Tsuneyuki , Abe Masao , Otsu Takayuki
Published: April 2003

The initiation mechanism for spontaneous alternating copolymerization of styrene (St) with maleic anhydride (MAn) was investigated by means of spin trapping technique. using 2‐methyl‐2‐nitrosopropane (7) as spin trapping agent. By means of ESR spectroscopy of the system St/MAn in ethylbenzene, a cyclic radical (13), produced via the Diels‐Alder intermediate 25, was detected as its aminyl oxide. A similar radical was also trapped from the system p‐methyl‐St/MAn and p‐dimethylamino‐St/MAn. It is formed faster in these systems than in the system St/MAn. In chloroform, however, two types of initiating radicals. 13 and the α‐styryl radical (15), were trapped. This indicates that these radicals are produced via 25 and the charge transfer complex 27, respectively. From these results an initiation mechanism is proposed. To clarify further the propagation mechanism, the spin trapping technique was applied to the system, which is initiated by tert‐butoxyl radical formed from di‐tert‐butyl peroxalate (8). The effect of the concentration of 7 on the ESR spectrum of the system St/MAn/8 shows that 27 also participates in the propagation of this alternating copolymerization. Finally, the high reactivity of 27, as compared with free monomers in alternating copolymerization systems, was attempted to be explained on the basis of the Evans‐Polanyi theory.
Die Bestimmung der Molekulargewichtsverteilung von nichtkristallisierenden Polymeren mit dem Elektronenmikroskop, 6. Fehlerkorrektur der experimentellen Zahlenverteilungsfunktion
Authors: Koszterszitz G. , Greschner G. S. , Schulz G. V.
Published: April 2003

A mathematical treatment is described, by means of which the effect of the measuring errors on the number molecular weight distribution of polymers, as obtained with an electron microscope (EM), can be eliminated. It is shown, that the difference in the nonuniformities of the measured and the corrected distribution would be negligible only in the case of samples with high average degrees of polymerization and sufficiently broad distributions. Otherwise differences of 10% or more can be found, depending on the size of the actual measuring error. This is shown by means of four practical examples. For a practical application the measuring error may not exceed some critical value, which, though always lies above the mean error of the EM‐method.
The α‐CH proton chemical shift in the coil conformation of poly(L‐alanine)
Authors: Asakura Tetsuo , Ando Isao , Nishioka Atsuo
Published: April 2003

In order to clarify the cause of the change of the α‐CH proton chemical shift through the helix‐coil transition of poly(L‐alanine), the α‐CH chemical shift in a coil form was calculated by taking into account the intramolecular shielding effect and compared with the value in a helical form.

The coil α‐CH peak was predicted to resonate upfield by about 0,1 ppm from the helical peak in contrast to the downfield shift observed in experiments. Thus it was suggested that the observed low field shift in trifluoroacetic acid (TFA) mainly comes from the solvent effect by TFA including the rearrangement of the charge distribution along the poly(L‐alanine) chain.
Reaktive copolymere des N‐vinyl‐2‐pyrrolidons zur immobilisierung von enzymen
Authors: Manecke Georg , Korenzecher Rafael
Published: April 2003

1‐Vinyl‐2‐pyrrolidone was copolymerized with maleic acid anhydride, with acrylic acid, and with tyrene respectively, using 1,4‐divinylbenzene as crosslinking agent. By polymeranalogous reactions isothiocyanato‐ and diazo groups were introduced into the styrene copolymers, respectively, and azido groups into the acrylic acid copolymers. These reactive, insoluble, hydrophilic carriers were used for the immobilization of enzymes by covalent binding. The copolymers, particularly their ability to immobilize papain as well as their enzymatic activity, were investigated.
Mehrparameterkorrelationen zur quantifizierung der kationischen copolymerisation von styrol undp‐substituierten styrolen
Authors: Heublein Günther , Wondraczek Reinhard
Published: April 2003

For cationic copolymerization of styrene andp‐substituted styrenes the experimental aim values, ratio of monomer reactivity ratios (log(r1/r2)) and average degrees of polymerization (log P̄), can be connected by linear multiparameter equations with parameters characterizing the influence of monomer structure (Δσp), solvent (ET), the reaction temperature (T) and the catalyst activity (χkat.; εGlas/Kat.). The equations allow qualitative and partially quantitative predictions for the selectivity of the cross‐propagation reaction in the copolymerization (log(r1/r2)).
Alternating copolymerization of acrylonitrile with butadiene in the presence of binary and ternary catalytic systems of Lewis acids type
Authors: Florjańczyk Zbigniew , Kuran Witold , Pasynkiewicz Stanisław , Kasprzak Elżbieta
Published: April 2003

Acrylonitrile (AN) and butadiene (BD) were copolymerized in the presence of binary C2H5AlCl2MtXn (MtXn = metal halide or metal alkoxide) and ternary ZnCl2RmMtXnVOCl3 (RmMtXn = metal alkyl or alkylmetal chloride) catalytic systems. The yield of the copolymer (mole ratio of units AN/BD = 1:1) formed in the presence of the above systems, and the effects of the molar proportion of catalyst components, of the reaction temperature and time on the copolymer yield in some systems were determined. The role of individual components of binary and ternary catalytic systems in the copolymerization is discussed.
Elektrokinetische untersuchungen an fasern, 2. Experimentelle untersuchungen
Authors: Aichele Wilfried , Schollmeyer Eckhard , Herlinger Heinz
Published: April 2003

An apparatus is described to measure streaming‐potentials as well as streaming‐currents at different concentrations of the solid. Zeta‐Potentials calculated according to Smoluchowski's equation can be corrected by conductance measurements using Ag/AgCl‐electrodes directly in dilute aqueous solutions containing more than 10−3mol/l KCl. They are in good agreement with the real dependence of zeta‐potentials from the “porosity” of the plug. For KCl concentrations smaller than 10−3mol/l, this correction must be done separately from measurements of streaming‐potential according to the method of Fairbrother and Mastin at higher electrolyte concentrations.

Among the different porosities given by Konzeny‐Carman, Goring and Mason, Biefer and Mason, and Fairbrother and Mastin, the latter describes best the dependence of the zeta‐potential on the concentration of solid for any kind of plug. These results and the limits of the approximation method are discussed.
Analyse der phasenstruktur von binären polymersystemen
Authors: Henkel Georg , Schindlbauer Hellmuth
Published: April 2003

Two sets of polymer blends have been prepared by mixing solutions or melts of polystyrene with polybutene‐1(poly(1‐ethylethylene)), cellulose acetate, poly(methyl methacrylate), polyisobutylene, atactic polypropylene, poly(vinyl chloride), high pressure polyethylene, and of poly(vinyl chloride) with high pressure polyethylene, ABS, poly(vinylidene chloride), poly(vinyl acetate), vinyl chloride/vinyl acetate copolymer. The phase structure of these blends was analysed by microscopic and differential calorimetric measurements and by determination of the turbidity of the films. Phase diagrams were prepared from the glass transition temperatures and melting points taken from DSC curves. In this analysis all systems show a distinct phase separation ensuing from incompatibility. The only exception is the blend: poly(vinyl chloride) + vinyl chloride/vinyl acetate copolymer.