bluuebunny/crossref_metadata_2025 huggingface dataset:
Strukturuntersuchung von polyestern durch direkten abbau im massenspektrometer, 1. Polyester der terephthalsäure
Authors: Lüderwald Ingo , Urrutia Hernando
Published: April 2003

Die Abbaureaktionen von Poly(äthylenterephthalat) (1a), Poly(tetradeuteroäthylenterephthalat) (1b), Poly(trimethylenterephthalat) (1c) und Poly(tetramethylenterephthalat) (1d) im Massenspektrometer wurden untersucht. Hierzu wurden die Polymeren direkt in der Ionenquelle des Massenspektrometers pyrolysiert und die entstehenden thermischen Bruchstücke durch Elektronenstoß ionisiert und fragmentiert. Die thermisch‐ und elektronenstoßinduzierten Abbaureaktionen lassen sich nebeneinander nachweisen.

Die untersuchten polymeren Terephthalate 1a–d folgen in beiden Abbauschritten den gleichen Mechanismen und können anhand ihrer Pyrolyse‐Massenspektren unterschieden werden.
Block copolymers polybutadiene/poly(benzyl‐L‐glutamate) and polybutadiene/poly(N5‐hydroxypropylglutamine) preparation and structural study by X‐ray and electron microscopy
Authors: Perly Bruno , Douy André , Gallot Bernard
Published: April 2003

AB block copolymers with an amorphous polybutadiene block and a polypeptide block were prepared. The method of synthesis consists in the preparation of a polybutadiene block by anionic polymerization followed by a chemical modification of its living end introducing a primary amine group which is able to intiate the polymerization of the N‐carboxy anhydride (NCA) of the chosen amino acid. By this way the block copolymers polybutadiene/poly(γ‐benzyl L‐glutamate) (14a) were prepared, in which the poly(γ‐benzyl‐L‐glutamate) block could be transformed into a poly(N5‐hydroxypropyl‐L‐glutamine) block by reaction with 3‐amino‐1‐propanol leading to the block copolymers polybutadiene/poly(N5‐hydroxypropylglutamine) (14b). By using X‐ray diffraction and electron microscopy it could be shown that the block copolymers 14a and 14b exhibit mesophases in different solvents and it was established that the structure of the mesophases is lamellar. Each sheet of the lamellar structure consists of the superposition of two layers: one formed by the polybutadiene chains in a more or less random coil conformation; the other formed by the polypeptide chains in an α‐helix conformation, arranged in an hexagonal array and folded.
Molecular weight determination and fractionation of poly(L‐histidine) by gel filtration
Authors: Miyatake Ryuichi , Kumanotani Ju
Published: April 2003

Dextran gel filtration (using Sephadex G‐75 gel) with a continuous monitoring system was applied to the determination of the molecular weight and for fractionation of poly(L‐histidine), poly[imino‐1‐(4‐imidazolylmethyl)‐2‐oxoethylene], (PLH). PLH was eluted satisfactorily with a pH 2,35 buffer, whereas it was adsorbed to the gel with a pH 5,40 buffer. The weight‐average and number‐average molecular weights (Mw and Mn) were determined from the calibration plot of molecular weight, obtained with proteins, and corrected by the Smith method. A highly fractionated “monodisperse” PLH with Mw/Mn = 1,14 to 1,22 was obtained from PLH with Mw/Mn = 1,43 by the use of a pH 4,95 acetic acid/ammonium acetate buffer.
Effect of some additions on the aqueous polymerization of acrylamide, initiated by permanganate‐oxalic acid redox system
Authors: Husain Md. Mukhtar , Gupta Archana
Published: April 2003

The effect of different additives on the aqueous polymerization of acrylamide, initiated by MnO‐oxalic acid redox pair, was studied at 25°C in an atmosphere of nitrogen. It was observed that the rate of polymerization increased in the presence of alkali metal (Li+ to Rb+) chlorides. Cupric chloride and ferric chloride were found to be polymerization retarders. Anionic and cationic detergents showed marked influence on the rate of polymerization. Also, the presence of water‐soluble alcohols lowered the polymerization rates to a sufficient extent.
Polymerization of bicyclic acetals, 5. Cationic polymerization of 6,8‐dioxabicyclo[3.2.1]oct‐3‐ene
Authors: Okada Masahiko , Sumitomo Hiroshi , Komada Hajime
Published: April 2003

The polymerization of 6,8‐dioxabicyclo[3.2.1]oct‐3‐ene (1) was carried out in methylene chloride at temperatures ranging from −78 to 0°C. Boron trifluoride etherate, triethyloxonium tetrafluoroborate, and iodine were used as initiators. Completely or nearly completely soluble polymers were obtained at −78°C in dilute monomer solution, whereas crosslinking occurred to an appreciable extent at higher temperatures or in concentrated monomer solution. 1H NMR and 13C NMR analyses of the soluble polymer, together with its catalytic hydrogenation, disclosed that the cationic polymerization of 1 proceeded, without isomerization of its dihydropyran ring, through the selective cleavage of the C5O6 bond to yield a polyacetal having a 5,6‐dihydro‐2H‐pyran ring in the repeating unit.
Synthesis of polystyrene containing transition metals
Authors: Muñoz‐Escalona Antonio , Di Filippo Giuseppe
Published: April 2003

The synthesis of styrene polymers containing transition metals was achieved by reaction of different polystyrenes with Mt(CO)6 or (CH3CN)3Mt(CO)3, (Mt = Cr, Mo, or W). Atactic, isotactic, and cross‐linked polystyrene (with divinylbenzene) were employed. Organometallic polymers with good stability were only obtained by coordination of tricarbonylchromium groups to the phenyl rings of the polystyrene. Tricarbonylmolybdenum‐ and tricarbonyltungsten complexed polystyrene showed very poor stability and could not be isolated. The amount of chromium incorporated depends on the molecular structure of the polymers, the chromiumcarbonyl complex used in the reaction, and the reaction time. The reactivity of the tris(acetonitrile)tricarbonylmetal‐complexes is higher than that of the hexacarbonylmetal‐complexes and the addition reactivity of the polymers is in the order: atactic > isotactic > cross‐linked polystyrene
New catalysts for the oxidative polymerization of 2,6‐dimethylphenol, 2. Complexes of manganese with toluene‐3,4‐dithiol and with 2,3‐dimercaptomaleodinitrile
Authors: Kaneko Masao
Published: April 2003

It was found that the manganese complex formed from toluene‐3,4‐dithiol and MnCl2 (Mn‐TDT) and the complex formed from disodium 1,2‐dicyanoethylenedithiolate (maleonitriledithiol) (Mn‐MNT) show high activities as catalysts for the oxidative polymerization of 2,6‐dimethylphenol. Mn‐TDT is active only in the presence of an alkaline agent such as potassium hydroxide. Its activity is still higher when it is synthesized in ethanol and isolated just before use. Mn‐MNT is similarly active without being isolated, and it is active even in the absence of potassium hydroxide when the mole ratio MNT/Mn is high. This is probably due to the alkaline character of MNT. Mn‐TDT or Mn‐MNT complex produce poly[oxy(2,6‐dimethyl‐1,4‐phenylene)] selectively, and no formation of the diphenoquinone 2,2′,6,6′‐tetramethyl‐1,1′‐dioxo‐4,4′‐bicyclohexa‐2,5‐dienylidene was observed.
Mechanismus der NCA‐Polymerisation, 4. Synthese und Reaktionen von N‐Acyl‐NCA
Authors: Kricheldorf Hans R.
Published: April 2003

Various N‐acyl NCAs (8a–c, 14, 15) were prepared by reaction of N‐acyl‐N‐trimethylsilylglycine trimethylsilyl esters (7a–c) with phosgen or by addition of NCAs or of N‐thiocarboxylic acid anhydrides (NTAs) on chlorosulfonyl isocyanate. Furthermore, the direct acylation of 4,4‐dimethylglycine NCA and of several NTAs could be achieved with 3,5‐dinitrobenzoyl chloride and triethylamine, a reaction, that involves NCA‐anions 3 as intermediates, in analogy with the sulfenylation and silylation of NCAs 1. N‐Acyl NCAs (3‐acyloxazolidine‐2,5‐diones) react with nucleophils exclusively at the carbonyl group C‐5. The addition of N‐acyl NCAs to a NCA‐polymerization initiated by a tertiary amine enhances the rate of the polymerization, but lowers the polymerization degree, because any N‐acyl NCA starts a growing chain by reaction with the NCA‐anions 3. The NCA‐polymerization with high ratios of N‐acyl NCA/NCA (1:4) yields, therefore, oligopeptides 20, which show an acyl and an NCA endgroup in the IR‐ and the 1H NMR spectrum. If the NCA‐polymerization initiated by a tertiary amine is carried out in the presence of isocyanates, polypeptides with an urea and an NCA endgroup are obtained (25). These results prove, that the so called “activated monomer mechanism” is predominating in the case of the polymerization of N‐unsubstituted NCAs 1 initiated by a tertiary amine. Pyridine as a weak base gives in high concentrations the same results as the strong base triethylamine. No evidence is found for a “zwitterionic mechanism” as with N‐alkyl NCAs 2 described in Part 3 of this series. For the polymerization of four different NCAs 1 initiated with pyridine the relationships between reduced viscosity (ηsp/c) and conversion were established. These curves show for a 0 to 95% conversion a kinetic behaviour similar to a “living polymerization”; but from 95 to 100% conversion the viscosity increases exponentially due to condensation steps. The concentration of NCA end groups decreases by condensation and termination reactions even after 100% conversion of the monomers 1. Various initiation, propagation, and termination reactions are discussed.
Synthèse de polymères ω‐hydroperoxyde
Authors: Catala Jean‐Marie , Riess Gérard , Brossas Jean
Published: April 2003

The general conditions are described for the synthesis of ω‐hydroperoxy polymers by reaction of oxygen with CLi bonds of anionic living polymers. Secondary reactions as interchain coupling and the formation of alcohols are also discussed. In order to obtain a quantitative hydroperoxydation the following experimental parameters must be observed: (a) slow addition of the living solution to a polar solvent saturated by oxygen; (b) low concentration of living ends; (c) bulky terminal units; (d) lowest possible temperature.
Mechanism of the formation of macrocycles during the cationic polymerization of cyclotrisiloxanes. End to end ring closure versus ring expansion
Authors: Chojnowski Julian , Ścibiorek Marek , Kowalski Józef
Published: April 2003

Studies of the distribution of cyclic oligomers formed in the first step of the cationic polymerization of hexamethylcyclotrisiloxane disclosed a correlation between the kinetically controlled concentrations of cyclic species and the statistical conformations adopted by the corresponding acyclic chains. The correlation found experimentally is in good agreement with the theoretical one predicted by the macrocyclization theory for non‐equilibrium chemical system and can be taken as evidence for the formation of macrocycles (even those containing about 100 atoms in the skeleton) by the intramolecular reaction between chain ends, a process which competes with the linear growth of the macromolecule. This approach may be useful in solving mechanistic problems involving polyreactions.
Polymerization of propadiene by some η‐allylic derivatives of rhodium(III)
Authors: Giarrusso Antonino , Gronchi Paolo , Ingrosso Giovanni , Porri Lido
Published: April 2003

An investigation has been carried out on the polymerization of propadiene (allene) by several η‐allylic derivatives of rhodium(III). Polymers of a high structural regularity were obtained, along with liquid oligomers, at ca. 70°C. The results are compared with those obtained using complexes of rhodium(I) as catalysts. The catalytic cycle is interpreted on the basis of the formation of a complex of rhodium(III) in the initiation and of a complex of rhodium(I) in the termination.
Polymerization of acrylamide photoinitiated by cobalt ammine complexes
Authors: Bhaduri Ramananda , Aditya Sukumar
Published: April 2003

The kinetics of polymerization photoinitiated by pentaammineoxalatocobalt(III) and tetraamminebis(oxalato)cobalt(III)complexes were investigated in aqueous and mixed solvents by irradiation of these complexes in the charge‐transfer bands at 35°C. Radiation of wavelength 420 nm was employed and the kinetics were followed by measurement of the rate of monomer disappearance (gravimetrically) and chain lengths of polymer formed (viscometrically). The dependence of the rate of polymerization and of the chain lengths on factors like absorbed light intensity, light absorption fraction, monomer concentration, initiator concentration, hydrogen ion concentration, viscosity of the medium, and the nature of the outer anion were studied in detail. A kinetic scheme is proposed and discussed in the light of experimental results, involving (i) a primary photo‐chemical act of excitation of the complex, followed by dark reaction of electron transfer within the complex, producing free radicals and bivalent Co2+ ions, (ii) initiation of polymerization by the free radicals generated, and (iii) termination of the active chain by a mixed process, namely mutual termination of macroradicals as well as termination by the complex depending on experimental condition.
Polymer‐cosolvent systems, 1. Polystyrene in acetone/cyclohexane mixtures
Authors: Deb Pramil C. , Prasad Jagdish , Chatterjee Satya R.
Published: April 2003

Attempts were made to explain the cosolvency or the solubilisation of polystyrene in cyclohexane/acetone mixtures at 30°C. Cyclohexane is a Φ‐solvent for polystyrene at 35°C. and acetone is a non‐solvent. The effective interaction parameter χms of Scott has been determined for the optimum solvent composition from the slope of a Stockmayer‐Fixman plot as modified by Yamakawa. The value of unperturbed dimension obtained for polystyrene at this solvent composition coincides very well with that obtained in cyclohexane (Θ‐solvent). The binary interaction parameter χ12, between the two liquids obtained from χms shows a certain amount of incompatibility between them. The values of λ*, the preferential adsorption coefficient, were calculated for the entire solvent spectrum assuming the binary interaction parameters χij as being independent of solvent composition. The inversion point (λ* = 0), the optimum solvent composition yielding [η]max, and the importance of χ123, the ternary interaction parameter, are discussed.
The flexibility of poly(2,4,5‐trichlorophenyl methacrylate)
Authors: Hadjichristidis Nikos
Published: April 2003

Light scattering in benzene and intrinsic viscosities [η] in tetrahydrofuran, chloroform, 1,4‐dioxane, and benzene of poly(2,4,5‐trichlorophenyl methacrylate) (PTCPh) were measured in dilute solutions. Relations between [η], z‐average root‐mean‐square end‐to‐end distance (r2z)1/2, and molecular weight M̄w were established. The unperturbed dimensions, calculated from viscometric and light scattering data by different methods, are in excellent agreement with one another. PTCPh has a lower flexibility factor (σ = 2,37) than poly(phenyl methacrylate) (σ = 2,5), in spite of the higher bulkiness of the side group of PTCPh. It seems, therefore, reasonable to suggest that the presence of the chlorine atoms hinders partly the interactions between the aromatic groups.
The 13C NMR spectra of poly(1‐pentenylene) and poly(1,3‐cyclopentylenevinylene)
Authors: Ivin Kenneth J. , Laverty D. Theodore , Rooney John J.
Published: April 2003

13C NMR spectra were obtained for polymers made by ring‐opening polymerization of cyclopentene and bicyclo[2.2.1]hept‐2‐ene respectively. The fraction of cis double bonds could be determined with much greater precision from 13C NMR spectra than from IR spectra and varied from 0,66 to 0,31 for the samples of poly(1‐pentenylene), (2), and from 1,0 to 0,14 for the samples of poly(1,3‐cyclopentylenevinylene), (4). This is the first time an all‐cis polymer of 4 has been reported.

The spectra of 2 showed a cis (upfield) and trans (downfield) peak for each of CH and α‐CH2, but only one peak for β‐CH2. The spectra of 4 showed multiple fine structure, the main splittings corresponding to a cis (upfield) and trans (downfield) peak for α‐CH, and a reverse line order for the other three carbons; subsidiary splittings were observed for all but the olefinic carbons, interpreted in terms of sensitivity of the chemical shifts to the cis/trans structure at the next nearest double bond. A complete interpretation of the line orders in 4 is given in terms of steric compression effects. The possibility that ring tacticity accounts for some of the fine structure cannot be entirely discounted.

The stereochemistry of 4 is discussed in relation to the four possible modes of addition of monomer to a carbene chain carrier during polymerization.
Phénomènes cinétiques associés à la transition vitreuse du polyisoprène de structure 1,4 prépondérante
Authors: Prud'homme Jacques , Goursot Paul , Laramée André
Published: April 2003

The thermal behavior of polyisoprene with a high content of 1,4 structures prepared by anionic polymerization has been investigated in the glass transition interval by means of differential scanning calorimetry (DSC). This polymer is of particular interest since it has a low glass transition temperature Tg and shows a substantial increase in heat capacity in the glass transition interval. When the thermal history of the polymer is fixed by linear cooling, the dependence of Tg (measured at the inflexion point of the experimental curve) on heating rate q, can be expressed by q=constant × exp{−E/(RTg)} where E varies from 127 to 144 kJ/mol when the cooling rate decreases from 80 to 1.25 K/min. It is shown that this behavior is consistent with a kinetic model for glass transition involving a simple relaxation process characterized by an energy of activation close to E.
Heats of mixing of polyriboadenylic acid and polyribouridylic acid in aqueous NaCl solution
Authors: Baba Yoshihiro , Tanaka Shigeyuki , Kagemoto Akihiro
Published: April 2003

The heats of mixing of polyriboadenylic acid (Poly A) and polyribouridylic acid (Poly U) in various proportions by changing the mole ratio n = [Poly U]/[Poly A] in 0,001, 0,1, and 0,5 molar NaCl solutions containing 0,1 molar tris‐HCl buffer solution were measured. Constant values for the heats of mixing of the (Poly A+n Poly U) system are found for n ≤ 1 and n ≥ 2. From the results of UV and CD spectra, it may be considered that the mixing of Poly A and n (Poly U) leads to the formation of Poly(A+U) for n ≤ 1, and to that of Poly(A+2U) for n ≥ 2, even at [NaCl] = 0,001 mol/l.

The enthalpies of formation of Poly(A+U) and that of Poly(A+2U) depend on the concentration of NaCl. This dependence may be attributed to the differences in conformation of Poly(A+U) in NaCl solution.
Die bestimmung der molekulargewichtsverteilung von nichtkristallisierenden polymeren mit dem elektronenmikroskop, 7. Präparation durch verdampfung des lösungsmittels aus lösung
Authors: Koszterszitz G. , Schulz G. V.
Published: April 2003

A preparation method is described by means of which it is possible to transfer individual molecules of a high molecular weight polymer on a support, in order to determine their mass and therefrom their molecular weight distribution, using our previously published electron microscopic method.

The advantages of the new procedure as compared to the previously described freeze‐drying are 1 that the range of solvents, which can be used is much larger, and 2 that the preparation is performed by evaporation from a dilute solution, which means that the molecules are distributed statistically on the support. The risk of formation of associates is avoided by keeping the polymer concentration correspondingly low and the rate of evaporation high. As examples the results for three samples of poly(methyl methacrylate) and one sample of natural rubber are reported and discussed.
Polymerization of vinyl acetate with 1,1′‐diacetoxy‐1,1′‐diphenylazoethane
Authors: Može Adolf , Vizovišek Ivan , Lapanje Savo
Published: April 2003

The kinetic and thermal parameters for the decomposition of 1,1′‐diacetoxy‐1,1′‐diphenylazoethane were determined using differential scanning calorimetry (DSC). The activation energy for decomposition is 145,1 kJ/mol, the heat of decomposition is −231,6 kJ/mol, and the rate constant (kd in s−1) obeys the relation in kd = 40,43 − (17460 K/T). This compound was used as initiator for the bulk polymerization of vinyl acetate. The polymerization was studied at 50, 55, 60, and 65°C. The rate of polymerization was followed dilatometrically. The per cent shrinkage was calculated from the partial specific volumes of polyvinyl acetate in vinyl acetate. The partial specific volumes were determined by means of an automatic digital densimeter. The number average of polymerization was obtained from viscosity data. The reaction order with respect to initiator concentration is smaller than 0,5 (between 0,27 and 0,31). The deviation is explained in terms of primary radical termination.

The bulk polymerization of vinyl acetate at 65°C using both 1,1′‐diacetoxy‐1,1′‐diphenylazoethane and 2,2′‐azodiisobutyronitrile as initiators was also investigated by DSC technique. The data were used for obtaining various kinetic parameters.
Polymere ester von säuren des phosphors, 6. Ringöffnende polymerisation cyclischer phosphite und phosphonite durch michaelis‐arbuzov‐reaktion.–Theorie zur struktur der hauptkette
Authors: Vogt Walter
Published: April 2003

The hypothesis of Harwood and Patel, suggesting for the polymerization of 2‐phenyl‐1,3,2‐dioxaphospholane a type of insertion reaction to explain the formation of ethylenediphosphinic ester structures besides the normal 2‐hydroxyethyl(phenyl)phosphonic ester structures is extended to similar monomers and its theoretical consequences are examined. It is shown that in such a system mutual transformations between ω‐hydroxyalkyl‐P‐acid and alkylenedi(P‐acid)structures should occur, establishing a dynamic equilibrium and leading to a sort of azeotropic polymer, in which only one unique composition is kinetically stable. Equations relating to different kinetic parameters are deduced.
Polymerization of lactams, 21. effect of activating agents on the anionic polymerization of 2‐pyrrolidone
Authors: Roda Jan , Kušková Marie , Králíček Jaroslav
Published: April 2003

The activated anionic polymerization of 2‐pyrrolidone (1a) was studied by using N‐potassium‐2‐pyrrolidone (1e) as initiator in a 1:1 mole ratio with N‐acetyl‐ (1b), N‐benzoyl‐ (1c), and N‐pivaloyl‐2‐pyrrolidone (1d), N‐benzoyl‐8‐octanelactam (2a) or N‐benzoyl‐12‐dodecanelactam (2b) as activators in the heterogeneous stage of the polymerization process under isothermal conditions.
The unperturbed dimensions of poly(2‐hydroxyethyl methacrylate)
Authors: Fort Richard J. , Polyzoidis Theodoros M.
Published: April 2003

Values of the unperturbed dimensions of poly(2‐hydroxyethyl methacrylate) have been determined in five non‐ideal solvents using viscometric data and a number of different theoretical treatments. Values of the steric factor σ, the characteristic ratio C∞ and the expansion factor α were also calculated. There was some variation of all these parameters with solvent but on the whole they were comparable to values for polymethacrylates with non‐polar side groups of a similar size.
Étude de la gélification d'un système triol/diacide/monoacide avec effect de substitution sur le triol
Authors: Durand Dominique , Bruneau Claude‐Marcel
Published: April 2003

Using a new general formulation of Flory's gelation criterion, a critical transition equation is derived for the trimethylolpropane (2,2‐bis(hydroxymethyl)‐1‐butanol)/adipic acid/lauric acid system having a substitution effect on the hydroxyl groups of the triol. The successive reactivity of the hydroxyl groups present in the trimethylolpropane has been formulated by the study of the condensation of the triol with the monoacid, lauric acid. From GPC measurements of the reaction medium for various degrees of conversion, the distribution curves of the different molecular species are plotted. Examination of these distribution curves has shown a non‐equireactivity of the sites of the polyol, which may be assigned to a positive substitution effect. Comparison of experimental distribution curves with the results of the kinetic analysis allows one to quantify the substitution effect. The gelation equation shows that a positive substitution effect on the hydroxyl groups of the triol decreases the extent of reaction necessary for the gelation. The difference between the experimental gelation curves and the theoretical curves with substitution effect may be assigned to intramolecular reactions.
Synthèse par voie radicalaire de polymères à extrémités hydroxylées, 6. Etude des réactions de transfert
Authors: Brosse Jean‐Claude , Legeay Gilbert , Lenain Jean‐Claude , Bonnier Maryvonne , Pinazzi Christian
Published: April 2003

Radical polymerizations in an alcohol, initiated by hydrogen peroxide were found to afford polymers with hydroxyl end groups. The constants of chain transfer to the initiator and to the alcohol were determined for the polymerization of vinyl acetate, isoprene, and butadiene. The results show the influence of the initiator and the nature of the alcohol in the polymerization mechanism.
Polymere aus Nitrilen, 5. Anionische polymerisation von fumaronitril. Kinetik und Mechanismus zur synthese eines molekulareinheitlichen oligomeren
Authors: Helling Günter , Wöhrle Dieter
Published: April 2003

Fumaronitrile can polymerize quantitatively under mild conditions with anionic initiators. With the initiator butyllithium the kinetics is examined with the help of the 1H NMR method. The mechanism of the polymerisation is described which is different in polar and unpolar solvents. In THF an electrontransfer mechanism is responsible for a molecularly uniform oligomer of structure 5 which does not contain the initiator. In benzene or hexane normal anionic addition of the initiator to the CN‐group of the monomer leads to oligomer 7.
Dynamic mechanical behaviour of linear polyamides with different degree of unsaturation in the chain
Authors: de Candia Francesco , Maglio Giovanni , Palumbo Rosario , Tortorella Vincenzo , Vittoria Vittoria
Published: April 2003

The dynamic mechanical behaviour of polyamide systems containing different degrees of unsaturation was analyzed. The results do not show any simple relation between unsaturation and mechanical response. Particular attention was given to the α‐transition, that is a glass transition, and experimental data suggest that the generally accepted mechanism for this transition requires a more extensive study.
X‐Ray diffraction and iodine adsorption of acid modified cellulose fibers
Authors: Shinouda Hakim Grace , Kinawi Anwar , Abdel‐Moteleb Mohamed Magdy
Published: April 2003

The crystallinity of acid modified fibers prepared from viscose rayon and cotton cellulose is determined by x‐ray diffraction and iodine adsorption methods. The results are analysed and interpreted in the light of the definition of each method. In addition, the role of low fractions as well as the effect of vacuum drying on the measured crystallinity are discussed. The literature shows a lack of consistency between crystallinity determined for cellulosic fobers using different methods. The present work is an attempt to analyse the crystallinities of hydrocellulose residues determined by the x‐ray diffraction and the iodine adsorption methods.
Das umalkylidenierungsverhalten von polybutadienen mit erhöhtem anteil an 1,2‐Einheiten
Authors: Čanji Ema , Perner Helmut
Published: April 2003

The olefin polymer metathesis reaction in the case of polybutadienes is influenced by the nature of the connection and the distribution of the 1,2‐units.
Interferenzmikroskopische Charakterisierung von Faserstrukturen, 2. Der Einfluß des Schrumpfes beim Thermofixieren von Polyäthylenterephthalat‐fasern mit extrem unterschiedlicher radialer Struktur
Authors: Kühnle Gerhard , Schollmeyer Eckhard , Herlinger Heinz
Published: April 2003

The change of the radial structure during the thermofixation of poly(ethylene terephthalate), [poly(oxyethyleneoxyterephthaloyl)], fibres with and without shrinkage is studied.

The fibre structure is described by interferometric measurements, which allow statements about order and orientation as a function of the fibre radius. The fibre interferograms are interpreted by an analytical model, which has been developed in the first part of this series.
Interaction between dyes and polyelectrolytes, 9. Effect of polyanions on alkaline fading reaction of methylene blue
Authors: Shirai Masamitsu , Yamashita Makoto , Tanaka Makoto
Published: April 2003

The effect of polyanions poly(potassium vinyl sulfate) (PVS), poly(sodium acrylate) (PANa), and poly(potassium p‐styrenesulfonate) (PSS), on the alkaline fading reaction of methylene blue (1) was investigated. The fading rate of 1 was extremely retarded on addition of polyanions. The binding type of 1 to polyanions was investigated spectrophotometrically by following the changes in the molar absorption coefficient (ε) at 664nm band. The relationship between the binding type and the fading rate of 1 in aqueous alkaline solution of polyanions is discussed.
Stufenweise Darstellung von Cyclo{quater[(5‐alkyl‐2‐hydroxy‐1,3‐phenylen)methylen]}en und ihr Vergleich mit linearen phenolischen Mehrkernverbindungen
Authors: Kämmerer Hermann , Happel Günter
Published: April 2003

The stepwise syntheses of cyclo{quater[(5‐alkyl‐2‐hydroxy‐1,3‐phenylene)methylene]}s (5) are described and compared with a one‐flask reaction procedure. The structures of the cyclic compounds 5 are analytically confirmed and their properties were compared with those of linear phenol formaldehyde condensates which have very similar structures and molecular weights.
Crystallization of glycine/β‐benzyl‐L‐aspartate copolymer in the course of polymerization
Authors: Kim Kea Yong , Kōmoto Tadashi , Kawai Tohru
Published: April 2003

In order to examine the structure and growth mechanism of copolymer crystals formed during polymerization, the heterogeneous copolymerization of glycine N‐carboxy anhydride and β‐benzyl‐L‐aspartate N‐carboxy anhydride, initiated by butylamine, was studied in acetonitrile. In all the copolymerization systems, the crystal growth took place through formation of the cross‐β structure, i.e., the introduction of glycine residues into the poly(β‐benzyl‐L‐aspartate) chain during this particular copolymerization broke the α‐helix of poly(β‐benzyl‐L‐aspartate). The growth mechanism of the copolymer crystals was compared with that for poly(β‐benzyl‐L‐aspartate) crystals reported previously.
Ringförmige verbindungen – bessere lösungsmittel für makromoleküle als die entsprechenden linearen
Authors: Horacek Heinrich
Published: April 2003

Polymers were dissolved in cyclic and linear compounds, in their di‐, tri‐ and n‐meres or in hydrocarbons, ethers, ketones, alcohols, chlorides and amines. Solutions of macromolecules in corresponding pairs of solvents exerted different activities, viscosities, and excess volumina. This result is explained by the measured diagrams of state or phases: For solutions of cyclic compounds the temperatures of experiments are farther away from those of phase separation; therefore, lower activities, higher viscosities, and smaller excess volumina are observed. From the larger area of infinite miscibility the common rule is derived that cyclic compounds are better solvents for macromolecules than the corresponding linear ones. The higher power of dissolution becomes evident considering the reduction of endgroups by polymerization as well as by cyclization. This compression of material increases density, viscosity, decreases cubic coefficient of expansion, compressibility and thus diminishes the difference between polymers and solvents. As the solubility parameter takes account of the more dense state of polymers, it is in many cases greater than that one of monomer or low molecular compound, which has to be adjusted to that of the polymer by cyclization. Recent thermodynamic calculations describe qualitatively the different dissolution power of cyclic and linear solvents by their different, P, V, T‐data.
Polymerization and quaternization of 1‐(2‐diethylaminoethyl)‐4‐vinylbenzene: A new cationic polyelectrolyte
Authors: Kataoka Kazunori , Tsuruta Teiji
Published: April 2003

Diethylamination of 1,4‐divinylbenzene catalyzed by lithium diethylamide gave rise to 1‐(2‐diethylaminoethyl)‐4‐vinylbenzene (3), quantitatively. Subsequent quaternization of 3 with ethyl bromide gave a cationic monomer, 4‐vinylphenethyltriethylammonium bromide (7). High molecular weight polymers, poly[1‐{4‐[2‐(diethylamino)ethyl]phenyl}ethylene] (5) and poly[1‐{4‐[2‐(triethylammonio)ethyl]phenyl}ethylene bromide] (8), were prepared from 3 and 7, respectively, by using radical initiators, especially with redox‐type ones. Anionic polymerization of 3 was also carried out. The relationship between the polymerization condition and the stereoregularity of the polymer was studied by Carbon‐13 NMR spectroscopy. A polyion complex (10) was prepared from 8 in combination with poly(sodium 4‐vinylbenzenesulfonate) (9) to evaluate its properties as biomedical material.
Cationic degradation of poly(propylene sulfide)
Authors: Simonds Ronald P. , Goethals Eric J.
Published: April 2003

Introduction of small amounts of sulfonium ions in poly(thiopropylene) (poly(propylene sulfide)) by means of triethyloxonium tetrafluoroborate was found to result in a rapid degradation reaction, first leading to low molecular weight polymers and ultimately to a mixture of low molecular weight cyclic products and propene. The reaction mixtures were analyzed by gas liquid chromatography, mass spectroscopy and, when the compounds could be isolated in sufficient amounts, by 1H NMR spectroscopy. The composition of the end product mixture was shown to depend on the concentration of sulfonium ions introduced at the beginning. With low initiator concentrations (≈ 10−3 mol.l−1) the main degradation product was found to be cyclic tetramer accompanied by decreasing amounts of cyclic pentamer, hexamer etc., and with high initiator concentrations (> 10−2 mol.l−1) the main degradation products are a mixture of dimethyl‐1,2,5‐trithiepanes and propene.
Réticulation anionique du polystyrène en présence de chaînes polymériques libres
Authors: Widmaier Jean‐Michel
Published: April 2003

Semi‐interpenetrating polymeric networks based on polystyrene were prepared by anionic polymerisation. Factors affecting synthesis, such as composition, molecular weight of either the unattached polystyrene or the polystyrene between crosslinks, have been varied. Their effect on network formation was examined by extraction experiments and swelling measurements.
Statistics of polyfunctional polycondensates formed under restrictions
Authors: Müller Michael , Burchard Walther
Published: April 2003

The scattering behaviour and the critical conditions where gelation takes place have been calculated for polycondensates formed under constraints. The general model includes fully random and stringently restricted reactions as limiting cases. Also polycondensates of glycerine‐type monomers are included as special cases. The particle scattering factors of the f‐functional random polycondensates differ remarkably from those polycondensates formed under strict constraints. The former show a Kratky plot of a simple curve, independent of the magnitude of the molecular weight and the number of functional groups, and the curve approaches a constant asymptote of u2·Pz(u)=3, the latter exhibits a maximum at u2=6 which becomes more pronounced with increasing molecular weight, (u2 = 〈S2〉zh2, with h, the value of the scattering vector). The scattering curves of the polycondensates formed under weak constraints show at low molecular weights the same behaviour as those formed under stringent constraints, but approach the behaviour of random polycondensates at large molecular weights. The scattering curves of the glycerine‐type polycondensates show no deviations in shape from random polycondensates.
Synthèse et étude structurale de copolymères séquencés polyisoprène‐poly(vinyl‐2 pyridine) et polyisoprène‐poly(vinyl‐4 pyridine)
Authors: Rossi Joel , Gallot Bernard
Published: April 2003

Block copolymers poly(1,2‐ and 3,4‐isoprene)‐poly(2‐vinylpyridine), poly(cis‐1,4‐isoprene)‐poly(2‐vinyl‐pyridine) and poly(cis 1,4‐isoprene)‐poly(4‐vinylpyridine) were synthesized by anionic polymerization. Their structure in the dry state and in concentrated solution was studied before and after polymerization of the solvent by low angle X ray scattering and by electron microscopy. The existence of lamellar and cylindrical structures was demonstrated. The effects of the copolymer composition, the nature, the concentration and the polymerization of the solvent on the type of structure adopted by the copolymer and on its geometrical parameters were established.
Copolymerisation of 4,4′‐divinylbiphenyl and of 4,4′‐diisopropenylbiphenyl with styrene in solution
Authors: Holdaway Ian , Haward Robert N. , Parsons Ian W.
Published: April 2003

Styrene has been copolymerised with 4,4′‐divinylbiphenyl and with 4,4′‐diisopropenylbiphenyl in 15% toluene solution at 95°C. The copolymers have been analysed via UV spectroscopy, to give estimates of total crosslinker incorporated and of the number of pendant double bonds remaining. Extrapolation of the results—including viscometry—to zero conversion indicates that both crosslinkers form intramolecular linkages (rings). These rings appear to be comparable in size with those formed with p‐divinylbenzene, but to occur rather more frequently. Estimates of copolymerisation reactivity ratios r1 (styrene=1) are, for 4,4′‐divinylbiphenyl 0,77, for 4,4′‐diisopropenylbiphenyl 1,3. It is concluded that, contrary to a previous suggestion, increasing separation of reactive groups leads to more, not less, intramolecular reaction.
Calorimetric study on the formation of polymer complexes through electrostatic interaction and hydrogen bonding
Authors: Abe Koji , Ohno Hiroyuki , Nii Atsushi , Tsuchida Eishun
Published: April 2003

Polymer complexes were formed through electrostatic interaction in poly(methacrylic acid)‐integral type polycation systems and hydrogen bonding in the poly(methacrylic acid)‐poly(N‐vinyl‐2‐pyrrolidone) system in several solvents. The composition of the polyelectrolyte complex was affected by the chemical properties of solvents, e.g., the dissociation of the component polyelectrolyte was interferred with decreasing the polarity of the solvent. The heats of mixing in case of the combination of poly(methacrylic acid)‐poly(N‐vinyl‐2‐pyrrolidone) were negative in N,N‐dimethylformamide but they were positive in water. In polyelectrolyte complex systems, they could not be measured by reason of some experimental difficulties. These results indicate that solvation of the component polymers is very important to clarify the mechanism of the formation of polymer complexes.
1H NMR and 13C NMR spectra of stereoisomers of the methyl methacrylate “dimer”: Dimethyl 2‐methoxymethyl‐2,4‐dimethylglutarate
Authors: Fujishige Shoei
Published: April 2003

Methyl methacrylate oligomers were prepared through anionic oligomerization initiated with sodium methoxide. The pure dimer, isolated by careful fractional distillation, was subjected further to a preparativescale liquid chromatography and separated into its constituent stereoisomers. 1H NMR and 13C NMR spectra of the stereoisomers were studied in various organic solvents at different temperatures. An a priori assignment of the resonance patterns was attained successfully and the fine structures of the spectra were characterized with respect to the stereospecific features of the chemical structure of the stereoisomers.
Measured and calculated solubility of polymers in mixed solvents: Co‐nonsolvency
Authors: Wolf B. A. , Willms M. M.
Published: April 2003

The phenomenon of co‐nonsolvency, i.e. the formation of nonsolvents by mixing two solvents, was studied for the system N,N‐dimethylformamide/cyclohexane/polystyrene (DMF/CH/PS) which is characterized by the fact that the components of the mixed solvent are only incompletely miscible below 48,6°C. A number of quasibinary sections (stepwise addition of the second solvent to given solutions of the polymer in the first solvent) for a sample (M = 110000) of high molecular uniformity yielded a cloud point surface which gives “island curves” (closed solubility gaps) for constant temperatures between the critical temperature of DMF/CH and the top of the cloud point surface (51,3°C). The attainment of equilibrium is facilitated by the addition of DMF to CH or solutions of PS in CH, as compared with the opposite procedure. By means of phase equilibrium experiments tie lines and the critical curve could also be constructed. For a theoretical calculation of the latter from information concerning the binary sub‐systems (e.g. light scattering of PS in DMF) the single liquid approximation was applied to DMF/PS instead of—with respect to miscibility—the more dissimilar DMF/CH; the results are in qualitative accord with experimental observations. Orienting measurements concering the chain length dependence of the partition coefficient in co‐nonsolvent systems indicate that their aptitude for fractionation is considerably worse than that of normal systems under comparable conditions.
Free radicals in colloidal systems: Formation and decay of radicals in the tensides α‐hexadecyl‐ω‐hydroxypoly(oxyethylene) and α‐tetradecyl‐ω‐(sodium sulfonato)tri(oxyethylene)
Authors: Henglein A. , Proske Th.
Published: April 2003

Organic radicals were produced in the tensides C16H33(OCH2CH2)21OH and C14H29(OCH2CH2)3‐SO3Na in aqueous solutions using a short pulse of high energy electrons. The radicals were formed by OH attack on the (OCH2CH2)x‐parts of the tensides. The decay of the 250nm absorption of the radicals was recorded at different initial radical concentrations and tenside concentrations. Several radicals could be produced in one micelle. Radicals formed in the same micelle decay within microseconds or faster. The half life time τ1 in a micelle carrying two radicals is 2,0·10−6 s for C16H33(OCH2CH2)21 OH and less than 6·10−7 s for C14H29(OCH2CH2)3SO3Na. A model for intramicellar radical‐radical reactions is proposed according to which the rate is faster in tensides of high critical micelle concentration. Single radicals in micelles of C16H33(OCH2CH2)21OH can deactivate each other without leaving the micelles. This intermicellar reaction is discussed in terms of the rate of diffusion‐controlled micelle‐micelle encounters, an encounter time of 7·10−8s, and the above time τ1 for intramicellar reaction. The observed rate constant 2k of intermicellar reaction is 3,5·106 mol−1·l·s−1. At low tenside concentrations, the bimolecular rate constant increases since more single tenside radicals are present in solution. They react rapidly (ca. 108 mol−1·l·s−1) with radicals in micelles. Single radicals in C14H33(OCH2CH2)3‐SO3Na micelles cannot directly react with each other because of the Coulombic repulsion between two anionic micelles. Reaction occurs after the exit of a tenside radical from its micelle, the rate of which depends on the micellar equilibrium Mn⇄Mn−1+M (M: tenside molecule; n: agglomeration number of micelle). A single radical in solution reacts with a single radical in a micelle with 2k = 1,0·108 mol−1·l·s−1 and with another single radical in solution with 4,0·107 mol−1·l·s−1.γ‐Irradiation of both tensides in aqueous solution leads to slight increases in viscosity, followed by turbidity beyond the “gel dose” and phase separation. These effects are explained in terms of crosslinking of tenside molecules. Formation of a large network requires bridges between all participating tenside molecules (not only bridges between micelles).
Effect of pressure on the termination rate constant in free radical polymerization. Correlation between rate constant and monomer viscosity
Authors: Ogo Yoshiaki , Kyotani Takashi
Published: April 2003

Viscosities of six kinds of monomers—styrene, methyl methacrylate, butyl methacrylate, butyl acrylate, vinyl acetate, and octyl methacrylate—were measured under high pressures up to 1000 bar at 30°C. The pressure dependences of the viscosities could be well expressed by an exponential function and correlated with the effect of the termination rate constant determined previously. Therefore, the termination constants at various pressures can be predicted by the evaluation of the pressure dependence of the viscosity of the corresponding monomer. The applicability of O'Driscoll's termination theory under high pressure is also discussed.
Elektrokinetische untersuchungen an fasern, 5. Ableitung einer strömungsstromgleichung für ein stabbündelfeld
Authors: Aichele Wilfried , Schollmeyer Eckhard
Published: April 2003

An equation is derived to relate the streaming current of an arrangement of cylinders parallel to a streaming fluid with the zeta‐potential of the solid‐liquid interface. The derivation is in analogy to the principles used by Smoluchowski to calculate the streaming current of a single capillary, i.e. a laminar streaming fluid and the applicability of Poisson's equation. It is shown that both equations are identical.
Equivalent hydrodynamic sphere models for viscosity, sedimentation, and diffusion
Authors: Mahabadi Hadi Kh. , Rudin Alfred
Published: April 2003

Available data for intrinsic viscosity, molecular weight and infinite dilution frictional properties of polymer‐solvent systems are used to establish the relation between the radius, rf, of a “frictional” equivalent sphere applicable to sedimentation and diffusion phenomena, and the radius, rη, of the “viscosity” hydrodynamic sphere. It is found that the experimental data agree with a common equivalent hydrodynamic sphere model in which rη = rf.
15N NMR spectroscopy, 13. Copolymerization of glycine‐N‐carboxyanhydride and β‐alanine‐N‐carboxyanhydride
Authors: Kricheldorf Hans R.
Published: April 2003

In contrast to 13C NMR spectra, 15N NMR spectra allow one to characterize the sequence of copolypeptides built up by glycyl and β‐alanyl residues, because the shifts of the Gly‐Gly, β‐Ala‐Gly, Gly‐β‐Ala, and β‐Ala‐β‐Ala bonds differ from each other by several p.p.m. Hence, the copolymerization of glycine‐NCA and β‐Alanine‐NCA can be investigated by quantitative evaluation of the 15N NMR spectra obtained from the resulting copolymers. The copolymerization of these two amino acid NCAs initiated by primary amines leads to random sequences; the copolymerization is azeotropic in nature, and both copolymerization reactivity ratio parameters are near 1. If aprotic bases like pyridine and triethylamine are used as catalysts, the rate of incorporation of glycine is higher than that of β‐alanine and the copolymers possess a block structure.
Diffusion rayleigh dans le rouge par les solutions de polymères. Application à quelques problèmes
Authors: Millaud Bernard , Strazielle Claude
Published: April 2003

This paper describes how a classical light scattering apparatus (FICA 42000) can be modified in order to allow measurements with red light using a gas laser. This apparatus is calibrated, and experimental results are compared with the theoretical results. The advantages of such measurements are that, when red light is used, one has no fluorescence problems, and the properties of the laser (i.e., collimation, stability and illumination) allow the possibility of simultaneous measurements of both gel permeation chromatography (GPC) and light scattering.
Peroxo salts as initiators of vinyl polymerization, 1. Effect of Ag(I) and Cu(II) on the polymerization of acrylamide initiated by peroxodisulfate ions
Authors: Singh Ulagaraj Chandra , Manickam Subramania pillai P. , Venkatarao Krishnarao
Published: April 2003

The kinetics of polymerization of acrylamide initiated by potassium peroxodisulfate, in the presence and absence of Ag(I) and Cu(II) ions, was studied. The rate law for the polymerization was established. Cu(II) ions were found to reduce both the rate and degree of polymerization.