bluuebunny/crossref_metadata_2025_split huggingface dataset:
Terpolymerization of sulfur dioxide and methyl acrylate with electron donor monomers
Authors: Florjańczyk Zbigniew , Floriańczyk Tadeusz , Zygadło Ewa 
Published: April 2003

AbstractThe radical terpolymerization of sulfur dioxide and methyl acrylate with 1,3‐butadiene, 2‐methylpropene, propene, 1‐hexene, 1‐octene and vinyl chloride was studied by comparing the composition of terpolymers obtained under different reaction conditions and by analysis of 13C NMR spectra of selected terpolymers and copolymers. In the majority of systems studied, products are formed in which the ratio of SO2 monomeric units to vinyl monomeric units is near to unity. The content of methyl acrylate monomeric units can change over a very wide range and depends mainly on the electron‐donor properties of the vinyl monomer used, feed composition and conversion. An increase of the methyl acrylate content is also observed in many systems with a rise of the reaction temperature. The results obtained are interpreted in terms of a mechanisms involving the addition of individual monomers and reversibility of steps in which carbon‐sulfur bonds are formed.
Radical ring‐opening polymerization behavior of ethyl 1‐substituted 2‐vinylcyclopropanecarboxylate
Authors: Endo Takeshi , Watanabe Makoto , Suga Katsufumi , Yokozawa Tsutomu 
Published: April 2003

AbstractEthyl 1‐substituted 2‐vinylcyclopropanecarboxylate derivatives (VCPs) were prepared from butadiene and the corresponding substituted diazoacetate in the presence of rhodium diacetate as a catalyst. The polymerization behavior of the obtained monomers was investigated revealing that VCPs undergo radical ring‐opening polymerization to form poly(1‐alkyl‐1‐ethoxycarbonyl‐3‐pentenylene)s and that there is a marked influence of the 1‐substituent of VCPs on the polymerization rate. The reaction of VCPs with thiophenol was also carried out as a model reaction of their polymerization.
Synthesis of poly(vinyl alcohol)‐graft‐poly(tetrahydrofuran)
Authors: Tezuka Yasuyuki , Okabayashi Atsushi , Imai Kiyokazu 
Published: April 2003

AbstractThe reaction of a living poly(tetrahydrofuran) (poly(THF)), prepared with methyl trifluoromethanesulfonate as an initiator, with 3‐sodiopropoxydimethylvinylsilane was carried out to produce a uniform poly(THF) macromonomer with a vinylsilane end‐group. Poly(vinyl acetate)‐graft‐poly(THF) of controlled graft segment length was then synthesized through radical copolymerization of this poly(THF) macromonomer with vinyl acetate. The subsequent saponification with NaOH in methanol provided poly(vinyl alcohol)‐graft‐poly(THF).
Morphology of cycloparaffins crystallized epitaxially on NaCl
Authors: Ihn Kyo Jin , Tsuji Masaki , Isoda Seiji , Kawaguchi Akiyoshi , Katayama Ken‐ichi , Tanaka Yasuyuki , Sato Hisaya 
Published: April 2003

AbstractThe cycloparaffins (CH2)36 and (CH2)60 were crystallized epitaxially from solutions on the (001) face of the NaCl crystal at various temperatures. Two types of crystals, so‐called edge‐on and flat‐on crystals, were separately obtained depending on crystallization temperature. The temperature for obtaining edge‐on crystals was higher by ca. 10°C than that for flat‐on crystals. In both flat‐on and edge‐on crystals, the long side (b‐axis) is aligned to the 〈110〉 direction of NaCl. The (001) plane in the flat‐on crystal and (202) in the edge‐on crystal are parallel to the substrate surface. The direction of the vector c′ defined as −a + c is parallel to the molecular axis in monoclinic cycloparaffin crystals. The angle β′ between c′ and the a‐axis is almost constant at about 119°, while c′ changes linearly with the number of carbon atoms in a molecule. The space group changes from Aa to Ia in the new unit cell with the dimensions a, b, c′ and β′.
Preparation of monomers functioning as initiators and use of their polymers for graft copolymerization
Authors: Yamada Bunichiro , Otsu Takayuki 
Published: April 2003

AbstractNew types of esters of methacrylic acid functioning as radical initiators, α,α′‐azobis(α‐methylbenzyl) dimethacrylate (1) and 1,1′‐azobis(1‐methylethyl) dimethacrylate (2), were synthesized by reaction of the corresponding chlorides with salts of methacrylic acid. These monomers1and2were utilized to produce copolymers containing the respective azoinitiator units. Decomposition of the initiator units in the presence of a second monomer resulted in graft copolymers. Polystyrene and poly(methyl methacrylate) were grafted onto the polymers bearing α‐azo‐α‐methylbenzyl units. Poly(styrene‐graft‐diisopropyl fumarate) was prepared by decomposition of polystyrene containing 1‐azo‐1‐methylethyl units in the presence of monomeric fumarate at 150 and 180°C. The number of the grafting sites along the main chain was estimated on the basis of the molecular weight of the polymer, the content of the initiator unit, and the decomposition rate.
Iodine‐poly(vinyl alcohol) interactions, 4. Stoichiometry of iodine/iodide in the polyiodide ion bound in the cage of poly(vinyl alcohol)
Authors: Yokota Toshio , Kimura Yoshiharu 
Published: April 2003

AbstractAqueous poly(vinyl alcohol) (PVA)‐iodine‐boric acid solution was treated with anion exchange resin and the system involving only the cage complex was isolated. The system was then extracted with carbon tetrachloride, and I2 and I−, which were released from the complex, were separated and pooled in the carbon tetrachloride and the aqueous layers, respectively. From the absorption spectra of the layers the amounts of I2 and I− were determined. The ratio I2/I− was found to be approximately 2,0, which corresponds to the I2/I− stoichiometry in the complex. This result suggested that the major species bound in the PVA cage are pentaiodide ions, i.e., I with linear configuration and/or I2· I with distorted chain structure. Judging from the resonance Raman spectrum of the PVA‐iodine solution that had been revealed before, it was concluded that the two absorption bands of the complex at λmax = 650 and 355 nm are ascribed to the I and I2 · I ions, respectively.
Solvent effect in radical copolymerization of styrene with p‐aminostyrene
Authors: Masuda Seizo , Tanaka Masami , Ota Tadatoshi 
Published: April 2003

Abstractp‐Aminostyrene (1, M1) and styrene (M2) were radically copolymerized at 60°C in various solvents. There is a significant solvent effect on monomer reactivity ratios, especially on r1, suggesting a specific interaction between the solvent and the polymer radical with the p‐aminostyrene moiety at the terminal position. In order to clarify the solvent factor influencing the relative reactivity, the hydrogen‐bond‐accepting basicity of the solvent (β) was determined from enhanced UV shifts for 1 relative to N,N‐dimethyl‐p‐aminostyrene. Regression analysis of r1 with the solvatochromic parameters revealed that β is the major factor responsible for r1‐variations.
Sulfur‐containing azoinitiators and their properties
Authors: Nuyken Oskar , Knepper Thomas , Voit Brigitte 
Published: April 2003

AbstractThe thermolysis and photolysis of arylazosulfonates (1–3) and of arylazo phenyl sulfones (4–6) was studied. Compounds 1 to 3 are soluble in water. They are thermally stable up to 200°C; however, if they are irradiated with the light of a mercury‐xenon high‐pressure lamp, they decompose at room temperature. Their photolysis was studied either in water or in ethanol as solvent. For the photolysis in water an ionic mechanism of decomposition is suggested, while the results of the photolysis in ethanol can be explained on the basis of a competition of a radical with an ionic mechanism. Compounds 4 to 6 are thermally and photochemically instable. The thermal decomposition of 5 was studied in detail and found to be comparable to that of AIBN. Its decomposition follows first‐order kinetics. The photolysis of 4–6 was carried out in ethanol or chloroform. The mechanism of photolysis depends on the solvent polarity. 5 was successfully used as initiator for the polymerization of methyl methacrylate.
The use of low‐molecular‐weight model compounds in an investigation of polyelectrolytes, 1. Potentiometric properties of poly(methacrylic acid) and its 2‐dimethylaminoethyl ester
Authors: Přádný Martin , Holata Jan , Ševčík Stanislav 
Published: April 2003

AbstractThe potentiometric behaviour of poly(methacrylic acid) (PMA), poly(2‐dimethylaminoethyl methacrylate) (PDAEM), and low‐molecular‐weight compounds modelling the structural diad of these polymers, 2,2,4,4‐tetramethylglutaric acid (TMGA) and its 2‐dimethylaminoethyl ester (ETMG), is reported. The dissociation constants of these compounds to the 1st and 2nd degree were measured and compared with the values for polymers. It appears that TMGA adequately models the behaviour of PMA up to the conformational transition compact coil (stage “a”) — random coil (stage “b”) at higher ionic strength values of the titrated solution. On the contrary, ETMG behaves as a typical low‐molecular‐weight compound with properties differing from those of PDAEM.
Stress‐optical and thermomechanical measurements on liquid crystalline elastomers
Authors: Hammerschmidt Kathrin , Finkelmann Heino 
Published: April 2003

AbstractFor liquid crystalline polysiloxane‐elastomers, the orientation of the mesogenic side groups is determined under uniaxial compression and without load in the isotropic state in the vicinity of the isotropic to nematic phase transformation. The experimental results clearly indicate the following fundamental properties of liquid crystalline elastomers:

Depending on the chemical constitution of the flexible spacer a mechanical force causes a macroscopic orientation of the mesogenic side groups parallel or perpendicular to the direction of the force.
Strain causes a parallel (perpendicular), while compression causes a perpendicular (parallel) orientation of the side groups with respect to the direction of the mechanical force.
Due to a macroscopic orientation of the mesogenic side groups in the liquid crystalline state, the physical properties of the elastomers become anisotropic, which is directly reflected in the thermomechanical properties.
Dynamic‐mechanical losses in elastin networks swollen with glycols of various lengths
Authors: Andrady Anthony L. , Mark James E. 
Published: April 2003

AbstractA Rheovibron DDV‐II‐C viscoelastometer was used to carry out loss tangent measurements on purified, swollen elastin networks. The diluents employed were HO(CH2CH2O)mH with m = 0–4, i.e. water, ethylene glycol, diethylene glycol (2,2′‐oxydiethanol), triethylene glycol (3,6‐dioxa‐1,8‐octanediol) and tetraethylene glycol (3,6,9‐trioxa‐1,11‐undecanediol) and the temperature range was −120 to 40°C. The results, in particular the effects of the various diluents on the α‐ and β‐transitions, are in support of the random‐network model rather than the twophase liquid‐drop model, for elastin in the rubberlike state.
Synthesis and gel‐permeation chromatography of oligo(oxyethylene) n‐alkyl ethers
Authors: Craven John R. , Mobbs Richard H. , Booth C. , Goodwin Elizabeth J. , Jackson David 
Published: April 2003

AbstractUniform samples of oligo(oxyethylene)s were synthesized: either H(OCH2CH2)mO(CH2)nH or CH3(OCH2CH2)mO(CH2)nH, with m in the range 4 to 16 and n = 9 or 15. The samples were eluted through a low‐porosity gel‐permeation chromatography column with either dichloromethane (DCM), tetrahydrofuran (THF) or N,N‐dimethylacetamide (DMA) as eluent. The elution volumes in the good solvents (DCM, THF) were insensitive to composition, while those in DMA depended on both chain length and composition.
Phosphorus functional telomers of vinyl polymers through functional thermal iniferter
Authors: Nair Chethrappilly P. Reghunadhan , Clouet Gilbert 
Published: April 2003

AbstractThe phosphorus‐functional iniferter, N,N′‐dimethyl‐N,N′‐bis[2‐(N‐diethoxyphosphinoyl‐N‐methylamino)ethyl]thiuram disulfide (2), was synthesized and characterized. Thermal polymerization of methyl methacrylate (MMA) and styrene in presence of this compound led to the formation of α, ω‐phosphorylated PMMA and polystyrene. The kinetics of polymerizations of MMA and styrene using this iniferter was studied at 70°C and the different parameters, related to initiation, chain transfer, and primary radical termination reactions, were evaluated. In the case of styrene the extent of primary radical termination was considerably less and mutual termination reactions were found to be absent. The telomers were analysed for their functionality.
Asymmetric induction in the cyclopolymerization of divinyl ethers derived from (R)‐ or (S)‐3,3′‐dimethyl‐1,1′‐bi‐2‐naphthol
Authors: Yokota Kazuaki , Kakuchi Toyoji , Sasaki Hiroshi , Ohmori Hiroshi 
Published: April 2003

AbstractOptically active divinyl ethers, (−)‐(R)‐ and (+)‐(S)‐2,2′‐bis[2‐(2‐vinyloxyethoxy)ethoxy]‐3,3′‐dimethyl‐1,1′‐binaphthyl [(R)‐1b and (S)‐1b] were polymerized to produce chiral poly(crown ether)s. Their optical rotation was found to be profoundly influenced by the polymerization conditions. When increasing the monomer concentration from 0,1 to 0,3 mol · 1−1, after polymerization with SnCl4 in CH2Cl2 at 0°C, the optical rotation of the resulting polymers is drastically changed from +44,5° to −17,3° for (R)‐1b and from −35,6° to +20,9° for (S)‐1b. The analysis of 1H NMR showed that the polymers have changed their optical rotation due to a configuration which has a tendency to be preferentially racemic diad at higher monomer concentrations in a nonpolar solvent. There are indications that the twist of 2,2′‐binaphtyl moieties, the methyl groups in 3‐, and 3′‐positions as steric barrier, and the intramolecular solvation of the growing carbo‐cation cooperatively control the propagation to induce the asymmetry in the main chain.
New polymer syntheses, 36. Functionalized aromatic polyethers derived from 4′‐substituted 2,6‐difluorobenzophenones
Authors: Kricheldorf Hans R. , Delius Ulrich 
Published: April 2003

AbstractToluene, anisol, thioanisol, 4‐phenoxyacetophenone and N,N‐diacetyl‐4‐phenoxyaniline were subjected to a Friedel‐Crafts acylation with 2,6‐difluorobenzoyl chloride. The resulting 4′‐substituted 2,6‐difluorobenzophenones 1a–e were condensed with trimethyl silylated Bis‐phenol‐A (2) to yield homopolyethers with pendant functional groups. A series of copolyethers was analogously prepared by concondensation of 4′‐substituted 2,6‐difluorobenzophenones with a diphenol and 4,4′‐difluorobenzophenone (4a) or bis(4‐fluorophenyl) sulfone (4b), and another series by cocondensation of 2 with mixtures of 4′‐substituted 2,6‐difluorobenzophenones and 2,6‐difluorobenzonitrile (8) or 2,6‐difluoropyridine (9). All polyethers were characterized by inherent viscosities, elemental analyses and DSC‐measurements. In individual cases GPC‐measurements, thermomechanical and thermogravimetric analyses were conducted. The quantitative polymer‐analogous oxidation of methylthio groups into methylsulfinyl and finally into methylsulfonyl groups is demonstrated.
Water‐soluble and photosensitive copolymers from methyl methacrylate and sodium 3‐vinylphenylazosulfonate
Authors: Nuyken Oskar , Voit Brigitte 
Published: April 2003

AbstractThe synthesis of sodium 3‐vinylphenylazosulfonate (4) and its copolymerization with acrylamide and methyl methacrylate (MMA) is described. Copolymers of 4/MMA containing more than 15 mol‐% of 4 are water‐soluble. The trans‐azosulfonate is perfectly stable up to 200°C. However, it decomposes at room temperature after transformation into the cis‐isomer by UV light. This irradiation reaction was used to convert completely water‐soluble copolymers from 4/MMA into water‐insoluble products.
A calorimetric investigation of interactions in aqueous solutions of poly(oxyethylene), 2. Determination of excess heat capacities and application of association theory
Authors: Živný Antonín , Biroš Ján , Pouchlý Julius 
Published: April 2003

AbstractExcess heat capacities are given as functions of composition and temperature for non‐dilute aqueous solutions of poly(oxyethylene) and its oligomeric models, i. e. from the glycol monomer to tetramer and dimethyl ethers of these compounds. A theoretical model based on the concept of association equilibria was used to predict the excess heat capacities of aqueous mixtures of dimethyl ethers at 298K and 350K. Numerical values of parameters of the model were obtained by treatment of the heats of mixing reported in the first part of this study. It was sufficient to adjust two parameters of self‐association of water, and for each system also the parameter characterizing hydration of ether groups in oligomers. The agreement between theory and experiment was very good for both enthalpy and heat‐capacity data, with the exception of the concentration range rich in water, where the interaction scheme is probably more complicated.
Kinetics of polymer degradation in transient elongational flow
Authors: Nguyen Tuan Q. , Kausch Henning‐H. 
Published: April 2003

AbstractAn expression of the kinetics describing the rate of bond scission under stress is proposed and applied to the case of degradation of polymers in transient elongational flow. The new equation permits to take into account the existence of critical values, either for molecular weight or strainrate, below which no chain scission occurs. Compared with the other types of mechano‐chemical degradation, depolymerization in transient elongational flow is characterized by a short residence time and an inhomogeneous flow field in which the scission rate constants change drastically with the spatial coordinates. The evolution of molecular size distribution during the degradation process has been investigated using a general polymer fragmentation scheme. The set of differential equations was solved exactly with a matrix technique. Excellent concordance between calculations and experimental results from dilute polystyrene solutions was obtained, providing the spatial distribution of the strain‐rate was properly incorporated into the degradation kinetics.
Purification of thermotropic liquid‐crystalline siloxane oligomer with supercritical carbon dioxide
Authors: Krishnamurthy Sushil , Chen Shaw H. 
Published: April 2003

AbstractThe effects of the purification of thermotropic liquid‐crystalline siloxane oligomer with supercritical carbon dioxide were investigated. It was found that low‐molar‐mass contaminants, presumably the two alkene precursors, can be effectively removed at 80°C and carbon dioxide pressures up to 31,0 MPa. In support of this observation is the fact that glass transition temperature goes up as a result of purification. In addition, the selective reflection wavelength was found to increase at increasing purity level, as achieved by extraction at increasing carbon dioxide pressure.
Acid‐ and base‐functionalization of ethylene‐propene rubbers, 3. Mechanical and dynamic‐mechanical characterization of the elastomer networks
Authors: D'Amore Alberto , Greco Pietro , Immirzi Barbara , Laurienzo Paola , Malinconico Mario , Martuscelli Ezio 
Published: April 2003

AbstractInfluences of type and content of functional groups on the mechanical response of various functionalized (grafted) ethylene‐propene rubbers (EPRs) are reported. Grafted molecules include succinic anhydride (SA), monomethyl succinate (MMS) and 2‐(dimethylamino)ethylsuccinimide (DAESI). A semiquantitative correlation between the decrease of the mechanical properties at high grafting degree and degradation of the polyolefinic backbone is given. Also a study of the dynamic‐mechanical properties of the functionalized rubbers is reported. A rubbery plateau is found, the strength and temperature dependence of which is a function of the type and content of the grafted molecules.
A carbonyl‐olefin exchange reaction. New route to conjugated polymers, 4. Chain growth. Side reactions
Authors: Schopov Ivan , Mladenova Lyudmila 
Published: April 2003

AbstractIn order to prove that the carbonyl‐olefin exchange reaction (COER) is a step reaction, a shorttime experiment was carried out, from which only linear oligomers were obtained. The dimer was identified by comparison with an authentic sample. The polymer can also be obtained starting from the dimer. The polymer retains its reactivity. Treated with WCl6 alone or in the presence of the corresponding monomer it yields products of increased molecular weight. The reaction takes place even in the presence of its low‐molecular‐weight by‐product benzophenone. Treatment of the polymer with benzophenone and WCl6 leads to a molecular weight increase. These results prove that the COER proceeds as a non‐equilibrium polycondensation.
Carboxymethyl‐histaminocarbonylmethylamylose as a mimetic system of chymotrypsin in the catalytic hydrolysis of esters
Authors: Hui Yongzheng , Zou Wei 
Published: April 2003

AbstractA new type of polysaccharide host, carboxymethyl‐histaminocarbonylmethylamylose (2b), containing carboxylic, imidazolyl and hydroxyl groups in the backbone, was used as a mimetic system for chymotrypsin in the catalytic hydrolysis of 3‐acetoxy‐N‐dodecylpyridinium iodide (1). The substrate is located in the hydrophobic cavity of the amylose helix. The apparent saturation, the entropy‐favored kinetics and the pronounced catalytic efficiency (9 times higher than that of a system consisting of the same concentration of carboxymethylamylose and histamine) show that 2b is a good enzyme model in which the definite binding site, active center and self‐organization characteristics are present. Most distinctly, the pH‐rate constant profile of the hydrolysis of 1 and 2b is of bell‐type and has an optimum at pH 7,98, which is very close to 7,90 for chymotrypsin. In conclusion, the charge relay mechanism is also involved in the catalytic effect of 2b.
Polymers with carbazolylalkyl groups and their charge transfer complexes with 2,5‐cyclohexadien‐1,4‐diylidenedimalononitrile (TCNQ)
Authors: Simionescu Cristofor I. , Grigoras Mircea , David Geta 
Published: April 2003

AbstractFour novel acrylic and methacrylic monomers (8b, c and 9b, c) containing carbazolylalkyl groups, their corresponding polymers and low‐molecular‐weight model compounds (7b, c) were synthesized. The charge transfer complexes of the synthesized polymers with 2,5‐cyclohexadien‐1,4‐diylidenedimalononitrile were prepared and characterized by UV‐vis spectroscopy. The ionisation potentials and complexation constants were determined. It could be shown that increasing spacer length favours the interaction between donor and acceptor. Polymethacrylates with 3 methylene groups in the spacer show the highest complexation constants.
Direct copolymerization of L‐lactic acid with γ‐butyrolactone in the absence of catalysts
Authors: Fukuzaki Hironobu , Aiba Yoshikazu , Yoshida Masaru , Asano Masaharu , Kumakura Minoru 
Published: April 2003

AbstractThe copolymerization of L‐lactic acid (LA) with γ‐butyrolactone (BL), performed without catalyst at 200°C under nitrogen in order to obtain a relatively low‐molecular‐weight copolymer, proceeds via direct condensation between linear LA and linear 4‐hydroxybutyric acid produced by hydrolysis of the cyclic BL. The copolymers were characterized with respect to the copolymerizability (13C NMR spectroscopy), composition (1H NMR spectroscopy), molecular weight (terminal group analysis and gel permeation chromatography), and crystallinity (differential scanning calorimetry). The copolymerizability of BL is low, e. g., the contents of BL units in the copolymers were found to be 12, 16, and 19 mol‐% for initial BL contents in the monomer feed of 30, 50, and 70 mol‐%, respectively, in which copoly(LA/BL) is composed of blocks of lactyl units separated by single γ‐oxybutyryl unit.