bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymerization of methylphenylketone and its copolymerization with benzaldehyde
Authors: Tsunetsugu T. , Arimoto K. , Fueno T. , Furukawa J. 
Published: April 2003

AbstractMethylphenylketene was polymerized by a variety of organometallic catalyst/solvent systems at −78 to −20°C. The polymer obtained was found to be exclusively polyster, in contrast to previous results which indicated that dimethylketene gave polyester, polyester, polyacetal, and polyketone, depending on the catalyst/solvent systems used.Copolymerization of methylphenylketene with benzaldehyde led to the formation of a 1:1 copolymer. Hydrogenolysis of the copolymer showed that it was practically an alternating copolymer and that its structure was predominantly of the polyester type.Both the homopolymer and copolymer have poor crystallinity as compared with those obtained from dimethylketene.
Asymmetric‐induction polymerization of β‐vinylacrylates
Authors: Tsunetsugu T. , Fueno T. , Furukawa J. 
Published: April 2003

AbstractOptically active polymers of methyl, ethyl, n‐butyl, and tert‐butyl β‐vinylacrylates were synthesized by using optically active catalyst systems such as n‐BuLi/sodium l‐menthoxide and n‐BuLi/sodium d‐bornoxide. The optically active alkoxides were found to be even more efficient cocatalysts for the asymmetric‐induced polymerization than were the corresponding ethers.The polymers obtained were characterized from their optical rotatory dispersion curves and infrared absorption spectra.
Aqueous polymerization of acrylic acid initiated by KMnO4 — H2C2O4 redox system
Authors: Misra G. S. , Narain Harish 
Published: April 2003

AbstractPolymerization of acrylic acid in aqueous solution initiated by permanganate‐oxalic acid redox pair has been studied at 32 ± 0.2°C in nitrogen atmosphere. The rate of polymerization has been found to be nearly independent of oxalic acid concentration within the range 1.87 to 9.33 · 10−3 mole/l. and decreases only at higher concentrations of the oxalic acid. The rate has also been found to vary with the first power of the monomer concentration (within the range 1.44 to 5.76 · 10−2 mole/l.) and the first power of the catalyst concentration (8.0 to 28.0 · 10−5 Mole/l.). It is, however, proportional to half power at relatively high catalyst concentration, at fixed concentrations of oxalic acid (1.03 · 10−2 mole/l.) and the monomer (5.76 · 10−2 mole/l.). At higher concentration of monomer the catalyst exponent has been found to be nearly unity for both the higher and lower concentrations of the catalyst. The initial rate of polymerization increases with increase in temperature. The overall energy of activation has been found to be 19.56 kcal/mole within the temperature range 30 – 45°C. Organic solvents and salts (KCI, Na2SO4, and Na2C2O4) depress the rate but MnSO4 4H2O has been found to increase the initial rate but depress the maximum conversion.
Quantitative IR‐spektroskopische untersuchungen zur temperaturabhängigkeit der CCl‐streckschwingungen von polyvinylchlorid
Authors: Pohl Von H. U. , Hummel D. O. 
Published: April 2003

AbstractVinylchlorid wurde bei verschiedenen Temperaturen strahlenchemisch in Masse polymerisiert; die Polymeren wurden bei Meßtemperaturen zwischen 30 und 200°C IR‐spektroskopisch untersucht. Es wird ein Verfahren angegeben, Komplexe, überlagerter Absorptionsbanden graphisch aufzutrennen. Der Komplex der ν(CCI)‐Schwingungen wurde in 7 Banden bei 603, 613, 624, 636, 647, 677 und 696 cm−1aufgelöst. Die Temperaturabhängigkeit der relativen integralen Extinktion dieser Banden wurde gemessen; die Zuordnung zu bestimmten Konfigurationen und Konformationen wird diskutiert.
Polyoxymethylene single crystals. II. The effect of substrate on annealing behavior
Authors: Garber C. A. , Geil P. H. 
Published: April 2003

AbstractThe annealing behavior of polyoxymethylene single crystals has been studied at various temperatures on five different substrates. Crystals were found to anneal faster on high energy substrates (mica, aluminum, NaCl) than on low energy substrates (polyethylene terephthalate and glass). These observations suggest the presence of interactions between substrate and folds.
Thermodynamisches verhalten, expansionskoeffizient und viskositätszahl von polystyrol in tetrahydrofuran
Authors: Schulz Von G. V. , Baumann H. 
Published: April 2003

AbstractStreulichtmessungen ergeben, daß Polystyrollösungen in Tetrahydrofaran stark exothermisch sind; der 2. Virialkoeffizient des osmotischen Druckes A2 wird überwiegend durch den Enthalpieterm A2,H bestimmt. Der Expansionskoeffizient gehorcht der (α5−α3)‐Beziehung mit der Konstante von STOCKMAYER und die h(z̄)‐Funktion der Gleichung von CASASSA. Die Viskositätszahl [η] wird durch die Gleichung von KURATA und YAMAKAWA erfaßt. Mit den drei Parametern β/M, K0 = r̄/M und b/M (b = hydrodynamischer Durchmesser) lassen sich A2, α, [η] und der Trägheitsradius r̄ über einen großen Molekulargewichts‐bereich in guter Übereinstimmung mit den Meßwerten berechnen (vgl. Abb. 3).
Effects of radiation on styrene and α‐methyl styrene in different organic solvents and in the pure state. A study by pulse radiolysis
Authors: Schneider Christel , Swallow A. J. 
Published: April 2003

AbstractStyrene and α‐methyl styrene, both in solution in organic solvents and in the pure state, have been subjected to 2 μ sec pulses of 4 MeV electrons. The absorption spectra of the transient intermediates formed have been measured and kinetic studies have been carried out. The results for styrene were similar to those for α‐methyl styrene. In the case of solutions of styrene in cyclohexane, transients absorbing at 320 mμ and 390 mμ were seen. The absorption at 320 mn is attributed in part to a slowly disappearing polymer radical with a structure resembling benzyl. The absorption at 390 mn disappears rapidly and is attributed to a radical anion. Various additives interfere with its formation. The effect of styrene concentration and dose rate on the formation of the transients is reported. Styrene reacts rapidly with solvated electrons in methanol, but the anion formed becomes proton‐ated rapidly. In benzene the absorption appears at a wavelength similar to that seen with pure benzene. Intense absorptions at 290 mμ and 320 mμ are seen in carbon tetrachloride solution. Absorptions at ∼320 mμ and ∼400 mμ are seen when pure styrene or α‐methyl styrene are pulsed. A stable species absorbing at 320 mμ is also present. Values for rate constants are compared with those obtained from measurements of polymer formation.
Ein perlförmiges cellulosegel für die chromatographie
Authors: Determann Von Helmut , Rehner Helmut , Mitarbeit Theodor Wieland , Meyer von Norbert , Wente Frank 
Published: April 2003

AbstractDurch Ausfällen mit organischen Säuren lassen sich aus verschiedenen in Benzol emulgierten Celluloselösungen mechanisch und chemisch widerstandsfähige Perlen von 30 bis 300 μm Durchmesser gewinnen. Sie haben Poren von durchschnittlich einigen hundert nm Weite, deren mittlerer Durchmesser von der Cellulosekonzentration in der Lösung abhängt. Hauptsächlich wurden die Gele aus 2, 6 und 10% cellulosehaltiger SCHWEIZER‐Lösung, welche mit benzolischer Benzoesäure regeneriert waren, in ihrer Fähigkeit zur gelchromatographischen Trennung von E.coli‐Bakterien, Dextranen der Molgewichte von 2·105 bis 7·106, verschiedenen Proteinen und Benzylalkohol im. wäßrigen System untersucht. Besonders die aus 6‐ und aus 10‐proz. Lösung erhaltenen Gelperlen eignen sich zur Trennung von Substanzen im Molekulargewichtsbereich von 104 bis 107. Die hygroskopische Essigsäure, statt Benzoesäure als Fällungsmittel bewirkt eine Schrumpfung, d.h. Porenverengung in der Nähe der Oberfläche.
Solid state polymerization of zinc methacrylate
Authors: Parrish C. F. , Kochanny G. L. 
Published: April 2003

AbstractZinc methacrylate has been polymerized in the solid state by the post‐irradiation technique at 89.5°C. The polymer produced was less isotactic than that obtained from barium methacrylate dihydrate when polymerized under similar conditions. The tacticity of the poly(zinc methacrylate) differed markedly from the polymer produced in the liquid phase from methyl methacrylate or methacrylic acid. X‐ray studies of the zinc methacrylate showed the monomer to have an orthorhombic unit cell with lattice constants of a = 17.94Å, b = 9.16 Å, and c = 13.2 Å. There are 8 molecules per unit cell and the symmetry can be classified as either Pnam or Pna2. The anhydrous monomer shows pronounced thermal polymerization at 89.5°C and the radiation‐induced reaction shows no measurable intensity dependency over a 6 fold change in dose rate.
Application of the FLORY‐FOX‐SCHAEFGENintrinsic viscosity molecular weight relation to high polymers
Authors: Patel J. R. , Patel C. K. , Patel R. D. 
Published: April 2003

AbstractThe relationship for the determination of unperturbed dimensions, as proposed by FLORY‐FOX‐SCHAEFGEN, has been found to be inapplicable to many polymer‐solvent systems. However, while plotting [η]2/3/M1/3vs. M/[η] for different solvents a common point of intersection which is not on the ordinate has been observed in all the cases. Unperturbed dimensions obtained from this point have been found to agree with those derived by using other methods.
A semi‐quantitative investigation of the cysteic acid‐containing peptides in a partial acid hydrolysate of γ‐keratose
Authors: Asquith Raymond Smith , Shaw Trevor 
Published: April 2003

Abstractγ‐Keratose, a soluble fraction of peracetic acid oxidised wool has been partially hydrolysed with 5 N hydrochloric acid under controlled conditions. The mixture of low molecular weight peptides has been separated into two fractions. The cysteic acid rich fraction contained 2750 μtmole/g of peptide‐bound cysteic acid. This accounts for 58% of the total cysteic acid present in γ‐keratose. The structures of a number of the cysteic acid peptides in this fraction have been deduced, and their amounts estimated on a semi‐quantitative basis. The following peptides have been identified and are listed in descending order of quantity present: Ser‐CySO3H.CySO3H.; Thr.CySO3H.CySO3H.; Gly.CySO3H.CySO3H.; CySO3H.;CySO3H.; CySO3H.Glu; Pro.CySO3H.CySO3H.; (Arg,CySO3H,CySO3H); Val‐(CySO3H)1–2. Without correction for losses during separation and analysis of the peptides it has been shown that at least 10.1% of the cysteic acid in γ‐keratose occurs in the sequence –CySO3H.CySO3H–. If a correction factor based on the recovery of cysteic acid from the analytical procedure is applied, then this sequence accounts for a minimum of 31.7% of the cysteic acid. Some consequences of a high incidence of this sequence are considered.
Polymerization and copolymerization of allyl ethenesulfonate
Authors: De Witte E. , Goethals E. J. 
Published: April 2003

AbstractAllyl ethenesulfonate (AES) has been polymerized by radical initiators under different conditions. The polymers consist of 67 to 86% of cyclic recurring units for monomer concentrations going from 8.9 (bulk) to 0.28 mole·1−1. The amount of allyl groups taking part in the polymerization is much higher than expected from the composition of copolymers obtained from propyl ethenesulfonate and allyl ethanesulfonate. The allyl group of AES is incorporated in the polymer chain only via the cyclopolymerization mechanism.AES has been copolymerized with styrene, methyl acrylate, and vinyl acetate. The folowing copolymerization parameters were found:

The percentage of cyclic recurring units is low in copolymers with methyl acrylate and with styrene but is high in those with vinyl acetate. In the copolymerization with styrene and with methyl acrylate the reactivity of AES is about equal to that of butyl thenesulfonate; in the copolymerization with vinyl acetate it shows a much higher reactivity than butyl ethenesulfonate. This increase in reactivity is attributed to the formation of cyclic radicals. AES is another example of an unsymmetrical 1.6‐diene wherein the reactivity of the less reactive double bond is greater than that observed in analogous monomers where only that double bond is present.
Predictions of polymer molecular weights from the theory of emulsion polymerization
Authors: Watterson J. G. , Parts A. G. , Moore D. E. 
Published: April 2003

AbstractThe theory of HARKINS, SMITH and EWART, describing the formation of latex particles in the emulsion polymerization system is used, to describe the average degree of polymerization of the formed polymer. Transfer reactions are assumed to be negligible. The average lifetime t̄ of growing polymer radicals – to which the average degree of polymerization is proportional – is found to be

where x = ρt/N is the dimensionless variable representing the average number of radicals created per latex particles by time t. ρ is the constant rate of production of radicals, N is the number of latex particles at the time of disappearance of micelles.
Studies on the polymerization of bifunctional monomers. XV. Anionic polymerization of o‐divinlbenzene
Authors: Aso Chuji , Kunitake Toyoki , Imaizumi Yoji 
Published: April 2003

AbstractAnionic polymerization of o‐divinylbenzene was carried out with organolithium and alkalimetal‐naphthalene catalysts. The extent of cyclization in polymer was generally smaller than in cationic polymerization. The influence of the counter cation and of the solvent on the cyclization constant, rc, observed in polymerization with alkalimetal‐naphthalene catalysts agreed qualitatively with that on the rate of anionic propagation of styrene in the same system, if rc was considered to increase with the reactivity of the uncyclized anion.In the sodium naphthalene/THF system, rc decreased on addition of NaBPh4 and this result was considered to indicate the free‐anion propagation. In the same system, the apparent difference in activation energy between intramolecular cyclization and intermolecular propagation was 2–3 kcal·mole−1.
Gel/water relationships in hydrophilic polymers: Nuclear magnetic resonance
Authors: Sterling Clarence , Masuzawa Mitsunobu 
Published: April 2003

AbstractThe spectra of nuclear magnetic resonance were recorded and analyzed for different concentrations of gels of agar, carboxymethyl cellulose, gelatin, and starch. The line width of the signal of the hydroxyl proton broadens with increasing concentration of polymer, and the signal height continually decreases. A small paramagnetic shift also occurs. Changes in signal areas are interpreted in terms of “solid”, “bound”, and “free” water, with no “solid” water found in gels of gelatin and starch. Free water decreases continuously with increasing concentration in all gels. The very great line‐broadening for low concentrations of agar gels is explained by the water‐organizing effect of the D‐galactopyranose moiety.
The reaction of propane sultone with macromolecules. II. Poly(vinyl alcohol)
Authors: Goethals Eric J. , Natus Guy 
Published: April 2003

AbstractThe sulfopropylation of poly(vinyl alcohol) (PVA) with propane sultone under different conditions has been studied. Attempts to carry out the reaction via the sodium alcoholate of PVA, prepared by different methods, failed, gave low yields or resulted in the formation of insoluble reaction products. The best way to obtain sulfopropyl poly(vinyl alcohol) (SPPVA) was to react propane sultone with PVA dissolved in dimethyl sulfoxide (DMSO) in the presence of potassium carbonate. Most probably the reaction occurs via dimethyl‐(3‐sulfopropoxy)sulfonium salt which is formed by reaction of propane sultone with DMSO. By passing a solution of the potassium salt of SPPVA through an acidified ion exchange column the free acid was obtained. Both the potassium salts and the free acids were hygroscopic, water‐soluble substances showing typical polyelectrolyte properties.
Formaldehyde resins. 94. On the reaction products of diphenyl ether and polymetylenediphenyl ethers with formaldehyde
Authors: Ninagawa Akira , Imoto Minoru 
Published: April 2003

AbstractFrom the reaction products of diphenyl ether and formaldehyde, o‐methylol diphenyl ether (o‐MMP) was isolated. Its amount was only 1/38 of that of p‐methylol diphenyl ether, as shown by v.p.c. The reaction of p.p′‐Diphenoxydiphenylmethane (M2P) and p.p′‐di‐(p″‐phenoxybenzyl)‐diphenyl ether (2M3P) with formaldehyde was also carried out in the presence of acidic catalysts in order to isolate the p‐monomethylol derivatives of M2P and 2M3P (p‐MM‐M2P and p‐MM‐2M3P) and p.p′‐dimethylol‐M2P (p.p′‐DM‐M2P).
Studies on the polymerization of bifunctional monomers. XVII. Cyclopolymerization of malealdehyde and the structure of the polymer
Authors: Aso Chuji , Kunitake Toyoki , Miura Masanobu , Kōyama Katsuhisa 
Published: April 2003

AbstractPolymerizations of malealdehyde were carried out with alkalimetal alkoxides, AlEt3, pyridine, AlEt3TiCl4 and BF3OEt2 as catalysts. All the polymers obtained with other catalysts than AlEt3 and AlEt3TiCl4 were composed only of the cyclized unit (dialkoxydihydrofuran ring) (> 95%) and the 1.2‐addition structure (< 5%). IR spectra of the polymers obtained with AlEt3 and AlEt3TiCl4 catalysts were suggestive of the presence of five‐membered lactone rings which may occur as a result of termination by hydride transfer. The steric structure (cis vs. trans) of the dialkoxydihydrofuran ring in polymer was inferred from the comparison of the IR spectra of the polymer with those of the isomeric dialkoxydihydrofurans in the 800 cm−1 region. Anionic catalysts gave higher contents of the cis configuration, while coordinated anionic catalysts gave comparable amounts of the cis and trans structures.
Zur wechselseitigen löslichkeitsbeeinflussung von polymeren mit versehiedenen molekulargewichten
Authors: Breitenbach Von J. W. , Wolf B. A. 
Published: April 2003

AbstractDie Trübungskurven für Lösungen von Mischungen aus gleichen Gewichtsanteilen einer Polystyrolprobe mit „wahrscheinlichster”︁ Molekulargewichtsverteilung (Pn = 3100) und eines Polystyrols mit relativ enger Molekulargewichtsverteilung (Pn = 800) in einem einfachen Lösungsmittel (Cyclohexan) und einem. Mischlösungsmittel (Benzol/Methanol im Vol.‐Verhältnis 3:1) wurden mit den Trübungskurven der Komponenten verglichen. Im Mischlösungsmittel nimmt im gesamten experimentell zugänglichen Konzentrationsbereich die Trübungstemperatur mit der Konzentration monoton zu; die Trübungskurve erstreckt sich hier über ein wesentlich größeres Temperaturgebiet als in Cyclohexan als Lösungsmittel.Sowohl in Cyclohexan als auch im Lösungsmittel/Fällungsmittel‐Gemisch liegen die Trübungstemperaturen der Polymermischung bei einer bestimmten Gesamtpolymerkonzentration zwischen den Trübungstemperaturen der Lösungen der Komponenten derselben Konzentration. Durch Vergleich der Trübungskurven bei den entsprechenden Partialkonzentrationen der Polymermischung erkennt man jedoch, daß im Falle von Cyclohexan die langkettigen Homologen von den kurzkettigen in Lösung gehalten werden und umgekehrt, während im Mischlösungsmittel jeder Polymerzusatz unabhängig von seiner Kettenlänge die Löslichkeit herabsetzt.Die beobachteten Unterschiede im Entmischungsverhalten von Polymerlösungen im Ein‐ bzw. Zweikomponentenlösungsmittel werden auf die bevorzugte Aufnahme der Lösungsmittelkomponente des Mischlösungsmittels ins Knäuelinnere zurückgeführt.
Kinetic studies on the polymerization of 1.3‐dioxolane catalyzed by triethyl oxonium tetrafluoroborate
Authors: Yamashita Yuya , Okada Masahiko , Kasahara Hideo 
Published: April 2003

AbstractThe kinetics of the polymerization of 1.3‐dioxolane with triethyl oxonium tetrafluoroborate has been studied in methylene chloride solution. The polymerization was preceded by an induction period. The addition of water to the system prolonged the induction period and decreased both rate of polymerization and molecular weight of the polymer. The induction period was found to be proportional to reciprocal of the initial catalyst concentration but to be independent of initial monomer concentration. Therefore it would appear that the induction period is mainly due to a reaction of the catalyst with water. A near linear relationship between the degree of polymerization and the conversion suggested that the polymerization proceeds essentially without termination and chain transfer reactions to an equilibrium conversion in the absence of water. The rate constant of propagation was estimated to be 4.3·10−2l./ mole sec in methylene chloride at 30°C.
Kinetic studies in ethylene polymerization with ziegler type catalysts. VI. Characterization of catalyst sites by polymerization experiments in the presence of deuterium
Authors: Schindler A. 
Published: April 2003

AbstractEthylene polymerization in the presence of deuterium was investigated with the four catalyst systems resulting from Et3Al and Et2AlCl in combination with either TiCl4 or TiCl3. From the effect of catalyst ratio on the kind and the amount of deuterated products formed the existence of three kinds of titanium sites could be inferred. An H, D‐exchange reaction involving the β‐hydrogen of the growing chain was found to be characteristic for chain growth on Ti(IV) sites. The inactivity of BuLi or Et2Zn systems in such exchange reactions implied the existence of bimetallic complexes in alkylaluminum systems. The exclusive formation of CH2D groups in the polymer by a transfer reaction was found to be characteristic for chain growth on Ti(III) sites. The occurrence of an H,D‐exchange reaction involving the monomer and the formaiton of deuterated ethanes was assigned to the presence of polymerization‐inactive titanium hydride sites, formed at high catalyst ratios.
Phase changes in polyethylene single crystals. The effects of thermal stress and electron irradiation
Authors: Kiho H. , Ingram P. 
Published: April 2003

AbstractSingle crystals of polyethylene have been reported to undergo a crystallographic phase change from an orthorhombic unit cell to monoclinic when heated to temperatures near their original crystallization temperatures. This change is shown to be due purely to thermal stresses set up between the crystals and substrate on which they lie, arising from a difference in expansion coefficients of crystals and substrate. The orientation of the monoclinic lattice with respect to the orthorhombic lattice is consistent with an effective deformation parallel to the orthorhombic b‐axis. At temperatures above 110°C the monoclinic phase relaxes almost completely back to orthorhombic primarily through the greatly increased mobility of the chains in their folded portions. The effects of an electron beam on the polyethylene crystal lattice have been studied by electron diffraction during irradiation at temperatures from −161 to + 110°C. The changes in dimensions of the unit (sub)‐cell were determined as functions of the time of irradiation. Above about 30°C a stable hexagonal phase is formed before the crystalline diffraction pattern degrades to a diffuse halo. This change is ascribed to (i) a depression of a transition temperature (due to defects) analogous to that found in n‐paraffins when the orthorhombic unit cell becomes hexagonal, and (ii) elastic distortions around the lattice defects. It is also noted that the transformation proceeds readily at 110°C in the absence of radiation if a small dose is given initially: the number of defects under these conditions are few and consequently on cooling to room temperature the hexagonal and orthorhombic phase co‐exist. Although no definitive conclusions as to the nature of the reaction can be determined, the evidence is that the defects are primarily scissions and cross‐links in the crystal lattice.