bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistics of random macromolecular networks, 2. Stepwise polymerization of polyfunctional monomers bearing A and B coreactive groups
Authors: Durand Dominique , Bruneau Claude‐Marcel 
Published: April 2003

AbstractThe development in the preceding paper is extended to the stepwise polymerization of polyfunctional monomers bearing A and B coreactive groups, a monomer being able to carry together A and B functional groups. The molecular parameters characterizing the post‐gel properties of such macromolecular networks are derived quite as directly as in the order I systems and have expressions which are morphologically analogous.
Liquid crystalline side chain polymers and their behaviour in the electric field
Authors: Ringsdorf Helmut , Zentel Rudolf 
Published: April 2003

AbstractThe electro‐optical properties of liquid crystalline polymers with polar mesogenic units in the side chain were investigated. It could be shown, that in an electric field, they show all effects known from low molecular weight liquid crystals, e.g. the Freedericksz‐transition, the DAP‐effect, the formation of William's domain, and the dynamic scattering. The optical response times are slightly longer than for low molecular weight liquid crystals, but in some cases at higher temperatures as short as 200 ms. By comparison of different polymers and some corresponding liquid crystalline monomers, it is found that: (1) the difference between the measuring temperature and the glass transition temperature mainly determines the optical response times, (2) the fixation of mesogenic groups to a polymer main chain via spacers influences the threshold voltage. Low values are found for long spacers. These results allow a discussion of the influence of polymer fixation of the mesogenic groups on their liquid crystalline properties, pointing to a partial decoupling of the motions of main chains and side chains.
Mathematical properties of polydisperse systems, 3. Calculation of molecular weight distribution from light scattering on gaussian polymer coils. Inversion by means of a nonlinear fit
Authors: Greschner Georg S. 
Published: April 2003

AbstractThe molecular weight distribution (MWD) of a high polymer is calculated from a weakly perturbed Zimm‐plot of the classical light scattering on dilute solutions of Gaussian polymer coils (theta state). A typical Zimm‐plot is simulated corresponding to the measurements of high accuracy as would be obtained by using the laser photometer described by Hack and Meyerhoff. The accuracy as published by these authors for small dissymmetries is used. Two numerical methods for calculating the MWD are briefly described and tested, both using an empirical formula for the Laplace image of the calculated MWD.
Phasentransferkatalysen durch ein polymers mit dibenzo‐18‐krone‐6 als ankergruppe
Authors: Blasius Ewald , Janzen Klaus‐Peter , Klotz Helmut , Toussaint Adrien 
Published: April 2003

AbstractAmong numerous polymers with cyclic polyethers and non‐cyclic ethers as anchor groups, the condensation resin with dibenzo‐18‐crown‐6 as anchor group (℗‐DB‐18‐C‐6), which can be easily prepared, exhibits the best properties for phase‐transfer catalysis. It catalyses substitution, dichlorocarbene and polymerisation reactions which do not take place at all or only in a low yield without the catalyst. For substitution reaction the highest yields are up to 95% in the liquid phase and up to 70% in the gaseous phase. For chlorocarbene reactions yields up to 76% are reached. For the polymerisation of 2‐pyrrolidone, started by potassium 2‐pyrrolidonate, the yield is at 80%.
Chain transfer of alcohols in the polymerization of acrylic esters
Authors: Nandi U. S. , Singh M. , Raghuram P. V. T. 
Published: April 2003

AbstractTransfer constants were determined from the thermal polymerization of methyl, ethyl, and butyl acrylates for methyl, ethyl, propyl, and isopropyl alcohols at 80 °C, utilising “mixedsolvent” systems wherever necessary. It was observed that the chain transfer constant for alcohols is not much affected by lengthening of the ester group in the acrylates, and the reactivity of the solvent is enhanced by an increased substitution at the α‐carbon atom in the alkyl group.
Caractérisation texturale par thermoporométrie et par adsorption‐désorption d'azote de résines à l'état gonflé
Authors: Brun Maurice , Quinson Jean‐François , Spitz Roger , Bartholin Michel 
Published: April 2003

AbstractThermoporometry is applied to determine the porous distribution of different resins in the swollen state. In some particular cases, a comparision is possible with results of the BET‐BJH methods applied to the same products dried by lyophylisation. Such a comparison enables a better understanding of the organisation and the formation of swollen systems. This determination of the porous texture of swollen resins is particularly useful for the understanding and the forecast of the general behaviour of resins.
Symmetric markov trials. Syndiotactic poly(propylene) and heterotactic polymers
Authors: Elias Hans‐Georg 
Published: April 2003

AbstractSymmetric Markov first order mechanisms are defined by equal conditional probabilities for the homotriad formation and a heterotacticity independent of homotacticity. The model predicts linear relationships between homotriad and diad fractions, restricted diad ranges, and a characteristic dependence of the persistence length on the diad fraction. Data on the syndiospecific propylene polymerization are in accordance with this model which also seems to describe heterotactic polymerizations.
Synthese neuer pseudoleiterpolymere mit 7H‐benzimidazo[2,1‐a]benzo[d,e]isochinolin‐7‐on‐3,11‐diyl‐einheiten in der hauptkette
Authors: Jedliński Zbigniew , Gaik Urszula , Kowalski Bogdan , Korshak Vasilii V. , Rusanov Aleksandr L. , Berlin Alla M. , Fidler Saul Kh. 
Published: April 2003

AbstractA series of novel semi‐ladder polymers containing 7H‐benzimidazo[2,1‐a]benzo[d,e]isoquinolin‐7‐on‐3,11‐diyl units in the chain was prepared by one‐step high temperature solution polycondensation of 4,4′‐oxy‐,4,4′‐carbonyl‐, and 4,4′‐sulfonyldi‐1,8‐naphthalenedicarboxylic anhydride (1a‐c) with 2,2′‐diamino‐4,4′‐oxydianiline (2) or 2,2′‐diamino‐4,4′‐hexafluoroisopropylidenedianiline (4). The similarity of the IR and UV spectra of the polymers and the model compounds 7a‐c confirms the presence of the benzimidazobenzoisoquinolinone rings in the polymer chain. All the resulting polymers have excellent thermal stability both in argon and in air. The polymers prepared from 4 are soluble in 1‐methyl‐2‐pyrrolidone and phenol/1,1,2,2‐tetrachloroethane.
Synthesis of casein‐g‐poly(vinyl acetate)
Authors: Mohan Doraiswamyraj , Radhakrishnan Ganga , Rajadurai Sambosankaran 
Published: April 2003

AbstractCasein‐g‐poly(vinyl acetate) was synthesized using potassium persulfate as initiator. Changes in monomer concentration, initiator concentration, backbone concentration, and temperature were effected. The rate of total conversion of monomer, the rate of homopolymerization and graft copolymerization, the grafting efficiency and the percentage of grafting were calculated. The grafting results were discussed in the light of grafting efficiency and percentage of grafting. They were found to be lower in the case of casein‐g‐poly(vinyl acetate) when compared to those of casein‐g‐poly(butyl acrylate).
Identification of polymers by mass spectrometry, 2. Polymers containing 1‐trifluoromethylvinylene, 1,4‐phenylene, and/or 2,5‐thiophenediyl units
Authors: Holzmann Gerhard , KoßMehl Gerhard , Nuck Rolf 
Published: April 2003

AbstractPolymers containing 1‐trifluoromethylvinylene, 1,4‐phenylene, and/or 2,5‐thiophenediyl units (6a, b and 8a‐d), obtained by base‐free Wittig condensation reactions with phase transfer catalysts, were investigated combining direct evaporation in the ion source of a double focusing mass spectrometer with the “Linked‐Scan” metastable technique. This method could be shown to allow the unequivocal identification and differentiation of components in polymers up to high mass regions (m/z ≤ 3000). The degree of polycondensation up to 18 aromatic/heteroaromatic units in the chain was determined by mass chromatography, which correlated with the HPLC results. Terminal groups and sequence ions were characterized by comparison of metastable transitions of selected ions with model compounds. Detailed information on the polycondensation reaction was obtained. In addition to linear products, cyclic species with 3 to 18 arylene‐1‐trifluoromethylvinylene units were formed. The main fragmentations may be explained by sterical effects of both the α‐trifluoromethylstilbene moiety and the heteroaromatic analogues in the polymeric chains.
The effect of electron donors on the polymerization of styrene initiated with organolithium compounds
Authors: Kmínek Ivan , Kašpar Miroslav , Trekoval Jiří 
Published: April 2003

AbstractThe kinetics of the polymerization of styrene with oligostyryllithium and butyllithium in the presence of electron donors was investigated calorimetrically. There is no simple correlation between the accelerating effect (1,2‐dimethoxyethane > tetrahydrofuran > N,N,N′,N′‐tetramethylethylenediamine = triethylamine) of the individual electron donors upon the polymerization and their ability to form complexes with the respective organolithium compounds. This is qualitatively explained by considering preceding coordination reactions between organolithium compounds (or their complexes with electron donors) and the monomer in the reaction scheme. An irreversible degradation reaction between butyllithium and 1,2‐dimethoxyethane occurring at T > 278 K is described. The products of this reaction are lithium methoxide, decane and hexyl methyl ether.
Investigation of the influence of the interaction between anionic detergents and a copolymer of n‐vinyl‐2‐pyrrolidone with vinylamine on the biological activity of these detergents
Authors: Solovsky Mikhail V. , Anufrieva Elizaveta V. , Panarin Evgenii F. , Pautov Vladimir D. , Afinogenov Gennadii, E. 
Published: April 2003

AbstractThe interactions between sodium dodecyl‐ and tetradecylsulfater or sodium alkylbenzenesulfonate and a copolymer of N‐vinylpyrrolidone with vinylamine (9 : 1 by mole) in aqueous solution were investigated by polarized luminescene. Polymer complexes of these anionic detergents with the copolymer were obtained and their antimicrobial and toxic properties as well as their effect on a bacterial enzyme, penicillinase, were investigated, It was found that these polymer complexes do not disintegrate on passing from aqueous to salt solutions, are 4 to 5 times less toxic than the initial anionic detergents and are comparable to the latter in both their antimicrobial activity and the ability for inhibiting penicillinase.
Relation entre les paramètres diélectriques et la cinétique de réaction de polymérisation en phase liquide
Authors: Soualmia Achour , Huraux Claude , Depax Bernard 
Published: April 2003

AbstractThe aim of this study is to characterize the state of progress of a polymerization reaction by a non‐destructive electric method. For this purpose, results deduced from measurements of complex permittivity are compared with those obtained from chemical analysis of the reaction mixture at successive instants of its evolution. Chemical analysis allows the rate of disapperace of expoxy groups during the polymerization reaction in liquid phase to be evaluated. Exploitation of electric measurements of complex relative permittivity enables the evolution of the polymerization to be followed from both the product of the epoxy group concentration and the square of the mean value of their dipole moment and also from the most probable relaxation time of this dipole. As expected, the variations of relaxation time are closely correlated to those of the viscosity of the medium.
Polymere mit phosphor‐stickstoff‐bindungen, 6. Zur polymerisation von hexakis(2,2,2‐trifluorethoxy)cyclotriphosphazen bei anwesenheit von bortrichlorid
Authors: Horn Hans‐Georg , Kolkmann Friedrich 
Published: April 2003

AbstractHexakis(2,2,2‐trifluorethoxy)cyclotriphosphazene (1b) reacts with borontrichloride at elevated temperatures to give a mixture of polymeric phosphazenes containing imino dichloro and imino bis(trifluoroethoxy)phosphoranetriyle units. The reaction was investigated by 31P NMR. Separation of several fractions of polymers was achieved by hexane/benzene solvent extraction. Molecular weights have been determined by means of membrane and/or vapor pressure osmometry. A reaction mechanism is discussed.
Electron‐transfer reaction of a copper(II) complex bound to an amphiphilic block copolymer: A plastocyanin model
Authors: Nishide Hiroyuki , Tsuchida Eishun 
Published: April 2003

AbstractA water‐soluble tri‐block copolymer (1) composed of hydrophilic poly(ethylene oxide) and hydrophobic poly(styrene‐co‐1‐vinylimidazole) was synthesized as a model compound of the apoenzyme of plastocyanin. Visible and electron spin resonance spectra of the Cu complex bound to the imidazole residue of 1 showed that the Cu complex is surrounded by a hydrophobic domain even in aqueous medium. The outer‐sphere electron‐transfer reaction of Cu(II) with Fe(II) (phenanthroline)3 proceeded faster (with a large activation entropy) for the polymeric Cu/1 complex than for the monomeric Cu/1‐ethylimidazole complex, while the reduction with ascorbic acid was slower for the polymeric complex.
Synthesis and free radical ring‐opening polymerization of 2‐methylene‐4‐phenyl‐1,3‐dioxolane
Authors: Bailey William J. , Wu Shang‐Ren , Ni Zhende 
Published: April 2003

AbstractThe cyclic ketene acetal, 2‐methylene‐4‐phenyl‐1,3‐dioxolane (3), was shown to undergo free radical ring‐opening polymerization to produce the polyester, poly[γ‐(β‐phenyl)butyrolactone]. The monomer 3 was synthesized by an acetal exchange reaction of chloroacetaldehyde dimethyl acetal with styrene glycol in an 87% yield followed by dehydrochlorination of the resulting cis and trans‐2‐chloromethyl‐4‐phenyl‐1,3‐dioxolane (2) with potassium tert‐butoxide in tert‐butyl alcohol in a 70% yield. 3 was shown to undergo essentially quantitative free radical ring‐opening at all temperatures from 60–150°C and also nearly complete regioselective ring‐opening with cleavage to give the more highly stable secondary benzyl free radical. Even in free radical copolymerization with styrene, methyl methacrylate, vinyl acetate, or 4‐vinylpyridine, 3 gives essentially complete ring opening to introduce an ester groups into the backbone of the addition copolymer. The structures of the polymers were established by elemental analysis and 1H and 13C NMR spectroscopy.
Biomimetic approach to the design of a pyridoxal enzyme model, 2. Cyclocopolymerization as a new method of constructing polymers with defined arrangement of functional groups in the chain
Authors: Belokon' Yuri N. , Tararov Vitali I. , Savel'eva Tatiana F. , Lependina Olga L. , Timofeyeva Galina I. , Belikov Vasili M. 
Published: April 2003

AbstractWater‐soluble polyacrylamide samples of various molecular weight, containing salicylaldehyde and lysine moieties, were prepared by copolymerization of (Nα‐5‐methacryloylamino‐salicylidene‐Nϵ‐methacryloyl‐(S)‐lysinato) (pyridine)copper (II) (1) with acrylamide, followed by destruction of the copper complex by the disodium salt of EDTA. It is shown that at pH > 6 the formation of “internal” aldimine occurs in these samples. The degree of assembly of “internal” Schiff base is considerably higher than in the model low‐molecular weight system and does not depend on: a) the molecular weight of the polyacrylamide sample; b) the polymer concentration in buffer solution; c) the presence of a cross‐linking agent. On the basis of these data a conclusion is made that in the copolymerization of 1 with acrylamide, methacryloyl moieties, bonded with the amino groups of salicylaldehyde and lysine, form macrocycles, the cyclocopolymerization rate being much higher than the rate of cross‐linked polymer formation. After the removal of copper ions from the polymer the lysine and salicylaldehyde moieties remain attached to the same polymer chain in the immediate vicinity of each other, thus favouring the formation of “internal” aldimine.
Oligomères amphiphiles obtenus par voie radicalaire, 1. Synthèse et caractérisation d'oligomères de l'acide acrylique à extrémité dodécylthio
Authors: Cellard Bernard , Pichot Christian , Revillon André 
Published: April 2003

AbstractOligomeric emulsifiers were prepared by the technique described by Roe, with special care of composition and molecular weight. Acrylic acid was polymerized in 2‐propanol with lauroyl peroxide as initiator in the presence (at various ratios) of 1‐dodecanethiol (8) as transfer agent to control the chain length. A good agreement was found between the various methods used for kinetic determination and oligomer characterization (1H NMR, sulfur analysis, vapor pressure osmometry, acidimetry, GPC). Values of kpkt‐1/2, transfer constants for thiol 8 and solvent, nature of chain ends, polydispersity, and molecular weight were determined. Polymer fractionation was successfully performed using different solvents for recovery.
Oligomères amphiphiles obtenus par voie radicalaire, 2. Propriétés stabilisantes de latex d'oligomères de l'acide acrylique à extrémité dodécylthio
Authors: Cellard Bernard , Pichot Christian , Revillon André 
Published: April 2003

AbstractThe efficiency of oligomeric acrylic acid with dodecylthio chain ends as emulsifier for stabilizing polymer emulsions (polystyrene as standard and vinyl acetate‐butyl acrylate copolymer latexes) against monovalent (NaCl) and divalent (CaCl2) electrolytes was tested. Oligomers which were not neutralized were found to impart effective stabilization in the presence of both electrolytes. In the case of the potassium salts, a strong stabilization was obtained against NaCl, but a poor one against CaCl2. It appeared that the polymer polarity was of minor importance for controlling the phenomenon. Stability results are interpreted in terms of differences in oligomer adsorption at the water‐polymer interface high ionic charge densities (as expected with the neutralized oligomers), and the steric effect of the hydrophilic sequence in the adsorbed oligomer layer.
Über enzymanalog gebaute polymere, 15. Über die synthese von (R)‐ und von (S)‐1‐(4‐vinylopohenyl)ethylamin und einiger anderer monomere mit funktionellen gruppen
Authors: Wulff Günter , Gimpel Jürgen , Feld Jochen , Hufnagel Ingo 
Published: April 2003

AbstractThe synthesis of a number of new polymerizable monomers containing functional groups is reported [(R)‐ and (S)‐1‐(4‐vinylphenyl)ethylamine (R)‐5 and (S)‐5, (R), (S)‐N,N‐dimethyl‐1‐(4‐vinylphenyl)ethylamine ((R),(S)‐6, (R), (S)‐trimethyl‐1‐(4‐vinylphenyl)ethylammonium iodide ((R),(S)‐7), dihydroxy‐6‐indenylborane (9), and (S)‐2‐(6‐indentyl)‐4‐methyl‐1,3,2‐dioxaborolane (10)]. By racemic resolution optically pure (R)‐ as well as (S)‐1(4‐vinylphenyl)ethylamine could be obtained. Furthermore dihydroxy(4,6‐dimethyl‐7‐indeyl)borane (11) was synthesized. The products were characterized by NMR spectroscopy.
Configurational characteristics of the polysulfides, 1. Dipole moments of poly(pentamethylene sulfide)
Authors: Riande E. , Guzman J. , Welsh W. J. , Mark J. E. 
Published: April 2003

AbstractPoly(pentamethylene sulfide)Structure‐based name: poly(thiopentamethylene).
(P5MS) [S(CH2)5]x was prepared by the condensation polymerization of nearly equimolar amounts of pentamethylene dibromide and the sodium salt of 1,5‐pentanedithiol. Selective precipitations were used to obtain a fraction of the polymer, and dielectric constant measurements on solutions of it in benzene were used to obtain dipole moments over the range 20–60°C. Rotational isomeric state calculations based on conformational energies obtained from semiempirical potential energy functions gave results in fair agreement with experiment. Since extensive previous studies on a number of polyoxides have demonstrated the difficulty in calculating the energy of the O…CH2 interactions, the energy of the corresponding S…CH2 interactions in P5MS was adjusted to obtain better agreement between theory and experiment.
Selective step‐growth phenol‐aldehyde polymerization, 1. Synthesis, characterization and X‐ray analysis of linear all‐ortho oligonuclear phenolic compounds
Authors: Casiraghi Giovanni , Cornia Mara , Sartori Giovanni , Casnati Giuseppe , Bocchi Vittorio , Andreetti Giovanni Dario 
Published: April 2003

AbstractThe series of dinuclear to nonanuclear all‐ortho methylene‐bridged oligophenols 2–9 has been synthesized according to a repetitive reaction sequence involving the C‐ortho regiospecific condensation of appropriate phenoxymagnesium precursors with salicyl alcohol or paraformaldehyde. IR, UV, mass, 1H and 13C NMR characteristics of these oligomers are discussed. X‐ray crystal structures of 2, 3, and 4 are also reported.
Synthesis of block copolymers containing a carbon chain and a polypeptide block
Authors: Vlasov Gennadij P. , Rudkovskaya Galina D. , Ovsyannikova Lujdmila A. 
Published: April 2003

AbstractThe bifunctional initiators, bis(2‐glycylaminophenyl) disulfide (1) and 2, 2′‐azo‐2,2′‐dimethyl‐dipropionohydrazide (2), were used to obtain polymeric initiators of two types: carbon chain initiators with amino end groups initiating the polymerization of amino acid N‐carboxyanhydrides (NCAs) and symmetric polypeptide initiators containing SS or NN groups, which decompose on exposure to UV light or elevated temperature forming free radicals. These polymeric initiators were used to synthesize block copolymers (BC) containing carbon chain and polypeptide blocks of ABA and AB structures. It is shown that AB block copolymers are capable of aggregation to a much higher extent than those of ABA type. These BC can form liquid‐crystalline polymer structures and undergo controlled biodegradation by enzymes.
Active centre determination in Ziegler‐Natta polymerization. A direct catalyst characterisation method
Authors: Burfield David R. 
Published: April 2003

AbstractIn contrast to conventional approaches to active centre determination in Ziegler‐Natta polymerization, a method is proposed whereby the active catalyst rather than the polymerization system as a whole is studied. The method is based on the observation that addition of non‐polymerizable olefins such as α‐methylstyrene to catalyst systems promoted with Al(iBu)3 leads to displacement of isobutene from the active sites. Active site concentration are derived from quantitative determination of liberated isobutene or labelled cumene derived by quenching the treated catalyst with [O‐3‐H]‐methanol. Values of active site concentration were found to be of the order of 0,3 mmol per mol of V and 2,6 mmol per mol of Ti for VCl3 and TiCl3. AA catalysts, respectively.
Über polyarylenalkenylene und polyheteroarylenalkenylene, 13. Synthesen und charakterisierung von poly (dithieno[3,2‐b: 2′, 2′,3′‐d]thiophen‐2, 6‐diylvinylenarylenvinylen)en und einigen modellverbindungen
Authors: Koßmehl Gerhard , Beimling Peter , Manecke George 
Published: April 2003

AbstractFrom Witting‐reactions of dithieno[3,2‐b: 2′, 3′‐d]thiophene‐2, 6‐dicarboxaldephyde (1) with “mono‐and bis‐Wittig‐salts” of the benzene and thiophene series poly(dithieno[3,2‐b: 2′,3′‐d]‐thiophene‐2,6‐diylvinylenearylenevinylene)s 3a—c and some model compounds 5a—c were obtained. Wittig‐reactions of dithieno[3,2‐b: 2′,3‐d]thiophene‐2‐carboxaldehyde (6) with “mono‐and bis‐Wittig‐salts” gave model compounds 7a—c and 8a, c. The structures of all compounds were confirmed by elements analyses, IR‐and electronic spectra, those of the model compounds additionally by mass spectra, and in case of sufficient solubility by 1 H NMR spectra. The electrical conductivities of all compounds and the thermooxidactive degradation of the polymers 3a, c were investigated.