bluuebunny/crossref_metadata_2025 huggingface dataset:
Calorimetric studies of drawn polyethylene terephthalate
Authors: Koenig J. L. , Mele M. D.
Published: April 2003

Dynamic differential calorimetry and density measurements have been made on drawn polyethylene terephthalate. The crystallinity and heats of fusion depend on the type of molecular rearrangements produced by the extent of draw and the temperature of draw. At low temperatures (near the glass transition) the molecules relieve strain by uncoiling with little sliding or alignment occurring. At temperatures above 100°C the molecules glide past one another to relieve strain with little uncoiling Strain‐induced crystals are formed in the samples drawn more than 160% at temperatures near the glass transition; at high strain, both chain alignment and uncoiling occur and produce crystallization at these temperatures. At higher temperatures and high strain, the uncoiling is too small to allow crystallization. Annealing a drawn sample under strain resulted in an increase in uncoiling which is proportional to the strain.
Permeation, diffusion, and solution of gases and water vapor in unplasticized poly(vinylchloride)
Authors: Tikhomirov B. P. , Hopfenberg H. B. , Stannett V. , Williams J. L.
Published: April 2003

The transport behavior of a number of permanent gases of varying molecular size and of water vapor was studied in calendered films of unplasticized poly(vinylchloride). Permeabilities, diffusivities, and solubilities were measured over a range of temperatures traversing the glass transition. A discrete change in the activation energy for diffusion was observed for Ar and Kr. No change in the activation energy for diffusion for He, Ne, CH4, N2, CO2, O2, and H2O was observed, as the glass transition was traversed. This appeared to be the first polymer system studied in detail in which the change in activation energy for diffusion is related to penetrant size rather than to a unique dependence upon polymer fine structurej
The polymerization of acrolein
Authors: Kitahama Yoshiharu , Ishida Shinichi
Published: April 2003

The polymerization of acrolein was carried out using the coordination Complexes of metallic salts with organic ligands. The polymer obtained had the same infrared spectrum and properties compared to that prepared by R. C. SCHULZ, who used sodium, and whose polymer consisted mainly of the structure produced by the aldehyde group polymerization of acrolein.

Active catalysts for the polymerization consist of metallic salts such as CdI2, ZnCl2 and ligands such as pyridine and triphenyl phosphine.

Rate of polymerization was considerably dependent on temperature, solvent and kinds of catalysts. These effects indicated that the polymerization proceeded through ionic mechanism.
Cationic copolymerization of trioxane with styrene. II. Some factors effect on the copolymerization of trioxane with styrene
Authors: Minoura Yuji , Mitoh Motonort , Mabuchi Yoshiki
Published: April 2003

The homogeneous copolymerization of trioxane with styrene was carried out using various catalysts and solvents. The copolymerization rate increased with increase in the dielectric constant of the solvent used and decreased with increase In the acidity of the catalyst used. The reactivity of styrene increased and on the contrary, the reactivity of trioxane decreased with increase in the dielectric constant of the solvent.
Vinyl polymerization. 221. Polymerization of methyl methacrylate in the presence of cellulose triacetate
Authors: Kubushiro Kanemitsu , Takemoto Kiichi , Imoto Minoru
Published: April 2003

A kinetic study on the polymerization of methyl methacrylate (MMA) was made in the presence of cellulose triacetate (CTA) and water. In this case, water was found to be not necessary for the initiation of polymerization. The reaction proceeds by a radical mechanism, and the rate of polymerization can be expressed by the following equation:

The overall activation energy for the polymerization was estimated as 7.9 kcal/mole. The grafting efficiency of polymethyl methacrylate (PMMA) to CTA decreased with increase in polymerization temperature. The molecular weight of the extracted PMMA decreased also slightly with increase in polymerization temperature and was independent on the concentration of CTA. These results suggest that the molecular weight of PMMA is mainly affected by the transfer of growing radical to monomer molecule.
Unperturbed dimension of polymer molecules from viscosity measurements
Authors: Deb P. C. , Chatterjee S. R.
Published: April 2003

Based on the theory of rate process for viscous flow, an expression for Φ (FLORY constant) has been given according to which Φ should depend on the polymer‐solvent pair and temprature. The variation of Φ, [η], and k, the latter two being fundamental terms of the equation c/ηsp = l/η − kc, has been utilised for the determination of unperturbed dimension of polymer molecules in solution. The importance of k and the alternative expressions for the same are discussd. The values of
\documentclass{article}\pagestyle{empty}\begin{document}$\[ \left( {{{\overline {\text{r}_\text{0}^\text{2} } } \mathord{\left/ {\vphantom {{\overline {\text{r}_\text{0}^\text{2} } } \text{M}}} \right. \kern‐\nulldelimiterspace} \text{M}}} \right)^{1/2} $\end{document}
are found to be in good agreement with the literature values.
Über die herstellung von tris‐O‐trimethylsilylpolysacchariden
Authors: Keilich Von G. , Tihlarik K. , Husemann E.
Published: April 2003

2.3.6‐Tris‐O‐trimethylsilyl‐amylose, ‐cellulose und Tris‐O‐trimethylsilyl‐pullulan entstehen durch heterogene Umsetzung der entsprechenden Polyglucane in Pyridin mit Trimethylchlorsilan; eine vollständige Substitution der verzweigten Polyglucane Dextran und Amylopektin wird dagegen nicht erreicht.
The structure of beryllium di‐n‐butyphosphinate poymer
Authors: Giancotti Vincenzo , Giordano Federico , Ripamonti Alberto
Published: April 2003

The results of the interpretation of the X‐ray fibre photograph of the copolymer

isomorphous with the homopolymer

are reported. The unit cell has a monoclinic symmetry with

.

The molecular chains are characterized by a backbone strucure with tetrahedral metal atoms bonded by alternate single and triple bridging phosphinate groups. The best agreement between observed and calculated intensities was obtained assuming the space group P21/m. Pairs of parallel chains are packed so that the triple bridged cages of one chain fall midway those of the other chain in a way similar to that found in the β‐form of the polymer
The second virial coefficient of polyelectrolytes
Authors: Patel J. R. , Patel R. D.
Published: April 2003

A critical analysis of the data, obtained by NAGASAWA et al. for the second virial coefficient (A2) determined by light scattering measurements have been carried out for sodium polystyrene sulfonate (NaPSS). The result are analyzed in light of the different theories for the second virial coefficient. Finally, a critical discussion has been made of the theory proposed for the separate determination of the electrostatic interactions and the chain character of the polyelectrolyte by means of which the deviation from ideality are meansured.
Mercaptale als spezifische inhibitoren für mit dibenzoylperoxid initiierte polymerisationen. Untersuchung von O‐, S‐ und N‐vinylverbindungen. IX.
Authors: Gollmer Von Kl. , Ringsdorf H.
Published: April 2003

Bei Versuchen zur radikalischen Polymerisation von S‐Vinylverbindungen haben sich Mercaptale als spezifische Inhibitoren für Dibenzoylperoxid (BPO) erwiesen. DieSCH2SGruppe bedingt einen induzierten Peroxidzerfall unte Bildung von Benzoesäure und Acyloxymercaptalen. Diese konnten durch Modellversuche mit gesättigten niedermolekularen und makromolekularen Mercaptalen isoliert bzw. nachgewiesen werdern.
Zur kinetik der polyreaktion von styrol mit löslichen ziegler‐natta‐katalysatoren. I.
Authors: Reichert Von K. H. , Berthold J. , Dornow V.
Published: April 2003

Die Polyreaktion von Styrol mit dem löslichen ZIEGLER‐NATTA‐Katalysator

wird kinetisch untersucht.

Durch Verwendung einer 14C‐markierten Katalysatorkomponente kann nachgewiesen werden, daß unter den gegebenen Reaktionsbedingungen die Polyreaktion von Styrol fast ausschließlich durch Insertion des Monomeren zwischen eine Metall‐Kohlenstoff‐Bindung erfolgt. Auf Grund der kinetischen Befunde lassen sich folgende Aussagen über das Reaktionsgeschehen dieser Polyreaktion machen:

In einer Folgereaktion des Mischkatalysators wird die eigentliche polymerisationsaktive Spezies gebildet, wobei die Bildungsgeschwindigkeit in Gegenwart von Styrol proportional der Aluminiumalkyl‐und Monomerkonzentration ist. Dieser aktive Zwischenkomplex kann die Polyreaktion des Styrols initiieren und gleichzeitig in einer Parallelreaktion unter Reduktion desaktiviert werden. Wachstum erfolgt, unter weitgehendem Ausschluß von Verunreinigungen und nur unter den gegebenen Katalysator‐Konzentrationsverhßältnissen, fast ausschließlich durch Insertion des Monomeren zwischen eine übergangsmetall‐Kohlenstoff‐Bindung des aktiven Komplexes. Als Abbruchreaktionen sind drei verschiedene Reaktionen anzunehmen, und zwar mit Monomerem, überschüssigem Aluminiumalkyl und dem aktiven Komplex selbst. Entsprechend ergibt sich, daß die maximale Bruttopolymerisationsgeschwindigkeit nur proportional der Monomerkonzentration im Quadrat und praktisch unabhängig von der Katalysatorkonzentration ist. Auf Grund der Befunde mit vorreagiertem Katalysatorsystem kann dem Komplex \documentclass{article}\pagestyle{empty}\begin{document}$ ({\rm C}_{\rm 5} {\rm H}_{\rm 5} )_2 {\rm C}_{\rm 2} {\rm H}_{\rm 5} {\rm TiCl} \cdot {\rm ClAlC}_{\rm 2} {\rm H}_{\rm 5} {\rm Cl,} $\end{document} oder einem im Gleichgewicht mit ihm stehendem Produkt die Polymerisationsaktivität zugesprochen werden.
Partielle spezifische refraktionen von polymethylmethacrylat und polystyrol. II. Eine methode zur endgruppenanalyse
Authors: Bodmann Von Otto
Published: April 2003

Als Methode zur Endgruppenanalyse bei polymerhomologen Reihen werden die Spezifische Refraktion und ihre Dispersion untersucht. Am Beispiel von Polymethylmethacrylat‐ und Polystyrolpräparaten, die mit Dibenzoylperoxid polymerisiert wurden, wird gezeigt, daß sowohl auf die Art wie auch auf die Zahl der Endgruppen pro Molekül Schlüsse gezogen werden können. Voraussetzung ist, daß (1) die spezifischen Refraktionen und Dispersionen von Kette und Endgruppen verschieden sind und (2) keine störenden Exaltationseffekte vorliegen.
Untersuchungen über den endgruppeneinfluß bei oligomeren. 1. Mitt.: Die abhängigkeit des enthalpiekoeffizienten vom polymerisationsgrad
Authors: Sotobayashi Von Hideto
Published: April 2003

Für Die Abhängigkeit des BH‐Wertes vom Polymerisationsgrad wurde mit Hilfe des Gittermodells eine neue Theorie aufgestellt, die einen Konformations‐ und Endgruppeneffekt berücksichtigt. Dabei wird angenommen, daß die internmolekularen Kontakte im Gitter statistisch verteilt und die Polymermoleküle steif sind.

Mit Hilfe enies Computers wurde die Konformation oligomerer Moleküle untersucht.

Für alle Konformationen wurde die glelche Auftrittswahrscheinlichkeit vorausgesetzt. Mit Hilfe der Theorie wurde die Abhängigkeit der BH‐Werte vorn Polymerisationsgrad für verschiedene Systeme berechnet. Die Übereinstimmung mit dem Experiment ist über einen großen Bereich des Polymerisationsgrads befriedigend.
Oligoester. III. The synthesis of oligohydroxypivalates having unprotected terminal groups
Authors: Iwakura Yoshio , Hayashi Katsumi , Iwata Kaoru , Matsuo Shunji
Published: April 2003

Linear oligohydroxypivalates terminated with a hydroxy and a carboxy group

were synthesized by the catalytic hydrogenolysis of the corresponding oligohydroxypivalate benzyl esters. The oligohydroxypivalate benzyl esters, in turn, were prepared by a stepwise method which involved the condensation of dichloroacetoxypivaloyl chloride with a preceding hydroxy terminated oligohydroxypivalate followed by removal of the dichloroacetyl group by mild alkaline hydrolysis. Melting points, infrared spectra and nuclear magnetic resonance spectra of the oligomers were studied.
Studies on the charge‐transfer complex and polymerizations. Part XIX. Spontaneous copolymerization of 1.2‐dimethoxyethylen and p‐dioxene with maleic anhydride
Authors: Kokubo Takashi , Iwatsuki Shouji , Yamashita Yuya
Published: April 2003

The kinetics of spontaneous copolymerization of 1.2‐dimethoxyethylene and p‐dioxene with maleic anhydride were studied and found to obey the following relation:

These results were explained by regarding the charge‐transfer complex between ethers and maleic anhydride as a single monomer and assuming the participation of the charge‐transfer complex in both the initiation and propagation steps.

The activation energies of thermal (spontaneous) polymerization were calculated for the p‐dioxene‐maleic anhydride system as follows:
The effect of hydroxyl ion concentration and ionic strength on the intrinsic viscosity of hydroxyethyl cellulose at high velocity gradients
Authors: Elmgren Hans , Norrby Sverker
Published: April 2003

The intrinsic viscosity of a fractionated hydroxyethyl cellulose sample (HEC) in solvents of various ionic strengths and pH (≥ 7) was measured at high rates of shear by means of a capillary viscometer. The results show that the cellulose molecule is a polyelectrolyte at pH values greater than 13, and that the charge density on the cellulose chain increases with increasing pH. The intrinsic viscosity decreases with increasing pH with its strongest pH dependence at pH ≈ 13.7. The results also show that the stiffness of HEC in neutral solvents is about the same as that of cellulose trinitrate in ethyl acetate1. The flexibility of HEC increases with increasing pH of the solvent. By means of the empirical method of hyperbolic extrapolation1 to infinite rate of shear, the same value of the intrinsic viscosity of the sample was obtained in all solvents except for those in which polyelectrolyte effects were not swamped out by an excess of salt. All these results are explained by a model which describes the extended configuration of cellulose molecules as partly due to intramolecular hydrogen bonds via the 6‐position hydroxyl proton to an adjacent anhydroglucose unit2.
The oligomerization of isoprene with modified ziegler catalysts
Authors: Itakura Jo , Tanaka Hisao
Published: April 2003

The oligomerization of isoprene with modified ZIEGLER catalysts was studied. Dimers of isoprene were obtained in 70–90% yield using combined catalysts of diethylaluminum chloride, dimethyl sulfoxide, and a titanium(IV) compound, such as titanium di‐(p‐toluenesulfonate) dichloride and N‐vinylpyrrolidone or alkylene carbonate complexes of titanium tetrachloride. Two isomeric dimers, produced in approximately equal molar ratio, were found as the main product accompanied by small amounts of a third dimer and of trimers. Each dimer was separated by means of preparative gas chromatography and subjected to analyses. The two predominant compounds were identified as 2.4‐dimethyl‐4‐ethenyl‐1‐cyclohexene and 2.7‐dimethyl‐1.3.6‐octatriene, respectively. Possible mechanisms are discussed in relation to the oligomerization of butadiene on the basis of the product analysis.
Radical reactions initiated by chelate complexes of transition metals. I. The kinetics of the reaction of bis‐(–)ephedrine copper(II) chelate with halogen containing compounds
Authors: Bartoň J. , Szöcs F. , Nemček J.
Published: April 2003

The kinetics of the reaction of bis‐(–)ephedrine copper(II) chelate with halogen containing compounds and carbon tetrachloride in benzene and/or cyclohexane solutions were studied. The course of chelate reaction with carbon tetrachloride is in agreement with the kinetic law for a pseudomonomolecular reaction, with the rate constant k′=8.60·10−5 mole−1 l. sec−1 at 20°C. In solutions of carbon tetrachloride in benzene and/or cyclohexane there was an increase of the rate constant with decreasing carbon tetrachloride concentration in the first case, while a decrease was observed in the second case. The variation of the rate constant of chelate reaction with carbon tetrachloride in presence of benzene and/or cyclohexane was interpreted by assuming the chelate molecule conformation to be influenced by the solvent. It was found that halogen compounds react the more readily with the chelate the more halogen atoms are present in the molecule. It was shown by means of ESR spectroscopy that in the course of the reaction of the chelate with carbon tetrachloride a reduction of the central metal of the chelate takes place. The rate constant k″ of the reaction Cu2+ + CCl4 → Cu1+ + products has a value of 4.63·10−6 mole−1 l. sec−1 at ambient temperature.
Monte‐carlo‐rechnungen an makromolekülmodellen. 1. Mitt.: Der quadratische mittelwert des fadenendenastands
Authors: Bruns Von Wolfgang
Published: April 2003

Monte‐Carlo‐Methoden wurden benutzt, um mit Hilfe einer Rechenmaschine Zufallsketten zu erzeugen, die als Vorlage für reale Makromoleküle dienen können. Dabei wurden zwei gitterfreie Modelle, bei denen entweder Valenz‐ und Rotationswinkel (A) oder die Rotationswinkel allein (B) frei wählbar waren, verwendet; die Wirkung des „ausgeschlossnen Volumens”︁ wurde berücksichtigt. Die Abhängigkeit des mittleren Quadrats des Fadenendenabstands von der Segmentzahl wurde an Hand von zwei aus der Literatur bekannten Gleichungen diskutiert. Sie läßt sich in guter Näherun, durch die Bezichungen h̄2= 1,68 n1,203bzw. h̄2= 1,21 n1,248wiedergeben.
Butene‐1/propylene copolymers. Influence of the comonomerie units on polymorphism
Authors: Gianotti Giuseppe , Capizzi Amedeo
Published: April 2003

Butene‐1/propylene copolymers at different compositions have been studied by differential scanning calorimeter (D.S.C.) and dilatometric techniques in order to ascertain the influence of the comonomeric units on polymorphism.

The results suggest that the phase transitions of these copolymers have the peculiar trend of polybutene‐1, whereas remarkable changes are observed in the kinetic parameters. Contrary to what known so far, for the himopolymer, they can also crystallize from the melt directly in a low‐melting form called modif. 1′.
Isotactic polybutene‐1: Internal pressure measurements
Authors: Turturro Antonio
Published: April 2003

Some internal pressure (Pi) measurements on modification 1 and 2 of isotactic polybutene‐1 are reported.

They confirm the solid‐solid transition at 65°C for form 2 and show Pi of 1, at room temperature, to be higher than that of both form 2 and the melt; the molten polymer has an internal pressure intermediate between form 1 and form 2.
Über eine neue Methode zur kinetischen Untersuchung der Perlpolymerisation
Authors: Gunesch Von Heinz , Schneider I. A.
Published: April 2003

Es wird in vorliegender Arbeit eine kinetische Untersuchungsmethode der Perlpolymerisation vorgeschlagen, wobei der isotherme Ablauf der Reaktion dadurch gewährleistet wird, daß die Polymerisationswärme von temperiertem Wasser aufgenommen wird, das in das Reaktionsgemisch einfließt.

Die zugeflossen Wassermenge als Funktion der Zeit ermöglicht nach einer vorherigen Eichung, kinetische Umsatzkurven für den ganzen Reaktionsablauf abzuleiten.

Es werden die verwendete Apparatur und die Überprüfung der Methode während der Perlpolymerisation des Vinylacetats beschrieben.
Vinyl Polymerization. 246. Polymerization of Vinyl Chloride with Monoethanolamine and Carbon Tetrachloride System
Authors: Takemoto Kiichi , Sasabe Masazumi , Imoto Minoru
Published: April 2003

Reaction of amines with carbon tetrachloride has received considerable attention1–3, and it has been pointed out that the presence of copper metal is substantial for the reaction4,5. On the other hand, oligomerization of ethylene was studied by amine and carbon tetrachloride system, and discussed whether any metal or metal salts can play a role for initiating the reaction6,7. Polymerization of vinyl monomers was also carried out by imidazole and carbon tetrachloride system8,9.
Über die Darstellung und Polymerisation von 4‐Vinyldiphenyl, 11‐Vinyl‐p‐terphenyl und 1 2‐Vinyl‐p‐terphenyl
Authors: Kern Von W. , Heitz W. , Jäger M. , Pfitzner K. , Wirth H. O.
Published: April 2003

Für die Darstellung von 4‐Vinyldiphenyl und 11‐Vinyl‐p‐terphenyl wurden einfache, verallgemeinerungsfähige Synthesen ausgearbeitet. Durch Umsetzung entsprechender Carbinole mit Methansulfonsäurechlorid in Pyridin gelang die Darstellung der Vinylverbindungen in einer einstufigen Reaktion.

Die Untersuchung der radikalischen Copolymerization der Monomeren mit Styrol ergab bei 4‐Vinyldiphenyl und 12‐Vinyl‐p‐terphenyl einen bevorzugten Einbau in die Polymerketten, während 11‐Vinyl‐p‐terphenyl nur in untergeordnetem Maße in Polystyrolketten eingebaut wurde.
Some products of interaction of p‐benzoquinone with styrene
Authors: Ghanem N. A. , Yehia A. A. , Rizk Nadia A.
Published: April 2003

Using equimolar concentrations of p‐benzoquinone and styrene at 100°C, a compound consisting of one molecule of benzoquinone, one molecule of hydroquinone and one molecule of styrene was separated from the complex reaction mixture in a small yield. Quinhydrone was separated at short reaction time and hydroquinone at prolonged reaction times. Reaction mechanisms for the formation of these compounds are proposed.

Solvent extraction, fractional precipitation, thin layer chromatography, IR and UV spectrophotometry, elementary analysis, and molecular weight determination were applied for separation and identification.
NMR studies of polymer solutions. VII. Effects of chain length on polymer NMR measurements
Authors: Liu Kang‐Jen
Published: April 2003

The strong short‐range near‐neighbor effect on the NMR spectra of poly(dimethyl siloxanes) as a function of chain length in bulk as well as in solution was further demonstrated. The internal methyl groups of the polymer are distinguishable as the chain length n ≥ 5. A main polymer NMR peak appears for poly(dimethyl siloxane) only when n ≥ 7. In addition to the short range effect on the NMR peaks of the „near‐end groups”︁ of a polymer, we have also shown that the main polymer NMR peaks of poly(dimethyl siloxane) and poly(ethylene glycol) are also affected by chain length in certain aromatic solvent media. This is due to the effect of chain length on the solvation behavior of the main polymer segments, and it may be considered as a long range effect. Both these short and long range effects on the NMR absorption peaks and the bandwidths have been discussed.
On the mechanism of chemiluminescence in oxidation of organic substances and polymers
Authors: Vassil'ev R. F.
Published: April 2003

Several mechanisms of chemiluminescence excitation in hydrocarbon oxidation are discussed. The excitation in bimolecular reaction between two free radicals is considered as more probable path than that in a non‐radical reaction leading to molecular products.
Cationic copolymerization of cyclic formals and vinyl ethers
Authors: Okada Masahiko , Yamashita Yuya
Published: April 2003

Copolymerizations of 1.3‐dioxepane with isobutyl vinyl ether and of 1.3.6‐trioxocane with 2‐chloroethyl vinyl ether were carried out in methylene chloride using boron fluoride ethyl ether complex as a catalyst. NMR and methanolysis studies on the copolymers have shown that both monomer units are not randomly distributed in these copolymers but that these monomers form blocks of relatively long sequences.
Imidazole catalyses in aqueous systems. II. Inhibition studies on the enzyme‐like catalysis in the hydrolysis of a phenyl ester by an imidazole‐containing copolymer
Authors: Kunitake Toyoki , Shimada Fumiko , Aso Chuji
Published: April 2003

Inhibitory actions of several organic compounds on the enzyme‐like catalysis of a water‐soluble copolymer of 1‐vinyl‐2‐methylimidazole and N‐vinylpyrrolidone were studied in the hydrolysis of 3‐nitro‐4‐acetoxybenzoic acid. The hydrolyses were carried out in 1 M KCl at 30°C, pH 8.0, using a pH‐stat system. The inhibitions were analyzed by the LINEWEAVER‐BURK plotting of the MICHAELIS‐MENTEN equation as in enzymatic reactions. Benzyl alcohol, the 2.4‐dinitrophenolate anion, and dioxane competitively inhibited the enzyme‐like catalysis of the polymer catalyst, Ki (inhibition constant) being 110, 42, and 1000 (10−3 mole · 1−1), respectively. Acetone showed a mixed‐type (competitive plus noncompetitive) inhibition. The rate‐depressing effect of the product, the dianion form of 3‐nitro‐4‐hydroxybenzoic acid, could not be included in the common category of inhibition. Observation of these competitive and other inhibitions and a comparison of Ki's supported the validity of the enzyme‐like catalysis proposed for the imidazole‐containing copolymer and endorsed the previous proposition that the catalytic site was bound to a substrate or an inhibitor by mainly hydrophobic forces.
Über die bildung freier radikale in röntgenbestrahlten vinylmercaptan/vinylpyrrolidon‐copolymeren
Authors: Mönig Von H. , Ringsdorf H.
Published: April 2003

Die Bildung und das Verhalten von strahleninduzierten Radikalen in Polyvinylmercaptan und Copolymeren aus Vinylmercaptan und Vinylpyrrolidon wurden mit Hilfe der ESR‐Spektroskopie untersucht. In allen Polymeren konnten RS•‐Radikale nachgewiesen werden, die im Fall der Copolymeren teilweise durch Kettenübertragung entstehen. Die Copolymeren werden nur schwach bzw. nicht vernetzt, was auf einen Schutz‐ bzw. Regenerationseffekt der Vinylpyrrolidon‐Einheiten durch die Mercaptogruppen zurückgeführt wird.
Die thermische diffusion von polystyrol in verschiedenen lösungsmitteln
Authors: Meyerhoff Von G. , Rauch B.
Published: April 2003

Es wird über Messungen von thermischen Diffusionskoeffizienten und LUDWIG‐SORET‐Koeffizienten von Polystyrol in den Lösungsmitteln Toluol, Methyläthylketon, Butylacetat und Cyclohexan berichtet. Es zeigte sich, daß der rein thermisch bedingte Diffusionsprozeß in Butylacetat und im Θ‐Lösungsmittel Cyclohexan unabhängig vom Molekulargewicht ist, wie as für Toluol bereits früher nachgewiesen werden konnte.

Für Methyläthylketon wurde eine schwache, aber deutliche Abhängigkeit von D' vom Molekulargewicht zu D' ∼ M−0,12 gefunden. Bemerkenswerterweise verhalten sich die beiden in Bezug auf Polystyrol thermodynamisch sehr ähnlichen Lösungsmittel Butylacetat und Methyläthylketon in dieser Hinsicht sehr verschieden.
The intrinsic viscosity‐molecular weight relationship for polypropylene
Authors: Yamaguchi Kinya
Published: April 2003

Measurements of intrinsic viscosity in decalin at 135°C and light scattering in α‐chloronaphthalene at 145°C were performed for several polypropylene fractions of molecular weight ranging up to 2.106. The specific refractive index increment at 436 mμ for the α‐chloronaphthalene solution was found to be −0.231 ml/g, which is considerably higher than those reported by CHIANG and others authors. However, no significant disparity is observed between the results of light scattering measurements by CHIANG and the present author. The intrinsic viscosity‐molecular weight relationship obtained is: [η] = 1.15·10−4 M, which is in good agreement with that reported by KINSINGER and HUGHES. This relationship is also compared with those of other authors observed at different conditions of viscosity measurements.
Alternative copolymerization of vinyl sulfides with maleic anhydride. III. Alternative copolymerization
Authors: Otsu Takayuki , Inoue Hiroshi
Published: April 2003

Ethyl vinyl sulfide (EVS) and phenyl vinyl sulfide (PVS) were found to undergo alternative copolymerization with maleic anhydride (MAn) even in the absence of radical initiators. It is noted that both the rates and the reduced viscosities in these alternative copolymerization show a maximum at 50 mole‐% comonomer mixture, anticipating that a 1 : 1 charge transfer complex is formed preceding polymerization. From spectroscopic studies, it was also observed that the formation of such a complex between vinyl sulfide and MAn was confirmed, but their equilibrium constants were quite small, i.e. 0.090 l./mole for PVS‐MAn in CHCl3 and 0.035 l./mole for EVS‐MAn in CH2Cl2 at room temperature. The mechanism of these alternative copolymerizations is discussed.
Growth of polyoxymethylene crystals in the course of the polymerization of trioxane in solution
Authors: Iguchi M. , Kanetsuna H. , Kawai T.
Published: April 2003

In order to pursue the possibility of the extended chain crystals of polymers formed in the course of polymerization, the cationic polymerization of trioxane in cyclohexane has been studied. The polymer, polyoxymethylene, was obtained in the form of a unique single crystal. From the morphological and physical studies of the resultant polymers as well as the kinetical studies of the polymerization, it has been revealed that long, needle‐like nuclei formed in the beginning of the polymerization grew into feather‐like platelets with twin habit. The degree of crystallinity of the nascent polymer was essentially 100% in terms of their densities. The molecular chains were fully extended and regularly aligned in the direction of the crystal growth. The growth of the crystal occurred as the polymerization proceeded. Thus it is considered that the crystal grows quite successively to the propagation of the chains through direct addition of the monomer molecules onto the reactive chain ends which are aligned two‐dimensionally on the growing surface of the crystal. The molecular length of the nascent polymer estimated from the solution viscosity, however, did not agree with the crystal dimensions measured in the direction of the molecular orientation, the former being rather small. The above results are explained in terms of the chain‐transfer reaction and the catalytic decomposition of the polymer chain.
Mechanism of thermal initiation in styrene polymerization1
Authors: Brown Weldon G.
Published: April 2003

New observations on the thermal polymerization of pure styrene at 130°C refute an earlier claim by MÜLLER that 1‐phenyltetralin is the major dimeric product. The principal dimeric products are cis‐ and trans‐1.2‐diphenylcyclobutane in a 1:2 ratio with relatively minor amounts of 1‐phenyltetralin, 1.3‐diphenylbutene, and 1‐phenyl‐1.2‐dihydronaphthalene. Data are also given for the dimers formed at 85°C and for the dimers isolated from a fully cured (180°C) polystyrene the significance of differences in minor constituent yields is assessed. MAYO's basic postulate of radical pair production by reaction of a DIELS‐ALDER type dimer with styrene is the starting point for a more extended reaction scheme in which cage reactions form minor dimeric and trimeric products in compeßition with chain initiation.
On the partially free draining effect in the intrinsic viscosity and sedimentation coefficient of cellulose nitrate solution
Authors: Kamide Kenji
Published: April 2003

The partially free draining effect on intrinsic viscosity, sedimentation and diffusion constant was evaluated for cellulose nitrate solution. The methods used in this study involve the analysis of (a) parameters in the KUHN‐MARK‐HOUWINK‐SAKURADA equation, (b) intrinsic viscosity [η] and concentration dependence of sedimentation coefficient ks, (c) [η], ks, molecular weight M, and second virial coefficient A2, (d) molecular weight dependence of sedimentation constant and the exponent a in the KUHN‐MARK‐HOUWINK‐SAKURADA equation, (e) a and molecular weight dependence of diffusion constant, (f) a and dependence of [η] on radius of gyration of a polymer chain R, (g) a and molecular weight dependence of R, (h) [η], M, R, and the linear expansion factor α, (i) [η], M, and A2. Draining parameters thus obtained, such as X, ν(X), and Δ which were defined in the theories of KURATA‐YAMAKAWA and KAWAI‐KAMIDE, are compared with those in literature. Although the methods used here have been derived from different theoretical bases using different approximations, ν(X) was evaluated as 0.3 ± 0.1 for cellulose nitrate with nitrogen content of 12 to 14%, irrespectively of the method used. This indicates that the draining effect can not be ignored, in other words, the intrinsic viscosity and sedimentation data can not be interpreted reasonably by the excluded volume theories, without taking into account the draining effect.
Crystallization of A‐B‐A type block copolymers of poly(ethylene oxide) and poly(α‐methyl styrene) from dilute solutions
Authors: Kawai Tōru , Shiozaki Shigeru , Sonoda Shinji , Nakagawa Hideaki , Matsumoto Takako , Maeda Hirokuni
Published: April 2003

In order to examine the possibilities of a heterogeneous fold structure proposed previously, in which large irregular loops are incorporated in regular sharply reentrant folds on the surface of polymer single crystals and of the molecular ties which connect lamellae in multilayer crystals, the morphologies of the solution grown crystals of the A‐B‐A type block copolymers of poly(ethylene oxide) (A) and poly(α‐methyl styrene) (B) have been studied mainly as a function of polymer concentration. The range of the content of polyethylene oxide (PEO) was from 0.551 to 0.860, the molecular weight of each sequence being in the order of 104 to 105. The solvents used were ethylbenzene, xylene, and isoamylacetate. It was found that the copolymers having the PEO contents beyond 0.643 crystallized from dilute solution (0.1 to 0.25%) into the form of square tablets, similar to the PEO single crystals. Electron micrographs of these crystals revealed that poly(α‐methyl styrene) chains were excluded from the crystalline part and deposited on the surface of the crystals during chain‐folding crystallization and long loops thus formed aggregated in the solution or on drying the crystals in a manner depending on the solvents used. When the polymer concentration was increased to 0.5%, irregularly shaped, multilayer crystals were formed where a number of holes were found on their surfaces, suggesting that the frequency of the formation of tie molecules increased rapidly with increasing concentration. Evidences have been supplied for the formation of the long loops on the surfaces of lamellar crystals and of inter‐lamellar tie molecules in the chain‐folding crystallization.
NMR studies on the microstructure of copolymers of 1.3‐dioxolane and 1.3.5‐trioxane
Authors: Yamashita Yuya , Asakura Toshiyuki , Okada Masahiko , Ito Koichi
Published: April 2003

The sequence distributions of the formal (OCH2) and ethylene oxide (OCH2CH2) units in copolymers of 1.3‐dioxolane (DOL) and 1.3.5‐trioxane (TOX) prepared under various polymerization conditions were determined by NMR. The results can be largely explained by a random copolymerization process including depolymerization, in which DOL is kinetically more reactive, but its incorporation is thermodynamically less favourable than that of TOX. However, in the later stages of the reactions the microstructure of the copolymer changes to give longer polyoxymethylene sequences, which produces very complicated thermodynamic problems.
Investigation on the interaction mechanism between the electrochemically produced benzophenone radical‐anions and various monomers
Authors: Mengoli Giuliano , Vidotto Graziano
Published: April 2003

The decay caused by the interaction between methacrylonitrile, methylmethacrylate, acrylonitrile, and methylacrylate and benzophenone radical‐anions produced through electrolytical reduction of benzophenone in dimethylformamide in the presence of tetraethyl‐ammonium perchlorate as background electrolyte, has been investigated at various temperatures by using the polarographic and amperometric techniques. Owing to the interaction with the monomers, the benzophenone radical‐anions fully reoxidate to benzophenone. Moreover, decay rates will depend on the square radical‐anions and first power monomer concentration and are inversely proportional to the concentration of unaltered benzophenone present in the system.

The experimental results are interpreted on the basis of a kinetic scheme which comprises the dismutation of benzophenone radical‐anions to dianions and benzophenone, and subsequent electronic transfer from dianions to monomers.
Herstellung und eigenschaften von photometrisch quantitativ bestimmbaren, bei der polymerisation vernetzenden bisacrylsäureestern und von bispropionsäureestern als modellverbindungen
Authors: Kämmerer Von Hermann , Mück Karl‐Friedrich
Published: April 2003

Es wurden 6 Bisacrylsäureester hergestellt, die photometrisch quantitativ bestimmbare Strukturgruppen enthalten. Angaben zur Löslichkeit, IR‐, UV‐Absorptions‐ und 1H‐NMR‐Spektren dienten zur Charakterisierung der Verbindungen. Daneben wurden Dipropionsäureester synthetisiert, die sich durch Austausch der Acrylsäure‐ gegen die Propionsäurereste von den Bisacrylsäureestern ableiten. Verdünnte Lösungen der Bisacrylsäure‐ und Dipropionsäureester folgen im Bereich von 250–450 mμ dem BOUGUER‐LAMBERT‐BEER‐schen Gestz. Aus den Ergebnissen der Homopolymerisation der Bisacrylsäureester läßt sich schließen, welche Ester für eine einfache photometrische Analyse schwach vernetzter Copolymerer in Betracht kommen.
Copolymerization of carbon dioxide and epoxide with organometallic compounds
Authors: Inoue Shohei , Koinuma Hideomi , Tsuruta Teiji
Published: April 2003

Attempts to copolymerize carbon dioxide with epoxide led us to the first success in using carbon dioxide as a direct starting material for synthesizing high polymers. Some organometallic catalyst systems were found to catalyze the alternate copolymerization of carbon dioxide and epoxide, resulting in the formation of polycarbonates, the structures of which were confirmed with the aid of IR, NMR and elemental analysis. Diethylzinc‐water system produced a methanol insoluble aliphatic polycarbonate of much higher molecular weight than that produced by polycondensation. Thermal properties of the methanol insoluble polycarbonate were studied by differential thermal analysis and thermogravimetric analysis.
Polymerization mechanism of N‐carboxy‐α‐amino acid anhydride by organometallic compounds. II.. Reaction with organozinc compounds
Authors: Makino Tetsuya , Inoue Shohei , Tsuruta Teiji
Published: April 2003

Reactions of N‐carboxy‐α‐amino acid anhydride (NCA) with dialkylzinc or related organozinc compounds were studied to elucidate the polymerization mechanism of NCA by dialkylzinc as initiator.

The first stage of initiation reaction is a hydrogen abstraction reaction of dialkylzinc from NH group of α‐amino acid NCA resulting in the formation of an activated NCA. The second stage of initiation is a reaction between two molecules of the activated NCA forming a zinc carbamate group.

Propagation reaction is a carbonyl addition of the zinc carbamate group to the activated NCA to form a mixed anhydride which changes into an amide group releasing carbon dioxide.

Regeneration of the activated NCA is supposed to be done by the reaction of free α‐amino acid NCA with the zinc atom bonded to nitrogen atom at the growing chain end.
Crystallization of cellulose from dilute solutions
Authors: Maeda Hirokuni , Kawada Haruo , Kawai Tōru
Published: April 2003

Cellulose samples having a degree of polymerization (P) of 400, 200, 100, and 50 were crystallized isothermally from dilute solutions of aqueous sodium hydroxide and from cellulose xanthate solutions. Observation of the suspension under an optical microscope revealed that in most cases various shapes of huge lamellae in the order of 10 to 50μ were formed. These lamellae could easily be disintegrated by ultrasonic cavitation and under an electron microscope they were seen as fibrous sheets. In all the cases studied, the lengths of the fibrils were equivalent to or longer than the fully extended molecular length. The huge lamellae viewed under an optical microscope are considered to be loosely packed aggregates of the fibrils. In view of the low crystallinity found in these fibrils, the fringed micelle model seems rather preferable to the extended chain crystals. Viscometric measurements showed that the induction period, where reduced viscosity decreased or did not change, was followed by the pre‐crystallization stage which was manifested by a sudden increase, and then crystallization started as revealed by a rapid decrease in the reduced viscosity. This implies that cellulose chains were stiffened by the formation of intramolecular hydrogen bonds before the intermolecular crystallization started. If the formation of the intramolecular hydrogen bonds prior to a regular ordering of the chains in a lattice was avoided, therefore, it is anticipated that cellulose crystallizes in the form of chain folded lamellae. This was actually achieved by using an aqueous solution of equal moles of sodium hydroxide and methanol as the solvent. In this case, the reduced viscosity did not increase appreciably and dropped as the crystallization started. Namely, stiffening of the cellulose chains did not occur in the pre‐crystallization stage. The electron microscopy revealed that the crystals formed were lamellar in this case. The size of the lamellae was in the range of 0.5 to 5μ, and their thickness was in the order of 80 to 120 Å. Molecular length of cellulose used being ca. 2000 Å, the chains must be folded in these crystals.
Sur les systèmes catalytiques TiCl4‐AlR3. V. Addition de l'alcoyl‐aluminium en deux étapes
Authors: Laputte Par Robert , Guyot Alain
Published: April 2003

Des systèmes catalytiques TiCl4‐AIR3 préparés de façon à obtenir l'optimum de l'ativité polymérisante vis‐à‐vis du butène‐1, sont modifiés par addition in situ d'une nouvelle charge d'un alcoyl‐aluminium éventuellement différent du composé initial. Cette addition provoque des changements importants des activités polymérisante et isomérisante, qui sont discutés en fonction de la variation de composition du solide catalytique obtenue.
Oxidative polymerization of aromatic amines in aqueous solution of iron chelate
Authors: Tsuchida Eishun , Kaneko Masao , Kurimura Yoshimi
Published: April 2003

Aromatic amines, such as p‐phenylenediamine (PD) or p‐aminophenol (AP) have been found to polymerize oxidatively at room temperature, catalyzed by ferric chelates, e.g., the Fe(III)‐salt of ethylenediaminetetraacetic acid, in aqueous solution. The polymers from PD or AP are black and do not melt below 300°C. They have paramagnetic and electroconductive properties (ca. 10−10 Ω−1 ċ cm−1). They have also reversible oxidation and reduction properties; in methanolic solution the polymer is reduced by an aqueous sodium hydrosulfite solution, resulting a light yellow solution, which is re‐oxidized by air to the original black polymer. The structures of the polymers are also presented.
Copolymerization of various isocyanates with ethylene oxide
Authors: Harada Kunihiro , Deguchi Atsushi , Furukawa Junji , Yamashita Shinzo
Published: April 2003

Copolymerization of various monoisocyanates with ethylene oxide was attempted in relation to the alternate copolymerization of phenyl isocyanate with ethylene oxide by triethylaluminum catalyst. It was found that aliphatic and alicyclic isocyanates are not copolymerizable at all while many of aromatic isocyanates give the copolymer. The copolymer obtained was supposed to be alternate one. As to the substituted phenyl isocyanates, it was shown that ortho‐substituted isocyanates give the copolymer in high yield, with one exception: o‐anisyl isocyanate. There is no relation between the copolymer yields and HAMMETT'S substituent constants. These results suggest that triethylaluminum may preferentially coordinate with the oxygen atom rather with the nitrogen of the isocyanate group and that the coordination of the catalyst with the substituent may also occur. These expectations were confirmed by the infrared technique and the copolymer structure.
Contact interactions of polydimethylsiloxane and its low oligomers with solvents
Authors: Morimoto Satoshi
Published: April 2003

The contact interaction parameters X12 for polydimethylsiloxane (PDS) and for some low oligomers with various solvents were calculated from the data obtained from the heat of mixing at infinite dilution using the statistical thermodynamic theory of liquid mixtures developed by FLORY et al.. Comparing these values with those of polyisobutylene (PIB), the results were explained by the difference of diameter between both polymer segments, by the existence of bonded oxygen in the PDS polymers, and by the difference of flexibility between the polymer and the long chain molecular solvent.
Thermal oxidative stability of some poly(phosphonylureas)
Authors: Carraher Charles E. , Krueger Calvin W.
Published: April 2003

The thermal oxidative stability of poly(phosphonylureas) of the below from was studied.
magnified image
The products show significantly better thermal stability than their carbon counterparts. The product where R is C6H5— and R′ is 1.3‐C6H4‐ has only 10% weight loss at 400°C and 40% weight loss at 600°C. The thermal degradation of the poly(phosphonylureas) followed using infrared spectroscopy. Possible initial degradation sites are discussed.
Structure and properties of polyvinylchloride. II. Dynamic‐mechanical properties of rigid PVC
Authors: Petersen Jörgen , Rånby Bengt
Published: April 2003

A recording torsion pendulum built for frequencies of 0.02 to 11 c/sec and temperatures of −196 to 250°C was used for rigid PVC (I) and low‐temperature polymerized PVC (II). The polymers showed a primary transition region at 78°C for I and 84°C for II related to the glass transition and a secondary transition region at about −55°C for I and II. Extensive measurements, where both frequency and temperature were varied, were made for I. The resulting master curve for the complex modulus G″ showed two maxima, one primary at 10−8.5 c/sec due to segment motion of the polymer chains, and one secondary maximum at 105 c/sec interpreted as due to vibrational motion of groups along the chains. From diagrams of the shift factor vs. 1/T, apparent activation energies of 169 and 15.7 kcal/mole monomer units were calculated for segment motion (< 32°C) and group vibration (> 32°C), respectively.
Use of azeotropes in the ebulliometry of polymers
Authors: Tsuchida Eishun , Kawata Tsutomu , Shinohara Isao
Published: April 2003

The effect of noise and drift in ebulliometer operation can be eliminated by the use of certain azeotropes. Such azeotropic mixtures are cyclohexane/acetone, carbon tetrachloride/acetone, benzene/methanol, carbon tetrachloride/methanol, and tetrahydrofuran/water. Other azeotropes were found unstable, however. The applicability of the “stable” azeotropes was tested via molecular weight determinations of poly(ethylene glycols).
Zur radikalkinetik im vakuumbestrahlten polyvinylchlorid
Authors: Bartl Von Anton
Published: April 2003

Mittels Elektronenspinresonanz wurde in vakuumbestrahltem Polyvinylchloridpulver (Suspensionspolymerisat) bei Zimmertemperatur die Radikalbildungskurve aufgenommen und das Verschwinden der Radikale nach dem Ende der Strahleneinwirkung im Vakuum bei Temperaturen zwischen 20 und 90°C untersucht. Es wurden der G‐Wert der Radikalbildung, die Geschwindigkeitskonstanten und die Aktivierungsenergie des Radikalzerfalls bestimmt. Unter Voraussetzung eines Käfigmodells für die Radikalrekombination kann der Verlauf der kinetischen Kurven im untersuchten Temperaturbereich befriedigend erklärt werden.
Polyhydrochinonsulfone1,2. III. Synthese einiger hydrochinonsulfone
Authors: Manecke Von G. , Beier J. , Wehr G.
Published: April 2003

Einige Modellverbindungen und Vinylmonomere für Redoxpolymere wurden synthetisiert, in denen ein Hydrochinonkern oder methylsubstituierter Hydrochinonkern über eine Sulfonbrücke mit einem substituierten Benzolkern bzw. einer Chloräthyl‐ oder Vinylgruppe verknüpft ist.
Darstellung und charakterisierung neuer polyampholyte durch alkalische hydrolyse von polyvinylpyrrolidon
Authors: Wolf Von Friedrich , Lohs Karlheinz , Böhm Siegfried
Published: April 2003

Bei der Hydrolyse von Polyvinylpyrrolidon (PVP) in wäßriger alkalischer Lösung erfolgt neben einer geringfügigen Bildung von Poly‐N‐vinyl‐γ‐aminobuttersäureeinheiten eine Abspaltung von γ‐Aminobuttersäure (AMBS) und Acetaldehyd. Der Acetaldehyd ist mit großer Wahrscheinlichkeit für die dabei auftretende Vernetzung verantwortlich.

Durch die Hydrolyse von PVP in der Schmelze eines kryoskopischen Gemischs von NaOH/KOH erhält man weitgehend hydrolysierte Produkte, die bis zu 2/3 ihres Gewichts Poly‐N‐vinyl‐γ‐AMBS‐Einheiten enthalten.

Die Eigenschaften dieser neuen Polyampholyte werden kurz charakterisiert.