bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical rotatory dispersion studies of poly(l‐α‐methylbenzyl methacrylate) and poly(menthyl methacrylate) in solution
Authors: Liu Kang‐Jen , Lignowski J. S. , Ullman Robert 
Published: April 2003

AbstractOptical rotatory dispersion studies were carried out on solutions of poly(l‐α‐methylbenzyl methacrylate) and poly (l‐menthyl methacrylate) samples of varying tacticity. Monomeric analogues α‐methylbenzyl pivalate and menthyl pivalate were also investigated in the same way. Ultraviolet spectra of the α‐methylbenzyl series were obtained.The general shape and form of the optical rotation spectra were similar for the several α‐methylbenzyl polymer samples and monomer analogue. The isotactic polymer showed generally higher optical activity than both the syndiotactic and atactic polymers and the monomeric analogue. This was found to be true in several solvent systems. The ratio of the optical activity of the polymer to that of the monomer increased uniformly with decreasing wave length. The temperature dependence of optical activity was small. The ultraviolet spectra of polymeric and monomeric species were very much the same down to the lowest wave lengths measured, of the order of 210 mμ.The menthyl polymers and monomer analogue also showed optical rotation spectra which were similar to each other. For this material all polymers had higher optical activity than the monomeric analogue, but in contrast to that which was found for the α‐methylbenzyl systems, the syndiotactic and atactic polymers showed higher optical rotation than the isotactic material.The relationship of the optical activity of the polymers in solution to the specific conformational structure present is obscured partly by solvent interaction and partly by the fact that the effects of polymer structure on optical activity are small since the asymmetric carbon or carbon atoms are connected by several intermediate bonds to the skeletal backbone of the molecule. The importance of the excited states of the important chromophoric groups of the polymer molecule on the optical activity is discussed.
Über das zustandsdiagramm binärer polymerengemische
Authors: Natov Von M. , Peeva L. 
Published: April 2003

AbstractDie Phasenzustände von folgenden binären Polymerensystemen, die aus je einer kristallisationsfähigen und einer nichtkristallisationsfähigen Komponente bestehen, wurden untersucht: Polyäthylenadipat/Polymethylmethacrylat, Polyäthylensebacinat/Polymethylmethacrylat und Polyäthylenadipat/Polyvinylchlorid. Es ergab sich, daß diese Mischungen homogene Systeme bilden können, die sich durch Zustandsdiagramme charakterisieren lassen, die denjenigen von niedermolekularen Verbindungen ähneln. Im einzelnen wurde die Abhängigkeit der Phasenzustände von den Molekulargewichten der Komponenten, der Temperatur und der Zusammensetzung der Gemische untersucht.
Die copolymerisation des trioxans mit substituierten 1.3‐dioxacycloalkanen
Authors: Weissermel Von K. , Hermann H. D. , Burg K. H. 
Published: April 2003

AbstractIn 2‐Stellung substituierte 1.3‐Dioxacycloalkane sind aus zweiwertigen Alkoholen und Aldehyden oder Ketonen leicht zugänglich. Sie zeigen bei der Copolymerisation mit Trioxan ein ungewöhnliches Verhalten. Es wird zunächst aus Trioxan unter Ringöffnung Formaldehyd abgespalten, der in einer Induktionsperiode mit dem substituierten Dioxacryloalkan unter Bildung von cyclischen Formalen und Freisetzung der Carbonylkomponente reagiert. Erst wenn these Umacetalisierung weitgehend beendet ist, kann sich monomerer Formaldehyd im Reaktionsgemisch bis zur ceiling‐Konzentration anreichern, so daß schließlich eine Copolymerisation von Trioxan mit unsubstituiertem 1.3‐Dioxacycloalkan ausgelöst wird.
Polyamide synthesis via enamines
Authors: Daly W. H. , Kern W. 
Published: April 2003

AbstractEnamines derived from cyclic ketones behave as difunctional intermediates when treated with phenyl isocyanate to produce dicarboxanilides. Reaction of bis(4‐isocyanatophenyl)‐methane with 1‐N‐morpholino‐1‐cyclopentene in DMSO leads to poly[iminocarbonyl(2‐morpholino‐1‐cyclopenten‐1.3‐ylene)carbonylimino‐p‐phenylenemethylene‐p‐phenylene], a polyamide. The effects of various cyclic enamines and diisocyanates on the polymerization are surveyed. Morpholine and piperidine are more effective than pyrrolidine or dimethylamine when incorporated into cyclopentanone enamines. The molecular weight of the polymer decreases when the ring size of the ketone component is increased. The efficiency of the diisocyanates decreases as follows: bis(4‐isocyanatophenyl)methane > tolylene diisocyanate > naphthylene diisocyanate > hexamethylene diisocyanate > sulfurly diisocyanate. Branched and crosslinked polymers were obtained in the presences of excess diisocyanate. A mechanism is proposed to account for these results.The polyamides obtained from 1‐N‐amino‐1‐cyclopentene were not thermally stable. The rate of degradation at 60°C was determined by measuring the decrease in viscosity with time. The enamine structural unit of the polyamides can be hydrolyzed with 98% formic acid to the corresponding polyketone, which yields a poly(2.4‐dinitrophenylhydrazone) upon treatment with DNPH in DMSO. Reaction of excess 2‐N‐morpholino‐1‐cyclopentene‐1‐carboxanilide with bis(4‐isocyanatophenyl)methane affords a model compound for the new polyamide. The infrared and NMR spectra of the polymers and their corresponding model systems were compared and found to be consistent with the proposed structures.
Solution properties of copolymer of p‐chlorostyrene and methyl methacrylate
Authors: Mohite R. B. , Gundiah S. , Kapur S. L. 
Published: April 2003

AbstractThe monomer reactivity ratios in the free radical copolymerization of methyl methacrylate and p‐chlorostyrene were obtained and an azeotropic copolymer containing the 0.484 mole fraction of methyl methacrylate was prepared. The copolymer was fractionated into nine fractions, which on the basis of their chlorine content and specific refractive index increments, were found to be homogeneous in their chemical composition. The solution behaviour of these fractions was examined by viscosity, osmotic pressure and light‐scattering techniques. The weight‐average molecular weights obtained in dioxane, chloroform and 78:22 v/v mixture of trans‐decalin and trichloro ethylene (Θ solvent at 22.3°C) were found to be identical but those obtained from benzene were as much as 80% higher, depending on the molecular weight. The data were treated by the method of STOCKMAYER and BENOIT and the deviation and square‐deviation of the chemical composition was obtained as zero and proportional to M1.5, respectively. The value of exponent “a” in the KUHN‐HOUWINK equation[η] = KMa obtained by use of the number‐average molecular weight and corrected weight‐average molecular weight, was identical but the apparent weight‐average molecular weights obtained in benzene gave a low value of “a” confirming the applicability of the STOCKMAYER‐BENOIT relationships. The value of the constant K obtained for the copolymer in the theta solvent was 6.4·10−4 compared with 4.9·10−4 and 5.0·10−4 obtained for poly(methyl methacrylate) and poly‐p‐chlorostyrene, respectively, indicating a 10% higher dimension for the copolymer.
Synthesis and reactions of functional polymers. XXIX. Preparation and polymerization of S‐vinyl‐N.N‐dialkyldithiocarbamates
Authors: Nakai T. , Shioya K. , Okawara M. 
Published: April 2003

AbstractSome S‐vinyl‐N.N‐dialkyldithiocarbamates were prepared in good yields by vacuum pyrolysis of the corresponding ethylene bis(N.N‐dialkyldithiocarbamates). S‐Vinyl‐N.N‐diethyldithiocarbamate was copolymerized with styrene. The ALFREY‐PRICE Q‐ and e‐values were calculated and compared with those of its oxygen analogues.
Über die Synthese und das Redoxverhalten einiger Modellsubstanzen für polymere Hydrochinon‐Chinon‐Redoxsysteme. V1
Authors: Manecke Von G. , Zerpner D. 
Published: April 2003

AbstractEinige Modellsubstanzen für polymere Hydrochinon‐Chinon‐Redoxsysteme wurden dargestellt, in denen zwei Hydrochinonkerne über eine Methylen‐, Äthylen‐ oder Trimethylenbrücke verknüpft sind. Ihr Redoxverhalten wurde durch potentiometrische Titration untersucht. Die Titrationskurven werden theoretisch gedeutet.
Deformation of extremely thin polyethylene films
Authors: Sakaoku K. , Peterlin A. 
Published: April 2003

AbstractIn order to establish a better correlation between the drawing mechanism of bulk polyethylene (PE) and the observation of plastic deformation of single crystals and the ensuing microfibril formation extremely thin PF films floating on hot water were deformed and studied by electron microscopy. The drawn film consists of about 300 Å wide folded chain blocks arranged in microfibrils. The chains are oriented in the microfibril axis. The lateral coalescence of the blocks into lamellae produces a surface structure of the same type as observed with bulk samples. One hence concludes that also in the latter case the destruction of the original spherulitic structure in the necking zone first produces microfibrils composed of blocks broken off a single lamella. The bundle of microfibrils from a single stack of lamellae with similar draw ratio and draw rate laterally coalesces forming a fibril, i.e., a stack of mosaic type lamellae with rather irregular fold containing surfaces and extending over more or less the whole cross section of the fibril.In contrast with bulk samples, but in agreement with the single crystal deformation, the long period of the drawn film agrees with that of the starting material. The same situation exists with annealing which increases the long period and the order in lamellar orientation and long period, but does not produce any crystal rotation about an axis in the sample surface and perpendicular to the draw direction which is so conspicuous with drawn bulk PE.
Die chemische heterogenität von copolymerisaten. 2. Die häfigkeitsiverteilung der chemischen zusammensetzung in binären copolymerisaten
Authors: Markert Von G. 
Published: April 2003

AbstractDa die Copolymerisationsgleichung unabhängig von bereits vorhandenem Copolymerisat gilt, existiert für jedes Monomerenpaar eine allgemeine, d.h. vom Ausgangsmischungsverhältnis der Monomeren losgelöste, Verteilungsfunktion der chemischen Zusammensetzung. Die beiden Grundtypen der Copolymerisationskurve ohne und mit Azeotrop finden sich entsprechend abgewandelt in den Häufigkeitsverteilungen wieder. Das Azeotrop teilt ein System in zwei voneinander unabhängrige Bereiche, ohne den Kurvenhabitus selbst weiter zu verändern. In Verbindung mit der Copolymerisationskurve ergibt die Häufigkeitsverteilung, eine übersichtliche Informationsquelle über den Aufbau von Copolymerisaten und bietet große Vorteile, wenn man z.B. Sequenzlängenverteilungencoder die Copolymerisation ternärer Gemische erfassen will, d.h. immer dann, wenn eine möglichst genaue und konzentrierte Darstellung der chemischen Verteilung notwendig ist.
Optically active polyamides with regular structural sequences prepared froni α‐amino acid
Authors: Saotome Kazuo , Schulz Rolf C. 
Published: April 2003

AbstractOptically active polyamides with regular structural sequences have been prepared from L‐lysine and adipic acid. A novel optically active symmetrical diamine, N.N'‐bis(L‐5‐amino‐5‐carboxyl‐amyl)adipamide, was obtained by treating L‐lysine with adipyl chloride in the presence of copper(II) ions. The interfacial polycondensation of this diamine with adipyl chloride afforded a regular polymer, while the polycondensation of L‐lysine with adipyl chloride gave an irregular polymer of the same analytical composition. The melting points, optical rotations and the optical rotatory dispersions of these polymers were investigated.
Polar effects in radical polymerization of vinyl monomers; radical copolymerization of several p‐substituted vinyl benzoates
Authors: Kinoshita Masayoshi , Irie Tsuyoshi , Imoto Minoru 
Published: April 2003

AbstractThe mutual radical copolymerizations of several p‐substituted vinyl benzoates such as vinyl p‐methoxy‐, p‐methyl‐, p‐chloro‐, p‐bromo‐, and p‐cyanobenzoate and vinyl benzoate were carried out at 60°C. The monomer reactivity ratios were determined by the method of FINEMAN and ROSS. The relative reaction rates of p‐substituted vinyl benzoates to a given poly‐vinyl‐p‐substituted benzoate radical plotted against HAMMETT'S σ‐values gave straight lines. The linear relationships and small ρ‐values show in contrary to p‐substituted styrenes that p‐substituents in this case have only a little polar effect on the vinyl group and on the polymer radical which are separated from the aromatic ring through the carboxyl‐group, and on the exaltation of resonance stabilization of polymerizing species at transition state. The observed σ‐values were correlated with the ρ‐values of p‐substituents on the polymer radicals. Polymers and copolymers of these monomers were hydrolysed to give polyvinyl alcohol.
The cationic nature of diethylzinc/water system as polymerization catalyst
Authors: Tsuchiya Shozo , Tsuruta Teiji 
Published: April 2003

AbstractThe nature of the binary system diethylzinc/water as catalyst for the ring opening polymerizations was found to be much influenced by the mole ratio of water to zinc. With mole ratios less than 1, the catalyst system induced the polymerization of tetrahydrofuran, 3.3‐bis(chloromethyl)oxetane and styrene with (or without in some cases) suitable cocatalysts; that points at a cationic character of the zinc catalyst. The 1:1 system, on the other hand, failed to polymerize any of these monomers.Discussions are presented on the characters of the two catalyst systems on the basis of these results together with those for D(+)‐propylene oxide polymerization.
Die herstellung molekulareinheitlicher leiteroligomerer und einer molekulareinheitlichen hexaacrylsäure. IV. Mitt.: Modelle für matrizenreaktionen
Authors: von Kämmerer H. , Önder N. 
Published: April 2003

AbstractDie phenolischen Hydroxylgruppen molekulareinheitlicher Mehrkernverbindungen mit vier und fünf pKresolbausteinen je Molekül konnten vollständig mit Acrylsäurechlorid in Gegenwart von Triäthylamin verestert werden. Ließ man auf die in siedendem Benzol stark verdünnten mehrafachen Acrylsäureester einen Überschuß an Radikalen aus α.α′‐Azoisobutyrodinitril einwirken, so bildeten sich mit guter Ausbeute molekulareinheitliche, dünnschichtchromatographisch reine Leiteroligomere. Die alkalische Verseifung des Leiteroilgomeren mit vier p‐Kresolbausteinen gab eine molekulareinheitliche Hexaacrylsäure, die als Hexamethylester durch Elementaranalyse und Molekulargewicht charakterisiert wurde; die gefundenen Werte stimmten innerhalb der üblichen Fehlerstreuung mit den berechneten überein. Die durchgeführte Reaktionsfolge ist eine synthetische Matrizenreaktion und vegleichbar mit einer natürlichen Matrizenreaktion.
Komplexbildung von acrylnitril mit AgNO3 und initiierung der lichtsensibilisierten polymerisation. Zur polymerisation von acrylnitril mit AgNO3, 4. Mitt.
Authors: Schnecko Von H. 
Published: April 2003

AbstractEs wird über die Komplexbildung von Acrylnitril (AN) mit AgNO3 berichtet, und die experimentellen Ergebnisse werden kinetisch ausgewertet; die Annahme, daß im Falle des AN die Initiierung aus einem Komplex des Monomeren mit dem Salz erfolgt, wird enhärtet. Daräber hinaus hängt die Polymerisationsgeschwindigkeit von der Wellenläange des eingestrahlten Lichts ab. für den Initiierungsmechanismus wird eine Reduktion des Metallions mit gleichzeitiger Bildung eines NO3‐Radikals vorgeschlagen, das den eigentlichen Initiator darstellt.
The stability of the helix of amylose and amylopectin in DMSO and water solutions
Authors: Erlander Stig R. , Tobin R. 
Published: April 2003

AbstractThe DMSO molecule behaves as a zwitterion having an electrostatic charge density on its oxygen atom comparable to that of the fluoride ion. Therefore the DMSO anion interacts with water to form an A‐region having two water molecules, i.e., a DMSO 2H2O complex at 66% DMSO. Studies on amylose and amylopectin show that DMSO 2H2O as well as anhydrous DMSO help to stabilize the helix structure of amylose and amylopectin. Because this helix structure is absent in dextran and hydroxyethyl cellulose, their properties in DMSO/water solutions are different from those of starch. The proposed model for the interaction of DMSO or hydrated DMSO with the starch helix shows how these molecules stabilize the helix by interacting with only one hydroxyl group of the C‐2 and C′‐3 hydrogen bonded hydroxyl groups. The α‐helix of amylose and amylopectin is more stable at acid pH values of 90 and 100% DMSO solutions than alkaline values because of the formation of the (CH3)2S+‐OH cation. The hydroxyl group of this cation salts‐out the hydrogen bonds just as the case of the hydrated A‐regions of Li+ and Na+ cations. Optical rotation studies show that the addition of hydrated Na+ ions also stabilizes the α‐helix just as a decrease in apparent pH. The greater stability of the helix in these DMSO solutions predicts that its average segment length will also increase. The decrease in the corrected specific rotation of amylose in going from water to DMSO solutions is most likely due to an increase in the thermal motion of the amylose rather than any decrease in the helix stability. The DMSO disperses starch because, unlike the hydrogen bonds in the helix, both of the hydroxyl groups involved in intermolecular hydrogen bonds can become complexed to DMSO anions. The lower pK of such Intermolecular hydrogen bonds also allows alkali in DMSO to increase the dispersion power of DMSO. Salt (NaCI) decreases the dispersion power of DMSO because of the formation of interchain linkages through the unhydrated Cl− ion. The (CH3)2S+‐OH cation increases the dispersion power of DMSO by favoring the formation of those hydrogen bonds involved in the helix.
Sedimentation studies on amylose acetate in nitromethane solution
Authors: Banks W. , Greenwood C. T. , Hourston D. J. 
Published: April 2003

AbstractMeasurement of the sedimentation coefficient of 12 amylose acetate fractions

in nitromethane solution showed that the relation

holds. Unperturbed dimensions were obtained using the COWIE‐BYWATER treatment of the sedimentation data. The FLORY‐MANDELKERN Constant, β, was independent of molecular weight, indicating that there was negligible draining of the amylose acetate moleclue in the molecular weight examined. It is concluded that the amylose acetate is extended in solution as a result of solute‐solvent interaction rather than to a high degree of steric hindrance; the polymer behaves as a random coil in agreement with the FLORY theory.
Ceric ion‐reducing agent redox initiated vinyl polymerisation
Authors: Subramanian S. V. , Santappa M. 
Published: April 2003

AbstractCeric perchlorate/formaldehyde (F)redox couple initiated polymerisation of the monomer methyl acrylate (MA), acrylonitrile (AN), and methyl methacrylate (MMA) in perchloric acid (25°C) was carried out. The rate of polymerisation was directly proportional to [M]2 and [F] for all the systems. The rate was independent of [Ce4+] for the systems with MA or AN, but inversely proportional to [Ce4+] with MMA as the monomer. The rate of ceric disappearance was directly proportional to [Ce4+], [F], and [M]. The results were explained by a kinetic scheme involving the oxidation of the substrate by Ce4+ to give the primary radical and further reaction of the latter with Ce4+ to give the final product, and initiation of polymerisation both by Ce4+ and the primary radical, propagation followed by termination by the metal ion. Only with MMA as the monomer, the initiation by Ce4+ was found to be negligible compared to that by primary radicals. In the system with the reducing agents t‐butanol and n‐butanol, there was found to be 1:1 complex formation between the substrate and Ce4+. Otherwise the scheme is similar to that proposed for the Ce4+/HCHO/HClO4/AN (MA) systems.
Cationic polymerization of formaldehyde
Authors: Yamaguchi Tadashi , Kawasaki Toshio , Matsuda Hiroshi 
Published: April 2003

AbstractCationic polymerization of monomeric formaldehyde has been studied at low temperature. It was found that high molecular weight polyoxymethylene with the reduced viscosity higher than 1.0 dl/g was readily obtained when the polymerization of formaldehyde was carried out in saturated hydrocarbons in the presence of LEWIS acids, BRÖNSTED acids, I2, ICl ICl3, IBr, sulfur dioxide and binary systems of sulfur dioxide with these compounds at considerably low temperature. The degree of polymerization was effected by the polymerization conditions, especially solvent, polymerization temperature and addition of chain transfer agents such as water, formic acid, methanol or methyl formate.
Syntheses and reactions of functional polymers. XXXI. Syntheses and some properties of polyethylenimines containing 2‐oxazolidone groups
Authors: Endō Takeshi , Okawara Makoto 
Published: April 2003

AbstractSome polyethylenimines containing 2‐oxazolidone ring in the side chain were synthesized by (1) the MANNICH type reaction of formaldehyde, 2‐oxazolidone, and polyethylenimine, (2) polymerization of N‐(1‐azirinomethyl)‐2‐oxazolidone, and (3) reaction of N‐hydroxy‐methyl‐2‐oxazolidone with polyethylenimine. These polymers were soluble in water, but insoluble in common organic solvents.They formed the complexes with phenol or p‐toluene sulfonic acid in alkaline solution.
Multimerisation: Assoziation und aggregation. VII. Poly‐γ‐benzyl‐L‐glutamat in reinen lösungsmitteln
Authors: Gerber Von Jakob , Elias Hans‐Georg 
Published: April 2003

AbstractMolekulargewichte und Virialkoeffizienten von 5 Poly‐γ‐benzyl‐L‐glutamaten (PBLG) mit Gewichtsmitteln des Molekulargewichtes zwischen 9600 und 550 000 wurden durch Streulicht und Osmose‐Messungen in Dimethylformamid (70 und 25°C) sowie bei 25°C in Dichloressigsäure, Dioxan, 1.2‐Dichloräthan und Chloroform bestimmt. In DMF bei 70°C ist PBLG mit höheren Molekulargewichten assoziiert, nicht aber mit niedrigen. Bei 25°C ist PBLG jeden Molekulargewichtes in DMF assoziiert. Bei 120°C wird PBLG in DMF abgebaut. In Dichloressigsäure bei 25°C ist die Assoziation bei den niedrigen Molekulargewichten stark, verschwindet aber bei den höheren Molekulargewichten. In Dichloressigsäure erfolgt bei 25°C kein Abba. Die Assoziation nimmt bei Dioxan und Chloroform ebenfalls mit steigenderm Molekulargewicht ab. In diesem Lösungsmittel folgt die Assoziation dem Typ der geschlossenen Assoziation, und zwar ausschließlich über Endgruppen. In Dichloressigsäure ist sie dagegen vermutlich vom Typ der offenen Assoziation. Die Virialkoeffizienten in helicogenen Lösungsmitteln sind unabhängig vom Molekulargewicht des Unimeren, dem Assoziationsgrad und der chemischen Natur des Lösungsmittels, mit Ausnahme des Produktes mit dem Molekulargewicht 9600. Aus den Virialkoeffizienten berechnet sich eine Ganghöhe der Helix von 1,6 Å pro Grundbaustein, was für eine α‐Helix (1,5 Å) spricht. Die abweichenden Befunde der Literatur können durch die Assoziation gedeutet werden.
Stereoregularity and dipole moments of optically active poly‐alkyl‐vinyl‐ethers
Authors: Luisi P. L. , Chiellini E. , Franchini P. F. , Orienti M. 
Published: April 2003

AbstractDipole moments of some samples having different stereoregularity of poly‐[(S)‐l‐methyl‐propyl]‐vinyl ether (A) andn poly‐[(S)‐2‐methyl‐buthyl]‐vinyl ether (C) have been determined and compared with those of samples having comparable stereoregularity of polyisopropyl‐vinyl ether (B) and poly‐isobutyl‐vinyl ether (D).The results indicate: (a) no remarkable dependence of dipole moments on stereoregularity, except for (B), of which the most isotactic fraction has the lowest moment; (b) the dipole moment of the most stereoregular fraction of (A) is higher than that of the corresponding fraction of the non optically active model compound (B); (c) for fractions having high and comparable stereoregularity, the dipole moments are lower in the case of (A) and (B), in which the branched carbon atom of the side group is nearer to the main chain.These data can be interpreted on the basis of the differences in conformational equilibria expected for the main chain of such polymers in solution.