bluuebunny/crossref_metadata_2025 huggingface dataset:
Kernresonanzspektroskopische mikrostrukturanalyse von vinylchlorid‐propen‐copolymeren, 2 NMR‐spektroskopische bestimmung der taxieparameter aus den häufigkeiten konfigurativer triaden
Authors: Sielaff Günter , Hummel Dieter O.
Published: April 2003

Copolymere aus Vinylchlorid (VC) und Propen (P) wurden durch hochauflösende magnetische Protonenresonanz bei 100 MHz untersucht. Die Methylresonanz der P‐Einheiten und die entkoppelte Methinresonanz der VC‐Einheiten konnten anhand eines graphischen Trennverfahrens konfigurativen Triaden zugeordnet werden.

Es wurde eine graphische Darstellung entwickelt, die sowohl die Werte der Cotaxieparameter Σs und Σp liefert als auch ein Test für das “ultimate model” ist. Aus der Abhängigkeit der Cotaxieparameter von der Polymerisationstemperatur konnten die Aktivierungsenthalpien der taktischen Wachstumsschritte ermittelt werden.
Versuche zum thermischen abbau von copolyamiden aliphatischer und aromatischer aminocarbonsäuren
Authors: Kricheldorf Hans R. , Leppert Elmar
Published: April 2003

An Gemischen niedermolekularer Carbonsäureamide sowie an Gemischen von Polyamiden mit Carbonsäureamiden oder anderen Polyamiden wurde nachgewiesen, daß Umamidierungsreaktionen bei 200°C nur in geringem Umfang und sehr langsam eintreten, bei 250°C jedoch rasch ablaufen. Der thermische Abbau von Copolyamiden aliphatischer und aromatischer Aminocarbonsäuren erfolgt fast ausschließlich durch Spaltung von Bindungen der aliphatischen Aminocarbonsäure. Dabei werden 4‐Aminobutyryl‐ und 5‐+ninovaleryl‐Reste bevorzugt als Lactame abgespalten, während bei α‐, β‐ und ε‐Aminoacylresten verschiedene Abbaureaktionen nebeneinander ablaufen. Die Lactamabspaltung kann ab ca. 250°C auch aus der Kette heraus erfolgen, führt dann aber nicht zum Kettenbruch, da die ursprünglich benachbarten Aminocarbonsäurereste bei der Lactamabspaltung wieder miteinander verknüpft werden. Das thermische Verhalten der Copolyamide wird mit den Eigenschaften niedermolekularer Modellsubstanzen verglichen und die Reaktionsmechanismen diskutiert.
Copolymerisation von aminosäure‐alkenylestern
Authors: Geckeler Kurt , Bayer Ernst
Published: April 2003

Radikalische Copolymerisationen einer Reihe von Aminosäure‐alkenylestern (1a–e) mit 1‐Vinyl‐2‐pyrrolidinon (2) und 2,2′‐Azoisobutyronitril als Starter werden beschrieben. Die erhaltenen Polymere sind sowohl in Wasser als auch in zahlreichen organischen +ösungsmitteln leicht löslich und können als Trägerpolymere zur Synthese von Peptiden verwendet werden. Aus dem Copolymer 3a, aus 2 und N‐tert‐Butyloxycarbonylalanin‐vinylester (1a), wird nach Abspaltung der Aminoschutzgruppe 3b erhalten, an das eine weitere Aminosäure gekuppelt wird. Dies zeigt, daß an den dargestellten Copolymeren polymeranaloge Umsetzungen durchgeführt werden können.
Préparation, polymérisation et réticulation du méthacrylate de (diméthyl‐2,2 dioxolann‐1,3 yle‐4) méthyle. Hydrolyse des polymères obtenus
Authors: Beinert Gérard , Hild Gérard , Rempp Paul
Published: April 2003

La préparation du méthacrylate de (diméthyl‐2,2 dioxolann‐1,3 yle‐4) méthyle (4) a été mise au point par réaction en milieu HMPT/éther d'un mélange d'acide méthacrylique et de chlorure de thionyle avec l'O‐isopropylidène‐2,3 glycérol (3).

La polymérisation anionique de ce monomère donne naissance à des polymères de faible polydispersité en masse moléculaire.

Si le poly[méthacrylate de (diméthyl‐2,2 dioxolann‐1,3 yle‐4) méthyle] [poly(4)] α,ω‐d+arbanionique «vivant» est utilisé comme promoteur pour la polymérisation d'une +ible quantité de diméthacrylate d'éthylène, la réaction conduit à la formation de réticu+ +odèle homogènes caractérisés par la longueur quasi‐constante de leurs éléments linéaires.

L'hydrolyse acide de la fonction acétal du poly(4) linéaire conduit au poly(méthacrylate de dihydroxy‐2,3 propyle).
Living radical polymerization of styrene and its block copolymerization with methyl methacrylate
Authors: Horie Kazuyuki , Mikulášová Darina
Published: April 2003

The existence of living polymer radicals in emulsion polymerization with a macromolecular heterogeneous initiator has been ascertained by preparing block copolymers of styrene with methyl methacrylate. Polymerization of styrene initiated by oxidized polypropylene and triethylenetetramine (3,6‐diaza‐1,8‐octanediamine) proceeds even after the removal of the initiator from the emulsion, reaches 100% conversion, and methyl methacrylate newly added to the system undergoes further polymerization. The molecular weight of polystyrene and of the block copolymer increases with the conversion. The yield of pure block copolymer is about 90% under optimal conditions. The turbidimetric titration curve of the block copolymer shows a characteristic plateau region and suggests monodispersity of the copolymer. Reasons for the absence of termination in this system are presented. This type of living radical polymerization offers some advantages for the preparation of block copolymers, as compared with the anionic living polymerization.
Polymères α,α'‐diméthylxylyléniques, 3. Copolycondensation du bis(chloro‐1 éthyl)‐1,4 benzène avec des hydrocarbures aromatiques mononucléaires
Authors: Iovu Mircea , Tudorache Elena
Published: April 2003

Nous avons étudié des réactions de copolycondensation du bis(chloro‐1 éthyl)‐1,4 benzène (1) avec le benzène, le toluène, le m‐ et le p‐xylène, le mésitylène et le tétraméthyl‐1,2,4,5 benzène.

Les réactions de copolycondensation étudiées donnent des produits à structure tridimensionnelle (infusibles et seulement partiellement solubles) měme dans le cas de tétraméthyl‐1,2,4,5 benzène où c'était à prévoir d'obtenir un produit linéaire.
Über die bestimmung der strömungsdispersion zur ermittlung von molekulargewichtsverteilungen mit der gelchromatographie
Authors: Berger Knud C.
Published: April 2003

Die Kenntnis der axialen Dispersion ist eine notwendige Voraussetzung zur Ermittlung von Molekulargewichtsverteilungen aus der gelchromatographischen Elutionskurve. Die vorliegende Arbeit beschäftigt sich mit der Bestimmung der axialen Dispersion unter Verwendung monodisperser Polymerer. Abschließend wird ein Verfahren vorgeschlagen, welches aus der gelchromatographischen Elutionskurve von Proben mit bekannter Molekulargewichtsverteilung die Dispersion näherungsweise zu ermitteln gestattet.
Structural and thermodynamic characteristics of chlorinated polyethylenes, 1
Authors: Erä Väinö A.
Published: April 2003

A series of suspension chlorinated and chlorosulfonated polyethylenes (CPE and CSPE resp.) of varying chlorine contents were investigated. The composition of the CPE polymers was determined from DSC measurements and specific volume determinations. Structural differences between CPE and CSPE polymers were confirmed by IR spectra and the heats and entropies of fusion.
Polymerization of β‐propiolactone by metal acetylacetonates and carboxylates
Authors: Kaeriyama Kyoji
Published: April 2003

Some metal acetylacetonates and carboxylates are effective for the polymerization of β‐propiolactone (2). The activity depends on the metallic ion. Heterochelates containing 2,2′‐dipyridyl or 1,10‐phenanthroline and acetylacetone as ligands have a large effect due to the tertiary amine groups. Titanocene dichloride is an effective promoter for these polymerizations. The combination of titanocene dichloride and metal acetylacetonates has an activity for the polymerization of 2‐chloroethyl vinyl ether, which neither component has separately.
Zum mechanismus der anionischen copolymerisation polarer ungesättigter monomere
Authors: Artamonowa Irina , Klenin Stanislaw , Troitskaya Alla , Erussalimsky Boris
Published: April 2003

Für Copolymere, die sich bei kleinen Umsätzen in den Systemen Acrylnitril (AN)‐Methylacrylat (MA) – Toluol – Butyllithium (BuLi) und AN‐MA‐Toluol‐Dipropylbutyllithiumcarbinolat (DPBL) bilden, wurde eine Uneinheitlichkeit der chemischen Zusammensetzung festgestellt. Der relative Anteil verschiedener Fraktionen und deren Zusammensetzung werden durch die Reaktionstemperatur und den Typ des Initiators beeinflußt. Diese Erscheinung wird der Koexistenz von aktiven Zentren mit verschiedenen Gegenionen zugeschrieben. Eine derartige Koexistenz kann entweder durch die Bildung von Nebenprodukten aus einer Reaktion zwischen Initiator und den Monomeren (System mit BuLi), oder durch die Dissoziation der assoziierten Lithiumderivate (System mit DPBL) verursacht sein.
Polymerisation of trioxane, 2. Kinetics of the reaction initiated by chlorosulphonic acid
Authors: Raman P. S. , Mahadevan V.
Published: April 2003

The kinetics of polymerisation of trioxane, initiated by chlorosulphonic acid have been studied in o‐dichlorobenzene, trichloroethylene, and carbon tetrachloride. The reaction is shown to be simple, though the kinetics are different in the above solvents. With very pure and dry substrates, no induction period is observed. Rate parameters have been evaluated.
Studies on metal chelating polymers, 3. Metal chelates of cationic polymers containing the 3‐formyl‐ or the 3‐acetyl‐4‐hydroxybenzyl group in the side chain
Authors: Haruta Masami , Harada Susumu
Published: April 2003

The stability constants for several metal complexes (Cu(II), Ni(II), Zn(II), Co(II), Fe(III), Al(III)) of terpolymers from diallyl[3‐formyl (or 3‐acetyl‐) 4‐hydroxybenzyl]methylammonium chloride, diallyldimethylammonium chloride, and sulfur dioxide were determined by potentiometric titration.

The results are discussed comparing the stability constants with those of o‐hydroxybenzaldehyde and o‐hydroxyacetophenone derivatives.
Organometallic compound with lewis base, 3. Polymerization mechanism of vinyl compounds by aluminum alkyl‐lewis base complex
Authors: Ikeda Masanori , Hirano Tsuneo , Nakayama Shinichi , Tsuruta Teiji
Published: April 2003

Complexes of aluminum alkyl (AlR3), formed with certain kinds of Lewis bases, induce anionic polymerization of polar vinyl compounds such as acrylonitrile (AN) or methyl methacrylate (MMA), whereas AlR3 by itself cannot polymerize AN and MMA anionically. When the ligand Lewis base is bidentate, the resultant complex with a formal coordination number of five shows high catalytic activity for anionic polymerization even if the basicity of the ligand is small. On the other hand, when the ligand Lewis base is monodentate, the complex is four‐coordinated and shows catalytic activity for the polymerization of AN and MMA only when the basicity of the ligand is sufficiently large. The initiation reaction for the polymerization of 1‐substituted vinyl compounds such as MMA should be the conjugate addition of one alkyl group of the activated AlR3 to the monomer. With 1‐unsubstituted vinyl compounds such as AN or methyl acrylate (MA), a part of the initiation and the chain transfer reactions seem to take place through the abstraction of the 1‐hydrogen of the vinyl monomer molecules.
Oxidative polymerization of 2,6‐dimethylphenol with semiconducting organic polymeric metal complexes containing the bis(ethylene‐1,2‐dithiolato)copper (II) structure, 1
Authors: Kaneko Masao , Manecke Georg
Published: April 2003

In the oxidative polymerization of 2,6‐dimethylphenol (8) the catalytic activities of the following semiconducting organic polymeric metal complexes were studied: polymeric complexes containing bis(ethylene‐1,2‐dithiolato)Cu(II) or Fe(III) complexes and copper(II) phthalocyanine structures (3a–c), catalysts consisting of bis(ethylene‐1,2‐dithiolato)‐Cu(II) or Fe(III) complex structures and hemiporphyrazine type structures (5a–c), and also polymers containing a copper complex of dimercaptomaleic acid monoamide (7). It was found that a suspension of the insoluble bis(ethylene‐1,2‐dithiolato)Cu(II) polymeric complexes of type 3 catalyzes the polymerization in the presence of oxygen in pyridine at room temperature producing poly[oxy‐(2,6‐dimethyl‐1,4‐phenylene)] (9) in very good yields. Polymeric complexes of type 5 were inactive by themselves. However, we showed that bis(ethylene‐1,2‐dithiolato)Cu(II) polymeric complexes of both the 3 and 5 type possess great activities if they are used in the presence of small amounts of copper(II)‐pyridine complex in pyridine solution (the chosen concentration was so low that the Cu(II)‐pyridine complex alone had only a small activity). Bis(ethylene‐1,2‐dithiolato)Fe(III) complexes of both the 3 and 5 type were inactive even in the presence of the Cu(II)‐pyridine complex.
Oxidative polymerization of 2,6‐dimethylphenol with semiconducting organic polymeric metal complexes containing the bis(ethylene‐1,2‐dithiolato)‐copper(II) structure, 2
Authors: Kaneko Masao , Manecke Georg
Published: April 2003

If an insoluble polymeric complex 1 which possesses both the bis(ethylene‐1,2‐dithiolato)Cu(II) a Cu(II)phthalocyanine type structure is treated with a pyridine solution of the Cu(II)‐pyridine complex in a low concentration, the filtrate obtains a high activity for the oxidative polymerization of 2,6‐dimethylphenol. This might be due to a partial decomposition followed by a partial dissolution of the polymer complex. The catalytic behaviour of the soluble part of the polymeric complex 1 was studied. The activity of this mixed catalyst system consisting of Cu(II)Py and the soluble part of 1 was found to be 6–50times higher than that of Cu(II)Py alone under the applied conditions.
Photosensitized polymerization of butyl acrylate under high pressure
Authors: Yokawa Masaru , Ogo Yoshiaki , Imoto Tatsuya
Published: April 2003

The propagation and termination rate constants for butyl acrylate polymerization under high pressure at 30°C were measured by the rotating sector method.

The effect of pressure on the individual rate constant was determined and the activation volumes for the propagation and the termination were obtained as −22,5 cm3/mol and 20,8 cm3/mol, respectively, and the overall activation volume was −26,3 cm3/mol. The rate constant and its dependence on pressure were compared with data previously obtained on methyl methacrylate and butyl methacrylate polymerizations, and the problem concerning the differences of the pressure effect between these reactions were discussed.
Non‐Newtonian behavior of cellulose solutions
Authors: Riandes Evaristo , Pereña José M.
Published: April 2003

The gradient dependence of viscosity was studied for fractionated cellulose in cadoxene and in cadoxene/water (1:1). The present experiments were performed in the shear stress range 1,4 to 1 000 dyn/cm2 (1,4.10−5 to 10−2 newton/cm2). The experimental results, viewed in the light of various theories, show that the excluded volume effects and the internal viscosity play an important role in non‐Newtonian behavior of cellulose solutions.
Chain conformation in linear polyethylene and paraffins defined by four NMR‐components
Authors: Phaovibul Orapin , Loboda‐Čačković Jasna , Čačković Hinko , Hosemann Rolf
Published: April 2003

A systematic investigation of a series of nuclear magnetic resonance spectra (NMR) of differently treated polyethylene (PE) and paraffin samples, indicates that all observed spectra can be analysed unequivocally as the sum of four standard functions which are attributed to four components, α, β1, β2, and γ, of increasing proton mobility. In some spectra most of the components are clearly separated from each other. The shape of their derivatives is therefore directly measurable and symmetric for the α‐component. For β1 the derivative is that of a Gaussian and for γ that of a Lorentzian function. β2 alone is not directly observable but appears as a remainder in the spectra of melt‐crystallized PE. It exhibits the shape of the derivative of a Lorentzian function, too. The basic hypothesis is that each of these four components maintains his characteristic shape even if they overlap each other. The line widths ΔH are: 13,2 to 17,9 Gauß (1 Gauß = 10−4Vs m−2), 3,0 to 6,0 Gauß, 0,85 to 1,2 Gauß, and 0,04 to 0,18 Gauß, depending on the history of the sample. The α‐component is assigned to protons in the microparacrystalline phase (regular backfolding included), fixed chain ends and tight tie‐molecules. In hotstretched PE the latter enlarge the α‐component by 4% without changing the “crystallinity” measured by the density. γ is assigned to longer chain ends undergoing micro‐Brownian motion. The more regular the lamella surface, the smaller is the contribution to the β1 and β2 component.

So‐called single crystals of PE e.g. have only 0,02% γ, which increases during melt‐crystallization to ca. 0,1% (sample MPE 5). Its extremely high value of 0,4% in all drawn samples (DPE) is attributed to an enlarged number of longer mobile endsegments generated by chain scission. β1 is attributed to less mobile chain ends, chains in lateral grain boundaries, defects within the paracrystals, chainfolds and tie‐molecules in the “amorphous” parts which are of great importance for the mechanical properties. If the component β1 e.g. is smaller than 15%, melt‐crystallized PE (MPE) is always brittle. When the melt is stirred, β1 in the MPE reaches values up to 19%. The tensile strength then is larger. In extended chain crystals (ECC) β1 is reduced to about 10% of the MPE‐value. This may indicate that about 10% of the ECC still have the folded structure. This is underlined by the fact that MPE alone has a remarkable β2‐component from segments more mobile than β1 which is reduced also to about 10% in ECC. The β2‐component is attributed to loose loops and loose connecting molecules, which connect neighbouring paracrystals.
Kinetics of the aqueous polymerization of acrylamide initiated by the permanganate‐ tartaric acid redox system
Authors: Misra Gauri S. , Rebello Joseph J.
Published: April 2003

The kinetics of the aqueous polymerization of acrylamide, initiated by the permanganate/tartaric acid redox system was studied at 35±0,2°C under nitrogen. The initial rate of polymerization remains independent of the tartaric acid concentration in the range 3,3.10—3 to 9,9.10—3mol/dm3. The order of the reaction with respect to the catalyst concentration (catalyst exponent) is found to be 0,55, indicating a bimolecular mechanism for the termination reaction. The rate of polymerization varies linearly at low monomer concentrations (1,25.10—2 to 5,0.10—2mol/dm3). With increase in temperature above 35°C, the initial rate increases but the conversion decreases. The overall energy of activation is found to be 18,68 kcal/mol (78,10kJ/mol) in the temperature range 30 to 50°C.

Water miscible organic solvents and neutral salts depress both the rate and the conversion. Addition of MnSO4 or the injection of more catalyst at intermediate stages raises both the initial rate and the maximum conversion. NaF decreases the rate but increases the conversion.
Polymere N‐Acylaminohydrochinone. Darstellung von polymerem N‐(2,5‐dihydroxy‐4‐methyl)phenyl‐p‐vinylbenzamid und einiger modellverbindungen
Authors: Wehr Gregor , Duchstein Hans‐Jürgen , Manecke Georg
Published: April 2003

Einige vinylgruppenhaltige N‐Acylaminohydrochinone wurden dargestellt. N‐(2,5‐Dimethoxy‐4‐methyl)phenyl‐p‐vinylbenzamid (2) konnte radikalisch polymerisiert werden. Die Entmethylierung des polymeren Hydrochinondimethyläthers (3) führte zum Redoxpolymeren, in dem die Redoxgruppen (Hydrochinon/Chinon) über Aminocarbonyl‐Brücken mit der Polymerenkette verknüpft sind. Es wurde ebenfalls eine Anzahl niedermolekularer Modellsubstanzen vom Typ der N‐Acylaminohydrochinone dargestellt und deren Redoxpotentiale potentiometrisch bestimmt.
Die kinetik der polyadditionsreaktionen des 1‐chlor‐2,3‐epoxypropans
Authors: Novák Jiří , Matušek Miroslav
Published: April 2003

Es wird eine neue Methode zur Auswertung der Abhängigkeit des Verhältnisses Konzentration/Zeit bei der kinetischen Untersuchung der Polyaddition von 1‐Chlor‐2,3‐epoxypropan (Epichlorhydrin) vorgeschlagen, die es erlaubt, neben der Geschwindigkeitskonstante der Initiierungsreaktion auch die Geschwindigkeitskonstante des Wachstums zu berechnen (gleiche oder wenigstens naheliegende Geschwindigkeitskonstanten der einzelnen Wachstumsstufen vorausgesetzt).
Copolymers of acrylonitrile and α‐methyleneglutaronitrile as model compounds for polyacrylonitrile initiated by the nitrobenzene radical anion in tetrahydrothiophene 1,1‐dioxide
Authors: Martinmaa Jukka , Patrakka Pirjo
Published: April 2003

The copolymerization constants for the radically initiated system acrylonitrile (AN)/α‐methyleneglutaronitrile (MGN) in bulk were determined by means of IR spectra using a base‐line technique and independently by means of NMR spectra. The constants obtained from the IR spectra were

whereas those from the NMR measurements were

The IR spectrum of polyacrylonitrile, obtained by anionic polymerization and initiation with the electrochemically generated nitrobenzene radical anion in sulfolane (tetrahydrothiophene 1,1‐dioxide), has been established to correspond to an AN‐MGN copolymer structure having on an average 4 to 6 ß‐cyanoethyl units per 10 backbone acrylonitrile units. A competitive addition‐prototropy mechanism is suggested to explain the formation of cyanoethyl groups.
Zur synthese von makromolekülen durch 1,3‐dipolare cycloaddition aus mesoionischen oxazolonen, 3
Authors: Manecke Georg , Klawitter Jürgen
Published: April 2003

N‐Acyl‐N‐alkyl‐diaminosäuren, die mit Acetanhydrid zu 1,3‐dipolaren mesoionischen Dioxazolonen reagieren, wurden mit Diäthinylverbindungen umgesetzt. Die entstandenen Polymeren enthalten Pyrrolkerne in der Kette. Ihre Struktur wurde durch Vergleich ihrer IR‐Spektren mit denen entsprechender Modellverbindungen gesichert. Die Additionsrichtung konnte in einem Fall mit Hilfe der NMR‐Spektroskopie aufgeklärt werden.
Studies on the structure of polyurethane elastomers, 4. NMR spectra of linear polyurethane based on 2,4‐tolylenediisocyanate
Authors: Chokki Yasuo
Published: April 2003

It is shown that urea and carbamoyl (urethane) groups in derivatives of 2,4‐tolylenediisocyanate (1) can be differentiated by their chemical shifts when the NMR measurements are carried out in N,N‐dimethylacetamide (DMA) which contains lithium chloride. This method can further be applied to the analysis of linear polyurethane prepolymers prepared from α‐(hydroxytetramethylene)‐ω‐hydroxypoly(oxytetramethylene) (2) and 1.
Über den thermo‐oxidativen Abbau von Polyvinylacetat unter thermogravimetrisch‐dynamischen Bedingungen
Authors: Mihai Elena , Biró Andreas C. , Onu Ana , Schneider Ioan‐Adam
Published: April 2003

In der vorliegenden Arbeit werden die Ergebnisse von Untersuchungen über das Abspalten von Essigsäure aus Polyvinylacetat an Luft unter thermogravimetrisch‐dynamischen Bedingungen besprochen. Die Abhängigkeit der kinetischen Größen vom Umsatz, der Aufheizgeschwindigkeit und dem mittleren Molekulargewicht der untersuchten Proben, sowie das Vorhandensein eines exothermen Prozesses gegen Ende der ersten Abbaustufe deuten auf eine Änderung des Reaktionsmechanismus, wahrscheinlich infolge einer Überlagerung durch einen Oxidationsprozeß bei höheren Temperaturen, hin.
The polymerisation of ethylene with high activity magnesium reduced titanium trichloride catalysts in the absence of hydrogen
Authors: Boucher David G. , Parsons Ian W. , Haward Robert N.
Published: April 2003

The polymerisation of ethylene using magnesium reduced titanium trichloride catalysts, together with the usual aluminium alkyl activators is described. The previously reported high activity of this type of catalyst was confirmed. At 50°C and 1 atm. (1,01325 bar) pressure a value of 3,4.106 g dm3 (mol TiCl3)−1h−1 was obtained for the activity constant, a value about 102 times larger than for a conventional aluminium reduced TiCl3. On the other hand the viscosity‐molecular weight‐time (or conversion) relations are not very different from those given by conventional catalysts. Analysis of the results suggests that a high proportion (e.g. 50%) of the titanium atoms in the magnesium reduced TiCl3 functions as active sites.
Reaktionen mit Silylaziden, 7. Über 4‐Isocyanatocarbonsäure‐trimethylsilylester und 4‐Aminocarbonsäure‐N‐carbonsäureanhydride
Authors: Kricheldorf Hans R.
Published: April 2003

Durch Umsetzung cyclischer 1,3‐Dicarbonsäureanhydride (10, 11, 12, 15) mit Trimethylsilylazid (9) wurden verschiedene 4‐Isocyanatocarbonsäure‐trimethylsilylester (6a–h, 13, 14, 16, 17) erhalten. Durch schonende Hydrolyse dieser Silylester ließen sich die entsprechenden 4‐Isocyanatocarbonsäuren freisetzen, die in allen Fällen der Additionspolymerisation zu den unbeständigen, linearen Oligo(4‐Aminocarbonsäure‐N‐carbonsäureanhydriden) unterliegen. Parallel dazu erfolgt in manchen Fällen Cyclisierung zu kristallinen, siebengliedrigen 4‐Aminocarbonsäure‐NCA (20—25), die aber nicht von allen 4‐Isocyanatocarbonsäuren beobachtet oder isoliert werden konnten. Beim Erhitzen sowie unter basischer Katalyse decarboxylieren sowohl die linearen als auch die cyclischen NCA unter Bildung von Oligoamiden (36, 37); parallel dazu erfolgt auch Ringverengung zu den entsprechenden fünfgliedrigen Lactamen (26–30), die insbesondere bei der thermischen Decarboxylierung die Hauptprodukte sind. Hochmolekulare Polyamide wurden in keinem Fall erhalten.
Allylic polymers, 1. Synthesis of polyallyl compounds containing 4‐oxycarbonylphthalimido units and their polymers
Authors: Hara Shigeyoshi , Iwata Kaoru , Yamada Takeyoshi
Published: April 2003

Various polyfunctional allyl compounds containing 4‐oxycarbonylphthalimido units were prepared including allyl N‐allyl‐4‐phthalimidecarboxylate (3), diallyl N‐N′‐alky‐lenebis(4‐phthalimidecarboxylates) 8a–c and alkylenebis(N‐allyl‐4‐phthalimidecarboxylates) 9a–e and 11.

These compounds were polymerized by heating them in the presence of dicumyl peroxide or benzoyl peroxide to afford network resins. The thermal stability of these resins was preliminarily investigated using thermogravimetric analysis (TG). The resins from 9e and 11 had essentially no weight loss up to 390 and 360°C, respectively, in nitrogen.
Introduction of carboxyl groups into crosslinked polystyrene
Authors: Harrison Charles R. , Hodge Philip , Kemp Joan , Perry Gordon M.
Published: April 2003

Carboxyl groups can be introduced into crosslinked polystyrene by a two step process involving 2‐chlorobenzoylation and cleavage of the product using a mixture of potassium tert‐butoxide and water. The reaction yields can be estimated easily by the change in weight of the resin and by chlorine analysis. Carboxyl groups can also be introduced via benzoylation. The previously described method of introducing carboxyl groups, in which crosslinked polystyrene is chloromethylated and the product oxidized to a formyl resin, which is then oxidized to a carboxyl resin, can be improved by using peracetic acid in methanesulphonic acid as the oxidant in the last step.
Nature des espèces «vivantes» en polymérisation anionique des diènes conjugués
Authors: Sledz Joseph , Kaempf Bernd , Schué François , Libs Mme. Suzanne
Published: April 2003

La nature des espèces «vivantes» propagatrices en polymérisation anionique des diènes conjugués est étudiée par résonance magnétique nucléaire. Un choix judicieux des effects monomères permet, en outre, de voir l'influence des effects électroniques et stériques sur les structures observées.

Il est montré que les oligomères «vivants» ne renferment que les motifs 4,1 et/ou 1,4 (cis et trans), et que l'espéce active peut ětre décrite sous une forme π‐allyle délocalisée. De plus, le point fondamental dans le mécanisme de l'action de l'amorceur sur le diène semble ětre l'association. En effet, l'association interne des organolithiens disparaǐt ou évolue vers l'association externe avec tout composé donneur d'électrons. Ce rǒle de nucléophile peut ětre joué par le diène lui‐měme. Un mécanisme basé sur le concept de l'association est proposé.
Polymerization of methyl methacrylate in the presence of poly(α‐amino acid)s
Authors: Fujie Akira , Kawai Tōru
Published: April 2003

The polymerization of methyl methacrylate (MMA) was studied in the presence of poly(α‐amino acid)s, water, and copper(II) ion. It was found that the polymerization behaviour depends very much on the conformation of the poly(α‐amino acid) in the system. If the poly(α‐amino acid) had the α‐helix conformation, the polymerization of MMA did not occur. This is supposed to be due to the stability of the intramolecular hydrogen bond in the α‐helix, which is too high to form a chelate complex between the copper ion and the polypeptide together with the MMA monomer and water. When the same polypeptides took a random coil conformation, however, the polymerization occurred, although to a small extent. Furthermore, when the polypeptide with the β‐conformation was used, the polymerization of MMA occured to a higher extent than in the case of the polypeptide with the random coil conformation. Therefore, it was concluded that the delocalization of electrons in the copper ion to the neighbouring atoms plays an important rǒle in the initiation of the polymerization of MMA.

It was also found that the size of the nonpolar side chain of the initiating polypeptides affects the polymerization of MMA. Since this polymerization is carried out in water, the hydrophobic bonds between the nonpolar side chain of the polypeptide and the MMA monomer may also play an important rǒle.
NMR‐Untersuchungen an Polyacetalen, 3. Sequenzanalyse bei 1,3,5‐Trioxan/1,3‐Dioxolan‐Copolymeren durch 13C‐NMR‐Spektroskopie
Authors: Fleischer Dietrich , Schulz Rolf C.
Published: April 2003

1H‐NMR‐Spektren von 1,3,5‐Trioxan/1,3‐Dioxolan‐Copolymeren zeigen für die Methylenoxidbausteine Triadensequenzen an, während für die Äthylenoxidbausteine praktisch keine Sequenzabhängigkeit beobachtet wird. In 13C‐NMR‐Spektren werden sowohl für die Methylenoxid‐ als auch für die Äthylenoxidbausteine Pentadensequenzen gefunden. Niedrige Konzentrationen an Verschiebungsreagenz (Eu(fod)3) in den NMR‐Proben ermöglichen die Identifizierung aller Pentadensequenzen, höhere Konzentrationen an Eu(fod)3 bewirken für beide Grundbausteine eine Aufspaltung der Signale in Heptadensequenzen.
Sequence distribution of components and stereoregularity in methyl methacrylate/methyl acrylate copolymers determined by proton nuclear magnetic resonance spectroscopy
Authors: Mori Yuichi , Ueda Akio , Tanzawa Hiroshi , Matsuzaki Kei , Kobayashi Hiroyuki
Published: April 2003

1H‐NMR spectra of methyl methacrylate/methyl acrylate copolymers obtained with radical and anionic initiators were analyzed in terms of sequence distribution of components and stereoregularity. Some rules related to the chemical shifts in triads centered with methyl methacrylate units were derived.
Study of stereoregularity of poly(vinyl ketone)s by proton nuclear magnetic resonance
Authors: Merle‐Aubry Liliane , Merle Yves , Selegny Eric
Published: April 2003

Two poly(vinyl ketone)s, poly(methyl vinyl ketone) (PMVK) and poly(phenyl vinyl ketone) (PPVK), are isotacticly synthesized. The 1H‐NMR spectra of these polymers and of the meso and racemic model dimers help to determine the percentage of isotactic dyads using the area of the peaks of the non equivalent protons (HA and HB) of the β‐methylene group of the chain. The difference between the chemical shifts of the HB and HB protons is exceptionally large (approximately 0,8 ppm for both isotactic PMVK and isotactic PPVK). The coupling constants and the β‐CH2 and the α‐CH groups' frequencies are determined by applying the ABX2 system.

A spontaneous epimerization of isotactic PPVK is found; this is always accompanied by a degradation and leads to the assumption of a simultaneous photochemical reaction of the Norrish II type.
Viscosity and optical observation on poly(ethylene terephthalate) during annealing and thermal scanning
Authors: Coppola Gerolamo , Fabbri Paolo , Pallesi Bice , Alfonso Giovanni Carlo , Dondero Giovanni , Pedemonte Enrico
Published: April 2003

Some results obtained with poly(ethylene terephthalate) [poly(oxyethyleneoxyterephthaloyl)] following by optical microscopy the isothermal annealing and the thermal scanning from room temperature or annealing temperature up to the melting point are reported. Besides, the variation of the molecular weight is controlled by viscometry. It is observed that the structure is always characterized by spherulites, whose sizes change only during the crystallization and in the melting range. The conclusion is reached that the structural modifications on which the large variations of the endothermal maximum of the DSC curve below the melting temperature (peak II) depend, occur inside the spherulites. The model suggested by Roberts and Holdsworth seems to be supported by our data.
Vinyl polymerisation by quinquivalent vanadium ions in aqueous solution: Polymerisation of methyl acrylate and methyl methacrylate
Authors: Nayak Padmalochan , Singh Baishnab C. , Mohanty Trijama R.
Published: April 2003

Polymerisation of methyl acrylate and methyl methacrylate initiated by the system cyclohexanone/V5+ was investigated at 40–50°C in sulphuric acid. The rates of polymerisation, of V5+ disappearance, and the chain lengths of the polymers were determined. The kinetics were found to be consistent with the formation of an intermediate complex between the ketone and the oxidant whose decomposition leads to the initiating radical. A suitable kinetic scheme was proposed and the various rate and energy parameters were evaluated.
Étude cinétique de la polymérisation anionique du styrène en présence d'un contre‐ion baryum
Authors: Mathis Claude , Christmann‐Lamande Lydia , Francois Bernard
Published: April 2003

Nous montrons que la polymérisation du styrène, amorcée par un promoteur bifonctionnel dérivé du baryum, en milieu tétrahydrofuranne, présente une propriété remarquable: à une température donnée, la vitesse de propagation est indépendante de la concentration en carbanions, dans un domaine compris entre 3.10−5 et 5.10−3 mole par litre. Ceci signifie que la constante de propagation kp varie de façon linéaire avec l'inverse de la concentration en centres actifs. L'énergie d'activation de la propagation est égale à 4,1 kcal/mol (17,1±1,3 kJ/mol).

Nous interprétons nos résultats expérimentaux en admettant que les molécules de polymères «vivants» sont bouclées sur elles‐mêmes par l'intermédiaire du cation divalent et forment, en outre, des agrégats «en rosace». L'existence de tels agrégats est étayée par l'étude spectrale et viscosimétrique des solutions de polystyrène vivant.
A quantum‐chemical study of the preferred conformations of the model compounds of polypropylene
Authors: Asakura Tetsuo , Ando Isao , Nishioka Atsuo
Published: April 2003

The total energies of some model compounds for polypropylene (PP) were calculated quantum‐chemically with the CNDO/2 method, taking into account their stereochemical configurations and preferred conformations.

The statistical weights, τ and ω, are estimated using 2‐methylbutane and pentane, respectively and are compared with those obtained with semiempirical potential functions, in order to obtain informations on the conformation and configuration of PP. Moreover, it is pointed out that the shape of the potential curves nearby the energy‐minimum state is considerably different among the preferred conformations in some model compounds, such as dimer, trimer, and tetramer and this result demonstrates that one should be cautious with the application of the rotational isomeric state model to PP and its model compounds.
The cyclo‐copolymerization of diallyl compounds and sulfur dioxide, 4. 4‐(4‐pyridyl)‐1,6‐heptadiene hydrochloride and sulfur dioxide
Authors: Amemiya Yasuhiro , Katayama Masamichi , Harada Susumu
Published: April 2003

Copolymers of 4‐(4‐pyridyl)‐1,6‐heptadiene hydrochloride (1) and 4‐(1‐buten‐4‐yl)pyridine hydrochloride (2) with sulfur dioxide were prepared and their properties were investigated. The effects of the copolymerization conditions on the yields and viscosities of the obtained copolymers were studied. Their structures were studied by elemental analyses, IR, and 1H‐ and 13C‐NMR spectroscopy.
Thermische spaltungsmechanismen in homo‐ und copolymeren aus α‐olefinen, 1. Grundlegende mechanismen und pyrolyse von linearem polyäthylen
Authors: Seeger Michael , Cantow H.‐J.
Published: April 2003

Der Abbau von linearem Polyäthylen (PE) vom Ziegler‐Typ und von n‐Alkanen wurde im Hinblick auf Spaltungsmechanismen von Vinylpolymeren und ihre Anwendung zur Ermittlung von Sequenzlängenverteilungen theoretisch untersucht. Die Pyrolyse erfolgte bei erhöhter Temperatur innerhalb weniger Sekunden und war gekoppelt mit der Hydrierung der Fragmente und linear temperaturprogrammierter Gaschromatographie. Durch Verbesserungen der Technik konnte die Fragmentverteilung bis C30 im FID (Flammenionisationsdetektor) aufgenommen werden. Die Ergebnisse werden auf Grund von allgemeinen Mechanismen der homolytischen Spaltung in Radikale interpretiert. Entsprechend werden Fragmentverteilungen vorausberechnet und diskutiert. So läßt sich die experimentelle Verteilung am besten durch eine überlagerung von primärer statistischer und sekundärer nichtstatistischer Spaltung erklären. Im Bereich der langen Fragmente läßt sich die Verteilung an eine statistische anpassen. Es folgt so eine Wahrscheinlichkeit s=0,07 für die statistische Spaltung in linearem PE. Diese ist zwischen 550 und 1000°C von der Temperatur des Pyrolysators unabhängig und läßt sich auch nicht durch die Anwesenheit von reaktiven Polyisobutylen‐Radikalen beeinflussen. Die Pyrolyse von kurzen n‐Alkanketten zeigt Verdampfung ohne Zersetzung. Intermolekulare Reaktionen wie Kombination von Bruchstucken sind in unserem System nicht nachweisbar.
Operating conditions for preparative successive solutional fractionation, 1. Effect of initial concentration and fraction size
Authors: Kamide Kenji , Miyazaki Yukio
Published: April 2003

Operating conditions, such as initial concentration, v0p, fraction size, Q, in preparative successive solutional fractionation (SSF) based on solubility are studied in comparison with successive precipitational fractionation (SPF), on various polymers having Schulz‐Zimm and Wesslau distributions. The partition coefficient σ is larger if SSF is performed on more dilute solutions. The volume ratio, R, of the polymer‐lean phase to the polymerrich phase in SPF is always large as compared with SSF. For the middle fractions obtained by SSF or SPF the content of both higher and lower degree of polymerization (X) regions in the molecular weight distribution decreases as v0p decreases. The v0p dependence of X̄w/X̄n in the fraction is remarkable in SPF as compared to SSF. SSF at a v0p lower than 0,1% is not effective for the preparative method and an unlimited decrease in X̄w/X̄n (till 1) of the fraction can not be expected. The fractionation efficiency does not reduce to zero even if v0p is in vicinity to the critical concentration. Neither X̄w/X̄n nor the standard deviation σ' in the fractions obtained by SSF exhibit a maximum at a specific v0p. In contrast to SPF, in SSF X̄w/X̄n in the fractions decreases without limit (to 1) with increasing total number of fractions, n, compared at a given X̄w. Actually n = 25–30 is necessary for preparation purposes. With a decrease in Q the X̄w/X̄n vs. v0p relations shift to lower X̄w/X̄n and the total profile of the relations is not essentially influenced by Q except for the higher v0p region.
Chelation of poly(O‐isophthaloylisophthalamide oxime) with copper(II) ions
Authors: Lehtinen Arja , Purokoski Seppo , Lindberg J. Johan
Published: April 2003

The chelation of poly(O‐isophthaloylisophthalamide oxime) (1) with copper(II) ions was carried out under various conditions and with different copper(II) compounds. The effect of the chelation conditions on the metal content of the chelated polymer was studied. All polymers were characterized by IR spectra, solubilities, thermal analysis, and X‐ray diffraction. It was found that the copper(II) chelates of 1 are thermally less stable than the cyclized prepolymer. A soluble chelate polymer was obtained by the reaction of the polymeric ligand with the o‐phenylenediamine‐copper(II) complex.
13C‐NMR‐sequenzanalyes, 3. Alternierende copolyamide aliphatischer und aromatischer aminocarbonsäuren
Authors: Kricheldorf Hans R. , Leppert Elmar , Schilling Gerhard
Published: April 2003

Durch Kondensationspolymerisation von 3‐ und 4‐Isothiocyanatobenzoyl‐ω‐aminocarbonsäuren (1a–e, 2a–c u. 3a–d) bei 200°C wurden Copolyamide gewonnen, welche stets einen aliphatischen und einen aromatischen Aminoacylrest im Verhältnis 1 : 1 enthalten. Anhand der 1H‐NMR‐Spektren sowie der 13C‐NMR‐Spektren wurde nachgewiesen, daß bei den meisten Kondensationsversuchen alternierende Sequenzen resultieren (4a–e und 5c–e), doch wurden aufgrund von Umamidierungsreaktionen in einigen Fällen auch unregelmäßige Sequenzen erhalten.
Polymere mit dem zentralatom eines makrocyclus in der hauptkette, 3.Polykondensationsreaktionen mit zinnkomplexen des meso‐tetraphenylporphins, phthalocyanins und hemiporphyrazins
Authors: Meyer Gunter , Hartmann Monika , Wöhrle Dieter
Published: April 2003

Dihydroxy‐meso‐tetraphenylporphinzinn (1b), Dihydroxyphthalocyaninzinn (1d) und Dihydroxyhemiporphyrazinzinn (1f) reagieren mit zweiwertigen Phenolen zu Polymeren des Typs B. Aus Äthylenglykol und 1b läßt sich die niedermolekulare Verbindung 3 erhalten, die unter Äthylenglykolabspaltung Poly[oxyäthylenoxy(meso‐tetraphenylporphin)stannandiyl] (4) ergibt.

Durch Dehydratation der Dihydroxy‐Verbindungen 1b, 1d, 1f lassen sich Polymere des Typs C synthetisieren.

Die IR‐Spektren der dargestellten Verbindungen werden diskutiert; thermogravimetrische und Halbleitermessungen (σ298K≈10−6−10−16Ω−1cm−1) werden beschrieben und mit den analogen Germaniumverbindungen verglichen.
Untersuchung von vinylpyridinium‐verbindungen, 6. Spontane polymerisation von 1,2‐dimethyl‐5‐vinylpyridiniumbromid
Authors: Mielke Ingolf
Published: April 2003

Der Mechanismus der spontanen Polymerisation von 1,2‐Dimethyl‐5‐vinylpyridiniumbromid in Wasser wurde untersucht. Die Reaktion wird durch Licht initiiert, doch findet auch in der Dunkelheit eine langsame Polymerisation statt, die durch den thermischen Zerfall eines angenommenen Peroxid‐Initiators erklärt werden kann.
Vinyl polymerization by metal complexes, 19. Formation of copper(II) chelates of vinylamine/vinyl alcohol copolymers
Authors: Kimura Keiichi , Inaki Yoshiaki , Takemoto Kiichi
Published: April 2003

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

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

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

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

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

The behaviour of the homogeneous catalyst system Ti(Oi‐C3H7)4/Al(C2H5)2F in ethylene/propene copolymerization was studied.

The copolymer structure is discussed in view of the stereoregulation mechanism previously proposed for vanadium‐based homogeneous catalyst systems.
Studies on functional micelles, 5. Solvent and salt effects on the micellar condensation of thioalanine S‐alkyl esters
Authors: Kawabata Yasuziro , Kinoshita Masayoshi
Published: April 2003

The condensation reaction of thioalanine S‐dodecyl ester (1c) was carried out in several organic solvents, or in their mixtures with water. In acetone, benzene, chloroform, or hexane, no cyclic dimer of alanine, 3,6‐dimethyl‐2,5‐piperazinedione (2) and in the water/organic solvent mixtures only low yields of 2 were obtained, contrary to the good yields which resulted in water alone. In the condensation reaction of thioalanine S‐octyl ester (1b) obvious salt effects were observed, especially with FeCl3.