bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new chain transfer reaction in the anionic polymerization of 2,3‐epoxypropyl phenyl ether and other oxiranes
Authors: Stolarzewicz Andrzej 
Published: April 2003

AbstractCarbonyl groups were found to be present in polymers of 2,3‐epoxypropyl phenyl ether obtained by anionic polymerization. On the basis of quantitative analyses these groups were assumed to be formed in a reaction involving chain transfer to the monomer which proceeds in a manner different from that reported in the literature. Results of the present study were compared with those referring to the polymerization of methyloxirane, phenyloxirane and some chlorophenyl 2,3‐epoxypropyl ethers.
Polylactones, 7. The mechanism of cationic polymerization of β‐propiolactone and ϵ‐caprolactone
Authors: Kricheldorf Hans R. , Jonté J. Michael , Dunsing Ruth 
Published: April 2003

AbstractHomopolymerisations of β‐propiolactone and ϵ‐caprolactone, initiated by means of methyl trifluorosulfonate, triethyloxonium tetrafluoroborate or acetylium perchlorate, were investigated. Both 1H and 13C NMR spectra proved that the alkylating initiators yield polyesters with alkyl ester end groups, indicating a chain growth via alkyl‐oxygen cleavage of the lactone. At temperatures below 100°C cationic polymerizations initiated by alkylating reagents were found to proceed via end groups which may cause degradation due to back‐biting. When ϵ‐caprolactone was reacted with excess methyl triflate, high concentration of triflate ester end groups were formed, whereas in the case of β‐propiolactone active end groups were not detectable by 1H NMR spectroscopy. Initiation with acetylium perchlorate yielded a polyester with acetate end groups. Acetate end groups were also obtained, when “living” polymers, initiated with methyl triflate, were reacted with acetic anhydride. It could be shown that the formation of acetate end groups does not indicate an electrophilic attack at the endocyclic oxygen. Furthermore, it is discussed that any experimental evidence for a cationic chain growth via acyloxygen bond cleavage is lacking.
Cyclopolymerization, 12. Mechanism of free‐radical cyclopolymerization of acryloyl‐ and methacryloylmethylallylamines
Authors: Kodaira Toshiyuki , Sumiya Yoshinori 
Published: April 2003

AbstractCyclopolymerizability of acryloylmethylallylamine (1b) was investigated and compared with that of methacryloylmethylallylamine (1a) which is known to yield a highly cyclized polymer with a small amount of pendant methacryloyl groups. The structural study of poly(1b) revealed that residual unsaturation consists exclusively of allyl groups and the degree of cyclization is very low. ESR measurements on the 1b polymerization system yielded only the acryloyl radical as propagating radical. Thus, 1b is incorporated into the polymer mainly through its acryloyl group and the rate‐determining step in the cyclopolymerization process of 1b is intramolecular cyclization. On the other hand, the ESR spectrum of 1a consists of cyclized and uncyclized radicals. In this case intramolecular cyclization does not proceed much faster than intermolecular propagation of the cyclized radical. ESR further revealed that the polymerization of 1a first involves the allyl group and then intramolecular cyclization occurs. The difference in cyclopolymerizabilities between 1a and 1b may be interpreted on the basis of the hypothesis that the lower the polymerizabilities of the monofunctional counterparts of unconjugated dienes, the higher their cyclopolymerizabilities.
Comparison of different polymolecularity correction formulae for the burchard‐stockmayer‐fixman relationship
Authors: Bareiss Rolf E. 
Published: April 2003

AbstractPolymolecularity correction of the original and the modified procedure according to Burchard, Stockmayer and Fixman, especially useful for the determination of the unperturbed dimensions of macromolecules, is derived via the general “principle of corresponding averages” and compared with the polymolecularity correction methods published by Sutter et al. and Rosenvasser et al. It is shown that the polymolecularity correction factor to be used with the mass‐average molar mass in the Burchard‐Stockmayer‐Fixman relationship is identical to that derived from the corresponding averages of this relationship. Numerical calculations with series of hypothetical monomolecular and polymolecular (exhibiting Schulz‐Zimm distributions of the molar mass) polymer‐homologous polymer samples in three different thermodynamically good solvents also demonstrate the superiority of the correction method according to Sutter et al. as compared to the correction method of Rosenvasser et al.
Studies on chitosan‐induced metachromasy, 4. Some correlations between dye structure and metachromatic behaviour
Authors: Gummow Beryl D. , Roberts George A. F. 
Published: April 2003

AbstractThe induction of metachromasy in 36 anionic dyes by addition of chitosan and in 4 cationic dyes by addition of sodium carboxymethylcellulose, was examined. The results show that metachromasy is exhibited by dyes having localised ionic charges as well as those in which the charge on the dye ion is delocalised over the chromophoric system, and by dyes containing more than one ionic group. Both bathochromic and hypsochromic shifts in λmax were found and the direction of shift correlated with the general structure of the dye and interpreted in terms of the probable arrangement of the dye ions in the dye aggregates.
Interaction of 14CO with Ziegler‐type heterogeneous catalysts and effect of interaction products on the determination of the amount of active centers
Authors: Bukatov Gennadii D. , Goncharov Valerii S. , Zakharov Vladimir A. 
Published: April 2003

AbstractThe interaction of 14CO with Ziegler‐type heterogeneous catalysts (titanium‐magnesium catalysts, titanium trichloride) in the absence of an olefin was studied. This reaction was found to produce radioactive products soluble in hexane. Formation of such products takes place in the presence of both titanium chloride and AlR3, and is attributed to the insertion of 14CO into the Ti‐R bonds. For titanium‐magnesium catalysts the number of labels in hexane may exceed the number of titanium atoms in the catalysts, which indicates that the Ti‐R bond may be regenerated by AlR3. In the starting phase labelled products are formed at maximum rate, which is an evidence that a rapid insertion of 14CO (some minutes) into Ti‐R bonds takes place. The effect of side labelled products on polypropylene radioactivity is examined and the necessity to purify the polymers from radioactive impurities is shown. The influence of the side process of the interaction of 14CO with the catalytic system on the determination of the amount of active centers is discussed.
Polymerization of propene in the presence of MgCl2‐supported Ziegler‐Natta catalysts, 3. Catalyst deactivation
Authors: Busico Vincenzo , Corradini Paolo , Ferraro Angelo , Proto Antonio 
Published: April 2003

AbstractThe different trends of polymerization rate as a function of time observed when polymerizing propene, ethylene and mixtures thereof in the presence of MgCl2‐supported catalysts are explained assuming that catalyst deactivation is due to the reduction of Ti (III) by alkylaluminium to lower, polymerization‐inactive oxidation states, and that ethyene polymerization is diffusion‐controlled. A possible route for Ti reduction is also presented, which might give the reason for the observed kinetics of polymerization rate decay.
Preparation and polymerization of 2‐chloroethyl 2‐(methacryloyloxy)ethyl hydrogen phosphate and 2‐bromoethyl 2‐(methacryloyloxy)ethyl hydrogen phosphate
Authors: Nakaya Tadao , Toyoda Hirokazu , Imoto Minoru 
Published: April 2003

Abstract2‐Chloroethyl 2‐(methacryloyloxy)ethyl hydrogen phosphate (5a) and 2‐bromoethyl 2‐(methacryloyloxy)ethyl hydrogen phosphate (5b) were synthesized, characterized, and polymerized with 2,2′‐azoisobutyronitrile (AIBN). In the polymerization of 5a in DMF with AIBN, the rate of polymerization was found to be proportional to [AlBN]0,54 and to [5a]1,54. The over‐all activation energy for the polymerization of 5a was estimated as 59,5 kJ · mol‐1. From the radical copolymerization of 5a with styrene in DMF at 60°C, Q and e values for 5a were evaluated as Q = 2,65 and e = 0,53.
Molecular relaxations in poly(ethylene adipate) and block urethane elastomers as studied by the spin probe method
Authors: Lembicz Franciszek , Kuriata Jerzy , Słonecki Jerzy 
Published: April 2003

AbstractThe spin‐probe method is used to study the rotational mobility of two different probes in poly(ethylene adipate) and a block urethane elastomer synthetized using poly(ethylene adipate), 4,4′‐methylenebis(phenyl isocyanate) and 1,4‐butanediol. The observed ESR spectra correspond to slow and rapid rotations of spin probe molecules. They are interpreted using both the isotropic and anisotropic models for the spin probe motion. It is found that at low temperatures the behaviour of spin probes is related to the β‐relaxation, whereas at higher temperatures to the α + β‐relaxation. Differences in mobilities are probably connected with different sizes of spin probes used.
Fixation d'anticorps par liaisons covalentes sur le polystyrène. Activation du support et utilisation répétée du système polystyrène anticorps après test immunoenzymatique
Authors: Couturier Roger , Ville Albert , Perrin Bernard , Favre‐Bonvin Guy 
Published: April 2003

AbstractAntibodies were immobilized by covalent linkage on polystyrene balls for use in solid phase enzyme‐linked immunoassays: application for detection of K 99+ E. Coli in calves. The method eliminates the problem of antibody desorption noted in coventional enzyme‐linked immunosorbent assays which are based on simple adsorption on polystyrene. Further, the bond between antibodies and polystyrene balls is stable under conditions under which usually antibody — antigen complexes dissociate and permit re‐use of the immobilized antibodies for immunoassay.
Influence of hydrogen bonding on the properties of elastomers and elastomeric blends
Authors: Stadler Reimund , Burgert Josef 
Published: April 2003

AbstractPolybutadienes and polyisoprene are modified using 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione. The resulting urazole moieties give rise to the formation of hydrogen bonds. From the temperature dependence of the dilute solution viscosity as well as from GPC it can be deduced that intra‐ and intermolecular hydrogen bonds are formed. The intermolecular hydrogen bonds can be used to overcome the demixing tendency in blends of polybutadiene and polyisoprene. DSC measurements indicate enhanced miscibility depending on the degree of modification.
Viscosity of aqueous and alkaline solutions of poly(ethylene oxide)
Authors: Gregory Peter , Huglin Malcolm B. 
Published: April 2003

AbstractViscosity measurements over a wide range of temperature were made on aqueous solutions of poly(ethylene oxide) samples of different molar mass and of low polydispersity. Above ca. 308 K the Mark‐Houwink exponent decreases and tends to a value of 0,50 at a lower critical solution temperature of 376 ± 2 K. The same value for this θ‐temperature is derived also as that at which the slope of Stockmayer‐Fixman plots tends to zero. At 298 K the unperturbed dimensions [〈r2〉0/M]1/2 = 0,089 nm · g−1/2 · mol1/2 and their temperature coefficient d ln 〈r2〉0/dT ≈ − 1,5 (±0,5) · 10−3 K−1. In aq. KOH the intrinsic viscosity [η] is virtually uninfluenced by pH at low‐medium pH, but at high pH, [η] falls sharply. Viscosity and phase separation measurements yield θ‐conditions in 1,24 M aq. KOH at 298 K. The derived polymer‐water interaction parameters χ increase from 0,449 at 276 K to 0,493 at 358 K, but the enthaplic component χH is incapable of yielding a meaningful value for the solubility parameter δ2 of the polymer in such a hydrogen‐bonding system. The calculated value of χ2 was 18,9 (kJ · dm−3)1/2.
Kinetics of radical polymerization of methyl methacrylate initiated with dimethyl 2,2′‐azodiisobutyrate
Authors: Stickler Manfred 
Published: April 2003

AbstractThe kinetics of free‐radical bulk polymerization of methyl methacrylate with dimethyl 2,2′‐azodiisobutyrate as an initiator was investigated at 40, 60, and 80°C. Non‐ideal polymerization behaviour was observed when the initiator concentration was varied by a factor of more than one thousand. This departure from classical polymerization kinetics is discussed in terms of primary radical termination and a chain length dependent termination rate constant, with the structural similarity of both primary and polymeric radicals facilitating the treatment very much. The kinetic analysis indicates that in the polymerization of methyl methacrylate the termination rate constant is a function of the degree of polymerization of the involved macroradicals.
Coordination polymers of N,N′‐bis(8‐hydroxy‐5‐quinolinyl)‐terephthalamide
Authors: Patel Ravji D. 
Published: April 2003

AbstractFe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of the bisbidentate ligand N,N′‐bis(8‐hydroxy‐5‐quinolinyl)terephthalamide (1) were synthesized. All the metal complexes are characterized by elemental analyses, infrared spectra, electronic reflectance spectra, magnetic susceptibility measurements and thermogravimetry. All the complexes showed a polymeric nature with a octahedral stereochemistry at the coordinated metal atom. The fungicidal screening of the coordination polymers showed them to be antifungal against Penicillium islandicum, Rizopus nigricans and Botrydiplodia theobromae.
Polymorphism and crystal structures of trans‐1,4‐polyisoprene. An analysis by conformational and packing energy calculations
Authors: Napolitano Roberto , Pirozzi Beniamino 
Published: April 2003

AbstractThe polymorphism of trans‐1,4‐polyisoprene is discussed on the basis of conformational and packing energy calculations. These calculations suggest chain conformation and mode of packing for the α and β modifications. Two other chain conformations with a c axis near to that of the α modification are energetically accessible.
Emulsion copolymerization of methyl methacrylate with ethyl acrylate, 1. Effect of the initiator concentration on the polymerization behaviour
Authors: Capek Ignác , Tuan Le Quang 
Published: April 2003

AbstractThe emulsion copolymerization of methyl methacrylate with ethyl acrylate, initiated by ammonium persulfate in the presence of both anionic and nonionic emulsifiers, was kinetically investigated at 60°C by the conventional gravimetric method. In the range of low conversions the rate of polymerization was found to be proportional to the 0,5 power of the initiator concentration. Over the range of medium conversions the rate of polymerization is approximately proportional to the 0,35 power of the initiator concentration and the number‐average molecular weight is inversely proportional to the 0,4 power of the initiator concentration. The molecular weight increases up to 30% conversion and then it remains constant up to the total monomer consumption. It was found that the mean particle diameter decreases while the number of particles per volume unit, the conductivity of final latices, the coagulate yield and the number of radicals per particle increase with increasing concentration of the initiator.
Smectic behaviour of linear random copolymers containing the stilbene‐4,4′‐dicarboxy group
Authors: Carfagna Cosimo , Roviello Antonio , Santagata Salvatore , Sirigu Augusto 
Published: April 2003

AbstractCopolymeric systems of the general formula: P1 = {((OCH2CH2)aOR)m ((OCH2CH2)bOR)n}x or P2 = {((OCH2CH2)aOR)m (O(CH2)bOR)n}x with R = OCC6H4CHHCC6H4CO were prepared and their mesophasic properties studied by polarizing microscopy, differential scanning calorimetry and X‐ray diffraction analysis. Enantiotropic smectic mesomorphism was directly observed in most cases. For all systems but P2(a = 2, b = 12) a single smectic phase was observed for all compositions, with a continuous variation of the smectic structural periodicity, isotropization temperatures and molar entropic changes close to the weighted average. This indicates a complete compatibility of the different monomer units in the formation of the smectic layers. On the contrary, system P2 (a = 2, b = 12) exhibits two smectic phases each within a definite range of composition. The two phases are sharply distinct as far as the structural periodicity is concerned. Both phases are present in the mesophasic state of copolymer with m = 75.
Molar mass dependence of rate constants for random scissions of macromolecules
Authors: Elias Hans‐Georg 
Published: April 2003

AbstractReported initial rate constants of the hydrolyses of oligomers and polymers of cellulose and glycine are shown to depend linearly on the inverse of the initial number of cleavable bonds. The slope of this function may be interpreted by many different assumptions on ultimate, penultimate, etc. effects.
Relationship between elastic modulus and volume swelling degree of polymer networks swollen to equilibrium in good diluents, 4. Interpretation of experimental results on the basis of scaling concepts
Authors: Hild Gérard , Okasha Rouzi , Macret Michel , Gnanou Yves 
Published: April 2003

AbstractThe results displayed in the present paper deal with the scaling behaviour of various polymer networks swollen at equilibrium in good diluents. The scaling law, established by de Gennes, between the elastic modulus and the equilibrium segment concentration was tested using polystyrene networks, poly(ethylene oxide) networks, and poly(2,3‐dihydroxypropyl methacrylate) networks. The experimental exponents s obtained are generally in agreement with the expected theoretical value (s = 2,25), especially for networks obtained at high conversion degrees whatever the nature of the polymer or the type of gelation. At incomplete conversions, the sol‐fraction is important and the defects are numerous; in this case discrepancies are observed between the theoretical and experimental exponents.
Etude structurale des télomères du méthacrylate d'époxy‐2,3 propyle avec les thiols
Authors: Bessière Jean‐Marie , Boutevin Bernard , Snoussi Mohamed‐Hichem , Taha Mohamed 
Published: April 2003

AbstractThe structure of telomers 5a, b, prepared from 2,3‐epoxypropyl methacrylate (2) and benzenethiol (1a) or 1‐dodecanethiol (1b) by UV irradiation, was studied by MS, IR, 1H and 13C NMR spectroscopy. The IR spectra of the products show that thiol addition occurs only at the double bond of monomer 2. Mono‐ and diadducts could be isolated by fractionation and were characterized spectroscopically together with higher telomers (10 < DPn < 200). Coupling constants and chemical shifts were assigned for the mono‐ and diadducts unambiguously. The tacticity of higher telomers was determined and found to follow the Bernoulli statistics.
Group transfer polymerization of methacrylonitrile
Authors: Bandermann Friedhelm , Witkowski Reiner 
Published: April 2003

AbstractThe group transfer polymerization of methacrylonitrile in acetonitrile, initiated by 2‐(trimethylsilyl)isobutyronitrile in presence of tetraethylammonium cyanide or tetrabutylammonium fluoride as coinitiator, is accompanied by an anionic polymerization initiated by the coinitiator alone so that polymers with bimodal molecular weight distributions are formed. In contrast, with tris(dimethylamino)sulfonium difluorotrimethylsilicate as coinitiator a pure GTP is observed leading to polymers with unimodal molecular weight distribution. In all systems, severe side reactions reduce conversions and molecular weights.
Interferenzeffekte von flüssigkristallinen block‐copolymeren (Einkettenrechnung)
Authors: Bonart Richard , Mulzer Georg 
Published: April 2003

AbstractA previously derived so called BBB‐equation Bonart‐Blackwell‐Biswas11 gives the interference effect of fully elongated statistical copolymer chains taking into account the molecular structure of the monomers. It is a one‐chain calculation neglecting packing effects between neighbouring chains. Starting from the BBB‐equation and taking the A‐ and B‐sequences of A/B‐block copolymers as “super comonomers” a BM‐equation (Bonart‐Mulzer) is found to describe the interference effect of nonstatistical copolymers. The BM‐equation is close to the well known interference function for ideal lamellar stacks given by J. J. Hermans. It contains the length distributions u(z) of A‐and B‐sequences, which, in the case of statistical copolymers are given by Schulz‐Flory statistics. However, any other type of distributions u(z) and v(z) may be considered as well. The BM‐equation thus provides a possibility for the sequence analysis of fully elongated (liquid‐crystalline) non‐random copolymers by X‐ray scattering.
Reactivity of N‐alkylated cyclic iminoether salts having vinyl groups, 4. Radical polymerization and copolymerization of 3‐methyl‐2‐vinyl‐5,6‐dihydro‐4H‐1,3‐oxazinium trifluoromethanesulfonate
Authors: Miyamoto Masatoshi , Sano Yoshiyuki , Saegusa Takeo 
Published: April 2003

AbstractRadical homopolymerization and copolymerizations of a new ionic monomer, 3‐methyl‐2‐vinyl‐5,6‐dihydro‐4H‐1,3‐oxazinium trifluoromethanesulfonate (2c), were studied. The homopolymerization was initiated with 2,2′‐azoisobutyronitrile or benzoyl peroxide in acetonitrile to produce a polymer, poly[1‐(3‐methyl‐5,6‐dihydro‐4H‐1,3‐oxazinium‐2‐yl)ethylene] (3c), with a relatively low solution viscosity ([η] ≈ 0,2). The monomer was found to be copolymerizable with both electron‐rich (styrene and butyl vinyl ether) and electron‐deficient monomers [methyl methacrylate (MMA)]. For the copolymerization of the monomer and MMA the reactivity ratios r1 = 0,31 and r2 = 0,37 (MMA) were determined. From these values the Q and e values were calculated to be 3,7 and 1,9, respectively. The e‐value is one of the highest among vinyl monomers reported thus far, which is consistent with the anionic polymerizability of monomer 2c.
Polymères thiocarboxyliques, 6. Réaction des dithiobenzoates d'ammonium quaternaire sur les chlorométhyloxiranne et ‐thiiranne; mise en évidence de la polymérisation anionique des thiirannes par les dithiocarboxylates d'ammonium quaternaire
Authors: Bonnans‐Plaisance Chantal , Levesque Guy 
Published: April 2003

AbstractThe reaction of quaternary ammonium dithiobenzoates (1) with chloromethyloxirane (2) leads to 1‐phenyl‐7‐oxa‐2,6‐dithiabicyclo[2.2.1]heptane (4) through participation of the thiocarbonyl group. According to the reaction conditions (temperature, concentrations) the same salts react with chloromethylthiirane (7) to give 1‐phenyl‐2,6,7‐trithiabicyclo[2.2.1]heptane (9) and/or substituted polymers of chloromethylthiirane. These results are explained considering the competition between monomolecular or biomolecular reaction paths involving addition of sulfide anions to the thiocarbonyl groups. The postulated reaction mecanisms are in agreement with the efficient anionic polymerization of methyl‐ and ethyl‐thiirane in the presence of quaternary ammonium dithiocarboxylates (aliphatic or aromatic).
Water‐soluble amino acid derivatives of syndiotactic poly(2‐methylallyl alcohol)
Authors: Dernst Christa , Klesper Ernst 
Published: April 2003

AbstractSyndiotactic poly(2‐methylallyl alcohol) was esterified with protected amino acids and carbodiimides as condensing agents to obtain homopolymers with amino acid side chains. The amino acids glycine, L‐proline, and L‐serine and the α‐NH2 protecting groups tert‐butoxycarbonyl and benzyloxycarbonyl, and the OH protecting group tert‐butyl were employed. Consecutively, the blocking groups were removed from the polymers by acidolysis in HBr/CH3COOH to obtain the corresponding deprotected polymers. Potentiometric titration was used to study the water solubility and pKaa values of the deprotected polymers. All polymers were characterized with respect to structure and conversion by 1H and 13C NMR spectroscopy.