bluuebunny/crossref_metadata_2025 huggingface dataset:
The reaction of propane sultone with macromolecules. III. Poly(ethylene imine)
Authors: Natus Guy , Goethals Eric J.
Published: April 2003

The reaction of propane sultone with poly(ethylene imine) (PEI) has been studied in benzene and in methanol. The reaction products are polyampholytes insoluble in water or any other solvent, but soluble in strong alkali or in concentrated acids. Depending on the molar ratio PEI: propane sultone, products having a degree of substitution between 0.23 and 0.64 were obtained. After treatment with excess sodium hydroxide and removal of the excess by dialysis, a polymer containing both sodium sulfopropyl groups and sulfopropyl groups in form of inner ammonium salts was obtained.
Thermodynamics of polymerisation of heterocyclic compounds. Part. III. The heat capacity, entropy, enthalpy, and free energy of tetroxan
Authors: Clegg G. A. , Melia T. P.
Published: April 2003

A precision, adiabatic vacuum calorimeter and a differential scanning calorimeter have been used to measure the heat capacity of tetroxan over the temperature range 80 to 420°K. An estimate has been made of heat capacity values below 80°K. Values of the heat capacity, entropy, enthalpy, and free energy are listed at 10° intervals. Values of 22.6 ± 0.4 kJ · mole−1 and 385 ± 1°K are obtained for the heat of fusion and melting temperature, respectively. The vapour pressure (P) of tetroxan has been measured over the temperature range 300–375°K. The results are summarized as

The results have been used in conjunction with previously published data to evaluate the entropy changes occurring in the system formaldehyde ⇌ trioxan ⇌ tetroxan ⇌ polyoxymethylene.
Polyhydrochinonsulfone. II.1. Poly[vinyl‐(2.5‐dihydroxy‐phenyl)‐sulfon]. Synthese von monomeren, homo‐ und copolymeren
Authors: Manecke Von Georg , Beyer Hans‐Jürgen
Published: April 2003

Vinyl‐[2.5‐diacetoxy‐phenyl]‐sulfon wurde dargestellt. Das Monomere wurde homopolymerisiert und mit Styrol sowie Styrol und Divinylbenzol durch radikalische Initiierung copolymerisiert. Nach Abspaltung der Acetyl‐Schutzgruppen resultierten Polymere, in denen die Redoxgruppe (Hydrochinon) über eine Sulfonbrücke direkt mit der Polymerenkette verbunden ist.
Partielle spezifische volumina von m.m′‐ditolyl und seinen oligomeren
Authors: Kern Von W. , Höcker H. , Heitz W.
Published: April 2003

Das partielle spezifische Volumen von m.m′‐Ditolyl in Toluol wurde durch Dichtemessungen über den gesamten Konzentrationsbereich bei 25°C bestimmt. Das hieraus berechnete molare Überschußvolumen beträgt −0,21 cm3/Mol bei einem Volumenbruch von 0,5. Die partiellen spezifischen Volumina von Oligomeren des m.m′‐Ditolyls wurden in einem niedrigen Konzentrationsbereich in Toluol, Benzol und Trichloräthylen bei 25°C bestimmt. Sie sind in erster Näherung dem Molekulargewicht umgekehrt proportional.
Über die polymerisation von methacrylsäuremethylester mit α‐aryl‐(p‐toluylsulfonylmethyl)‐urethanen
Authors: Brachel Von Hanswilli V. , Engelhardt Fritz
Published: April 2003

Verbindungen der allgemeinen Formel
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initiieren in Gegenwart von Kupfer(Il)‐ und Halogenid‐Ionen sowie von Sauerstoff die Polymerisation von ungesättigten Monomeren. Am Beispiel der Polymerisation des Methacrylsäuremethylesters wird die Abhängigkeit der Polymerisationsgeschwindigkeit von der Substitution des Initiators in R′ bestätigt und gezeigt, daß sie der HAMMETT‐Beziehung gehorcht.
Interaction of polylysine with phosvitin and nucleic acids
Authors: Roychoudhury K. , Biswas B. B. , Pal M. K.
Published: April 2003

DNA dependent RNA asynthesis in inhibited by basic proteins like histones or polylysine This inhibitory effect is found to be suppressed by phosvitin, which is a phosphoprotein. Turbidometric studies indicate that polylysine interacts with DNA and RNA stoichiometrically. This interaction with DNA has been thought to be the cause of this inhibitory effect. Phovitin also interacts with polylysine more effectively than DNA. Phosvitin in quantities much less than the stoichionietric amount can compete with DNA for the polylysine and can thus make DNA free and available as template for the RNA synthesis. Phosphoserine, unlike pbosvitin, is ineffective in suppressing the inhibitory effect of polylysine.
Studies on organometallic compounds as polymerization catalysts. IV. Polymerization of propylene oxide catalyzed by zinc chloride‐alkali metal alkoxide system
Authors: Ishimori Michihro , Hsiue Ginho , Tsuruta Teiji
Published: April 2003

Binary system of zinc chloride‐alkali metal alkoxide was studied as catalyst for propylene oxide polymerization. The reaction of zinc chloride with alkali metal alkoxide was found to proceed steppwise according to the equations:

Formation of high molecular weight polymer in the propylene oxide polymerization catalyzed by zinc chloride‐alkali metal alkoxide system is found to be caused by zinc dialkoxide formed in the reaction system. The results support our previous conclusion that the presence of alkyl‐zinc bond in zinc alkyl‐alcohol system is not necessarily an indispensable factor for high molecular weight polymer‐forming reaction.
The polymerization mechanism of methyl methacrylate initiated with ceric ion
Authors: Narita Hiroshi , Okamoto Susumu , Machida Seishi
Published: April 2003

The polymerization of methyl methacrylate in the presence of ceric ion and pinacol in acetic acid solution has been investigated. Acetone formed in the reaction products has been determined and the mechanism and kinetics of the polymerization have been studied. It has been confirmed that the primary radical formed from pinacol reacts with not only the monomer to produce a monomer radical and initiate the polymerization but also with ceric ion. Under the present experimental conditions, the reaction of the primary radical with ceric ion is about 127 times as fast as that with monomer. The monomer radical produced reacts with another monomer to propagate polymerization. The polymerization is terminated by reaction of the polymer radical with ceric ion. The rate of polymerization was proportional to [pinacol], [monomer]2 and reciprocal to [CeIV].
Studies in polymerisation of vinyl acetate. I.
Authors: Potnis S. P. , Deshpande A. M.
Published: April 2003

Polymerisation of vinyl acetate has been studied in bulk and solution at 60°C using benzoyl peroxide as initiator. From the results obtained, it has been shown that, the rate of polymerisation is proportional to the square root of initiator concentration in both the cases. The values of the transfer constants due to the monomer and initiator, (CM), (CI), the overall rate constant (K), the quotient of the rate constant of propagation and the square root of the rate constant of termination (KP/Kt1/2) and the rate constant for the initiation (Ki) have been determined for bulk polymerisation. Utilising some of the constants obtained in bulk polymerisation and studying the polymerisation of vinyl acetate in glacial acetic acid in detail, values of CI, K, (Kp/Kt1/2), Ki at different ratios of solvent (S) and monomer (M) concentration ([S]/[M]) as also chain transfer constant (Cs) for glacial acetic acid have been calculated.
Copolymerization of α‐hydroxyisobutyric acid anhydrosulfite with vinyl compounds1
Authors: Inoue Shohei , Tsubaki Kazumi , Yamada Takeyoshi , Tsuruta Teiji
Published: April 2003

Polymerization of α‐hydroxyisobutyric acid anhydrosulfite was carried out in some vinyl compounds in the presence of azo‐bis‐isobutyronitrile at 80°C. In acrylonitrile, a graft copolymer consisting of polyacrylonitrile and polyester[OC(CH3)2CO]x̄chains was obtained. Free radical nature of the grafting reaction is suggested. In methacrylonitrile a polymeric product was formed with polymethacrylonitrile main chains in which the cyano groups partly reacted with one molecule of the anhydrosulfite, introducing the units of [OC(CH3)2CO] into the polymer.
Cyclopolycondensations. XI. Syntheses of alicyclic polybenzoxazinones
Authors: Hagiwara Yoshichi , Ikeda Kojuro , Kurihara Masaru , Yoda Naoya
Published: April 2003

Alicyclic polyamic acids and their polybenzoxazinones were prepared by the polycondensation of trans‐ and cis‐1.4‐ and 1.3‐cyclohexane dicarboxylic acid chloride with 4,4′‐diaminobiphenyl‐3.3′‐dicarboxylic acid. Comparing these alicyclic polymers with corresponding fully aromatic polybenzoxazinones, it was demonstrated that the symmetry of the molecules rather than aromaticity is a more important factor for the solubility of polymers. The trans‐1.4‐acid chloride is easier polymerizable than the cis‐1.4‐isomer. The polybenzoxazinone from the trans‐1.4‐isomer shows higher thermal stability than that from the cis‐1.4‐isomer. The reaction variables of the cyclopolycondensation were studied and some of the properties of the resulting polymers are described.
Cationic polymerization of α·β‐disubstituted olefins. Part X. Effect of polymerization conditions on the steric structure of poly(methyl propenyl ether)
Authors: Higashimura Toshinobu , Ohsumi Yukihiko , Okamura Seizo , Chûjô Riichiro , Kuroda Takamune
Published: April 2003

The effect of polymerization conditions on the steric structure of the polymer was studied for the polymerization of methyl propenyl ether (MPE) catalyzed by BF3·O(C2H5)2. The steric structure of the α‐ and β‐carbon atoms of the polymers were measured by NMR spectroscopy. The threo‐meso configuration of the α‐ and β‐carbons of the polymer obtained from mixtures of cis‐ and trans‐MPE increased with increasing amount of trans‐isomer in the monomer mixture. We conclude that the pure trans‐isomer would give a threo‐di‐isotactic polymer. As the polarity of the solvent increased, the proportion of threo‐meso structure decreased in the polymer obtained from trans‐rich monomer, but it increased in the polymer obtained from cis‐rich monomer. The effect of the solvent on the steric structure of the polymer obtained from the cis‐isomer was greater than on that of the polymer from trans‐isomer. An interaction between the β‐methyl group of the attacking monomer and that of the penultimate unit was recognized on the basis of the change in the steric structure of the polymer with polymerization temperature. The α‐carbons of the polymer obtained were found to have the racemic configuration whilst the β‐carbons are hardly ever racemic. The mechanism of the propagation reaction is discussed on the basis of these results.
Die chemische Heterogenität von Copolymerisaten. 5. Sequenzlängenverteilung
Authors: Markert Von Gerhard
Published: April 2003

Die bekannten Gleichungen zur Berechnung von Sequenzlängen gelten für chemisch einheitliche Copolymerisate. Es wird eine Methode beschrieben, wie man die Sequenzlängenwahrscheinlichkeiten für chemisch heterogene Copolymerisate ermitteln kann, wenn die Häufigkeitsverteilung der chemischen Zusammensetzung bekannt ist. Das Verfahren wird am Beispiel des Monomerenpaares Methylmethacrylat/Äthylacrylat demonstriert und diskutiert.
Mechanochemische Synthesen durch Polykondensation mit Polyestern als Grundsubstanz. 1. Mechanochemische Polykondensation von polyäthylenterephthalat mit Äthylendiamin
Authors: Oprea Von Cleopatra Vasiliu , Neguleanu Claudia , Simionescu Cristofor
Published: April 2003

Es wird erstmals untersucht und bestätigt, daß die Auslösung von Polykondensationsvorgängen auf mechanochemische Weise möglich ist, wobei als polymerer Träger das Polyäthylenterephthalat und als Kondensationspartner Diamine (Äthylen‐ und Hexamethylendiamin) sowie zweibasische Säuren (Adipinsäure) verwendet werden. Der Einfluß der Dauer der mechanischen Beanspruchung und des Mischungsverhältnisses der Reaktionspartner auf den Umsatz wird diskutiert. Die Kondensationsprodukte werden durch chemische und spektroskopische Methoden sowie durch Bestimmung von Löslichkeit und Schmelzpunkt gekennzeichnet.

Die Existenz mechanochemischer Umsetzungen wird auch an anderen Systemen (Polyamiden/zweiwertigen Alkoholen) nachgewiesen.
Über das 3.4‐diamino‐styrol. I
Authors: Manecke Von G. , Rotter U.
Published: April 2003

Bei der Darstellung von 3.4‐Diamino‐styrol aus 1‐[3′.4′‐Diamino‐phenyl]‐äthanol sowie aus 3.4‐Diamino‐zimtsäure entsteht 3.4‐Diamino‐äthyl‐benzol als Nebenprodukt. 3.4‐Diamino‐styrol wird ohne Nebenprodukt durch Reduktion von 3‐Nitro‐4‐amino‐styrol erhalten; es läßt sich zu entsprechenden Vinylheterocyclen kondensieren.
Kinetic studies on the polymerization of 1.3‐dioxepane: Initiated with triethyl oxonium tetrafluoroborate
Authors: Okada Masahiko , Kozawa Shigeyuki , Yamashita Yuya
Published: April 2003

The kinetics of the polymerization of 1.3‐dioxepane by triethyl oxonium tetrafluoroborate has been studied in methylene chloride. The polymerization was preceded by a long induction period characteristic of the polymerization of cyclic formals by this initiator. The degree of polymerization of the polymer was rather high from the outset of the polymerization, increased linearly with increasing conversion up to about 50% and then leveled off. The formation of a polymer in an equimolar reaction of the monomer and the initiator can be explained by initiation being rather slow compared with propagation. It was found that addition of a small amount of isobutyl vinyl ether accelerated the rate of polymerization and shortened the induction period markedly.
The structural effects of annealing time and temperature on the paracrystal‐crystal transition in isotactic polypropylene
Authors: Zannetti Roberto , Celotti Giancarlo , Fichera Annamaria , Francesconi Romolo
Published: April 2003

The influence of different annealing treatments on the crystalline order of isotactic paracrystalline polypropylene is described.

The result support an intramolecular transformation mechanism based on a rewinding of hellcal segments of different lengths having opposite senses of spiralization. Such a mechanism is in agreement with the annealing time dependence of a particular order parameter and is sensitive to the temperature and not to the annealing time once the saturation order value is reached. This saturation phenomenon occurs very quickly at the higher temperatures.
Poly(2‐[α‐3H]vinylpyridine 1‐oxide)
Authors: Gregson Leslie , Holt Paul
Published: April 2003

Poly(2‐vinylpyridine 1‐oxide), when injected into animals, counteracts the pathogenic effects of inhaled silica dust. To study its distribution in the cells, a specifically labelled polymer has been synthesised by reducing 2‐acetylpyridine with tritium, dehydrating, polymerising then oxidizing the polyvinyl product. Some of the tritium (17%) enters the aromatic ring by exchange and there is a small loss of tritium by exchange with solvents. At the stage of reduction, there is preference for CT bond formation rather then CH.
Theoretical relationships between parameters in the KUHN‐MARK‐HOUWINK‐SAKURADA equation
Authors: Kamide Kenji , Kataoka Akira
Published: April 2003

Some general theoretical relationships between Km and a in the KUHN‐MARK‐HOUWINK‐SAKURADA equation:

have been derived on the basis of the treatments of UEDA‐KAJITANI (UK) and SHIOKAWA‐OYAMA (SO) which relate viscosity expansion factor αη to excluded volume effect z, combining with the FLORY‐FOX (FF) intrinsic viscosity equation.

The combination of the treatments of FLORY‐FOX and UEDA‐KAJITANI (FF‐UK) led to

and of the FLORY‐FOX and SHIOKAWA‐OYAMA (FF‐SO) to

In these equations K is FLORY's K value and M0 is a molecular weight representative of the molecular weight range covered by the intrinsic viscosity/molecular weight study.

It has appeared that the upper limit of a applicable in the treatments including the FF‐UK and FF‐SO thus obtained follows the order:

where Fi is FIXMAN, KSR, KURATA‐STOCKMAYER‐ROIG, KY, KURATA‐YAMAKAWA.

The Km‐a relations predicted by the theoretical treatments mentioned above has been examined by the experimental data on atactic polypropylene, polyhexene‐1 sulphone, polyvinyl acetate, polymethyl methacrylate, polystyrene, and polyacrylonitrile.
Polymer synthesis by 1.3‐cycloaddition reaction. II
Authors: Gilliams Y. , Smets G.
Published: April 2003

Aliphatic bisazides, 1.5‐bis‐azidopentane, 1.4‐bis‐azidobutane and bis‐(β‐azidoethyl)‐ether have been condensed with hexamethylene, m‐ and p‐phenylene bismaleimides and give poly‐Δ2‐1.2.3‐triazolines. Similarly 1.4‐ and 1.5‐bisazidoalkanes were condensed with m‐ and p‐diethinylbenzene, and afford the corresponding triazole polymers. With 1.6‐bis‐diazohexane, the diethinylbenzene give pyrazolenine or pyrazole polymers depending on the reaction conditions.

The structures of these new polymers were demonstrated on the basis of their infrared and NMR spectra, and comparison with those of their low molecular weight model substances.
Polymerization of styrene initiated by trichloroacetyl chloride and water
Authors: Sakota Naokazu , Nakamura Hiroshi , Nishihara Koji
Published: April 2003

The polymerization of styrene initiated by trichloroacetyl chloride (TAC) and water was investigated. The reaction proceeded by an ionic mechanism and polymers of relatively low molecular weight were formed. From the analytical results of the polymer, it was suggested that the ionic decomposition of an intermediate complex formed by TAC and water yielded chloroformic acid which induced cationic polymerization of styrene.
Polymers containing intra‐molecular crosslinks
Authors: Longi P. , Greco F. , Rossi U.
Published: April 2003

Previous research on polymer intra‐molecular crosslinks has been pursued in order to obtain copolymers containing very stable intra‐molecular crosslinks in amounts of 1.5–3 mole‐%.

From viscometric and osmotic molecular weight determinations of the obtained copolymers, it can be inferred, as theoretically expected, that formation of intra‐molecular crosslinks remarkably reduces the size of random coiled macromolecules in diluted solutions, regardless of chemical structure of such crosslinks and such macromolecules.
The determination of the distribution of molecular weight of polymer samples
Authors: Carraher Charles E. , Brandt Thomas W.
Published: April 2003

A new method is presented for the determination of the molecular weight distribution from intrinsic viscosity and weight fraction data obtained for a series of fractions. A GAUSSian distribution of molecular weights for the individual fractions is assumed. The experimental intrinsic viscosity of the individual fractions is identified with the maxima of the differential mass distribution of the individual fraction. The weight fraction as a function of molecular weight for the individual fractions are summed to give a molecular weight distribution curve characteristic of the unfractionated sample. Theoretical relationships for the approach are presented. The corresponding computer program is given in Fortran IV. The method is tested using literature data and original measurements on a polyurea.
Gelchromatographie. 9. Mitt.: Polymethacrylatgele1
Authors: Heitz Von Walter , Winau Herbert
Published: April 2003

Der Einfluß der Herstellungsbedingungen auf die gelchromatographischen Eigenschaften von Polymethylmethacrylatgelen, die mit Glykoldimethacrylat vernetzt sind, wurde untersucht.

Homogen‐vernetzende Copolymerisation führt zu Gelen mit Ausschlußmolekulargewichten bis ca. 6000. Durch Copolymerisation in Gegenwart von Inertkomponenten entstehen heterogene Strukturen. Durch heterogen‐vernetzende Copolymerisation können Gele mit Ausschlußmolekulargewichten, die formal 1010 und mehr entsprechen, erhalten werden.

Die Änderung der Vernetzerkonzentration und des Solvatationsvermögens der Inertkomponente erlaubt es, die Ausschlußmolekulargewichte der Gele in weiten Grenzen zu variieren.

Die Polymerisation der Dimethacrylate von Polyäthylenoxiden führt zu hydrophilen Gelen, die keine Hydroxylgruppen enthalten. Sie sind zu Trennungen in Wasser und in organischen Lösungsmitteln geeignet.
Oligomere als modelle für poly‐p‐xylyliden. Untersuchungen über stilbene. XLIX.1
Authors: Drefahl Von Günther , Kühmstedt Rolf , Oswald Hermann , Hörhold Hans‐Heinrich
Published: April 2003

Die folgenden durch π‐Elektronen bedingten Eigenschaften einer Reihe von wohldefinierten Oligoxylylidenen mit trans‐Doppelbindungen der allgemeinen Struktur I
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werden untersucht: UV‐Spektren in Lösung, UV‐Spektren der Festkörper (Reflexionsspektren), Festkörperfluoreszenzspektren und die spektrale Abhängigkeit der Photoleitfähigkeit. Mit einem quantenmechanischen Näherungsverfahren werden die π–π*‐Anregungsenergien für die Glieder der Reihe berechnet. Es wird gefunden, daß die betrachteten elektronischen Eigenschaften sehr schnell gegen einen Grenzwert konvergieren, der praktisch schon mit n = 3 erreicht wird. Hieraus ist die Extrapolation auf entsprechende Eigenschaften des Polyxylylidens möglich.
Viscosity of polyelectrolyte solutions
Authors: Vink Hans
Published: April 2003

The viscosity behaviour of polyelectrolytes in solutions of low ionic strength has been investigated. The dependence of the viscosity on the degree of substitution, the molecular weight and the velocity gradient was studied in detail. The measurements were carried out in solutions of different ionic strength and the limiting intrinsic viscosity at zero ionic strength was determined by extrapolation. It was found that at zero ionic strength the exponent in the KUHN‐MARK‐HOUWINK equation has the value a = 1.1. It was further found that the intrinsic viscosities in the low and medium molecular weight region were considerably higher than those expected for rigid rodlike molecules of comparable size. The exceptionally high values of the intrinsic viscosity in solutions of low ionic strength indicate the presence of a pronounced “electroviscous effect” in these solutions.
Application of proton magnetic resonance spectroscopy to phenol novolak: Chemical shift in pyridine of methylene protons of phenol novolaks
Authors: Yoshikawa Toshio , Kumanotani Ju
Published: April 2003

The NMR spectroscopy of cresols, benzylphenols, and di‐, tri‐, and tetra‐nuclear phenolformaldehyde condensates using pyridine as solvent proved that their methyl or methylene groups which have ortho‐phenolic hydroxyl groups show their signals at much lower τ‐values as compared with those compounds having no ortho‐phenolic hydroxyl groups. Thus, the signals of ortho‐ortho, ortho‐para, and para‐para methylene types in novolak compounds could be separately observed in pyridine solution. Due to this specific properties of pyridine as NMR solvent, various phenol novolak resins could be characterized according to their modes of methylene links.
Fold structure of solution grown crystals of alkyl‐branched copolymers of polyethylene
Authors: Kawai Tōru , Ujihara Közaburo , Maeda H.
Published: April 2003

According to the hypothesis that uncrystallizable units are excluded from the crystalline lattice into the surface of the crystals and concentrated in the folds, morphologies and textures of solution grown crystals of branched polyethylenes have been studied as functions of content and length of the branches by means of various techniques.

Methyl, ethyl, and propyl branches were introduced into polyethylene chains by polymerization of mixtures of diazomethane and the corresponding higher diazoalkane. The crystals of these branched polymers grown from dilute solutions were treated with a selective oxidizing agent, fuming nitric acid. The degraded products were examined as regards the changes during the oxidation in molecular weight, weight‐loss, layer thickness (by low angle X‐ray studies), branch content (by IR analysis), unit cell dimensions, density and X‐ray crystallinities and morphology (by electron microscopy), with the aim of clarifying the nature of disordered material in polymer single crystals. It emerges that the thickness of the surface layer increases with the content and length of the branches and that the folds may be considered as irregular loose loops for crystals of polymers with a branch content beyond ca. one per 100 carbon atoms. The results also revealed less perfect order of the crystal lattice for polymers with higher degree of branching. Thus, the branches seemed to be concentrated in the loose loops in the surface layer and within the crystal defects, both of which are accessible to oxidation. The concentration of the branches within the folds was discussed in terms of the content and the length of the branches. It was also found that the thicker the surface layer, the poorer the morphology of the crystals.
Thermal degradation of poly‐4‐methylpentene‐1. Part 1. The products of degradation
Authors: Reginato Luigi
Published: April 2003

Poly‐4‐methylpentene‐1 was degraded in the temperature range 291–341°C. The decomposition products were determined and their rate of evolution followed. Their formation is explained on the basis of a free radical chain mechanism in which hydrogen transfer plays an important role. A free radical abstracts a hydrogen on a tertiary carbon atom by a “back‐biting” mechanism, although there is also evidence of the abstraction of secondary hydrogen atoms. A split in the chain follows and a volatile fragment is formed. Isobutene and propane are the main components of the fraction volatile at room temperature, which accounts for about 9% of the total loss of weight. The rest consists of higher molecular weight branched hydrocarbons and olefins. The energy of activation for the loss of weight was found to be 53.5 kcal/mole.
ÜBer die aktivität von katalysatorgemischen aus metallorganischen verbindungen und TiCl4 bei der trioxanpolymerisation
Authors: Kabaivanov Von V. , Glavcev I. , Natov M.
Published: April 2003

Die Geschwindigkeit der Trioxanpolymerisation, die Ausbeute an Polyoxymethylen und das Molekulargewicht des Polymeren wurden als Funktion des Ionencharakters der MeC‐Bindung in einer Reihe von Katalysatorsystemen aus TiCl4 und (C2H5)4Pb, (C2H5)4Sn, (C2H5)3Al, C2H5MgBr und n‐C4H9Li untersucht. Es ergab sich, daß die Aktivität der Katalysatorsysteme vom Ionencharakter der MeC‐Bindung abhängt. Die größte Aktivität bei TiCl4 als Cokatalysator weisen die metallorganischen Verbindungen mit 15–20% Ionencharakter auf.
Thermal properties of an ethylene/1‐butene block copolymer
Authors: Glegg G. A. , Gee D. R. , Melia T. P.
Published: April 2003

A precision, adiabatic vacuum calorimeter and a differential scanning calorimeter have been used to measure the heat capacity of an ethylene/1‐butene block copolymer over the temperature range 80–450°K. An estimate has been made of heat capacity values below 80°K. Values of the heat capacity, entropy, enthalpy, and free energy are listed at 10°K intervals. A glass transition (200°K), a transition of unknown origin (335°K) and a melting transition (400°K) were observed.
Free rotation dimensions of linear polymers and application to polyalkylene oxides and polyalkylene sulphides
Authors: Huglin M. B. , Stepto R. F. T.
Published: April 2003

A general expression has been derived for the mean square end‐to‐end distance 〈r2〉0f of linear polymers in the unperturbed freely rotating state. For a chain having q bonds per segment, a degree of polymerisation p and a total of N (= pq) bonds in the chain, the expression may be written 〈r2〉0f = N[A0/q + AB/pq]. Here A0 is the sum of scalar products of the bond vectors within a segment and A is the corresponding sum for pairs of bond vectors in adjacent segments. B denotes a series having a value dependent on p and the bond angles. The formula has been applied to the particular cases of [(CH2)m−X−]p where X = oxygen, X = sulphur and m = 1, 2, 3, 4, 6, and 10. Calculations of [〈r2〉0f/N]1/2 have been made for values of p in the range 1 ⩽ p ⩽ ∞, and the variation of [〈r2〉0f/N]1/2 with both chain length and chain structure discussed.
Ein beitrag zur kenntnis der N‐vinylimide
Authors: Hopff Von Heinrich , Becker Gert
Published: April 2003

Die Darstellung von N‐Vinylsuccinimid, N‐Vinylphthalimid und 4‐Trimethylsilyl‐N‐vinylphthalimid durch Umvinylierung der Imide, durch alkalische Bromwasserstoffabspaltung aus N‐2‐Bromäthylimiden sowie durch katalytische Dehydratation von N‐2‐Hydroxyäthylimiden wurde untersucht; dabei wurden durchlaufene Zwischenstufen aufgeklärt.

Die Copolymerisationsparameter der folgenden Monomerenpaare wurden bestimmt und die Q‐ und e‐Werte berechnet: N‐Vinylsuccinimid/N‐Vinylcarbazol, N‐Vinylsuccinimid/Maleinsäureanhydrid, N‐Vinylsuccinimid/Maleinsäuredimethylester, N‐Vinylphthalimid/Maleinsäureanhydrid, 4‐Trimethylsilyl‐N‐vinylphthalimid/Styrol.
MERRIFIELD‐synthese der insulinsequenz B 1–8 mit verschiedenen thiolschutzgruppen,
Authors: Hammerström Von Knut , Lunkenheimer Winfried , Zahn Helmut
Published: April 2003

Durch die MERRIFIELD‐Synthese des Oktapeptid‐Derivats Phe‐Val‐Asn‐Gln‐His(Bzl)‐Leu‐Cys(R)‐Gly wurden die S‐Schutzgruppen R gleich Benzyl (Bzl), p‐Methoxybenzyl (Mbzl), Diphenylmethyl (Dpm), Trityl (Trt), Tetrahydropyranyl (Thp), Benzylthiomethyl (Btm), äthylcarbamoyl (Ec), Benzyloxycarbonyl (Z), Acetyl (Ac) und Benzoyl (Bz) auf ihre Brauchbarkeit bei Festphasen‐Synthesen geprüft. Der Bzl‐, Mbzl‐, Dpm‐, Btm‐ und Ec‐Rest haben alle Operationen gut überstanden, wurden aber außer der Bzl‐Gruppe zum Schluß mit HBr/Trifluoressigsäure zu einem geringen Teil abgelöst. Auch die Thp‐Gruppe war während der Synthese stabil, jedoch wurde sie durch HBr/Trifluoressigsäure völlig abgespalten. Nach Oxydation mit Luft und Gegenstromverteilung wurde mit hoher Ausbeute das Disulfid III erhalten. Die Oktapeptid‐Derivate mit dem Bzl‐, Mbzl‐, Dpm‐ und Btm‐Rest wurden mit Hilfe der Gegenstromverteilung rein dargestellt. Nach Deblockierung und nachfolgender Oxydation lieferten das Bzl‐, Mbzl‐ und Dpm‐Derivat das Disulfid II bzw. III in mäßiger bis geringer Ausbeute.
The polymerization, copolymerization and terpolymerization of 1‐isopropylidene‐3a.4.7.7a‐tetrahydroindene by anionic coordinate, radical and anionic catalysts
Authors: Cesca S. , Roggero A. , Salvatori T. , De Chirico A. , Santi G.
Published: April 2003

By means of vanadium based anionic coordinate catalysts 1‐isopropylidene‐3a.4.7.7a‐tetrahydroindene (I) can be terpolymerized with ethylene and propylene and copolymerized with ethylene. IR, NMR, UV spectroscopic data, and mol. wt. distributions are reported for the polymers.

The incorporation of I is predominantly by opening of the cyclohexene double bond. The content of I was generally less than 10 mole‐%.

Attempts to obtain homopolymers of I and copolymers of propylene and I with this type of catalyst were unsuccessfull.

No solid polymer could be produced from I by free radical or anionic catalysts. With AIBN only oligomers were obtained which had cyanoisobutyric groups attached to the conjugated double bond system. K or KNH2 in ammonia solution react with I in equimolar ratios to give waxy products which do not contain NH2 groups. With K di‐hydrogenated derivatives of I are formed.

The results have been interpreted in terms of stabilized radicals and anions derived from I which are unable to propagate.
The effects of ionizing radiation on the thermal properties of linear high polymers. Part 5. Ethylene/isotactic propylene block copolymer
Authors: Gee D. R. , Melia T. P.
Published: April 2003

The results of heat capacity measurements (over the temperature range 200–500°K) on an ethylene/isotactic propylene block copolymer (containing 12 mol‐% ethylene), which had been subjected to different doses of gamma radiation (0–1,000 Mrads) at 298°K, are described. After irradiation a single endotherm replaces the two observed with the unirradiated sample. The dependence of both the enthalpy and entropy of fusion on radiation dose is similar to that observed previously with isotactic polypropylene.
Investigations on polyethers containing nitro‐groups. I. The cationic copolymerization of glycidyl nitrate with other cyclic ethers
Authors: Abe Satsuki , Ito Mamoru , Namba Keiho
Published: April 2003

Cationic copolymerizations of glycidyl nitrate (GN) with some cyclic ethers were carried out to determine conditions under which glycidyl nitrate could be copolymerized with other ethers. Propylene oxide (PO), 3.3‐bis(chloromethyl) oxacyclobutane (BCMO), THF and trioxane (TO) were used as comonomers. In LEWIS acids, boron trifluoride complexes were the most active catalysts.

The copolymerization parameters were estimated as follows: r1 = 0.03 and r2 = 1.85 for GN(M1)/PO(M2), r1 = 0.07 and r2 = 0.88 for GN(M1)/THF(M2) and r1 = 0.3 and r2 = 0.35 for GN(M1)/TO(M2) copolymerization.
Monte‐carlo‐rechnungen an makromolekülmodellen. 2. Mitt.: Quadratischer mittelwert des trägheitsradius und expansionskoeffizient
Authors: Bruns Von Wolfgang
Published: April 2003

Für zwei gitterfreie Modelle wurden mit Hilfe der Monte‐Carlo‐Rechnung unter Berücksichtigung des „ausgeschlossenen Volumens”︁ Zufallsketten erzeugt, die als vereinfachtes Bild linearer Polymermoleküle dienen können. Die Ketten bestanden aus maximal etwa 100 Struktureinheiten. Die Abhängigkeit des mittleren Quadrats des Trägheitsradius von der Bindungszahl wurde bestimmt und dafür für n > 15 r̄2 = 0,229 n1,237 bzw. r̄2 = 0,185 n1,250 gefunden. Das Verhältnis h̄2/r̄2 nähert sich asymptotisch einem Wert von ca. 6,5. Sechs aus der Literatur bekannte Beziehungen zwischen dem Expansionskoeffizienten α und dem Wechselwirkungsparameter z wurden getestet. Für den untersuchten Bereich erwiesen sich die Näherung von FIXMAN, die allerdings modifiziert werden mußte, und die von JAMES als die besten. Letztere besitzt jedoch den Nachteil, daß ihre Anwendung für längere Ketten problematisch ist, während die Gleichung nach FIXMAN, wie Untersuchungen an Gittermodellen gezeigt haben, auch dort gültig ist. Die Größe des „ausgeschlossenen Volumens”︁ und des Verhältnisses von der Segmentzahl zur Zahl der Struktureinheiten wurde anhand der Ergebnisse diskutiert.
Production of organometallic polymers by the interfacial technique. XI. Synthesis of poly(organotin esters) and a study of some associated reaction variables
Authors: Carraher Charles E. , Dammeier Roger L.
Published: April 2003

Polyesters of the form below are prepared by the interfacial method. Isolation procedures are presented and discussed.
magnified image
Polymer yield is constant as stirring rate, stirring time and nature of the organic solvent are varied. Molecular weight is constant as stirring rate and organic solvent nature are varied. Molecular weight increases as reaction time increases. No correlation is found between polymer molecular weight and polymer softening range.
Structure of poly‐1.3‐pentadiene prepared with lithium initiators
Authors: Inomata Jihei
Published: April 2003

The microstructure of poly‐1.3‐pentadiene prepared with lithium metal or lithiumalkyles in hydrocarbon solution has been studied by NMR spectroscopy (60 MHz and 100 MHz) and by IR spectroscopy. It was found that the chemical shifts (CHCl3 solution) of methyl protons in 1.4 units were δ(ppm) = 0.94 and 0.91, corresponding to cis and trans configurations of the double bonds in the polymer backbone, respectively, and that the chemical shifts of the methyl protons in 1.2 units were δ(ppm) = 1.66 and 1.60 corresponding to cis and trans configurations, respectively. As a result, the method of analysis for microstructure was established. Furthermore, the sequence of units in 1.4 structure of these polymers has been measured by IR studies on the hydrogenated polymers. According to this result, the ratio of the head‐to‐head/head‐to‐tail sequences among 1.4 units in poly‐1.3‐pentadiene was found to be 0.05 to 0.06.
Synthesis and conformational aspects of optically active oligo‐1‐methylethyleneurethans (L‐form) and oligo‐1‐benzylethyleneurethans (L‐form). Oligourethans. IX
Authors: Iwata Kaoru , Iwakura Yoshio
Published: April 2003

Optically active oligo‐urethans

(R = methyl (L‐form), n = 1–7 and R = benzyl (L‐form), n = 2–4, respectively) were prepared by the stepwise method. The ORD of the oligomers obeyed the one‐term DRUDE equation in benzene, ethanol, and dioxane indicating that the oligomers form no helical conformation.
Free radicals in diene polymers induced by ultraviolet irradiation. I. An ESR study of cis‐1.4‐poly(isoprene)
Authors: Carstensen Peter
Published: April 2003

Two different samples of purified cis‐1.4‐poly(isoprene) were irradiated in vacuo at 77°K with ultraviolet light from a medium pressure mercury lamp. The free radicals formed by this irradiation were studied by electron spin resonance (ESR). The spectra obtained were interpreted as due to radicals formed by scission of the CC bonds midway between the double bonds. However, no radicals formed by hydrogen abstraction were observed. The radicals which contributed to the ESR spectra were:
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In addition the spectra contained a weak singlet interpreted as due to polyenyl radicals:
magnified image
with n equal to 3.

The radical concentration was found to be dependent on the temperature. At liquid nitrogen temperatures all radicals were stable, but near the glass transition temperature the radical concentration decreased sharply.

A sample of purified trans‐1.4‐poly(isoprene) showed after UV irradiation the same ESR spectra as cis‐1.4‐poly(isoprene), and was accordingly interpreted in the same way.

The microstructural changes of poly(isoprene) caused by UV irradiation are discussed in relation to the identified radicals.
The polymerization of N‐vinylcarbazole by tetracyanoethylene
Authors: Nakamura Takahiro , Soma Mitsuyuki , Onishi Takaharu , Tamaru Kenzi
Published: April 2003

Kinetic and spectroscopic studies were carried out on the cationic polymerization of N‐vinylcarbazole (NVC) in the presence of tetracyanoethylene (TCNE) in benzene solution. On the basis of the experimental results the mechanism of this polymerization was discussed. It is concluded that the polymerization of NVC in the presence of TCNE proceeds through the formation of tetracyanocyclobutylcarbazole rather than that of a charge transfer complex.
The cationic polymerization of 1‐isopropylidene‐3a.4.7.7a‐tetrahydroindene
Authors: Cesca S. , Roggero A. , Palladino N. , Chirico A. De
Published: April 2003

By means of different cationic catalysts 1‐isopropylidene‐3a.4.7.7a‐tetrahydroindene (I) can be homopolymerized in a wide range of temperatures.

Amorphous polymers having\documentclass{article}\pagestyle{empty}\begin{document}$$\overline {MW}$$\end{document}in the range 1,000–17,000 were obtained. IR, NMR, and UV data indicate the 1.4‐opening of the conjugated double bond system of (I). An α value of 0.68 in the KUHN‐MARK‐HOUWINKequation and the presence of two double bond for every repeating unit support the linear structure of the polymers obtained.

The system Me3CCl/Et2AlCl was investigated. The co‐catalyst was consumed during the polymerization. The best yields were observed for values of the molar ratio Me3CCl/Et2AlCl ≥ 3. A strong alkylating ability of this catalyst toward toluene was found even at −78°C. No substantial structural differences were observed in the polymers obtained at different temperatures. Eapp= ‐3.23 kcal/mole was calculated from the log\documentclass{article}\pagestyle{empty}\begin{document}$$\overline {DP}$$\end{document}vs.1/T plot.

Chlorine was found in the polymer; traces of aromatic rings were present when the polymerization was carried out in toluene; no hydroxyl groups were detected.

The results obtained are discussed in terms of the nucleophilicity of (I) and of the pKavalues of the initial carbonium ions derived from (I).
Cationic polymerization of cyclic sulphides. I. Kinetic study of the polymerization of 3.3‐dimethylthietane initiated by triethyloxonium tetrafluoroborate
Authors: Goethals E. J. , Drijvers W.
Published: April 2003

The kinetics of the cationic polymerization of 3,3‐dimethylthietane with triethyloxonium tetrafluoroborate in methylene chloride at 20°C have been studied. The polymerization is characterized by a very fast initiation reaction. The propagation occurs most probably via cyclic sulphonium ions. The existence of a termination by reaction of the growing chains with sulphur atoms of the polymer chain was demonstrated by kinetic and molecular weight measurements. The propagation constants kp and termination constants kt at different temperatures were calculated.

The enthalpies of activation for the propagation and termination reactions are, respectively, ΔH≠p = 12.5 kcal mole−1, ΔH≠t = 7.4 kcal mole−1, and the corresponding entropies of activation are ΔS≠p = ‐26 cal deg−1 mole−1, ΔS≠t = ‐49 cal deg−1 mole−1.
Polymerization of 2‐vinyl‐1.3‐dioxolane and 2‐methyl‐2‐vinyl‐1.3‐dioxolane
Authors: Madrid J. Martínez , Mateo J. L.
Published: April 2003

The polymerization of 2‐vinyl‐1.3‐dioxolane was examined with radical, anionic and cationic catalysts in the range from −80 to +40°C. The polymerization with radical initiators occurs exclusively through the vinyl double bond. With butyl lithium, a gas evolution takes place without polymer formation. The polymerization with BF3·OEt2 gave linear or cross‐linked polymers according to the type of solvent and polymerization temperature used. The runs giving soluble polymers are the result of vinyl‐vinyl addition (60–65%) and ring opening (35–40%); when ring opening takes place, 3–10% ester groups are formed due to hydride shift, while the remainder is produced by normal opening of the dioxolane cycle. Polymerization in acetone gave solid, linear polymers with a softening point of about 120°C.

2‐Methyl‐2‐vinyl‐1.3‐dioxolane was synthesized and polymerized with radical, anionic and cationic catalysts. Unlike the dioxolane mentioned above the polymerization with BF3·OEt2 occurs at much slower rates, and all polymers obtained in homogeneous phase are soluble, independent of the solvent used. At the same time, the formation of ester groups has been observed. This fact seems to indicate the existence of an isomerization due to a shift of a methyl group.

An explanation of the cleavage of the dioxolane ring in these derivatives with the substituent in position 2 is given.
Copolymères séquencés polyvinyl‐2 pyridine/polyvinyl‐4 pyridine: Synthèse, caractérisation et étude des phases mésomorphes
Authors: Grosius Par Paul , Gallot Yves , Skoulios Antoine
Published: April 2003

On a synthétisé à l'aide de la technique de polymérisation par voie anionique, des copolymères biséquencés polyvinyl‐2 pyridine/polyvinyl‐4 pyridine et polyvinyl‐4 pyridine/polyvinyl‐2 pyridine. On a opéré sous vide en milieu tétrahydrofuranne qui est un mauvais solvant, sinon un précipitant, de la polyvinyl‐4 pyridine; l'initiateur utilisé était le diphénylméthylsodium. On a montré que la copolymérisation est indépendante de l'ordre d'introduction des monomères dans le milieu réactionnel.

Les échantillons ont été fractionnés par addition progressive d'heptane à leur solution dans un mélange tétrahydrofuranne/alcool méthylique. Les différentes fractions ont été caractérisées par diffusion de la lumière, osmométrie et analyse élémentaire. On a montré que les copolymères bruts ainsi préparés renfermaient très peu d'homopolymère et que les fractions recueilles avaient une polydispersité très faible, tant en masse qu'en composition.

On a examiné par diffraction des rayons X aux petits angles de BRAGG, la structure des gels mésomorphes obtenus avec ces copolymères en présence soit d'octanol, solvant préférentiel des séquences polyvinyl‐4 pyridine, soit de tétrahydrofuranne, de dioxanne ou de benzène, solvants préférentiels des séquences polyvinyl‐2 pyridine. On a mis en évidence deux types de structure, l'une correspondant à un empilement périodique de feuillets, l'autre à un assemblage de cylindres selon un réseau héxagonal. On a déterminé la valeur des paramètres structuraux et on les a exprimés en fonction du degré de gonflement du gel.
Über die struktur der aus maleinsäureanhydrid in gegenwart organischer basen erhaltenen polymeren
Authors: Schopov Von Iwan
Published: April 2003

Untersucht wird die Struktur der in Gegenwart von Triäthylamin und Pyridin aus Maleinsäureanhydrid anfallenden dunkel gefärbten Polymeren. Dem mit Triäthylamin erhaltenen Polymeren wird die Struktur von cis‐Polyvinylenketoanhydrid zugeordnet, ebenso dem in Gegenwart von Pyridin erhaltenen, dessen Kette jedoch auch andere Bausteine (Cyclopentanon, Maleinsäureanhydrid) enthält.

Die Polymeren zeigen die Eigenschaften der polykonjugierten Polymeren: dunkle Farbe und Paramagnetismus; sie sind nur in polaren Lösungsmitteln löslich.
High pressure copolymerization of styrene with maleic anhydride
Authors: Enomoto Goichi , Ogo Yoshiaki , Imoto Tatsuya
Published: April 2003

The radical copolymerization of styrene with maleic anhydride was investigated in an acetone solution at 40°C under high pressure up to 4000 kg/cm2. Effects of pressure on the monomer reactivity ratio considering the influence of the penultimate monomer unit were studied from kinetic data and IR spectra. It has been found that the radical copolymerization rate increases with pressure, especially concerning the reaction of maleic anhydride with a polymer chain possessing a maleic anhydride unit preceding the active styrene chain end.
Oligomers of phenylpropiolonitrile and their chromatographic separation
Authors: Janić Milan , Beneš Milan J. , Peška Jan
Published: April 2003

Oligomeric products of the anionic polymerization of phenylpropiolonitrile were separated by elution chromatography on calcium hydroxide. The separation occurs not only according to the molecular weight, but mainly due to the cis‐trans‐isomerism. Four isomeric trimers were found among the isolated fractions, which demonstrated the polymerization to be non‐stereospecific.
Pyrolysis‐gas chromatographic investigation on structure of chlorinated 1.4‐polybutadienes
Authors: Ito Hajime , Tsuge Shin , Okumoto Tadaoki , Takeuchi Tsugio
Published: April 2003

Thermal degradation of chlorinated cis‐ and trans‐polybutadienes was studied by means of pyrolysis‐gas chromatography. The mechanism of chlorination reaction and thermal degradation of the polymers was examined over a wide range of degree of chlorination. The steric structure of so‐called head‐to‐head polyvinyl chloride was elucidated by analysis of such characteristic degradation products as o‐, m‐, and p‐dichlorobenzenes and vinylidenechloride.
Polykondensation von pyromellithsäuredianhydrid mit bisamidrazonen
Authors: Kersten Von Hilde , Meyer Gerhard
Published: April 2003

Die Umsetzung von Pyromellithsäuredianhydrid mit Bisamidrazonen wurde untersucht. Es entstehen dabei unter Addition Polyacylamidrazoncarbonsäuren (A), die in zahlreichen organischen Lösungsmitteln löslich sind. Aus diesen Lösungen lassen sich z. B. Folien herstellen.

Bei der thermischen Behandlung dieser Polymeren bilden sich unter Wasseraustritt zunächst Polyimidoamidine (B), die bei weiterem Erhitzen zu Polytriazolo‐iso‐indolonen (C) kondensieren. B und C sind in organischen Lösungsmitteln unlöslich und einige davon bis zu Temperaturen von 450–500°C stabil.
Die wechselwirkung der desoxyribonucleinsäure mit dem actinomin nach röntgenkleinwinkelmessungen
Authors: Wawra Von H. , Müller W. , Kratky O.
Published: April 2003

Es wird die Wechselwirkung von Na‐DNS und Actinomin in verdünnten, wäßrigen NaCl‐Lösungen mit den Methoden der Röntgenkleinwinkelstreuung untersucht. Dafür mußten aus hochmolekularer DNS durch Ultraschallabbau Teilchen geeigneter Länge hergestellt werden, so daß neben dem Querschnitt auch die Teilchenlänge mit der Röntgenkleinwinkelstreuung noch zu erfassen war. Die Messungen erfolgten an mit Actinomin gesätigten DNS‐Lösungen bis herab zu einer DNS‐Konzentration von 0,045 g/100 ml. Es konnte dabei eine Streckung der abgebauten DNS‐Partikel bei Anlagerung von Actinomin um 18% festgestellt und die Menge des an die DNS gebundenen Actinomins bestimmt werden: im Mittel wird auf 7,1 Basenpaare ein Actinomin‐Molekül angelagert. Gleichzeitig wurde eine die DNS‐Partikel umgebende Hülle aus Gegen‐ und Bei‐Ionen durch Beugung festgestellt und deren räumliche Dimension ermittelt. Im Verlauf der Auswertung ist es auch gelungen, aus den vorliegenden Pseudo‐Querschnittsstreukurven die für unendlich lange Teilchen gültigen Querschnittsstreukurven‐Innenteile zu rekonstruieren.