bluuebunny/crossref_metadata_2025 huggingface dataset:
Polymerizability of methyl substituted 1,3‐dioxolanes
Authors: Okada Masahiko , Mita Koji , Sumitomo Hiroshi
Published: April 2003

The polymerization of 4‐methyl‐, 4,4‐dimethyl‐, cis‐4,5‐dimethyl‐, and trans‐4,5‐dimethyl‐1,3‐dioxolanes was investigated with boron trifluoride etherate and the perchloric acid‐acetic anhydride binary system as initiators. The polymerization of 4‐methyl‐1,3‐dioxolane (1) involves an equilibrium between monomer and polymer, and the polymer consists of alternating oxypropylene and oxymethylene units. The thermodynamic parameters for the polymerization were determined from the temperature dependence of the equilibrium monomer concentrations in the temperature range from −20 to 5°C: ΔH1c = −3,2±0,2kcal/mol and ΔS = −12,7±0,8 cal mol−1 K−1. Dimethyl substituted 1,3‐dioxolanes are very reluctant to polymerize: only a liquid oligomer was obtained in poor yield from cis‐4,5‐dimethyl‐1,3‐dioxolane, and neither polymer nor oligomer was produced from 4,4‐dimethyl‐ and trans‐4,5‐dimethyl‐1,3‐dioxolanes at temperatures above −;78°C. The effect of methyl substituents on the cationic polymerizability of 1,3‐dioxolanes is discussed from the thermodynamic point of view.
Effect of molecular weight distribution of the original polymer on separation characteristics in successive solutional fractionation
Authors: Kamide Kenji , Miyazaki Yukio
Published: April 2003

An attempt has been made to clarify the effect of molecular weight distribution (MWD) in the original polymer on the separation characteristics in successive solutional fractionation (SSF) and comparisons were made with successive precipitational fractionation (SPF). Polymers with Schulz‐Zimm distribution and Wesslau distribution of the degree of polymerization (ratio of the weight‐ to number‐average degree of polymerization, X̄/X̄ = 2 to 5) were brought into solution, and cooled to cause precipitation according to the modified simulative procedure of Kamide and Sugamiya, based on the Flory‐Huggins's theory of dilute solutions of polymers. No double‐peak distributions were observed in the fractions obtained by SSF under the conditions which give double‐peak distributions in the case of SPF. The minimum value of X̄w in the fractions obtained in a given run is almost the same for SSF and SPF, the minimum increasing with decreasing X̄/X̄ (the suffix zero denoting the original polymer). The ratio X̄w/X̄n in the fractions is not greatly influenced by X̄/X̄ except for the first few fractions. The standard deviation σ′ of the MWD in the fractions decreases with increasing X̄/X̄ in an initial stage, while this situation is reversed in the later stages. In general SSF furnishes sharp fractions regardless of X̄/X̄.
The Cu‐catalyzed oxidative polymerization of phenols
Authors: Tsuchida Eishun , Nishide Hiroyuki , Nishiyama Toshio
Published: April 2003

The reactivity of phenols in the Cu complex catalyzed oxidation was studied by measuring the oxidation rate, the rate constant of the electron‐transfer step (Ke), and the reduction potential of the Cu complex (Ered). Linear relationships were observed between log Ke and the logarithm of the oxidation rate, Ered, and Hammett's σ value of the phenol. The larger Ke values were obtained in the oxidation of the ε‐conjugated 2,6‐diphenylphenol, and in the oxidations with the Cu complexes involving pyridine derivatives. It was found that for each case there is a most suitable pair of a Cu catalyst and a phenol to produce a polymeric phenylether in high yield, i.e. an oxidation product is predictable from Ered of the catalyst and the σ value of the phenol. On the other hand, p‐substituted phenols could be polymerized only by strong oxidizing agents.
Operating conditions for preparative successive solutional fractionation, 2. Miscellaneous factors including experimental performance, a modified procedure, and repetition of fractionation
Authors: Kamide Kenji , Miyazaki Yukio
Published: April 2003

Preparative successive solutional fractionation (SSF) of macromolecules has been rigorously computerized on the basis of a modified Flory‐Huggins polymer dilute solution theory. The polymers having Schulz‐Zimm and Wesslau distributions with the weight‐to number‐average degree of polymerization X̄0w/X̄0n = 2–5 and X̄0w = 300 have been employed for this purpose. Accurate control of amount of fractions, Q, and separation of two solution phases (i.e., a polymer‐lean phase and a polymer‐rich phase) were much more easy in SSF as compared to successive precipitational fractionation (SPF). Effect of the concentration dependence parameter p of the polymer/solvent thermodynamic interaction parameter χ on the molecular weight distribution (MWD) of the fractions have been examined in detail. A new modified SSF procedure was proposed in order to reduce the volume of solvent necessary for a single run. The relationships between initial concentration, amount of fraction Q and X̄w/X̄n for the first fractions isolated by SSF were established for the case where the original polymer had Schulz‐Zimm and Wesslau distributions. In SSF repetition of fractionation was absolutely ineffective in contrast to SPF.
X‐ray structural studies of the atactic polymers poly(1‐methylhexamethylene), poly(1‐methyloctamethylene), poly(1‐methyldecamethylene), and poly(1‐methyldodecamethylene), model polymers of ethylene/propene‐copolymers
Authors: Bassi Ivano W. , Scordamaglia Raimondo
Published: April 2003

Poly(1‐methylhexamethylene) (1a), poly(1‐methyloctamethylene) (1b), poly(1‐methyldecamethylene) (1c), and poly(1‐methyldodecamethylene) (1d) were studied by high‐angle X‐ray diffraction methods. The polymers reveal a partial intramolecular and intermolecular order and may be considered as ethylene/propene copolymers containing, along the chains, regular sequences of 2,3,4, and 5 ethylene units every propylene unit, respectively.

Configurational disorder at the tertiary carbon atoms was evidenced so that the polymers are atactic. In the ordered regions, the backbone chains assume planar zig‐zag conformations. The packing of the macromolecules is conditioned by the side methyl groups, and their influence increases going from 1d to 1a.

An intermolecular “long range order” was evidenced for the backbone chains, while + an intermolecular “short range order” is present for the methyl side groups. The structures proposed for these polymers seem to be possible also for ethylene/propene +dom copolymers having similar compositions.

The low and high‐temperature structures of propene/butadiene alternating copolymers are also described.
The thermodynamics of polymerisation of aldehydes and cyclic ethers, 4.1,3‐dioxocane and 1,3,6‐trioxocane
Authors: Busfield W. Kenneth , Lee R. Martin
Published: April 2003

The equilibrium between gaseous monomer (g) and amorphous polymer (c) has been studied for 1,3‐dioxocane and 1,3,6‐trioxocane between 100 and 137°C. From the equilibrium pressures of monomer, the ΔH and ΔS values have been calculated. Thermodynamic data for the vaporisation of each monomer have also been measured so that values of ΔH and ΔS for the polymerisations could be calculated (l: liquid phase).
For 1,3‐dioxocane:

For 1,3,6‐trioxocane:
Study on the possibility of reverse‐order fractionation in successive precipitational fractionation
Authors: Kamide Kenji , Miyazaki Yukio
Published: April 2003

An attempt has been made to account for the occurrence of reverse‐order fractionation (ROF) phenomena in successive precipitational fractionation (SPF) in terms of the newly established rigorous fractionation theory, assuming complete thermodynamic equilibrium conditions between a polymer‐rich phase and a polymer‐lean phase and to throw light on operating conditions under which ROF occurs. For this purpose, the simulation technique was employed. ROF occurs not only between 1st and 2nd fractionation steps but also between two successive higher order steps even under thermodynamic equilibrium state. The molecular weight distribution of the original polymer contributes very sensitively to ROF: For the Schulz‐Zimm type polymer ROF is highly observed at a large amount of fraction Q in a narrow range of initial concentration v whereas for the Wesslau type polymer large ROF occurs at small Q over a relatively wide v range. In general, there exist appropriate ranges of the weight‐average degree of polymerization of the initial polymer X̄ the solvent nature expressed by the concentration dependence of the polymer/solvent interaction parameter p, and the initial polymer concentration v for ROF. A broad original polymer gives rise to large ROF. The theoretical predictions obtained here can explain very clearly the experimental results by Fujisaki and Kobayashi concerning the effect of X̄, p, and v on ROF in SPF of polyacrylonitrile.
Orientierungsmessungen an uniaxial verstreckten polyacrylnitrilfilmen
Authors: Siesler Heinz Wilhelm
Published: April 2003

Aus dreidimensionalen Untersuchungen von uniaxial verstreckten Polyacrylnitrilfilmen mit linear polarisierter IR‐Strahlung werden Orientierungsparameter der v(CN)‐ und δ(CH2)‐Absorptionsbanden in den drei Filmkoordinatenrichtungen abgeleitet. In Verbindung mit Röntgenbeugungsaufnahmen werden Rückschlüsse auf den Typ und Grad der bei der Verstreckung auftretenden molekularen Orientierung gezogen.
Darstellung und spektroskopische analyse von oligo{[4‐(1,1,3,3‐tetramethylbutyl) (bzw. 4‐octyl)‐2‐hydroxy‐1,3‐phenylen]methylen}en und ihrer Ausgangsverbindungen
Authors: Kämmerer Hermann , Eberle Klaus , Böhmer Volker , Großmann Max
Published: April 2003

4‐(1,1,3,3‐Tetramethylbutyl)phenol und 4‐Octylphenol, erhalten durch Friessche Verschiebung der entsprechenden Phenylester und anschließende Reduktion der Carbonylgruppe, wurden in ortho‐Stellung monobromiert und mit Formaldehyd hydroxymethyliert. Aus diesen Verbindungen konnten sechs 2,2′‐Methylendiphenole (2a–f) sowie sieben 2,6‐Bis(2‐hydroxybenzyl)phenole (3a–g) dargestellt werden, die in 4‐Stellung zu den phenolischen Hydroxygruppen Methyl‐, 1,1,3,3‐Tetramethylbutyl‐ und Octyl‐Substituenten in verschiedenen Verhältnissen enthalten. Die IR‐ und 1H‐NMR‐spektroskpischen Analysen bestätigten die angegebenen Strukturen der dargestellten phenolischen Mehrkernverbindungen.
High resolution 1H‐NMR study of association of polymers in solution. Poly(methyl methacrylate) and poly(vinyl chloride)
Authors: Spěváček Jiří , Schneider Bohdan
Published: April 2003

A procedure for the determination of the contents and the thermal stability of associated structures in solutions of polymers is described, making use of the anomalous values and changes of integrated band intensities in high‐resolution 1H‐NMR spectra. In this way, associated structures in solutions of isotactic and syndiotactic poly(methyl methacrylate), (PMMA), were detected and characterized. The associated structures in solutions of isotactic PMMA are much more stable than the aggregates in solutions of the syndiotactic PMMA. Two types of aggregates differring in stability were also observed in solutions of atactic poly(vinyl chloride).
Enthalpies of dilution of poly(1‐vinyl‐2‐pyrrolidone) + aqueous methanol solution
Authors: Murakami Sachio , Kimura Fumio , Fujishiro Ryoichi
Published: April 2003

Enthalpies of dilution of poly(1‐vinyl‐2‐pyrrolidone), (poly[1‐(2‐oxopyrrolidin‐1‐yl)ethylene]), in aqueous methanol solutions of different methanol contents were measured at 298 K. The molecular weight of the polymer was 10000 and 40000, respectively.

The experimental results were analysed with a modified Tompa formula containing an interaction parameter dependent on concentration; so the interaction parameter at infinite dilution between the polymer and the mixed solvent was derived.

The influence of methanol on the interaction between polymer and water molecules was discussed from the change of the interaction parameter at infinite dilution for the transfer process from water to aqueous methanol solvent.
Infrared spectroscopic studies on polyethylene, 2. The characterisation of specific types of alkyl branches in low‐branched ethylene polymers and copolymers
Authors: McRae Margaret A. , Maddams William F.
Published: April 2003

Bands characteristic for some specific branches have been found in two regions of the IR spectra of near linear polyethylenes made by the Phillips process. Polymers with methyl branches give a band at 935 cm−1, probably the methyl rocking mode. The intensity of this band is proportional to the methyl branch content, thus providing a quantitative method for its estimation. No band specific for ethyl branches has been found, but propyl and longer branches show one at 890 cm−1 and this is also assigned to the rocking mode. This band is observed more readily if the polymers are brominated at ambient temperature, to remove interfering unsaturation bands. The results for methyl and ethyl branched near linear polymers differ significantly from those obtained with polypropylene, poly(1‐butene), and ethylene copolymers with high concentrations of methyl and ethyl branches. This is very probably the result of the presence of blocks of the repeating unit CH2CH(R) in the latter materials. Methyl branched polymers show a band at 1150 cm−1, assigned to the methyl wagging mode of branches present in the crystalline phase. Its intensity is proportional to the methyl branch content and it may be used for quantitative purposes. Ethyl and longer branches do not give a methyl wagging band of detectable intensity.
Metallkomplexe mit polymeren liganden, 13. Poly(4‐pyridyläthylen) als ligand in metallkomplexen mit einem oder zwei zentralmetallen
Authors: Biedermann Hans‐G. , Seidl Peter
Published: April 2003

Ataktisches Poly(4‐pyridyläthylen) (1) bildet mit zahlreichen Metallchloriden in Äthanol Komplexe mit verschiedenen Koordinationszahlen in Abhängigkeit vom eingesetzten Metallion. Komplexierungsreaktionen mit zwei Metallchloriden gleichzeitig führen je nach Reaktionsbedingungen zu Komplexen unterschiedlicher Zusammensetzungen. IR‐Spektren, elektrische Leitfähigkeit und das magnetische Verhalten werden diskutiert.
Polymerization of acrylonitrile initiated by 2‐tetrazene/haloacetic acid systems
Authors: Sugiyama Kazuo
Published: April 2003

The polymerization of acrylonitrile initiated by binary 2‐tetrazene/haloacetic acid systems was studied in N,N‐dimethylformamide (DMF). A kinetic investigation was also undertaken of decomposition of 2‐tetrazenes in the presence of various haloacetic acids in DMF. The decomposition rate decreased with increasing halogen‐carbon bond energy of the haloacetic acid.
Kinetik der bromierung von phenolen und phenolischen mehrkernverbindungen, 2. Die reaktionsfähigkeit isomerer zweikernverbindungen
Authors: Böhmer Volker , Niemann Wilhelm
Published: April 2003

Die Geschwindigkeit der Bromierung von 6 isomeren Zweikernverbindungen mit jeweils einer reaktionsfähigen Stelle (Hydroxydimethylbenzyl‐methylphenole 1, 2 und 3) wurde in Eisessig bei 22°C UV‐spektroskopisch bestimmt. Für die Reaktion in ortho‐Stellung zur phenolischen Hydroxy‐Gruppe ergibt sich eine Verminderung der Geschwindigkeit um den Faktor 3–3,5 wenn zwischen den Hydroxy‐Gruppen der beiden Phenolbausteine eine intramolekulare Wasserstoffbrücke sterisch möglich ist (1a). In den anderen Fällen (1b, 2a, 2b) verläuft die Bromierung ungefähr ebenso schnell wie bei 2,4‐Dimethylphenol. Die schneller verlaufende Reaktion in para‐Stellung (3a, 3b) wird durch eine Wasserstoffbrücke um den Faktor 1,4 verlangsamt. Das Verhältnis der Geschwindigkeitskonstanten für den Term dritter und zweiter Ordnung, k3/k2, ist bei allen Verbindungen annähernd gleich. Man mußannehmen, daß durch eine Wasserstoffbrücke zwischen den phenolischen Hydroxy‐Gruppen Elektronenpaare am Sauerstoffatom des reagierenden Bausteins blokkiert werden, was über einen geringeren + M‐Effekt zu einer Verminderung der Elektronendichte dieses aromatischen Systems führt.
The conformational transition in poly(methacrylic acid) and butyl vinyl ether/maleic anhydride copolymers studied by 1H NMR linewidth measurements
Authors: Kay Peter J. , Kelly David P. , Milgate Geoffrey I. , Treloar F. Edward
Published: April 2003

Linewidth measurements on the 1H NMR spectra of D2O solutions of poly(methacrylic acid), (PMA), and the hydrolyzed form of butyl vinyl ether/maleic anhydride copolymer show a sharp decrease in the linewidths of side chain resonances at a degree of neutralization α ≈ 0,2. This is the region in which potentiometric titrations previously have shown a conformational transition to occur. Such a change does not occur in poly(acrylic acid) on the one hand and methyl vinyl ether/maleic anhydride copolymer on the other. The nature of the transition is discussed in terms of the freedom of rotation of the side chains about the main chain.
UV‐photometrisch bestimmte relative molare massen von anionisch erzeugten polyäthylenoxiden mit unterschiedlichen endgruppen
Authors: Kämmerer Hermann , Grover Pran Nath
Published: April 2003

Äthylenoxid wurde mit Kalium‐4‐(phenylazo)benzylalkoholat (1f) polymerisiert, die gereinigten Produkte fraktioniert und anschließend acyliert. Die UV‐photometrische Bestimmung der Endgruppen ergab, daß HO‐Endgruppen, verglichen mit den Starterendgruppen, in großem Überschuß vorhanden waren. Aus den Endgruppenwerten ließen sich Zahlenmittel des Molekulargewichts (M̄n) ableiten. Sie wurden mit osmotisch bestimmten M̄n‐Werten und Viskositätsmittel (M̄η)‐verglichen und bestätigten die angenommene Struktur der Polyäthylenoxide.
Kinetic investigations on biosynthesis of bacterial cellulose, 2. Distribution of the degree of polymerization for different numbers of bacterial generations
Authors: Marx‐Figini Marianne , Pion Beatriz
Published: April 2003

The chain length distribution of polymer analogous nitrates of two native bacterial celluloses is investigated. The polymerization times of the latter differend in the numbers of generation of the bacteria produced during the fermentation of acetobacter xylinium. The resulting distribution curves show that polydispersity and number of maxima increase with increasing number of generation. This result supports the hypothesis deduced from former kinetic investigations that each generation of bacteria initiates a certain number of molecules and that chain growth takes place without termination step.
Zur deutung der sogenannten a‐orientierung in polyäthylenterephthalat
Authors: Biangardi Harald J. , Zachmann H. Gerhard
Published: April 2003

Bei der Kristallisation von schwach orientierten Polyäthylenterephthalat‐Folien erhält man eine Struktur, für die in der Röntgenweitwinkelstreuung der 100‐Reflex am Meridian und der 010‐Reflex am Äquator liegt. Die Röntgenkleinwinkelstreuung zeigt ein Intensitätsmaximum am Meridian.

Man kann diese Befunde mit einem Modell aus tordierten Lamellen erklären, deren Torsionsachsen bevorzugt senkrecht zur Verstreckrichtung liegen. In einer solchen tordierten Lamelle liegen die (001)‐Ebenen der Kristallite parallel zur Lamellenoberfläche und die b‐Achsen in Richtung der Torsionsachse. Die bei dieser Struktur auftretende negative Doppelbrechung kann mit diesem Modell ebenfalls erklärt werden.
Effects of salts, solvents, and substituents on the reaction of cellulose with epoxy compounds
Authors: Tanaka Yoshio , Shimura Yukio , Shiozaki Hideki
Published: April 2003

Effects of salts, solvents, and substituents on the reaction of cellulose with epoxy compounds were re‐investigated and compared with the published data. The salt effect could be described mainly by the electronegativity or the acidity of the cations, and also by the nucleophilicity or the basicity of the anions. The variation of the reaction with solvents for epoxy compounds could be explained by the solubility parameter of the solvents. The substituent effect of the epoxy compounds on this addition reaction was elucidated by the modified Taft's equation, (logk−logk0)/σ*=(Qp–QsEs)/σ*. The mechanism for the reaction was discussed in the light of the reinvestigated phenomena.
Über polymere Alloxazine, 2
Authors: Manecke Georg , Reuter Peter
Published: April 2003

7‐Vinylalloxazin (4) wurde auf einem neuen Weg dargestellt. Es konnte weder in DMSO noch in DMF polymerisiert werden. Poly(7‐vinylalloxazin) (7) wurde durch polymeranaloge Reaktionen von Poly(4‐aminostyrol) ausgehend dargestellt; seine Eigenschaften bei der Komplexierung mit Ag+‐ und Hg2+‐Ionen wurden untersucht.
Acrylonitrile polymerization in aqueous solution
Authors: Morris Carolyn E. M. , Parts Adolf G.
Published: April 2003

The polymerization of acrylonitrile in aqueous solution in the presence of an anionic soap was examined, particular attention being paid to the size of the latex particles as a function of the extent of the reaction. It was found that in some systems the rate of polymerization became irreproducible at conversions higher than about 25%. A tendency to gel formation in systems of quite low solids content was also noted.

For one system the size of the latex particles at various conversions was determined by light scattering using the dissymmetry method. The average particle size was found to be essentially constant up to about 20% conversion and to increase slowly at higher conversions.

A mechanism of particle formation and growth is proposed to account for these observations.
Calculation of the characteristic ratio of polypropylene containing chemical inversions (head‐to‐head and tail‐to‐tail units)
Authors: Asakura Tetsuo , Ando Isao , Nishioka Atsuo
Published: April 2003

The characteristic ratio (CR, i.e., a measure for the end‐to‐end distance) of polypropylene was calculated taking into account the chemical inversions such as head‐to‐head and tail‐to‐tail units in the chain and compared with the values calculated previously as a function of the tacticity.
Reactivity of polystyrene and model compounds toward tert‐butoxy radicals
Authors: Dulog Lothar , David Karl‐Heinz
Published: April 2003

tert‐Butoxy radicals were generated by decomposing di‐tert‐butyl hyponitrite. The relative reactivities of substrates were measured from the ratio of tert‐butanol and acetone formed. Polystyrene was found to be less reactive than model compounds. Activation parameters for the hydrogen abstraction reaction for cumene, 3‐phenylpentane, and 2,4‐diphenylpentane are reported and show small differences for the enthalpy of activation; large negative values for the entropy of activation demonstrate the importance of steric hindrance in the hydrogen abstracting step. 2,3‐Diphenylbutane as model compound for head to head links in polystyrene exhibits low reactivity, whereas 2,5‐diphenylhexane, a model for tail to tail links, is more reactive than the dimer head to tail model. Still more reactive is 2,4‐diphenyl‐2‐pentene as model for an unsaturated unit in polystyrene.
Schlangenkäfig‐polymere, 2.N‐chlorierung verschiedener schlangenkäfig‐polyelektrolyte auf der basis von polyacrylamiden und einem anionenaustauscher
Authors: Kaczmar B. Ulrich , Traser Sigrid
Published: April 2003

Schlangenkäfig‐Polyelektrolyte auf der Basis von Polyacrylamiden und einem Anionenaustauscher wurden, soweit sie sekundäre Amidgruppen enthalten, N‐chloriert. Die Geschwindigkeit und das Ausmaß der N‐Chlorierung sowie die Stabilität der Polyacrylamide wurden untersucht und diskutiert. Schließlich wurde die Chloraufnahme des Anionenaustauschers zeitlich verfolgt und interpretiert.
Interpretation of monomer‐polymer equilibria in the polymerization of alkyl substituted 1,3‐dioxolanes
Authors: Okada Masahiko , Mita Koji , Sumitomo Hiroshi
Published: April 2003

The thermodynamic parameters for the monomer‐polymer equilibria in the polymerization of 4‐methyl‐, 4‐ethyl‐, 4‐isopropyl‐, 4,4‐dimethyl‐, and cis‐ and trans‐4,5‐dimethyl‐1,3‐dioxolanes were calculated from the number of conformational isomers. The number of conformational isomers and the gauche interactions involved were enumerated for the monomeric unit of each polymer, whilst the number of conformational isomers and their energies due to the gauche interactions, bond opposition strain (“Pitzer strain”) between the cis neighbouring bonds of the ethylene part of the 1,3‐dioxolane ring, and 1,3‐nonbonded interaction were estimated for each monomer. On the basis of these enumerations, the enthalpy and entropy values for the polymerization of the alkyl substituted 1,3‐dioxolanes were computed by using the observed values for 1,3‐dioxolane as the standard for the calculation. From the comparison of the calculated values with the experimental results, it is concluded that the effects of alkyl substituents on the monomer‐polymer equilibria can arise principally from the various conformational isomers in the monomeric and polymeric states.
Homo‐ und copolymerisation von N,N‐disubstituierten carbamoyloxyalkylacrylaten und ‐methacrylaten
Authors: Probst Joachim , Kolb Günter
Published: April 2003

Es wurden Methacrylate und Acrylate (3a–i) von N,N‐disubstituierten 2‐Hydroxyalkyl‐carbamaten (2) dargestellt und radikalisch homo‐ und copolymerisiert. Dabei wurde gefunden, daß die Homopolymerisation nach den üblichen kinetischen Gesetzmäßigkeiten verläuft. Die physikalisch‐chemischen Eigenschaften der Polymeren werden durch die sperrigen und polaren Seitengruppen bestimmt, was sich bei Viskositäts‐, GPC‐, Röntgen‐, DTA‐ und Kernresonanzmessungen bemerkbar machte. Das Verhalten der Methacrylate bei der radikalischen Copolymerisation mit einer Reihe von Comonomeren zeigte Ähnlichkeit mit dem des Methylmethacrylats, jedoch wiesen die neu dargestellten Methacrylate cine geringere Einbautendenz in die Copolymeren auf als das Methylmethacrylat, was wohl wiederum auf die unterschiedlichen sterischen Effekte zurückzuführen ist.
Vinyl polymerisation of acrylonitrile by the vanadium(V)‐glycerol redox system
Authors: Rout Anuradha , Singh Baishnab C. , Santappa M.
Published: April 2003

A kinetic study of the thermal polymerisation of acrylonitrile initiated by the redox system V5+ ‐glycerol in sulfuric acid and perchloric acid was made in the temperature range 35–45°C. The rates of polymerisation and V5+ disappearance wee measured with respect to their dependence on time, monomer, metal ion, glycerol, acid, and ionic strength. Experimental evidences provide support to a mechanism involving initiation by a free radical produced by the decomposition of the acyclic complex between V5+ and glycerol. The kinetics are consistent with a linear termination of polymerisation (1st order in respect of growing radicals) at higher concentration of V5+. The various rate and activation parameters were evaluated and an appropriate reaction scheme is proposed. The induction period and the polymerisation rate of the V5+ ‐glycerol system were compared with those involving polyhydroxy alcohol systems such as sorbitol and mannitol.
Synthèse par polymérisation anionique de copolymères biséquencés polybutadiène‐poly(vinyl‐2 naphtalène). Étude de leur structure en solution concentrée avant et après polymérisation du solvant
Authors: Douy André , Jouan Gilbert , Gallot Bernard
Published: April 2003

Nous avons préparé par polymérisation anionique sous vide des copolymères biséquencés polybutadiène‐poly(vinyl‐2 naphtalène) (BVN) et nous discutons les conditions de polymérisation qui conduisent à des copolymères isomoléculaires. En utilisant la diffraction des rayons X aux petits angles et la microscopie électronique nous avons déterminé structure des mésophases obtenues par dissolution des copolymères BVN dans un vant préférentiel des séquences poly(vinyl‐2 naphtalène) et des copolymères organisés des préparés par polymérisation du solvant de la mésophase. Nous avons montré que les copolymères BVN présentent en fonction de la composition du copolymère les mêmes types de structure que les copolymères bi‐ et triséquencés polystyrène‐polybutadiène. Nous décrirons en détail les structures lamellaire et hexagonale inversée des polymères BVN et l'influence de la concentration, de la nature et de la polymérisation solvant sur leurs paramètres géométriques.
Verschiedenartige Additionsreaktionen von 2‐Cyano‐2‐propylradikalen an p‐Tolylmethacrylat und 4‐Cyclohexylphenylmethacrylat
Authors: Kämmerer Hermann , Pachta Jiri
Published: April 2003

Durch Umsetzung von p‐Tolylmethacrylat oder 4‐Cyclohexylphenylmethacrylat in stark verdünnter, siedender Benzollösung mit einem sehr großen Überschuß an 2,2′‐Azoisobutyronitril wurden die erwarteten Additionsprodukte mit 2‐Cyano‐2‐propylradikalen (1) erhalten, nämlich p‐Tolyl‐ bzw. 4‐Cyclohexylphenyl‐[4‐cyano‐2‐(2‐cyano‐2‐propyl)‐2,4‐dimethyl]valerianat (3a bzw. 3b) mit rund 50% Ausbeute. Daneben wurden p‐Tolyl‐ bzw. 4‐Cyclohexylphenyl‐(4‐cyano‐4‐methyl‐2‐methylen)valerianat (4a bzw. 4b), p‐Tolyl‐ bzw. 4‐Cyclohexylphenyl‐[4‐cyano‐2(2‐cyano‐2‐methyl‐1‐propyl)‐4‐methyl]valerianat (5a bzw. 5b), p‐Tolyl‐ bzw. 4‐Cyclohexylphenyl‐(4‐cyano‐2,4‐dimethyl)valerianat (6a bzw. 6b) und p‐Tolyl‐ bzw. 4‐Cyclohexylphenyl‐(4‐cyano‐2,4‐dimethyl)‐2‐pentenoat (7a bzw. 7b) isoliert. Ihre Strukturen wurden durch Massenspektrometrie, Elementaranalysen, Mikrohydrierungen, IR‐ und UV‐Spektren bestimmt. Es konnten, bezogen auf die eingesetzten Monomeren, 95 bzw. 100% in ihrer Struktur aufgeklärte Reaktionsprodukte gefaßt werden. Die Entstehung der Verbindungen kann durch ein Zusammenspiel von Additionen der 2‐Cyano‐2‐propylradikale (1), Abspalten von Wasserstoff bzw. Disproportionierungen erklärt werden.
New catalysts for the oxidative polymerization of 2,6‐dimethylphenol, 2. Copper complexes containing the dicyanoethenedithiolatocuprate structure as the ligand
Authors: Yoshimura Tamotsu , Storck Winfried , Manecke Georg
Published: April 2003

It was found that the reaction of 1,2‐dicyano‐1,2‐ethenedithiolate, resp. of bis(1,2‐dicyano‐1,2‐ethenedithiolato)cuprate(2‐), with Cu2+ does not lead to copper bis(1,2‐dicyano‐1,2‐ethenedithiolato)cuprate(2‐) dihydrate (1a) as described in the literature but to a reaction product which has a complex structure containing mainly Cu+. This compound as well as complexes with the same ligand, but with Cu+, Cu2+ or Cu3+ as the central atom, were synthesized and tested with and without added cuprous chloride as catalysts for the oxidative polymerization of 2,6‐dimethylphenol. Included in this investigation were some copper complexes with the isomeric ligand 2,2‐dicyano‐1,1‐ethenedithiolate.
Coenzyme models, 5. Addition reaction of cyanide ion to monomeric and polymeric nicotinamides. Correlation between equilibria and reaction rates
Authors: Shinkai Seiji , Tamaki Kiyoshi , Kunitake Toyoki
Published: April 2003

Rate and equilibrium constants (kf and K, respectively) for the addition of cyanideion to poly[1‐(4‐vinylbenzyl)nicotinamide chloride] (poly{1‐[4‐(3‐aminocarbonylpyridiniomethyl)phenyl]ethylene chloride}) (poly(1)) and a corresponding monomeric derivative of nicotinamide, 3‐aminocarbonyl‐1‐benzylpyridinium chloride (2), were evaluated at 30°C, in an aqueous system. The rate constant for the reaction of poly(1) with CN− at μ = 0,1 mol 1−1 was found to be higher by a factor of 22 and the association constant by a factor of about 65, compared with those for the reaction of 2 with CN−. At a lower ionic strength (μ = 0,008 mol 1−1), the reaction parameters were markedly enhanced (108‐fold and 218‐fold, respectively). The rate enhancements in the polymeric system are attributable to the increase in the ΔS term. This favorable entropy term caused the deviation from the linear log K‐log Kf relationship which holds strictly for monomeric compounds.
Asymmetric synthesis catalyzed by (S)‐alanine‐N‐propylamide as a terminal model of poly[(S)‐alanine]
Authors: Ueyanagi Kaoru , Inoue Shohei
Published: April 2003

The asymmetric addition of 1‐dodecanethiol (1) to isopropenyl methyl ketone (2) catalyzed by (S)‐alanine‐N‐propylamide (5) as a terminal model of poly[(S)‐alanine] (3c) was studied. When the asymmetric addition reaction was carried out in chloroform, it was accompanied with a slow competitive racemization of the product by the catalyst. On the other hand, when ethanol was added to the reaction system, the racemization was much depressed.
Branching and unsaturated structures in radically polymerized poly(vinyl chloride)s studied by high‐resolution proton magnetic resonance
Authors: Pétiaud Roger , Pham Quand‐Tho
Published: April 2003

Radically polymerized PVC obtained in bulk was fractionated and examined by high resolution NMR using spectrum accumulation. The main unsaturation found consists of 1‐chloro‐2‐pentene structures, and the saturated chain end should be a 1,2‐dichloroethyl group. Owing to the semi‐quantitative determinations, there are, independently of molecular weight, two or three double bonds per 1000 monomer units, while the number of branches was found to increase with increasing molecular weight.
Über einige besonderheiten der polymerisation von 2,3‐dimethylbutadien in durch lithiumorganische verbindungen initiierten prozessen
Authors: Smirnowa Natalia , Sgonnik Vladimir , Kalninsch Karl , Erussalimsky Boris
Published: April 2003

The polymerization of 2,3‐dimethylbutadiene (DMB) induced by butyllithium (BuLi), oligo‐2,3‐dimethylbutadienyllithium (ODMBL), and by the system ODMBL/N,N,N′,N′‐tetramethylethylenediamine (TMD) was investigated in heptane at 60°C. The reaction order with respect to the organolithium compound was found to be for these cases −0,32, 0,28, and 0,56 respectively. The negative reaction order for BuLi is caused by the existence of the mixed associates (BuLi)x. (MnLi)y which follows from the negative influence of BuLi on the propagation reaction rate in the system DMB/ODMBL. Contrary to butadiene and isoprene, catalytic amounts of TMD decrease the propagation rate of DMB. This phenomenon is ascribed to a weak tendency of the complexes of the DMB‐living chains to dissociate into the monomeric form MnLi. TMD. The UV‐ and IR‐spectra of the living DMB‐chains and their complexes with TMD are studied.
Anionic polymerization of siloxanes, 2. Internal multifunctional assistance of siloxane system to the siloxane bond cleavage by alcali metal silanolates
Authors: Mazurek Mieczysław , Chojnowski Julian
Published: April 2003

The kinetics of the reaction of potassium phenyldimethylsilanolate (1) with the series of linear trimethylsilyl‐end‐blocked dimethylsiloxane oligomers and with the series of cyclic dimethylsiloxane oligomers was studied to clear some mechanistic problems of anionic polymerization of siloxanes.

The results indicate that the high reactivity of the siloxane bond in linear and higher cyclic oligomers—responsible for the large scope of chain redistribution and cyclization processes in the siloxane anionic polymerization system—is due to a mechanism involving multifunctional interaction of siloxane with silanolate, which gives assistance to the siloxane bond cleavage. This mechanism is impeded when strong cation solvating agents are present in the system.
Die Bestimmung der Molekulargewichtsverteilung von nichtkristallisierenden Polymeren mit dem Elektronenmikroskop, 4. Weiterentwicklung der Präparationsmethode durch Gefriertrocknung
Authors: Koszterszitz G. , Barnikol W. K. R. , Schulz G. V.
Published: April 2003

Molecular weigth distribution curves determined by electron microscopy exhibit a deviation when approaching a molecular weight of 106. Picturing of single molecules therefore was improved by the introduction of shadowing by electron beam. Techniques of preparation (by freeze‐drying) and shadowing are described in detail. The scanning size of the electron beam shadowing is in between 15 and 20 Å and is given by the structure of the supporting film. By double shadowing from different sides it is demonstrated, that there is no “decoration effect” in electron beam shadowing. The lower limit of an exact determination of the dimensions is a molecular weight of ca. 105. It is shown with latex particles that there is a change of shape with time of the particles after sedimentation on the support which is dependent on the kind of polymer and of the conditions. Their volume though remains constant within the limits of error.
Structural study of polybutadiene‐poly(ethylene oxide) block copolymers. Influence of the nature of the amorphous block on the refolding of the poly(ethylene oxide) chains
Authors: Gervais Monique , Gallot Bernard
Published: April 2003

Our earlier studies on block copolymers polystyrene‐poly(ethylene oxide) has allowed to state the influence of the molecular weight of the copolymer and of its composition on the refolding of the crystallized poly(ethylene oxide) chains. To precise the effect of the nature of the amorphous block, we have studied by X‐ray diffraction and differential scanning calorimetry, the lamellar crystalline structures exhibited by block copolymers polybutadiene‐poly(ethylene oxide) (BEO) in the presence of a preferential solvent of one block: xylene for polybutadiene (PB), acetic acid or acrylic acid for poly(ethylene oxide) (PEO). In systems BEO copolymer/preferential solvent of PEO, the lamellar structure with crystallized PEO chains (LCC) exists at temperatures below about 45°C and for solvent concentrations ranging from 0 to a value characteristic of the copolymer. In the LCC structure, the chains of PEO crystallize in two layers; the solvent forms a third layer located between the PEO layers. We have studied the influence of the nature of the amorphous block on the variation of the structural parameters with the solvent concentration. In systems BEO copolymer/preferential solvent of PB, the lamellar structure with crystallized PEO chains (LC) appears at temperatures below about 50°C and for all solvent concentrations where the mesophase exists. In the LC structure, the chains of PEO crystallize folding in two superposed layers. We have established the influence of the solvent concentration and the nature of the amorphous block on the number of folds and the crystallinity of the PEO chains.
Über die möglichkeiten zur bestimmung von mischungsenthalpien und ‐volumina aus der molekulargewichtsabhängigkeit der kritischen entmischungstemperaturen und ‐drücke am beispiel des systems trans‐decahydronaphthalin/polystyrol
Authors: Wolf B. A. , Jend R.
Published: April 2003

Cloud‐point curves and critical curves (Tc = f(p)) have been measured for the system trans‐decahydronaphthalene/polystyrene and three different molecular weights of the polystyrene component (2,5 · 106; 3,9 · 105; 1,1 · 105). It turned out that by variation of the pressure the metastable region can be investigated up to the spinodal curve.

A comparison of the theta‐temperatures and the enthalpy contributions χH (to the Flory‐Huggins interaction parameter χ) resulting from the measured critical temperatures according to Shultz‐Flory, with the corresponding directly obtained literature data, demonstrates that, although the extrapolation of Tc to infinite molecular weight is feasible, χH obtained in this way is greater by a factor of approximately three, due to the concentration dependence of χ. The same is true for the determination of χV (the contribution of the work in change of volume to χ) from the molecular weight dependence of the critical pressure. The determination of χV from the slope of the critical curves and known χH is, however, possible; the results are in good agreement with direct measurements.

The shape of the critical curves calculated theoretically according to Prigogine and Patterson, turns out to be very sensitive to the precise values chosen for the mechanical data of the pure components. By adjustment of the system‐specific parameters the measured critical curves can be well represented analytically.
Terpolymerization of polar vinyl monomers with butadiene and styrene in the presence of Lewis acids
Authors: Kuran Witold , Pasynkiewicz Stanisław , Nadir Riad
Published: April 2003

Terpolymerizations of polar vinyl monomers, acrylonitrile, methyl acrylate, or methyl methacrylate with butadiene and styrene in the presence of ethylaluminium dichloride, zinc chloride, or other Lewis acids were carried out. The yield and the contents in monomer units of the terpolymer and the yields of the polar vinyl monomer/butadiene 1,4‐cycloaddition byproduct formed in these systems were determined. Butadiene conversions in the above terpolymerizations and 1,4‐cycloaddition side reactions were related to those in the copolymerization and 1,4‐cycloaddition proceeding in corresponding binary systems without styrene. The results are discussed in terms of a radical polymerization and a polar 1,4‐cycloaddition mechanisms.
Mechanism of the NCA‐polymerization, 5. Catalysis by secondary amines
Authors: Kricheldorf Hans R.
Published: April 2003

L‐Phenylalanine NCA and glycine NCA react with excess diisopropylamine or dicyclohexylamine to give only polymeric products. In contrast, excess morpholine or diethylamine produces no polymerization but instead yield amino acid amides (2) and hydantoic acids (6), which indicate the intermediate formation of NCA anions 4, which are in equilibrium with the isomeric α‐isocyanatocarboxylates (5). Diisopropylamine and dicyclohexylamine in the presence of N‐acetylglycine NCA (13) yield also quantitative polymerization of glycine NCA, from which oligomers 14 with acetyl and NCA end groups may be isolated. Under the same conditions morpholine and diethyl amine yield no polymerization, since these amines are acylated by excess N‐acetylglycine NCA. These results show that secondary amines with small substituents react preferentially as nucleophiles so that the NCA‐polymerization proceeds, as with initiation by primary amines, through propagation by nucleophilic end groups. Secondary amines with bulky substituents, in analogy with the tertiary amines, produce only NCA anions which polymerize according to the “activated monomer mechanism”, i.e., through reaction with the electrophilic NCA chain end. Apparently contradictory experiments of Seeney and Harwood were reinvestigated and the results are discussed.
Microstructure of 1,5‐cyclooctadiene oligomers
Authors: Sato Hisaya , Tanaka Yasuyuki , Taketomi Takanao
Published: April 2003

1H and 13C NMR spectra of 1,5‐cyclooctadiene oligomers were investigated and compared with those of 1,4‐polybutadiene. The oligomers were prepared with Rh2O7 as catalyst and fractionated by vacuum distillation or gel‐permeation chromatography. It was found that each fraction consists of a mixture of steric isomers possessing cis and trans structures in different ratios. The 13C NMR spectra of oligomers with less than 24 carbons vary with ring size, which is explained in terms of ring strain effects. The 13C NMR spectra of oligomers with more than 28 carbons are identical with the spectrum of 1,4‐polybutadiene. It resulted that the ratio of cis to trans structure in the oligomers decreases with increasing molecular weight from 70:30 (C16) to that in the cyclooctadiene polymer (40:60).
Elektrokinetische untersuchungen an fasern, 1. Theoretische zusammenhänge
Authors: Aichele Wilfried , Schollmeyer Eckhard , Herlinger Heinz
Published: April 2003

Some relations between electrokinetic properties are shown. First by means of phenomenological equations, the electroviscose effect is explained to be due to the electroosmotic backstreaming. It is shown that in principle the equivalence of streaming‐current‐and streaming‐potential‐methods to get zetapotentials is included in these equations. This equivalence was used first by Smoluchowski to derive his equation for the zeta‐potential for the special case of a single capillary. The equation he found concerning the relations between both zeta‐potential and streaming‐potential and streaming current between the ends of a capillary was extended by different authors to bundles of capillaries and then to plugs. It is discussed, which of the extensions are correct and which properties should be included in a so‐called “porosity factor”.

From a mathematical treatment of the surface conductivity in case of capillaries it is shown that zeta‐potentials can be obtained in principle by measuring the conductivity of the system plug‐electrolyte. For this system a procedure is deduced to calculate approximately the porosity factor from measurements of the electrical resistance.
Crystal and molecular structure of 1,4‐bis(chloroacetyl)‐trans‐2,5‐dimethylpiperazine, a model compound of poly(trans‐2,5‐dimethyl‐1,4‐piperazinediylfumaroyl)
Authors: Bassi Ivano W. , Scordamaglia Raimondo
Published: April 2003

The molecular and crystal structure of 1,4‐bis(chloroacetyl)‐trans‐2,5‐dimethylpiperazine synthesized by us, was determined from X‐ray diffractometer data. The structure was solved by Patterson and Fourier methods and refined by least‐squares techniques to R 0,065 for 1081 independent reflections. The crystals are monoclinic, space group P21/n, with Z = 2 in a unit cell of dimensions: a = 9,486 (6), b = 9,139 (6), c = 7,036 (5) Å, β = 95,73 (10)°, the numbers in parentheses being the estimated standard deviations refering to the last significant digit. The trans‐2,5‐dimethylpiperazine ring is in a flattened‐chair conformation with the side methyl groups in axial position. The atoms of the amide are nearly coplanar. It seems to be proved that the structure of the trans‐2,5‐dimethylpiperazine ring in poly(trans‐2,5‐dimethyl‐1,4‐piperazinediylfumaroyl) is similar to that found for 1,4‐bis(chloroacetyl)‐trans‐2,5‐dimethylpiperazine.
Monomeric and polymeric azoinitiators
Authors: Walz R. , Bömer B. , Heitz W.
Published: April 2003

The reaction of ethylene glycol, 1,4‐butanediol, 1,6‐hexanediol, 3,6‐dioxaoctane‐1,8‐diol (triethylene glycol), poly(ethylene oxide)s with M̄n = 300,1000 and 3000, or with poly(propylene oxide)s with M̄n = 425 and 2000 in excess with AIBN leads to the corresponding bis(hydroxyalkyl) 2,2′‐azodiisobutyrates (1a–i). These initiators are suited to synthesize telechelics. With equimolar amounts of AIBN and 3‐oxapentane‐1,5‐diol (diethylene glycol), poly(ethylene oxide)s with M̄n = 300, 1000 and 12000, poly(propylene oxide) with M̄n = 425, or with poly(tetrahydrofuran) with M̄n = 1000 and 2000 polymeric azoinitiators of structure 2 are formed. Blockcopolymers may be synthesized by means of these polymeric azocompounds.
Cyclic oligomers formed during the polymerization of 1,3,6,9‐tetraoxacycloundecane
Authors: Rentsch Christoph , Schulz Rolf C.
Published: April 2003

The cationic polymerization of 1,3,6,9‐tetraoxacycloundecane (3) in CH2Cl2 at 0°C gives polymers with a regular OCH2(OC2H4)3 sequence. High polymers are obtained only after the formation of a considerable amount of oligomers. The oligomers up to the octamer ((C7H14O4)x; x=2–8) have been isolated individually and indentified by means of HP‐GPC and NMR as homologues of the cyclic monomer. The equilibrium concentrations of monomer and dimer are the same when the monomer and the dimer are polymerized and when the high polymer is depolymerized.
Untersuchung des abbaus hochmolekularer polyäthylenoxide im festzustand
Authors: Bortel E. , Lamot R.
Published: April 2003

With thermogravimetric analysis, IR and ESR measurements it could be shown that the low stability of high molecular poly(ethylene oxide) is due to a statistical degradation following a radical mechanism which leads to the formation of aldehyde groups at the end positions of the fragments. Mass spectroscopical investigations of degraded (aged) as well as of freshly prepared poly(ethylene oxide) revealed a consistent and easily comprehensible picture. Always 3 series of peaks could be found and the difference between two successive peaks amounts to 44 mass units in each series, corresponding to the oxyethylene unit. The mass spectra of degraded poly(ethylene oxide) were found to be always more rich in fragmentations than those of non degraded ones. The mechanism of poly(ethylene oxide) degradation caused by the action of electrons could be explained with the help of the obtained mass spectra. The degradation of high molecular poly(ethylene oxide), which even takes place at room temperature in the dark and in the absence of air, could be restricted considerably by adding a suitable stabilizer to the polymerization mixture.