bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ethylene‐propylene based terpolymers containing tricyclo[5.2.1.02,6]deca‐2,5,8‐triene
Authors: Cesca Sebastiano , Arrighetti Sergio , Priola Aldo , Duranti Publio V. , Bruzzone Mario 
Published: April 2003

AbstractTricyclo[5.2.1.02.6]deca‐2,5,8‐triene (1) (trivial name: dehydro‐isodicyclopentadiene) or a mixture of its methyl derivatives were used as termonomers to obtaine ethylene‐propylenetriene terpolymers (EPTM's) having unusual properties in the curing process, even at low levels of triene (ca. 1 wt‐%). Three types of catalyst systems have been investigated, i. e. based on VCl4, VO[O(CH2)3CH3]3, or V(acac)3 and (C2H5)2AlCl. Several parameters of the terpolymerization process were studied (e.g. Al/V mole ratio; catalyst and termonomer concentration; polymerization time; presence of a Lewis base or chain transfer agent) and their influence on Mv and EPTM composition were evaluated. Fractionation data and the use of model compounds allow to conclude that 1 enters EPTM chains randomly and by selective opening of the norbornenic double bond, whereas the conjugated diene system is involved in side‐reactions if the catalyst has some acid character or the concentration of the triene is above some critical values.
Kristallisations‐ und schmelzverhalten von copolymeren aus 3,3‐bis(chlormethyl)oxetan und ß‐propiolacton
Authors: Wiemers Norbert , Wegner Gerhard 
Published: April 2003

AbstractEinkristalle von Copolymeren aus 3,3‐Bis(chlormethyl)oxetan und ß‐Propiolacton wurden bezüglich Schmelzverhalten, Schmelzenthalpie, Dichte und Langperiode untersucht. Aus der Messung der Schmelzenthalpie und der Dichte berechnen sich Kristallisationsgrade von 50—60% in guter Übereinstimmung mit einem Modell, welches den Ausschluß der aus ß‐Propiolacton (PL) entstandenen Grundbausteine von dem aus Sequenzen der 3,3‐Bis(chlormethyl)oxetan (BCMO‐)Einheiten aufgebauten Gitter verlangt. Im Vergleich zu reinem Poly‐BCMO wird die Dicke der Copolymereinkristalle nur wenig durch Änderung der Kristallisationstemperatur beEinflußt. Wegen des blockartigen Aufbaus der Copolymeren bestimmt die mittlere Sequenzlänge der BCMO‐Einheiten die Kristallitdicke. Im Bereich der Schmelztemperatur treten typische Rekristallisationsvorgänge auf. Das dabei stattfindende Langperiodenwachstum und seine Auswirkung auf den Schmelzvorgang wurden durch Untersuchungen an getemperten Einkristallen geklärt. Der PL‐Gehalt der Copolymeren beEinflußt deren Rekristallisationsgeschwindigkeit. Die beobachteten Schmelzpunktdepressionen von Einkristallen unterschiedlichen PL‐Gehalts können durch Kristallitgrößeneffekte beschrieben werden. In der Schmelze der Copolymeren +heinen die reinen BCMO‐ und die BCMO‐PL‐Sequenzen entmischt vorzuliegen. Beim Auflösen der Einkristalle tritt jedoch eine Mischung der verschiedenen Sequenzen und Grundbausteine des Copolymeren ein. Daher wird eine Depression der Lösungstemperatur beobachtet, die durch die zugehörige Mischungsentropie bedingt ist.
Chemical modification and conformation studies on bence jones protein
Authors: Liaw Wen‐Yi Vicki , Nakagawa Yasushi , Jirgensons Bruno 
Published: April 2003

AbstractA λ‐type Bence Jones protein was chemically modified by carbamaylation of the ε‐amino groups of its lysine side chains and by nitration and reduction of its tyrosine residues. All 30 ε‐amino groups were carbamylated, but only 6 of the 14 tyrosine side chains were nitrated. The gross conformation of the macromolecules (shape) was not altered in these reactions, as tested by intrinsic viscosity and sedimentation coefficient determinations. Also, the immunoprecipitability was not affected by the chemical modification. However, circular dichroism (CD) spectra revealed slight to moderate changes in the conformational details within the macromolecules. The appearance of a positive CD band at 240 nm on nitration was caused by 3‐nitrotyrosine residues, whereas the new band at 300 nm was probably due to change of asymmetric environment of tryptophan chromophores.
Darstellung und charakterisierung von einigen neuen bis(1‐phenylvinyl)‐verbindungen
Authors: Lattermann Günter , Höcker Hartwig 
Published: April 2003

AbstractEinige neue Bis(1‐phenylvinyl)‐Verbindungen (1b, c und 2a–d) wurden aus den entsprechenden Diacetylverbindungen und Phenylmagnesiumbromid dargestellt. Ihre IR‐, NMR‐und Massenspektren werden diskutiert.
Study of radical polymerization by means of ESR, 2. Homogeneous polymerization of methyl methacrylate and vinyl acetate
Authors: Bresler Semen E. , Kazbekov Embek N. , Shadrin Vladimir N. 
Published: April 2003

AbstractA very efficient ESR spectrometer was applied to the measurement of the stationary concentration of macroradicals in homogeneous polymerization. From these data the rate constants of chain propagation and chain termination for the polymerizations of methyl methacrylate and vinyl acetate were found in a direct way. Activation energies of these elementary reactions were measured.
Studies on polymeric azomethines. Preparations and properties of polymeric azomethines from terpolymers containing the 3‐formyl‐4‐hydroxybenzyl group in the side chain, and several amines
Authors: Haruta Masami , Kageno Kenji , Harada Susumu 
Published: April 2003

AbstractPolymeric azomethines (5a—d) were prepared by the reaction between the terpolymer 3 and butylamine, ethylenediamine, aniline, or 4‐aminomethylbenzylamine. 3 was obtained by terpolymerization of diallyl(3‐formyl‐4‐hydroxybenzyl)methylammonium chloride (1), diallyldimethylammonium chloride (2), and sulfur dioxide.IR‐spectra, solubilities, and thermal stabilities of the azomethines were examined. The formation constant of azomethine 5a, (prepared from butylamine and 3) was determined by the spectroscopic method and discussed comparing with those of o‐hydroxybenzaldehyde derivatives.
Polymerization of cis‐ and trans‐8‐oxabicyclo[4.3.0]nonane
Authors: Kops Jørgen , Spanggaard Hans 
Published: April 2003

AbstractThe polymerization of cis‐ and trans‐8‐oxabicyclo[4.3.0]nonane in bulk was investigated with PF5 as initiator. The trans‐isomer polymerizes very readily to high polymers (M̄w up to 200 000), whereas the cis‐isomer under identical conditions fails to polymerize. This difference in behavior is attributed mainly to the fact that the strain in the trans‐isomer is much higher than in the cis‐isomer. The polymerization results with the trans‐isomer for the temperature interval of −25 to 75°CC are interpreted in terms of propagation/depropagation reactions via an oxonium ion mechanism and a concurrent chain breaking reaction which is noticeable by the decrease in molecular weight with time. The polymerization systems are not reversible with changing temperature and the data indicate that at the upper end of the temperature interval there is a deactivation, which was investigated.Copolymerization of the cis‐ and trans‐isomers shows that the cis‐isomer is reactive in the presence of the trans‐isomer. The molecular weight of the polymers decreases with increasing cis‐isomer content in the feed.
Production of organometallic polymers by interfacial technique, 33.. Synthesis of oligomeric cobalticinium containing dialkylstannanediyl polyesters
Authors: Carraher Charles E. , Peterson George F. , Sheats John E. , Kirsch Ted 
Published: April 2003

AbstractOligo(oxycarbonyl‐1,1′‐cobalticendiylcarbonyloxydialkyl (or diaryl)stannanediyl hexafluorophosphate)s (3) were synthesized by condensation of alkali salts of 1,1′‐dicarboxycobalticinium hexafluorophosphate (2) with dialkyl (or diaryl) tin dihalides in CCl4/water using the interfacial technique.Variation of the halide and of the alkyl or aryl group causes an increase of the yield in the order I≈Br > Cl and C6H5 > H2CCH >(CH3)3CH > C2H5 >H3C(CH2)7  ≈ C6H5CH2 > CH3The polymeric product (3) undergoes an exchange of the hexafluoro phosphate ion in a suitable aqueous salt solution to give soluble products.
Polymerization and copolymerization of cyclic unsaturated sulfides
Authors: Carbon Albert L. , Goethals Eric J. 
Published: April 2003

AbstractThe polymerization and copolymerization behaviour of the unsaturated cyclic sulfides 2,3‐dihydrothiophene (1), 2,3‐dihydrothiopyran (2) and p‐Dithiene (3) was studied. With cationic initiators such as borontrifluoride etherate, all three monomers were transformed into polymers. The five‐membered ring compound 1 gave quantitative yields, the two six‐membered ring compounds 2 and 3 gave limited conversions. This was attributed to the advantageous geometrical position of the pen‐penultimate sulfide function toward the growing chain‐end to form a sulfonium ion. Radical homopolymerization was impossible for all three monomers but copolymerization with different vinyl monomers yielded copolymers with various sulfide unit contents. From the copolymerization reactivity parameters of the copolymerization with methyl acrylate, the reactivity of the different monomers towards a growing polymer chain ending with a methyl acrylate radical could be compared. The sequence was 1≥vinyl sulfides ≫2>3. Copolymerization with maleic anhydride yielded alternating copolymers independent of the monomer feed composition. This copolymerization is believed to occur via the formation of a charge‐transfer complex between the two comonomers. The association constants of complex formation in chloroform were measured.
Die substanzpolymerisation von acrylnitril
Authors: Marquardt Klaus , Mehnert Peter 
Published: April 2003

AbstractDie Substanzpolymerisation von Acrylnitril wurde unter Anfangsbedingungen (Umsatz ≤ 15%) mit Hilfe einer verbesserten dilatometrischen Technik und eines neuen Auswertungsverfahrens untersucht. Aufbauend auf den Ergebnissen der kinetischen Analyse wurde ein neuer, einfacher Polymerisationsmechanismus gefunden, dessen Übereinstimmung mit den Versuchsergebnissen anhand des integrierten Zeitgesetzes gezeigt werden konnte. Dieser Mechanismus läßt sich durch folgendes Scheme ausdrücken:
magnified imageund besagt, daß neben einer Polymerisation in homogener Lösung auch ein Polymerwachstum in heterogenem Zustand stattfindet, bei dem bimolekulare Abbruchsreaktionen vernachlässigt werden können. Zu Beginn der Reaktion wurden Induktionsperioden nachgewiesen, die wegen ihrer guten Reproduzierbarkeit und ihrer Abhängigkeit von der Anfangsinitiatorkonzentration nicht auf Verunreinigungen im Monomeren zurückgeführt werden können. Für 60°CC wurden folgende Geschwindigkeitskonstanten berechnet bzw. abgeschätzt:magnified image
On the catalytic activity of alkylaluminum compounds in acrylonitrile‐propylene alternating copolymerization
Authors: Kuran Witold , Pasynkiewicz Stanisław , Florjańczyk Zbigniew , Kowalski Apolinary 
Published: April 2003

AbstractThe alternating copolymerization of acrylonitrile and propylene in the presence of organoaluminium compounds of the type RAlCl2 could be shown to be initiated by free radicals formed by cleavage of the AlR bond. The R. and Al. radicals were detected under polymerization conditions by ESR spectroscopy. The yield and the intrinsic viscosity of the acrylonitrile/propylene copolymer were studied in relation to the nature of organic substituents in the organoaluminium compounds. The results were discussed in terms of an initiation mechanism previously postulated by the authors.
Polymer modification and synthesis using sulphenyl derivatives, 2. Preparation of poly(β‐chlorothioether)s, poly(sulphone)s and poly(disulphide)s
Authors: Cameron G. Gordon , Hogg Donald R. , Stachowiak Stephen A. 
Published: April 2003

AbstractThe preparation of a further series of poly(β‐chlorothioether)s, from reaction of 4,4′‐methylenedisulphenyl chloride (2) with diolefins, is described. Poly(sulphone)s were prepared by controlled oxidation of the poly(β‐chlorothioether)s from 2 and from 4,4′‐biphenyldisulphenyl chloride (1). Poly(disulphide)s were prepared by reaction of 1 or 2 with dithiols or lithium metal. All the above polymers were characterized by NMR, IR, elemental analysis, and rel. mol. mass determinations.
On the chain growth in three‐component copolymerizations
Authors: Tosi Camillo , Campadelli Fabio 
Published: April 2003

AbstractThe chain propagation step in three‐component copolymerizations was studied by comparing the composition of the growing chains with the limiting value obtained from the terpolymerization equations. On the basis of a classification of terpolymers according to the products of reactivity ratios for the three binary copolymerizations, the close similarity of the curves regarding terpolymers and binary copolymers was shown.
Kinetic study of the quaternization of tertiary amine as functional group in the poly(vinylpyridine) series with alkyl bromide
Authors: Morcellet‐Sauvage Joëlle , Loucheux Claude 
Published: April 2003

AbstractThe reactivity of tert‐amine groups was studied by quaternization of homopolymers and copolymers of 2‐vinyl‐, 2‐methyl‐5‐vinyl‐ and 4‐vinyl‐pyridine with butyl bromide. The reactivity of the corresponding model compounds was taken as a reference: in this case second order kinetics is obeyed until complete reaction of the pyridine derivatives. If the pyridylethylene repeating unit is included in a statistical styrene/vinylpyridine copolymer (with a low content of pyridylethylene units), the kinetics are of second order too, except for the styrene/2‐vinylpyridine copolymer. In this case the steric hindrance due to the position of the nitrogen atom is the preponderant factor. For homopolymers, in the case of the quaternization of poly(1‐pyrid‐4‐ylethylene) [poly(4‐vinylpyridine)] second order kinetics are observed, until the adjacent reactive groups are quaternized. In the case of poly[1‐(6‐methyl‐3‐pyridyl)ethylene] [poly(2‐methyl‐5‐vinylpyridine)] a second order law is obeyed only until one of the ajacent groups is quaternized.For poly(1‐pyrid‐2‐ylethylene) [poly(2‐vinylpyridine)] steric hindrance effects govern strictly the behaviour of the functional group.These results were interpreted by introducing three individual velocity constants which were determined graphically.
Polymérisation et copolymérisation de l'acétoxy‐1 butadiène
Authors: Gressier Jean‐Claude , Pinazzi Christian P. , Levesque Guy 
Published: April 2003

AbstractL'acétoxy‐1 butadiène (1a, b) est polymérisé par les amorceurs radicalaires aussi bien en masse, en solution benzénique ou en émulsion aqueuse. Les polyméres formés renferment 80% de motifs ‐1,4 (4) et 20% de motifs ‐3,4 (5) ainsi qu'il ressort de l'étude de modèles (2 et 3) de ces structures. L'importance des réactions de transfert de chaǐne au monomère a été mesurée et rend compte de la valeur faible des masses molaires moyennes (M̄n ≈ 5000).La copolymérisation radicalaire a été étudiée avec des composés acryliques, vinyliques et diéniques: 1a, b présente une réactivité trés proche de celle de l'isoprène. Les copolymères ont couramment des M̄n de l'ordre de 20 000.Les polymères préparés par amorçage cationique sont instables à moins d'ětre soigneusement purifiés; enfin les amorceurs anioniques sont détruits dès −80°C par ce monomère.
Gelchromatographie, Versuche zur Strömungsdispersion mit radioaktivem Polystyrol
Authors: Berger Knud C. 
Published: April 2003

AbstractExperimente mit Mischungen aus mit 14C radioaktiv markiertem, monodispersem Polystyrol mit inaktivem Polystyrol zeigen, daß bei der gelchromatographischen Trennung ein molekularuneinheitliches Polymeres sich wie die Summe aus molekulareinheitlichen Proben verhält.
A study on initiation of vinyl polymerization with diacyl peroxide‐tertiary amine systems by spin trapping technique
Authors: Sato Tsuneyuki , Kita Shinji , Otsu Takayuki 
Published: April 2003

AbstractTo characterize the intermediate radicals produced in the initiation of vinyl polymerization with binary systems of diacyl peroxides and tertiary amines, spin trapping technique was applied by using 2‐methyl‐2‐nitrosopropane (8) as a spin trapping reagent. In the reactions of N,N‐dimethylaniline (2a) and N‐N‐diethylaniline (2b) with benzoyl peroxide (1a), N‐methylanilinomethyl (7) and N‐ethylanilino‐1‐ethyl radicals (16), respectively, were trapped, contrary to benzoyloxyl (4a) and phenyl radicals which were not trapped. This was explained by assuming that benzoyloxyl radicals (4a) react faster with 2a or 2b to give the radicals 7 and 16, than being trapped with 8. From this, 4a and 7 or 16 were concluded to be the initiating radicals in these systems. In the reaction of lauroyl peroxide (1b) with 2a or 2b, however, undecyl radicals were trapped together with the radicals 7 or 16. In the case of N‐ethyl‐N‐methylaniline (2c) both, N‐ethylanilinomethyl (18) and N‐methylanilino‐1‐ethyl radicals (20), were trapped. Further, it was found that in the reaction of 1a with poly(p‐dimethylaminostyrene), both poly{1‐[4‐(N‐methyl‐N‐methylylamino)phenyl]ethylene} (22) and phenyl radicals were trapped, contrary to the reaction of 1a with 2a.
Effects of 2‐tetrazenes on vinyl polymerization
Authors: Sugiyama Kazuo , Nakaya Tadao , Imoto Minoru 
Published: April 2003

AbstractThe rate of the thermal decomposition of 2‐tetrazenes (1–5) was measured in the pure state. The activation parameters were calculated from the dependence of the rate constants on the temperature. In order to elucidate the effects of 2‐tetrazenes on the radical polymerization, a kinetic investigation of the polymerization of styrene initiated by 2,2′‐azoisobutylonitrile in the presence of 2‐tetrazene derivatives was also undertaken.
Trägersynthesen, 6. Träger‐Oligonucleotidsynthese an unvernetzten Copolymeren aus Vinylalkohol und N‐Vinylpyrrolidon
Authors: Seliger Hartmut , Aumann Gerd 
Published: April 2003

AbstractUnvernetzte Copolymere aus Vinylacetat und N‐Vinylpyrrolidon wurden verseift und die erhaltenen Copolymeren als Träger für eine Oligonucleotid‐Synthese in homogener Phase eingesetzt. Desoxythymidin als Kettenanfang wurde über eine Carbonyloxy‐Brücke an den Träger angeknüpft. Die Kettenverlängerung erfolgte zunächst durch Oligokondensation mit ungeschütztem Desoxythymidinphosphat, sodann durch Anbau einer geschützten Nucleotideinheit an das 3′‐Ende. Oligonucleotide des Typs dT (pdT)n und dT (pdT)n– rU wurden auf diesem Wege gewonnen.
The polymerization of vinyl monomers with N‐chlorosuccinimide in the presence of protic acids
Authors: Ko Munan , Sato Tsuneyuki , Otsu Takayuki 
Published: April 2003

AbstractThe polymerization of vinyl monomers with N‐chlorosuccinimide (1) in the presence of protic acids such as p‐toluenesulfonic acid (PTS) was investigated. From the kinetic studies of the reaction of 1 with PTS and the polymerization of methyl methacrylate (MMA) with the above combined initiator system, it was found that the polymerization is initiated by a radical produced by a bimolecular reaction between 1 and PTS, and is terminated by a second order reaction. ESR investigations on the reaction mixture of 1 with PTS by spin trapping technique clearly showed that the initiating radical is the N‐succinimidyl radical. This radical results from a homolysis of the NCl bond of the protonated N‐chlorosuccinimide 2.
Polymere mit dem Zentralatom eines makrocyclus in der hauptkette, 2. Polykondensationsreaktionen mit Germaniumkomplexen des Phthalocyanins und meso‐Tetraphenylporphins
Authors: Hartmann Monika , Meyer Gunter , Wöhrle Dieter 
Published: April 2003

AbstractDihydroxyphthalocyaningermanium (1b) und Dihydroxytetraphenylporphingermanium (3b) werden mit verschiedenen einwertigen Alkoholen zu den niedermolekularen Bisalkoxy‐Derivaten (1c–f bzw. 3c–h) umgesetzt. Mit zweiwertigen Alkoholen und Phenolen können Polymere der Struktur 5 und 6 bzw. 8a, 9a und 8b, 9b erhalten werden.Dichlorphthalocyaningermanium (1a) und Dichlortetraphenylporphingermanium (3a) reagieren mit Phenol bzw. Hydrochinon ebenfalls zu niedermolekularen und polymeren Phenoxy‐Derivaten. Die Umsetzung von 1b und 3b mit ein‐ und zweibasischen Carbonsäuren führt zu den entsprechenden Estern.Durch Dehydratisierung von 3b kann das polymere Porphin 15 hergestellt werden.Die IR‐Spektren der dargestellten Verbindungen werden im Vergleich zu den analogen Hemiporphyrazingermaniumkomplexen diskutiert. Thermogravimetrische und Halbleitermessungen (σ298 K = 10−10 – 10−15Ω−1 cm−1) werden beschrieben.
Ionic polymerization of cyclic ethers, 3. Polymerization of 2,3‐epoxypropanal and its 2‐methyl and 2,3‐dimethyl derivatives in the presence of aluminum 2‐propoxide as catalyst
Authors: Jedliński Zbigniew , Rybczyk Marzenna , Majnusz Jerzy , Janik Stefan 
Published: April 2003

AbstractThe polymerizations of 2,3‐epoxypropanal (glycidaldehyde) (1a) and its 2‐methyl and 2,3‐dimethyl derivatives (1b, 1c) were studied in the temperature range of 20–50°C in the presence of aluminum 2‐propoxide as catalyst.The polymerization of these epoxyaldehydes was found to proceed in two stages. A Tishchenko reaction leading to the formation of the corresponding esters 2 was found to be predominant in the first stage of polymerization. In the case of aldehydes having a methyl group in the 2‐position, the β‐lactones 3 are formed.Polymer chain growth takes place in the second stage of the polymerization reaction with the participation of the epoxide groups of the dimers 2 produced in the first stage, which leads to the formation of non‐crosslinked polyethers having short ester side chains with epoxide groups or side chains with β‐lactone rings.The structure of the starting monomer was shown to determine directly the differences in polymerization rates and in the structure of the polymers and intermediate products.
Determination of the structure parameters of styrene/butadiene block copolymer in heptane by means of small‐angle X‐ray scattering
Authors: Pleštil Josef , Baldrian Josef 
Published: April 2003

AbstractSmall‐angle X‐ray scattering was used to investigate dilute solutions of the styrene/butadiene block copolymer in heptane as a selective solvent for polybutadiene. The solutions contained two types of particles of different size. The weight fraction and sizes of both types of particles were determined at four temperatures ranging from 18 to 50°C. Absolute intensity measurements were used to determine the weight of the micelles (large particles) and the degree of swelling of the individual copolymer components.By using a simple structure model as a basis, the data determined by absolute intensity measurements at the four temperatures were employed to calculate the diameter of the polystyrene nucleus (222–181 Å), the total diameter (558–532 Å), and the radius of gyration (191–180 Å) of the micelles. The values obtained were in good agreement with those determined directly from the small‐angle scattering curves in a relative scale. The number of macromolecules in a micelle varies from 100 (at 50°C) to 190 (at 18°C).