bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mischkristalle aus Oligo(1,4‐phenylenisopropyliden)en und Cyclohexanderivaten
Authors: Krimm Heinrich 
Published: April 2003

AbstractAusgehend von 2‐Chlor‐2‐propylbenzol bzw. 1,4‐Bis(2‐chlor‐2‐propyl)benzol (7) wurden durch Friedel‐Crafts‐Reaktionen drei Reihen oligomerer 1,4‐Phenylenisopropylidene (4, 5 und 6) hergestellt. Von unterschiedlichen Kettenlängen an bilden diese Kohlenwasserstoffe mit Cyclohexanderivaten wie Cyclohexan, Cyclohexanon oder Cyclohexanol kristallisierte Addukte. Durch thermische Analyse der binären Gemische einzelner Verbindungstypen wurde der Mischkristallcharakter der Addukte bewiesen. Die bisher gültige Formulierung der Bildungsbedingungen für Mischkristalle wurde erweitert.
The microtacticity of poly(acrylic esters)
Authors: Matsuzaki Kei , Uryu Toshiyuki , Kanai Taiichi , Hosonuma Kunihiko , Matsubara Tetsuyuki , Tachikawa Hiromichi , Yamada Masai , Okuzono Shuichi 
Published: April 2003

AbstractSeveral acrylic esters were polymerized with radical and anionic initiators and the stereoregularity of the polymers was determined. The radical polymerization of tert‐butyl acrylate gave syndiotactic‐rich polymers at low temperatures as did isopropyl and trimethylsilyl acrylates. A radically obtained polymer of triphenylmethyl acrylate was atactic in contrast to poly(triphenylmethyl methacrylate). In the anionic polymerization with phenylmagnesium bromide or butyllithium as catalyst, the stereoregularity of the polymers was governed by the coordination of the catalyst which depends on the polarity and bulkiness of ester groups, the polarity of solvents, and the temperature in the polymerization.
New catalysts for the oxidative polymerization of 2,6‐dimethylphenol, 3. Copper(I) cluster complexes
Authors: Yoshimura Tamotsu , Storck Winfried , Manecke Georg 
Published: April 2003

AbstractThe catalytic activities of various copper(I) clusters in the oxidation of 2,6‐dimethylphenol (XOH) in pyridine and the preparative oxidative polymerization of XOH with these complexes were investigated. It was found that the copper(I) cluster containing 1,2‐dicyano‐1,2‐ethenedithiolate ligands is more effective in the oxidative polymerization of XOH than the complex containing isomeric ligands. The electric conductivities of these Cu(I) complexes are small.
Synthesis and characterization of some poly[nitrilo‐bis(phenylamino)phosphoranetriyl]s
Authors: Busulini Loris , Osellame Mirko , Lora Silvano , Pezzin Giovanni 
Published: April 2003

AbstractPoly[nitrilo‐bis(phenylamino)phosphoranetriyl]s (3a–d) were synthesized and characterized in dilute solution and in the solid state. The synthesis was accomplished by thermal polymerization of of 2,2,4,4,6,6‐hexachloro‐‐triazatriphosphorane (1) at 240°C, followed by the reaction of the soluble product, poly(nitrilodichlorophosphoranetriyl) (2), with aniline or its derivatives. Elemental analyses show the presence of some residual chlorine, which, according to the IR spectra, does not seem to be ascribed to an incomplete substitution. All the polymers have intrinsic viscosities in tetrahydrofuran higher than 100ml g−1, and high weight average molecular weights (Mw ≥ 7 · 105). The molecular weight distribution is very broad (Mw/Mn ≥ 13,4) which could suggest either a branched structure or a complex mechanism of polymerization. From DSC measurements the glass transition temperatures are found to be between 70 and 98°C and the related values of specific heat increments, ΔC,p, are between 0,13 J g−1 K−1 and 0,27 J g−1 K−1; the densities are in the order of 1,3 g ml−1.
Polymerization of propylene with tetrabenzylzirconium
Authors: Soga Kazuo , Izumi Katsuyuki , Ikeda Sakuji , Keii Tominaga 
Published: April 2003

AbstractTetrabenzylzirconium (ZrBz4) was synthesized and used as catalyst for the polymerization of propylene in toluene in the temperature range from 0°C to 65°C. The isotacticity of the produced polymer was analysed (by IR and NMR spectroscopy) as well as the molecular weight distribution (by gel permeation chromatography). No colloidal particles could be usually observed after the polymerization, but both the isotacticity and the Q value (Mw/Mn) calculated from the molecular weight distribution curve increased with increasing polymerization period. The Q value was estimated always far greater than 2, which would be obtained in the case of homogeneous polymerization. From these results, it was concluded that isotactic polymer derives from polymerization on small (invisible) colloidal particles formed by decomposition of ZrBz4 during the course of polymerization.
Cationic polymerization of styrenes by protonic acids and their derivatives, 3. Propagating species in the polymerization of styrene by trifluoroacetic acid
Authors: Sawamoto Mitsuo , Masuda Toshio , Higashimura Toshinobu , Kobayashi Shiro , Saegusa Takeo 
Published: April 2003

AbstractThe nature of the propagating species in the cationic polymerization of styrene by trifluoroacetic acid was investigated with special attention to the possibility of ester propagation. The molecular weight distribution (MWD) of polymers formed at 50°C in 1,2‐dichloroethane (DCE) and mixtures of DCE and benzene was found to be bimodal, and increasing solvent polarity facilitated the formation of the higher polymers. From this evidence, coupled with the effects of a common ion salt on the MWD, it was concluded that the bimodal MWD results from concurrent propagation of two ionic species. 19F NMR spectra of the polymerization system in DCE at 50°C showed two peaks, one of which was assigned to the acid and the other to its styryl and polystyryl esters. The esters were formed slowly and the polymerization rate fell more rapidly than corresponded to the fall in monomer concentration. The styryl ester (1‐phenylethyltrifluoroacetate) could not initiate the polymerization under the same conditions. These results indicate that an ester is not the propagating species in the present system. A kinetic treatment based on the inertness of the ester gave a satisfactory interpretation of the results.
Potassium hydroxide inhibition in poly(propylene oxide) autoxidation
Authors: Griffiths Peter J. F. , Hughes John G. , Park Geoffrey S. 
Published: April 2003

AbstractA systematic study of the effect of potassium hydroxide on the autoxidation of poly(propylene oxide)s with number average molecular weights, M̄n, in the range 400–3000 has been made in the range of temperature 110–140°C. For all the polymers a considerable increase in the induction time was produced by KOH in solution in the polymer, the increase being most marked for the polymer of lowest molecular weight. For the polymers of molecular weight 1000 and lower, the rate of the subsequent autoxidation was considerably reduced by the KOH, the effect being greatest for the polymer of molecular weight 400. For polymers of molecular weight 2000 and above no change in rate was observed. The effectiveness of KOH as an antioxidant is shown to depend on the concentration of terminal hydroxyl groups and is explained by the non‐radical decomposition of RO ions.
Kinetics of oxidative dimerization of ethynylbenzene catalyzed by copper complexes of 2‐phenylpyridine and a polymeric pyridine derivative
Authors: Meinders Herman Casper , Prak Nanno , Challa Ger 
Published: April 2003

AbstractThe kinetics of the oxidative dimerization of ethynylbenzene (1) at 25°C was studied in a mixture of 1,2‐dichlorobenzene and pyridine, catalyzed by soluble complexes derived from copper(I) chloride and pyridine derivatives. The influence of the concentrations of cosolvent pyridine, of copper salt, of 1, and of the ligands 2‐phenylpyridine (4) and partially 2‐pyridyl substituted atactic polystyrene (3) on the initial reaction rate was determined. In the initial stages the reaction is first order in [CuCl]0 up to the solubility limit of the complex at [CuCl]0 = 2,8 · 10−3 mol dm−3. The order in 1 is 0,5 in the case of the pyridine complex and 2 in the case of the complex with the polymeric ligand 3. These results are in agreement with a previously proposed reaction scheme. It was also found that the cosolvent pyridine acts as a slightly activating ligand reaching a maximum reaction rate only for very high N/Cu ratios. The above mentioned ligands 3 and 4 can rapidly displace a pyridine ligand from the complex yielding much more active complexes.
The electro‐initiated cationic polymerization of indene, 1
Authors: Bhadani Suraj N. , Baranwal Panchdeo P. 
Published: April 2003

AbstractThe electro‐initiated anodic polymerization of indene in ethylene dichloride solutions of tetraethylammonium hexachloroantimonate and tetrabutylammonium perchlorate as background electrolytes was studied. The polymerization was conducted either under continuous electrolysis or by addition of the monomer to the pre‐electrolysed solution of the salt. The polymer formation was affected by the amount of electricity, the monomer concentration, and the nature of the electrolytes. The rate and degree of polymerization with the hexachloroantimonate salt are relatively high in comparison with the perchlorate salt. The characteristically colored species, formed during polymerization, were investigated spectrophotometrically. Mechanisms for the initiation processes of both procedures were elucidated.
Spektroskopische analyse mehrfacher methacrylsäureester von oligo[(2‐hydroxy‐1,3‐phenylen)methylen]en mittels UV‐, IR‐, 1H NMR‐ und massenspektren
Authors: Kämmerer Hermann , Pachta Jiri , Ritz Jürgen 
Published: April 2003

AbstractThe structures of two homologous series of oligo[(2‐hydroxy‐1,3‐phenylene)methylene]s completely esterified with methacrylic acid, were spectroscopically analysed. The molar decadal absorption coefficients of ultraviolet absorption maxima of the two homologous series confirm Hunter's relation. The vinylidene, ester, and substitution bands of the infrared spectra as well as the mass spectra agree with the accepted structures. The 1H NMR spectra permit to differentiate between exterior and interior groups of the molecules.
Application of spin trapping technique to radical polymerization, 12 The polymerization of N‐vinylcarbazole with benzoyl peroxide
Authors: Sato Tsuneyuki , Abe Masao , Otsu Takayuki 
Published: April 2003

AbstractTo clarify the initiation and propagation mechanisms of the polymerization of N‐vinylcarbazole (1) initiated by benzoyl peroxide (2), the spin trapping technique using 2‐methyl‐2‐nitrosopropane (5) was applied. From the ESR spectrum observed from this system, the 1‐(N‐carbazolyl)‐2‐benzoyloxyethyl radical (6a) was found to be trapped as its nitroxyl radical 6b, which was confirmed by a comparison with similar nitroxyl radicals (7b and 8b) derived from the systems, di‐tert‐butyl peroxalate/1/5 and 2/N‐ethylcarbazole/5, respectively. Therefore, it was concluded that the 1/2 system produces easily a primary propagating radical of 1 viz. 6a. Further, the monomer 1 was found to show a remarkable accelerating effect on the radical decomposition of 2. From the copolymerization of 1 with styrene initiated by 2, it was concluded that 6a propagates by ordinary successive ß‐attack to the monomer 1.
Application of spin trapping technique to radical polymerization, 13 Polymerization of methyl methacrylate with 1,2,3,10a‐tetrahydrophenanthrene‐1,2‐dicarboxylic anhydride
Authors: Sato Tsuneyuki , Abe Masao , Otsu Takayuki 
Published: April 2003

AbstractThe polymerization of methyl methacrylate (MMA) with 1,2,3,10a‐tetrahydrophenanthrene‐1,2‐dicarboxylic anhydride (TH) (10), which is a stable Diels‐Alder adduct of α‐vinylnaphthalene and maleic anhydride, was investigated by kinetic and spin trapping methods. TH could induce radical polymerizations of MMA and methyl acrylate with a considerably high rate, and the rate of polymerization (Rp) of MMA was found to follow the equation: Rp = k[TH]0,3 [MMA]1,6. The overall activation energy and the chain transfer constant to TH for this polymerization were determined to be 47,7 kJ/mol and 0,52, respectively. From these results, an initiation mechanism involving a hydrogen‐transfer from TH to MMA was proposed, which is similar to Mayo's initiation mechanism for the thermal polymerization of styrene. To confirm this mechanism, the spin trapping technique was applied. The results obtained regarding the trapping of the initiating radicals supported this hydrogen‐transfer initiation mechanism.
The oxidative coupling of 2,6‐xylenol catalyzed by polymeric complexes of copper, 2. Physicochemical study on copper(II) complexes of partially dimethylamino‐methylated polystyrene
Authors: Schouten Arend Jan , Wiedijk Dick , Borkent Jan , Challa Ger 
Published: April 2003

AbstractThe polymeric catalyst formed by complexation of copper(II) chloride and partially dimethylaminomethylated polystyrene was investigated to explain its behaviour in the oxidative coupling of 2,6‐xylenol (3). Viscometric studies indicated that at low polymer concentrations coordination of tertiary amine groups to copper(II) causes an intramolecular crosslinking. UV measurements and preliminary results of ESR point to a dimeric structure of these complexes with two amine groups per copper. A mechanism for the action of this polymeric catalyst is suggested, based on these results and on those described in Part 1. It appeared that some “free” copper(II) is essential for the catalytic activity, without which the reoxidation of copper(I) cannot take place.
The heats of dilution of polystyrene solutions
Authors: Baba Yoshihiro , Fujimoto Kenji , Kagemoto Akihiro , Fujishiro Ryoichi 
Published: April 2003

AbstractThe heats of dilution of atactic polystyrene‐anisole, ‐dibenzyl ether, and ‐acetophenone systems were measured in the concentration range of 0,168 to 0,02 in volume fraction of the polymer, by adding successively 1 ml of the solvent to the solution of a known concentration by using an isothermal calorimeter at 303K. The heats of dilution of all systems obtained proved to be exothermic.The interaction heat parameter depends considerably on the concentration of the polymer and also on the molecular weight of the polymer. In polystyrene‐anisole and ‐dibenzyl ether systems an interesting fact was found: the χ1‐parameter is negative and its absolute value increases at first, reaches a maximum and then decreases as the molecular weight of the polymer increases.
Bindungsfähigkeit von casein für natriumchlorid bei hohen wasseraktivitäten. Untersuchungen mit einer neuartigen isopiestischen sorptionsapparatur
Authors: Gál Stefan , Hunziker Max 
Published: April 2003

AbstractA new isopiestic sorption apparatus and its application to the determination of the binding capacity of casein for sodium chloride are described. The method provides reliable binding values in equilibrium with salt solutions of medium and high concentrations.
Homopolymerization of maleic anhydride
Authors: Bhadani Suraj N. , Prasad Jagdeo 
Published: April 2003

AbstractPyridine and picoline initiated polymerizations of maleic anhydride were investigated in acetic anhydride. It was found that the electrical conductivity of the polymerizing mixture increases in the course of the reaction, and that the initial rate of polymerization increases with increasing monomer and pyridine concentrations, and its values, measured at different temperatures, show the apparent overall activation energy to be about 10 kcal/mol (41,87 kJ/mol). The rates of polymerization and the increase of specific conductivities of the reaction mixtures show the following order of initiator activity: γ‐picoline > β‐picoline > pyridine > α‐picoline. Therefore, the results of the kinetic and conductivity measurements suggest that the polymerization rate depends on the basicity of the initiator.
Synthesis of a metal containing ladder‐polymer by solid‐state polymerization of bis(1,3‐pentadiynyl)mercury
Authors: Steinbach M. , Wegner G. 
Published: April 2003

AbstractBis(1,3‐pentadiynyl)mercury (3) polymerizes quantitatively in the solid‐state if irradiated with UV‐light or annealed at 100–200°C. The polymer shows resonant Raman frequencies at 1412, 1454, 2024, and 2070cm−1 typical for polymers containing butadiynyl (diacetylene) groups. The intensity of IR peaks due to the monomer triple bonds at 2098 and 2220 cm−1 decreases during polymerization and vanishes at completion. From experimental evidences it is inferred that the polymerization is lattice controlled and can be described, similar to the solid state polymerization of butadiynyl derivatives, by the formation of a ladder polymer of two strands of a poly(2‐butynediylidene) linked together by mercury.
The color reaction between partially saponified poly(vinyl acetate) and iodine‐iodide in the presence of boric acid
Authors: Hayashi Sadao , Tanabe Youichi , Hojo Nobumasa 
Published: April 2003

AbstractThe effect of the boric acid concentration on the color reaction between partially saponified poly(vinyl acetate), which is dissolvable in water, and iodine‐iodide was investigated. As the concentration of boric acid increased, the absorbance at λmax = 488 nm of the red‐violet complex, which is due to a long sequence of vinyl acetate units distributed along the polymer chain, increased gradually, reached a maximum, and then decreased from the point in which the absorbance at λmax = 656nm of the blue complex, based on the vinyl alcohol units in the polymer, was observed. The color complex in an excess of boric acid transferred from red‐violet to red‐tinged blue with time. From the color change, the molar absorption coefficient at λmax = 656 nm for the iodine molecule in the blue complex was found to be 3,92.104l/(mol cm).
Reduction of nitrile end groups in styrene polymers and their subsequent determination by dye partition technique
Authors: Kanjilal Chinmay , Mitra Bhairab C. , Palit Santi R. 
Published: April 2003

AbstractNitrile groups were incorporated in polystyrene through (i) initiation with azoisobutyronitrile (AIBN) and (ii) copolymerization with a trace of acrylonitrile. Their detection and estimation by dye partition technique were experimentally realized. The method consists in first converting nitrile end groups magnified image to primary amino end groups magnified image by reducing with lithium aluminium hydride in tetrahydrofuran medium followed by testing and quantitatively estimating the amino end groups in the resultant polymer by the usual dye partition technique. AIBN initiated polystyrene was found to contain on the average 2 nitrile end groups per polymer molecule supporting the fact that combination is the predominant mode of termination in styrene polymerization. The copolymer reactivity ratio (r1) for styrene (M1) – acrylonitrile (M2) copolymers as determined by this technique agrees fairly well with the existing literature values. This verifies the quantitative applicability of the dye partition method for the study of macromolecular reactions.
Electrical conductivity variation of native and denatured DNA in the solid state as a function of acidity and structure
Authors: Lecompte Marie‐France , Jozefowicz Marcel 
Published: April 2003

AbstractD. c. electrical solid state conductivity of either native or heat‐denatured calf thymus DNA sodium it has been studied as a function of the acidic state of the samples. Conductivity implies major ionic carriers and depends on the secondary structure of the DNA sample. Its variation is correlated to the ion exchange properties of DNA solid phase suspension in a solvent. Partial renaturation of heat denatured DNA samples, induced by salt addition, increases the DNA solid state d.c. conductivity.
The effect of complexing agents on the radical polymerization of polar vinyl monomers
Authors: Kuran Witold , Pasynkiewicz Stanisław , Nadir Riad , Florjańczyk Zbigniew 
Published: April 2003

AbstractRadical polymerizations of acrylonitrile, methacrylonitrile, methyl acrylate, and methyl methacrylate in the presence of Lewis acid type complexing agents like ZnCl2, SnCl4, or (C2H5)nAlCl3−n (n = 1,2,3) were investigated. The accelerating or inhibiting effects of the complexing agents on the polymerization of individual monomers were observed depending on the concentration and the character of the complexing agent. These effects were found to be also influenced by the monomer structure. The polymerization mechanism is discussed.
Vinyl polymerization by a cobalt complex
Authors: Kothandaraman Harimurthi , Sundaram Periannan Gnana 
Published: April 2003

AbstractThe rate of decomposition of the complex, sodium bis(diethanolamine)cobaltate octahydrate was studied at pH 7 and pH 1,6, respectively. This complex was found to initiate the vinyl polymerization (polymerization of acrylamide and methacrylamide) at pH 1,6 in aqueous medium. There was no polymerization at pH > 4. The dependences of the rate of polymerization on monomer concentration, initiator concentration, temperature, and pH were studied. The overall activation energy of the polymerization reaction was calculated. A kinetic reaction scheme is proposed on the basis of the experimental data.
The stability and chemical stress relaxation of peroxide cured polyurethane elastomers
Authors: Barrie James A. , Ludbrook Bryan D. , Thomas David K. 
Published: April 2003

AbstractThe chemical stress relaxation of two polyurethane elastomers Genthane S and Adiprene CM has been studied in air and in nitrogen in the temperature range 60 to 150°C. Both continuous and intermittent stress relaxation measurements were made on well characterized samples covering a range of crosslink densities. Scission and crosslinking reactions were observed for both the polyester based Genthane S and the polyether based Adiprene CM. The degradation of Genthane S is largely non oxidative and the scission reaction involves the main chain. The behaviour of Adiprene CM under nitrogen broadly resembles that of Genthane S; it differs from Genthane S in that it also undergoes an oxidative reaction. Activation energies for the scission and crosslinking processes were evaluated from kinetic analysis. Pretreatment of the elastomers with isocyanates inhibits both of these reactions. A mechanism involving the urethane group is proposed to account for the degradation behaviour and the role of water in this respect is discussed briefly.
On the mechanism of the carbon dioxide/propylene oxide alternating copolymerization in the presence of organozinc catalysts
Authors: Kuran Witold , Pasynkiewicz Stanisław , Skupińska Jadwiga 
Published: April 2003

AbstractCarbon dioxide and propylene oxide were copolymerized in the presence of the catalytic systems diethylzinc/polyhydric phenols modified by pretreatment with one of the monomers. The mechanisms of initiation, propagation, termination, and chain‐transfer reaction in the copolymerization are suggested and discussed.
Aminolyses of monomeric and polymeric 4‐nitrophenyl esters of N‐methacryloylamino acids
Authors: Rejmanová Pavla , Labský Jiří , Kopeček Jindřich 
Published: April 2003

Abstract4‐Nitrophenyl esters of N‐methacryloylamino acids and their copolymers with N‐(2‐hydroxypropyl)‐methacrylamide were synthesized. The effect of the ester and amine structure and of the reaction medium on the rate constant of aminolysis was studied.