bluuebunny/crossref_metadata_2025 huggingface dataset:
Zur Natur der durch katalytische Mengen von N,N,N′,N′‐Tetramethyläuthylendiamin in Organolithium/Isopren Systemen bedingten Effekte
Authors: Davidjan Asya , Nikolaew Nikolai , Sgonnik Vladimir , Belenkii Boris , Nesterow Vladimir , Erussalimsky Boris
Published: April 2003

N,N,N′,N′‐Tetramethyläthylendiamin (TMD) ruft in den Systemen Organolithium (RLi)/Isopren schon beim Molverhältnis [TMD]/[RLi]≈1 eine beträchtliche Zunahme der Polymerisationsgeschwindigkeit und bevorzugte Bildung von 3,4‐Kettengliedern in den Polymeren hervor. Um die Natur dieser Effekte zu klären, wurden Fraktionen der Polymeren untersucht, die sich beim parallelen Verlauf der Wachstumsreaktion an RLi‐Agenzien und deren Komplexen mit TMD bilden, was durch die Wahl des Verhältnisses [TMD]/[RLi]=0,01 erreicht wurde. Der höchste Gehalt an 3,4‐Gliedern in dem unter dieser Bedingung erhaltenen Polyisopren wurde für die Fraktion mit dem kleinsten Molekulargewicht festgestellt. Es wird ein möglicher Mechanismus für diese Erscheinung vorgeschlagen.
Effect of ethanol on the asymmetric synthesis catalyzed by poly(5‐benzyl L‐glutamate) and poly(4‐benzyl L‐aspartate)
Authors: Fukushima Hisao , Inoue Shohei
Published: April 2003

In the asymmetric addition of dodecanethiol (1) to isopropenyl methyl ketone (3) catalyzed by the terminal amino group of poly(5‐benzyl L‐glutamate) (PBLG) (7b) and poly(4‐benzyl L‐aspartate) (PBLA) (7a), the effect of addition of ethanol was studied. In the reaction catalyzed by PBLG, the magnitude of the optical rotation of the addition product increased without changing the sign with the addition of ethanol. In the reaction catalyzed by PBLA, on the other hand, the sign of the optical rotation of the product was inverted with the addition of ethanol. The effect of ethanol was discussed in relation to the mechanism of the reaction as well as the conformation of the polymeric catalyst.
Radical polymerization by silyl radicals. Photopolymerization of styrene by bis(trimethylsilyl)mercury
Authors: Ikeda Hisayoshi , Miura Yozo , Kinoshita Masayoshi
Published: April 2003

The photopolymerization of styrene (St) by bis(trimethylsilyl)mercury (1) was studied. Kinetic studies indicated that the rate of polymerization can be expressed by the following equation:

IR and NMR spectra of the polymer indicated that trimethylsilyl groups were incorporated. By reaction of 1 with an equimolar amount of St in benzene under UV irradiation a radical coupling product, 2,2,7,7‐tetramethyl‐4,5‐diphenyl‐2,7‐disilaoctane (2) was formed in 22% yield. By spin trapping technique using 2,4,6‐tri‐tert‐butylnitrosobenzene (3) as a trapping agent, N‐trimethylsiloxy‐2,4,6‐tri‐tert‐butylanilino radicals were obtained.

On the basis of these results, it was concluded that the polymerization was initiated by trimethylsilyl radicals formed by photodecomposition of 1.
Analyse von polystyrolharzen mit funktionellen gruppen mittels IR‐spektroskopie und pyrolyse‐gaschromatographie‐massenspektroskopie
Authors: Oehme G. , Baudisch H. , Mix H.
Published: April 2003

Styrol/Divinylbenzol‐Copolymere mit funktionellen Gruppen CH2X [XH, Cl, J, OCOCH3, OH, OC2H5, NH2, NHC2H5, N(C2H5)2, CN, C(NOH)NH2, NCS, COC2H5, (CH2)3CH3] in para‐Stellung wurden qualitativ analysiert durch die Kombination von Infrarotdaten mit den Ergebnissen von Curiepyrolyse‐Gaschromatographie‐Massenspektroskopie. In allen Beispielen war eine Strukturbestimmung durch direkte oder indirekte Aussagen mindestens einer der beiden Methoden möglich. Einige Strukturbeweise wurden durch eine “Thermolyse” bei 400°C vervollständigt.
Dégradation oxydante du polystyrène à 25°C. Origine du benzaldéhyde et de l'acétophénone
Authors: Crouzet Claude , Marchal Jean
Published: April 2003

La dégradation oxydante du polystyrène à 25°C conduit à la production de benzaldéhyde et d'acétophénone par des réactions primaires de coupure de radicaux alcoxyles. Ces radicaux alcoxyles précurseurs sont formés à température ambiante par interaction bimoléculaire non terminante des macroradicaux peroxyles tertiaires et secondaires produits par l'autoxydation du polymère. Les radicaux précurseurs du benzaldéhyde et de l'acétophénone ont été caractérisés. La réaction produisant le précurseur de l'acétophénone implique la propagation intramoléculaire de l'hydroperoxydation du polymère.
Ring opening polymerization of L‐methyl 2‐(2‐methyl‐1‐aziridinyl)acetate and its racemic stereoisomer: 13C NMR study
Authors: Samyn C. , Toppet S. , Smets G.
Published: April 2003

Poly[L(and D, L)‐N‐(methoxycarbonylmethyl)iminopropylene] (5) were synthesized by cationic polymerization of methyl 2‐(2‐methyl‐1‐aziridinyl)acetate (4) in the presence of dimethyl sulfate as initiator. The stereoregularity of the polymer obtained from the L‐aziridine 4 was determined by 13C NMR study of the L‐ and D,L‐polyesters 5. It could be shown that the opening of the aziridine ring proceeds mainly at the unsubstituted methylene carbon atom, retaining the configuration of the asymmetric carbon to at least 85%.
The introduction of chloromethyl groups into styrene‐based polymers, 1. Synthesis of 4‐chloromethylstyrene and 4‐methoxymethylstyrene and their copolymerisations with styrene
Authors: Arshady Reza , Kenner George W. , Ledwith Anthony
Published: April 2003

Details are given for the synthesis of 4‐methoxymethylstyrene (5), 4‐chloromethylstyrene (6), and their resulting polymers and copolymers with styrene and 1,4‐divinylbenzene. Conversion of the polymer‐bound methoxymethyl substituents into the corresponding chloromethyl groups is especially convenient as a means of producing resins for solid phase peptide synthesis and may be readily effected by reactions of appropriate methoxymethyl derivative with boron trichloride in CCl4 at 0°C.
Lithiation du squalène
Authors: Clouet Gilbert , Brossas Jean
Published: April 2003

Pour préciser le mécanisme de lithiation des polydiènes, le squalène (1), qui est considéré comme une molécule‐modèle de polyisopène, a été métallé à température ambiante dans l'heptane, par le complexe sec‐butyllithium‐N,N,N′,N′‐tétraméthyl éthylènediamine (sec‐BuLi‐TMEDA). L'étude des produits obtenus après désactivation des sites carbanioniques par différents agents de terminaison montre que seul le groupement méthyle est métallé et que la microstructure des produits obtenus varie avec le désactivant.
Syntheses and properties of N‐(1,3‐diisocyanato‐1‐propyl)phthalimide and its polymers
Authors: Yang Chin‐Ping , Iwakura Yoshio , Uno Keikichi , Toda Fujio
Published: April 2003

N‐(1,3‐Diisocyanato‐1‐propyl)phthalimide (5) was synthesized as a new monomer from glutamic acid (1) through N‐phthaloylglutamic acid (2), N‐phthaloylglutamoyl dichloride (3) and N‐phthaloylglutamoyl diazide (4), followed by a Curtius rearrangement. In the Curtius rearrangement, the carbonylazido group with the phthalimido group in 4‐position decomposes at 25°C, whereas the other carbonylazido group with the phthalimido group in 2‐position is stable up to 45°C. The monomer is a viscous and transparent liquid which can be purified by molecular distillation without racemization. A series of polymers, including polyureas (13a–i), polyurethanes (15a–d) and a poly(urea‐urethane) 17), were synthesized from monomer 5 and their thermal properties and solubilities were determined. It was found that all investigated polymers decompose readily between 200°C and 250°C.
Analyse von Copolymeren aus Vinylestern und Acrylestern
Authors: Aydin Oral , Schulz Rolf C.
Published: April 2003

Die Copolymeren aus Vinyl‐ und Acrylestern werden in abgeschmolzenen Ampullen durch 2 M NaOH verseift. Die aus den Vinylester‐Grundbausteinen gebildeten Säuren werden durch potentiometrische Titration bestimmt; liegen verschiedene Vinylester nebeneinander vor, so wird das Mengenverhältnis der Säuren gaschromatographisch ermittelt. Die bei der Verseifung aus den Acrylester‐Grundbausteinen entstehenden Alkohole werden gaschromatographisch identifiziert und gegen tert‐Butanol als internen Standard quantitativ bestimmt. Ein besonderer Vorteil der Methode besteht darin, daß auch wäßrige Dispersionen ohne vorherige Abtrennung des Copolymeren eingesetzt werden können.
Zur Aufklärung des Initiierungsschrittes der kationischen Polymerisation von Tetrahydrofuran mit PF5
Authors: Hoene Richard , Reichert Karl‐Heinz W.
Published: April 2003

Es wurde der Ablauf der kationischen Initiierung der ringöffnenden Polymerisation von Tetrahydrofuran (THF) mit Phosphorpentafluorid (2) im Bereich oberhalb der Ceiling‐Temperatur untersucht. Bei der Reaktion von 2 mit THF bzw. mit 2‐Methyltetrahydrofuran (MTHF) wurde qualitativ und quantitativ die Bildung von Hexafluorophosphat aus dem zunächst spontan entstehenden Donor‐Acceptor‐Komplex zwischen Ringäther und 2 nachgewiesen, die dem Induktionsschritt der THF‐Polymerisation entspricht. Als Reaktionsprodukt von 2 mit THF wurde ein Dikation, 1,1′‐Tetramethylen‐bis(tetrahydrofuranylium)‐bis(hexafluorophosphat), (6), isoliert, dessen Struktur durch Gruppenanalyse, chemische Reaktionen, 1H‐NMR und 31P‐NMR sichergestellt wurde. Dabei entstehendes POF3 wurde qualitativ nachgewiesen. Postulierte Reaktionszwischenstufen blieben unter der analytischen Nachweisschwelle. Aufgrund der Ergebnisse werden bifunktionelle Oxoniumionen als aktive Spezies der Polymerisation von THF mit 2 diskutiert, die ein bifunktionelles Kettenwachstum auslösen.
Free radical polymerization of unconjugated dienes, 15. Dependence of the composition of poly(methacrylic anhydride) on the monomer concentration
Authors: Chiantore Oscar , Camino Giovanni , Chiorino Anna , Guaita Marino
Published: April 2003

The free radical polymerization of methacrylic anhydride in chloroform solutions was investigated at different temperatures. By employing statistical analysis of the experimental data, it could be shown that in all the cases the dependence of the mole fraction of cyclic structural units on the monomer concentration, at which the polymer has been obtained, is in agreement with a kinetic relationship generally valid for the free radical cyclopolymerization of symmetrical unconjugated dienes.
Coenzyme models, 6. Addition reaction of sulfite ion to monomeric and polymeric nicotinamides. Correlation between equilibria and reaction rates
Authors: Shinkai Seiji , Kunitake Toyoki
Published: April 2003

Rate and association constants (k and K) for the addition of sulfite ions to five nicotinamides substituted at the ring nitrogen, (2a–e), and to poly(1‐(4‐vinylbenzyl)nicotinamide chloride) (poly{1‐[4‐(3‐aminocarbonylpyridiniomethyl)phenyl]ethylene chloride}) (poly(1)) were determined at 30°C in aqueous systems. It was found that the reaction parameters for the addition of SO to poly(1) are markedly enhanced (20500‐fold in the k term and 510‐fold in the K term) compared with the addition to the corresponding monomeric compound, 3‐aminocarbonyl‐1‐benzylpyridinium chloride (2d), and the enhancements are suppressed with increased ionic strengths. These enhanced reaction parameters for poly(1) are deviated to the upper area by two logarithmic units from a linear log K vs. logk relationship which holds for monomeric nicotinamides. This means that the rate constant is enhanced more effectively that the association constant in the polymeric system. Plots of log KCN− vs. log K and of log kf, CN‐ vs. log k‐ gave good linear relationships. The plot for poly(1), greatly deviated again to the upper area. The SO ion interacts with poly(1), a cationic polyelectrolyte, more strongly than the CN− ion.
Some aspects on the crystallization of cellulose
Authors: Ramesh Ravi , Patel Chiman K. , Patel Raman D.
Published: April 2003

It was endeavored to investigate some details of the effects of solvent and temperature on the crystallization behavior of cellulose. It is found, as in the case of synthetic linear polymers, that solvent and temperature do have a specific role in dictating the overall morphology of cellulose. Some hitherto unreported morphological features of cellulose are incorporated in the present paper.
The cyclo‐copolymerization of diallyl compounds and sulfur dioxide, 5. Copolymerization of some 4‐substituted 1,6‐heptadiene derivatives with sulfur dioxide
Authors: Amemiya Yasuhiro , Katayama Masamichi , Harada Susumu
Published: April 2003

Copolymers of sulfur dioxide with N‐substituted 4‐(1,6‐heptadiene‐4‐yl)pyridinium chlorides and bromides (1) and N‐substituted 4‐(3‐butenyl)pyridinium chlorides and bromides, and some other 1,6‐heptadiene derivatives 3 substituted in 4‐position were prepared. The effects of the copolymerization conditions on the conversions and viscosities of the copolymers were studied and their structures by elemental analyses, IR and 1H NMR spectroscopy. The thermal stabilities of the copolymers were also examined.
Kinetics of living radical polymerization of styrene with macromolecular initiator
Authors: Mikulášová Darina , Chrástová Viera , Citovický Pavol , Horie Kazuyuki
Published: April 2003

Kinetics of living radical polymerization of styrene in emulsion initiated by polypropylene hydroperoxide with triethylenetetramine is proposed on the basis of a two stage mechanism. In the first stage fast initiation and propagation occur on the surface of polypropylene. In the second stage continuous chain propagation without termination proceeds in polymer particles in the emulsion. Dependence of rate and degree of polymerization on reaction time, initiator and activator concentrations predicted by the kinetics are ascertained by experimental results. Each polymer particle in the emulsion is suggested to consist of one polymer molecule with a living chain end. Main requisites for the living nature of this system are probably fast and/or limited decomposition and heterogeneity of the initiator in the emulsion polymerization.
Effect of pressure on the propagation and termination rate constants of radical polymerization
Authors: Ogo Yoshiaki , Yokawa Masaru
Published: April 2003

The effect of high pressure on the propagating and terminating steps of free‐radical polymerization was summarized from our experimental data which were already described on the six polymerization systems: styrene, methyl methacrylate, butyl methacrylate, butyl acrylate, vinyl acetate, and octyl methacrylate. Using these data, the functional dependence of the rate constants for individual steps on pressure was investigated with a view to obtaining reliable values under high pressure. In practice, a linear function is the best description of the pressure dependence of the logarithmic propagation rate constant regardless of the polymerization type. It can be concluded, therefore, that the activation volume can be used as a pressure‐independent parameter for the propagating step in our pressure range (1–1000 bar). The empirical relation to estimate the pressure dependence of the propagating step for other polymerization systems was obtained from the correlation for the activation volumes and the volume contractions of polymerization. The effect of pressure on the termination step is also discussed. A quadratic polynomial is generally the best representation of the pressure dependence of the logarithmic termination rate constant.
Zur strukturbestimmung des 1,4‐poly(2,3‐dimethyl‐1,3‐butadien)s durch 13C NMR‐spektroskopie
Authors: Ritter Wolfgang , Elgert Karl‐Friedrich , Cantow Hans‐Joachim
Published: April 2003

cis and trans Configuration of monomeric units in 1,4‐poly(2,3‐dimethyl‐1,3‐butadiene), poly(1,2‐dimethyl‐1‐butenylene), has been determined by 13C NMR spectroscopy.
Ceric ion‐initiated polymerization of acrylonitrile in the presence of polyols
Authors: Rout Anuradha , Rout Swoyam P. , Singh Baishnab C. , Santappa M.
Published: April 2003

The polymerization of acrylonitrile was studied in aqueous sulfuric acid with the redox initiator system, ceric ammonium sulfate/glycerol at 15–25°C. The initiation was effected by the ceric ion and the radical produced from the reaction of Ce4+ with glycerol. At lower concentrations of Ce4+, the rate of monomer disappearance was proportional to [M]1,5, [G]0,5, and [Ce4+]0,5, and the rate of ceric ion disappearance was directly proportional to [Ce4+] and [G]. The results were explained by a kinetic scheme involving the oxidation of substrate by Ce4+ to give the primary radical and further reaction of the latter with Ce4+ to give the final product, and initiation of polymerization both by Ce4+ and the primary radical. The initiation by Ce4+ was found to be negligible as compared to that by the primary radical. The termination step is postulated to be mutual at lower concentrations of Ce4+ and linear at higher concentrations of Ce4+. The induction period and the rate of polymerization was compared with those of other polyol systems, such as sorbitol and mannitol.
High electric field birefringence and association modes of poly‐γ‐benzyl‐L‐glutamate solutions
Authors: Pyżuk Wiesław , Krupkowski Teodor
Published: April 2003

The Kerr constants of poly‐γ‐benzyl‐L‐glutamate, (poly[imino‐1‐(2‐benzyloxycarbonylethyl)‐2‐oxoethylene]), (PBLG), solutions in several solvents were measured as functions of the molecular weight of PBLG and electric field intensity. The results were interpreted in terms of association modes of PBLG.
The persistence of birefringence of polyethylene above its melting temperature
Authors: Czornyj George , Wunderlich Bernhard
Published: April 2003

It has long been known that polyethylene shish‐kebob crystals show birefringence which can persist up to 150°C or higher, while the equilibrium melting temperature is 141,4°C. Birefringence in macromolecules may be due to crystallinity or to orientation in the amorphous state. By carrying out parallel birefringence and heat of fusion measurements it is shown that polyethylene shish‐kebob crystals are metastable and have a zero entropy production melting temperature of 134–135°C. Their melting region is shifted to higher temperature due to effects of orientation in the amorphous portions of partially crystallized molecules.
Copolymerization of N‐vinyl‐ε‐caprolactam with maleic anhydride
Authors: Boghină Constantin
Published: April 2003

The copolymerization of N‐vinyl‐ε‐caprolactam (VCL) with maleic anhydride (MA) in homogeneous solution of N,N‐dimethylformamide at 70°C, initiated by benzoyl peroxide, is studied. VCL and MA form a 1:1 charge‐transfer complex which is confirmed by spectroscopic analysis. The complex is decisive in the copolymerization reaction and has an equilibrium constant of 0,2 l/mol. The reactivity ratios of the VCL‐MA pair are determined as follows:
Die Wärmekapazität von vollständig kristallinen Copolymeren des Polyoxymethylens
Authors: Dröscher Michael
Published: April 2003

The molar heat capacity of fully crystalline copolymers of trioxane and 1,3‐dioxolane can be discribed by the equation Cp(x2, T) = 36,75 + 0,1425 (t2 − 25) + 80 x2 in the temperature range 25°C < t < 140°C and at mole fraction of oxyethylene units x2 < 0,16. For x2 < 0,1 the molar heat capacity depends linearly on the reduced temperature T/Tm(x2), but is independent from counit content.
Polymere 3‐acryloyloxyalkyl‐ und 3‐acryloyloxyaryl‐4‐thiazolidone als strahlenschutzsubstanzen
Authors: Montoya Rolando , Schmidt Eckhard , Soto Jorge , Lüderwald Ingo
Published: April 2003

The syntheses of 3‐acryloyloxyalkyl‐ and 3‐acryloyloxyaryl‐2‐phenyl‐4‐thiazolidones (3a–c) from the corresponding hydroxyl derivatives 2a–c and acrylic acid chloride are described. These monomers were homopolymerized and copolymerized with N‐vinyl‐2‐pyrrolidone by radical initiation. The resulting water soluble copolymers were tested in animals for radioprotective activity and prolongation of efficiency.
Réactions primaires de dégradation oxydante au cours de l'autoxydation du poly(oxytétraméthylène) à 25°C, 3 Cinétique de la production des coupures statistiques et caractérisation de la réaction bimoléculaire non terminante des radicaux peroxyles secondaires
Authors: Thomassin Claude , Marchal Jean
Published: April 2003

The kinetics of the production of random chain scissions by oxidative degradation of poly(oxytetramethylene) was determined during the radiation‐induced autoxidation of solutions of the polymer in chloroform at 25°C. Ethylene oxide resulting from autoxidation of ethylene produced by unimolecular decomposition of alkoxy‐1 alkylperoxy radicals partly inhibits the chain scission. This property allowed the characterization of the existence of a second primary mechanism of oxidative degradation of the polymer as non‐terminating bimolecular reaction of these peroxy radicals followed by a ß‐scission of the produced alkoxy radicals.
Nebenreaktionen der radikalisch ausgelösten cyclisierung von 2,2′‐methylen‐bis(4‐methyl‐1,2‐phenylen)‐dimethacrylat
Authors: Kämmerer Hermann , Pachta Jiri
Published: April 2003

2,2′‐Methylene‐bis(4‐methyl‐1,2‐phenylene) dimethacrylate (1) was reacted with an excess of 2,2′‐azoiso‐butyronitrile (mole ratio 1:15) highly diluted in boiling benzene. The reaction products were separated by column chromatography. It was found that the 1‐cyano‐1‐methylethyl radical induced the cyclization of 1 to yield the product of a head to tail addition (2) in 55% yield. In addition, the product of a head to head addition (3) was isolated in 4% yield. 35% of 1 reacted in the same way as it has already been observed as suppression of polymerization in the case of p‐tolyl methacrylate to give the products 4 and 5. The structures of the products were confirmed by elemental analyses, by IR‐UV‐, 1H NMR‐ and mass‐spectra as well as by the determination of their relative molecular masses and by quantitative hydrogenations.
Polymer modification and synthesis using sulfenyl derivatives, 5. Adducts with cis‐1,4‐polybutadiene
Authors: Brydon Albert , Cameron G. Gordon , Muir Robert B.
Published: April 2003

cis‐1,4‐Polybutadiene (PBD) was reacted with a number of sulfenyl derivatives to produce adducts of varying degrees of saturation. The glass transition temperature (Tg) of the modified polymer increases with extent of reaction with p‐toluenesulfenyl chloride (1c) and 2‐nitrobenzenesulfenyl benzoate (2a). DSC traces indicate a “blocky” structure in adducts of 1c but not of 2a. The tensile strengths at break of the adducts of 1c show a progressive increase with increasing degree of saturation.
Osmotic coefficients of aqueous polyelectrolyte solutions at low concentrations, 4. Modified cylindrical cell model and its application
Authors: Oman Srečko , Bratko Dušan
Published: April 2003

A modified rodlike model of linear polyelectrolytes is described and the calculated osmotic coefficients are presented as a function of the degree of polymerization of polyions. A comparision with experimental data is included and rather good agreement with theory is found at concentrations above 5.10−3 basemol/l. The concentration dependence of the properties of diluted polyelectrolyte solutions is discussed.
Photoconductivities of poly[γ‐(β‐N‐carbazolylethyl)‐L‐glutamate] and its charge‐transfer complex with 2,4,7‐trinitrofluorenone
Authors: Tanikawa Kiyoshi , Okuno Zenjiro , Iwaoka Takehiko , Hatano Masahiro
Published: April 2003

Poly[γ‐(β‐N‐carbazolylethyl)‐L‐glutamate] (PCLG) was prepared by polymerizing the monomer which was synthesized by adapting the NCA method to a reaction product between L‐glutamic acid and N‐(β‐hydroxyethyl)carbazole. PCLG films were prepared on a quartz Nesa (In2O3) plate by casting technique. The charge‐transfer complex could be successfully formed only near the surface of the PCLG film by immersing the PCLG film into either a benzene or a methyl ethyl ketone solution of 2,4,7‐trinitrofluorenone (TNF), since both benzene and methyl ethyl ketone were poor solvents for PCLG and suitable solvents for TNF. A photocell was formed by depositing a translucent gold electrode with vaccum evaporation onto the immersed film. For a small content of TNF in both the immersed films and the homogeneously mixed films of PCLG with TNF, the photocurrent of PCLG was successfully sensitized by TNF, but the sensitized photocurrents retained the relation I>I in a similar way as the photocurrent of PCLG alone, where I was the photocurrent under illumination onto the positive Au electrode and vice versa. On the other hand, as the TNF content increased, I became remarkably greater than I. The PCLG polymer, therefore, can behave as a p‐type photoconductor, while the well‐doped PCLG‐TNF complex can behave as an n‐type photoconductor.
Sequence distribution of 1,4‐polybutadienes
Authors: Tanaka Yasuyuki , Sato Hisaya , Hatada Koichi , Terawaki Yoshio , Okuda Hiroshi
Published: April 2003

The spin‐decoupled 1H NMR and 13C NMR methods were presented for the determination of the cis‐trans sequence distribution in polybutadiene. Poly(butadiene‐2,3‐d2) and cis‐trans isomerized polybutadienes were used for the peak assignment and the resonance of methylene protons in cis‐trans linkage could be described as an A2B2 system. The dyad and triad sequence distributions of cis‐1,4 and trans‐1,4 units were determined for isomerized, equibinary and lithium catalyzed polybutadienes, and polycyclooctadienes. The accuracy of the measurements was also studied comparing the results with those by infrared method.
Simultaneous anodic and cathodic polymerizations of acrylamide
Authors: Bhadani Suraj N. , Prasad Yugal K.
Published: April 2003

The electrolysis of acrylamide in sodium nitrate/N,N‐dimethylformamide solutions leads to polymer formations simultaneously in the anode and cathode compartments. The influences of monomer concentrations, current levels, nature of some electrode metals and supporting electrolytes on polymerization were examined. Anodic polymers of high molecular weights were obtained (ca. 105). The current‐voltage curves and other experimental findings strongly suggest that the direct reduction of acrylamide at the cathode leads to the cathodic polymerization which is like the polymerization by anionic initiators in which the monomer gives a polymer of amide structure via a hydrogen transfer process. On the other hand, the anodic polymerization is possibly initiated by the species produced by the anodic reaction of the supporting electrolyte and is analogous to the free‐radical polymerization of acrylamide. Infrared spectra of the polymers show that the cathodic polymer is a polyamide \documentclass{article}\pagestyle{empty}\begin{document}$ \left( { \ldots \hbox{---} {\rm CH}_{\rm 2} \hbox{---} {\rm CH}_{\rm 2} \hbox{---} {\rm CO}\hbox{---} {\rm NH}\hbox{---} \ldots } \right) $\end{document} whereas the anodic has a CC chain structure \documentclass{article}\pagestyle{empty}\begin{document}$ \left( { \ldots \hbox{---} {\rm CH}_{\rm 2} \hbox{---} {\rm CH}\left( {{\rm CONH}_{\rm 2} } \right)\hbox{---} \ldots } \right) $\end{document}.
Thermal resistance of crosslinked and substituted poly(phenylene sulfide)s
Authors: Hortling Bo
Published: April 2003

Crosslinked and substituted poly(phenylene sulfide)s, prepared by reacting p‐chlorosubstituted benzenes with sulfur, were investigated by TG in air. Using the difference method and an assumed first‐order calculation, the reaction order, activation energy and frequency factor were determined. The pyrolyses were carried out under nitrogen and in the presence of 5% oxygen. The IR spectra and the sulfur contents of the polymers and pyrolysis products were determined. The highest activation energies were found for unsubstituted polymers. Linear poly(phenylene sulfide) has the best thermal stability, but also the other polymers show rather good stabilities up to 400–500°C. The IR spectra and sulfur‐contents of the pyrolysis products suggest stable, condensed, and sulfur containing aromatic intermediates formed during the degradations. The obtained polymers can be manufactured over large temperature ranges by common techniques.
Kettenübertragung durch tetrabromkohlenstoff bei der polymerisation von styrol und von vinylacetat
Authors: Gleixner Günther , Breitenbach Johann Wolfgang , Olaj Oskar Friedrich
Published: April 2003

The constant of chain transfer to carbon tetrabromide in the polymerization of styrene has been redetermined by directly measuring the consumption of the chain transfer agent using a GC‐technique and simultaneously evaluating the conversion of monomer to polymer. Values of 250 (at 60°C) and 185 (at 95°C) have been obtained by this method. These values agree in order of magnitude with those recently obtained by Thomson and Walters from the determination of polymer molecular weights and, accordingly, exceed the values previously reported by approximately two powers of ten. An analysis of the limiting viscosity numbers of the polymers prepared in presence of carbon tetrabromide shows an excellent agreement with these new high values of the chain transfer constant of carbon tetrabromide. For the constant of chain transfer to carbon tetrabromide in the polymerization of vinyl acetate a value of 6·103 has been obtained at 60°C, which again is two to three orders of magnitude higher than those values given previously.
Photochimie de la polyacrylophénone en solution, 1. Cinétique de transfert d'énergie triplet‐triplet
Authors: Salvin Roger , Meybeck Jean , Faure Jean
Published: April 2003

The kinetics of triplet‐triplet energy transfer is studied in fluid solution with polyacrylophenone, (poly(1‐benzoylethylene)), (PAP) as the energy donor and 1‐methylnaphthalene (MeN) as quencher. The rate constant of quenching Kq is obtained from the Stern‐Volmer constant Kqτ for the inhibition of main chain scission in PAP, the lifetime τ of the excited state being measured by picosecond laser photolysis. Kq does not verify the scheme of a diffusion controlled reaction generally applied for small molecule as valerophenone. We proposed a kinetic scheme based on the Voltz theory of energy migration where a migration term Ω of the excitation energy in PAP adds to the material diffusion of MeN. The good agreement obtained for the value of Ω determined by extrapolation at infinite viscosity of solvent, where the material diffusion is negligible, supports our hypothesis of energy migration in PAP at room temperature.
Étude de la solvatation préférentielle des poly(méthacrylates de méthyle) dans quelques mélanges de solvants
Authors: Katime Issa , Strazielle Claude
Published: April 2003

The behavior of some poly(methyl methacrylate)s in solvent‐mixtures (benzene‐methanol, carbone tetrachloride‐methanol and dioxane‐methanol) was investigated. The dependence of microstructure and molecular weight of the polymer on the preferential solvation was determined. The existence of a conformational transition for syndiotactic poly(methyl methacrylate) in dioxane and in dioxane‐methanol could be shown.
Notes on the determination of unperturbed dimensions of stiff chain polymers by hydrodynamic methods
Authors: Kovář Josef , Fortelný Ivan , Bohdanecký Miloslav
Published: April 2003

An analysis was carried out of the possibilities provided by the Yamakawa‐Fujii theory of the hydrodynamic properties of polymer solutions for the determination of the structure parameters (especially of unperturbed dimensions) of polymers with stiff chains. Conditions for using the plots M/[η] vs. M1/2 and M/[f] vs. M1/2 for the given purpose were defined. The occurrence of a minimum in the former plot observed for ladder polymers was explained. The confrontation of the results of the analysis with hydrodynamic data for polychlorophenylsilasesquioxane and polyphenylsilasesquioxane indicate a branched structure of these ladder polymers.
1H NMR and2D NMR relaxation and wide line measurements in partially deuterated polystyrenes
Authors: Willenberg Bernd , Sillescu Hans
Published: April 2003

Solutions of chain‐ (PS‐d3) and phenyl ring (PS‐d5) deuterated polystyrenes in perdeuterated PS‐d8have been investigated with1H and2D NMR relaxation and wide line methods. The intra‐ and intermolecular parts of the1H second moments at −100°C are 3,7 G2and 2,0 G2, respectively, for PS‐d3, and 14,7 G2and ca. 0 G2, respectively, for PS‐d5. The intermolecular contribution to the1H spin lattice relaxation rate, determined at 55 MHz between 150°C and 250°C, is about one third of the total rate in PS‐d3, and negligible in PS‐d5. We suggest that this contribution is caused by rotational fluctuations of the intermolecular H ⃛H vectors. The intramolecular1H‐ and2D‐relaxation rates indicate that the phenyl group motion is somewhat faster than the rotational segmental motion of the polymer chain.
Solution properties of poly(butyl methacrylate‐co‐acrylonitrile)
Authors: Arulsamy S. M. , Santappa M.
Published: April 2003

Poly(buty1 methacrylate‐co‐acrylonitrile) of 1 : 1 molar composition has been prepared by bulk polymerization process using 2,2′ ‐azoisobutyronitrile (AIBN) as the initiator and fractionated using ethyl methyl ketone and methanol as the solvent and the precipitant respectively. The identical value of the refractive index increments (dn/dc) of these fractions indicated their homogeneity in chemical composition. The dilute solution properties of these fractions in N,N‐dimethylformamide (DMF), ethyl methyl ketone (MEK), and acetone have been investigated employing light‐scattering, osmometry and viscometry techniques. The following Mark‐Houwink relationships have been established at 25°C:

The unperturbed dimensions for the copolymer have been evaluated and compared with those for the constituting homopolymers. A solvent dependence of the unperturbed dimension has been observed. The steric factor, σ, was found to be 2,64 in DMF and 2,48 in MEK for poly(buty1 methacrylate‐co‐acrylonitrile) compared to a value of 2,20 for poly(acrylonitri1e) in DMF, and 2,09 for poly(buty1 methacrylate) in MEK which suggests the greater stiffness of the copolymeric chain compared to the constituting homopol ymers.
Chelatbildung von 5‐methyl‐5‐hexen‐2,4‐dion/styrol‐copolymeren in lösung und an metallischen oberflächen
Authors: Brito Heide , Brito Victor , Springer Jürgen
Published: April 2003

The preparation and characterization (analyses of IR and mass spectra) of 5‐methyl‐5‐hexen‐2,4‐dione (1) and its polymerization and copolymerization with styrene are described. Poly(1) and copolymers from 1 and styrene give metal chelates in solution and on metal surfaces. Copolymers of 1 and styrene increase the adhesion and the resistance against corrosion of varnishes for metals on the basis of melamine.
1,3‐Bis(1‐phenylvinyl)benzene and its reactions with electron transfer reagents
Authors: Schulz Günther G. H. , Höcker Hartwig
Published: April 2003

The investigation of electron transfer and subsequent reactions of divinylidene compounds not capable of anionic homopolymerization was extended to 1,3‐bis(1‐phenylvinyl)benzene (2). A new method for the preparation of this compound is described. Its reaction with Li, Na, and K as electron transfer reagents in THF as solvent results in an increasing yield in polymeric combination products of the radical anions formed primarily with increasing reducing power of the alkali metal.

The main product, however, in any case is the cyclic dimeric tetra‐anion of 2, which upon protonation yields 1,4,11,14‐tetraphenyl[4.4]metacyclophane (3).
The electro‐initiated cationic polymerization of indene, 2. Kinetics of polymerization
Authors: Bhadani Suraj N. , Baranwal Panchdeo P.
Published: April 2003

The electrolytically initiated anodic polymerization of indene in the solutions of tetraethylammonium hexachloroantimonate and tetrabutylammonium perchlorate in nitrobenzene under constant electric current and constant potential electrolysis conditions was studied. The polymerization was followed either under continuous electrolysis or by addition of the monomer to the pre‐electrolysed solution of the salt. The monomer consumption follows the first‐order rate‐law, log[M]0/[M]t=kt, and the rate constant of the polymerization increases with increasing current level. The polymer formation was greatly affected by the change of the dielectric constant of the medium, the anode material, and the nature of the supporting electrolyte. The mode of initiation process depends upon the type of the salt. Mechanisms for the initiation reaction were elucidated.
Koagulation unlöslicher, gefällter polymermoleküle, grundlagen der trübungstitration
Authors: Hoffmann Martin , Urban Heinrich
Published: April 2003

After the precipìtation of polymer from a solution of concentrationcthe light scattering intensityR0(in the direction of the primary beam) usually does not reach a constant value but is equal tokc2t,tbeing the time since precipitation. The constantkdoes not depend on molecular weightM(104<M<106) and is proportional to 1/η1, η1being the viscosity of the dispersing medium. Various polymers with refractive index incrementsvihave nearly the same value ofk/v. Furthermore long chain branching or intramolecular crosslinks do not influence this value. These results prove that the coagulation of polymers is controlled by diffusion (theory of coagulation bySmoluchowski).

Coagulation and coalescence are retarded if the polymer molecules are able to associate or to crystallise. They stop at low particle weights if the particles are hard or if they carry about 10 electric elementary charges per particle.

During turbidimetric titrations freshly precipitated molecules are quickly adsorbed by the existing particles, thus increasing mainly the number average particle weight. If this increase in turbidity is small compared to that resulting from the coagulation of particles, the increase ofR0·V/V0with logVis proportional to the square of the concentration of all the precipitated molecules during titrations of chemically equal molecules. (Vis the volume of the titrated solution.) From titration curves one may thus derive the distributions of solubilities and molecular weights. Similar evaluations give the distribution of chemical compositions, if polymers with nearly equal molecular weights are titrated (GPC‐eluates).
Thermal decomposition of γ‐ray irradiated poly(vinylidene fluoride) and the copolymer of vinylidene difluoride with vinyl fluoride
Authors: Hagiwara Miyuki , Ellinghorst Guido , Hummel Dieter O.
Published: April 2003

The thermal decomposition of γ‐irradiated poly(vinylidene flouride) and the copolymer of vinylidene difluoride and vinyl fluoride has been investigated by means of thermogravimetry (TG), differential thermal analysis (DTA) and mass spectral analysis of the evolved gas. Under non‐isothermal conditions (heating rate = 2 K min−1), polymers were found to lose their weight in two stages. The main process of the weight loss was the splitting‐off of HF. Various aromatic compounds containing F were also observed to evolve, although their contribution to the total weight loss was small. For the volatilization reaction occurring at high temperature, initiation through random chain scission was suggested. Kinetical analysis of TG traces for the volatilization showed that the apparent overall activation energy decreases with increasing dose.
Studies on chitin, 4. Evidence for formation of block and random copolymers of N‐acetyl‐D‐glucosamine and D‐glucosamine by hetero‐ and homogeneous hydrolyses
Authors: Kurita Keisuke , Sannan Takanori , Iwakura Yoshio
Published: April 2003

Chitin was deacetylated by heterogeneous and homogeneous alkaline hydrolyses. In the heterogeneous hydrolysis, upper limits in the degree of deacetylation were found to exist at low reaction temperatures. The products obtained were all insoluble in water and those with a degree of deacetylation up to 80% retained some crystallinity. These results seemed to indicate that the deacetylation under the heterogeneous conditions proceeded preferentially in the amorphous region to give block‐type copolymers of N‐acetyle‐D‐glucosamine and D‐glucosamine units. In the homogeneous hydrolysis, on the other hand, all the products with a degree of deacetylation of ca. 50% were found to be soluble in water independent of the hydrolysis temperature. The crystallinity of the products decreased much more rapidly and samples with a degree of deacetylation >40% were amorphous. These results suggested that the deacetylation under homogeneous conditions proceeded randomly to give the random‐type copolymers of the two units. This randomness was concluded to have brought about the interesting water‐solubility of products with a degree of deacetylation of ca. 50%.
Herstellung und eigenschaften von polyacenaphthylen, 1. Die darstellung von oligoacenaphthylene mit funktionellen endgruppen
Authors: Springer Jürgen , Win Tin
Published: April 2003

Experiments regarding the anionic polymerization of acenaphthylene with different initiators (lithiumnaphthalene complex, 1,2‐diphenylethylenedilithium, 1,1,4,4‐tetraphenyltetramethylenedilithium and butyllithium) and solvents (tetrahydrofuran and benzene) show that only short chain (P̄≈ 20) and coloured polymers with broad molecular weight distribution are obtained, because of chain transfer reactions to the monomer. A mechanism of this polymerization is proposed. By radical polymerization short chain polyacenaphthylene with definite end groups can be obtained.
Laccase‐catalyzed polymerization of urushiol in precisely confined Japanese lacquer system
Authors: Kumanotani Ju
Published: April 2003

Japanese lacquer is a sole, enzymatically drying natural lacquer, giving films with excellent durability. Oligomerization of urushiol (1) (a major component of the lacquer) in the lacquer system was reviewed. The enzymic formation of the urushiol‐quinone (3) from urushiol was studied by laccase‐catalyzed reactions with pyrocatechols. On the basis of the separated urushiol dimers in both the lacquer and model reaction systems, a nonenzymatic CC and CO coupling reaction of the urushiol‐quinone with the unsaturated chain or with the nucleus of urushiol is discussed as significant reaction path in the polymerization of Japanes lacquer. The films of the lacquer made by a mild oxidation process, a technique applied for so long time in practice, retained their dynamechanical properties completely over 16 years.
Zur struktur der produkte der reaktion von 2‐cyano‐2‐propylradikalen mit 1,4‐benzochinon
Authors: Gleixner Günther , Breitenbach Johann Wolfgang , Olaj Oskar Friedrich
Published: April 2003

The products of the reaction of 2‐cyano‐2‐propyl radicals with 1,4‐benzoquinone in toluene solution have been investigated by 1H NMR spectroscopy and mass spectroscopy. In agreement with the findings of Bickel and Waters the main reaction products are the hydroquinone monoether 1 and the hydroquinone diether 2. In addition two ringsubstituted products, 5 and 6, have been obtained. The structures 3 and 4, which have been proposed for the main products by Yassin and Rizk, are shown to be in error.
Synthèse et réactions photochimiques d'homopolymères et de copolymères de la p‐vinylbenzophénone et du vinylferrocène
Authors: Sánchez Germán , Weill Gilbert , Knoesel Roger
Published: April 2003

Poly(p‐vinylbenzophenone), (poly[1‐(4‐benzoylphenyl)ethylene]), (PVB) has been synthesized for the first time directly from its monomer p‐vinylbenzophenone (VB) the preparation of which was improved. In a second step, copolymers containing blocks of photosensitive VB units separated by isolated quenching vinylferrocene (VF) units have been prepared. PVB and the VB‐VF copolymers were irradiated in the presence of isopropyl alcohol in benzene solutions. The benzophenone groups inserted in these macromolecular chains obey the same reaction scheme as the photoreduction of the small molecule of benzophenone. However, recombination of the radicals located along the polymeric chain leads to intra‐ and intermolecular reactions changing drastically the macromolecular morphology by the formation of cycles and networks and by chain scissions. The quantum yields of the photochemical transformations were measured, but they could not be related quantitatively to morphological parameters. In all cases the ferrocene group inhibits strongly the photochemical reaction.
Electron spin resonance study of polymer degradation, 2. Photolysis at 365 nm of polystyrene containing benzophenone
Authors: David Christiane , Piret Willy , Sakaguchi Masato , Geuskens Georges
Published: April 2003

Polystyrene containing benzophenone, present either as an additive or linked to the polymer chain has been irradiated at 365 nm at room temperature and the ESR spectra were analyzed. When benzophenone is linked to the chain, equal proportions of the “ketyl macroradical” 2 and of the “polystyryl radical” 3 resulting from abstraction of the tertiary H‐atom of the styrene unit are detected. These decay on warming the sample and at 410K only about 20% of the ketyl radicals is still present. Very fast radical decay occurs at room temperature on addition of oxygen to samples where radicals 2 and 3 are trapped as pairs. In samples annealed at 410K, the isolated ketyl radicals decay slowlier by second order kinetics under the same conditions. If benzophenone is present as an additive, only a small amount of isolated polystyryl radical 3 is trapped at room temperature since most of the polymer radicals have reacted with the mobile ketyl radicals. These isolated radicals 3 decay by second order kinetics on addition of oxygen.
Polymere hydrochinoncarbonamide. Darstellung von redoxharzen auf der basis von N‐(3‐vinylphenyl)‐2,5‐dihydroxy‐4‐methylbenzamid bzw. N‐(2,5‐dihydroxy‐4‐methylphenyl)‐4‐vinylbenzamid
Authors: Manecke Georg , Krämer Andreas , Wehr Gregor
Published: April 2003

N‐(3‐Vinylphenyl)‐2,5‐dimethoxy‐4‐methylbenzamide (3) was synthesized. By copolymerization of 3 and of N‐(2,5‐dimethoxy‐4‐methylphenyl)‐4‐vinylbenzamide, respectively, with 4‐vinylpyridine and 1,4‐divinylbenzene protected redox resins were obtained. By removal of the protective groups the corresponding free redox resins were obtained. Their chemical stability and redox capacities were investigated. The influence of the anilinocarbonyl group on the midpoint potential of the hydroquinone/quinone system was studied on the model compound N‐phenyl‐2,5‐dihydroxy‐4‐methylbenzamide.
Synthesis and activity of a polymer which contains insulin covalently bound on a copolymer of N‐(2‐hydroxypropyl)methacrylamide and N‐methacryloyldiglycyl p‐nitrophenyl ester
Authors: Chytrý Vladimír , Vrána Antonín , Kopeček Jindřich
Published: April 2003

Insulin bound on a polymer carrier has been prepared by a reaction of insulin with the copolymer of N‐(2‐hydroxypropyl)methacrylamide and N‐methacryloyldiglycyl p‐nitrophenyl ester. The product isolated by gel chromatography contains ca. 60 wt.‐% of insulin. It preserves ca. 10% of the radioimmunoreactivity of the starting insulin, and in biological tests exhibits a slowed‐down onset and a slight prolongation of the hypoglycaemic effect.
Strukturuntersuchung von polyestern durch direkten abbau im massenspektrometer, 3. Poly‐β‐propiolacton, poly‐β‐pivalolacton und poly‐δ‐valerolacton
Authors: Kricheldorf Hans R. , Lüderwald Ingo
Published: April 2003

Poly(oxycarbonylethylene) (poly‐β‐propiolactone), poly(oxycarbonyl‐1,1‐dimeothylethylene) (poly‐β‐pivalolactone), and poly(oxycarbonyltetramethylene) (poly‐δ‐valerolactone) were pyrolyzed directly in the ion source of a mass spectrometer and their thermal and electron impact induced degradation mechanisms are established. Poly‐β‐propiolactone is thermally degraded by rupture of the OCH2‐bond by a cis elimination to give carboxyl and acryloyl endgroups, whereas poly‐δ‐valerolactone depolymerizes to δ‐valerolactone. Poly‐β‐pivalolactone degrades thermally to cyclic oligomers of pivalolactone, which could be proved by a separated pyrolysis and IR‐spectroscopy and gel chromatography.