bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ring‐opening polymerization of cyclic compounds with bifunctional groups. V. Polymerization of 7‐oxo‐4‐phenyl‐1,4‐azaphosphepane (phospha‐caprolactam)
Authors: Ogata Naoya , Saito Seiichiro 
Published: April 2003

Abstract7‐Oxo‐4‐phenyl‐1,4‐azaphosphepane (II) (phospha‐caprolactam) and its 3,5‐tetramethyl derivative (IV) containing an amide group and a phosphorus atom in the same ring, have been synthesized and polymerized in the presence of various catalysts. II polymerized with Al(C2H5)2Cl or SnCl4 as catalysts to give polyamide of low molecular weight, whereas IV did not polymerize with satisfactory results. On the other hand, the copolymerization of the tetramethyl substituted “phospha‐caprolactam” IV with other cyclic compounds including lactams, lactones or cyclic ethers took place in the presence of cationic catalysts.
Optically active copolymers of l‐menthyl methacrylate and l‐menthyl vinyl ether
Authors: Matsuzaki Kei , Sugimoto Toshio 
Published: April 2003

AbstractOptically active copolymers of l‐menthyl methacrylate or l‐menthyl vinyl ether with maleic anhydride or N‐(p‐tolyl)maleimide were prepared. The optical activity of the co‐polymers of l‐menthyl methacrylate was almost proportional to the contents of l‐menthyl methacrylate units in the copolymers, and after removal of the optically active side groups by hydrolysis, the optical activity disappeared. On the contrary, the optical activity of the copolymers of l‐menthyl vinyl ether was considerably lower than the proportionality, and after removal of the side groups, optical activity opposite to the parent copolymers was observed. The cause for asymmetric induction was ascribed to the rigidity of the polymer chain.
Polymérisation de dérivés du cyclopropane. IV. Polymérisation du bicyclopropyle
Authors: Pinazzi Chr. P. , Legeay G. , Brosse J. C. 
Published: April 2003

AbstractLe bicyclopropyle, isomère du diméthyl‐2,3 butadiène‐1,3, mis en présence d'acides de LEWIS ou de divers catalyseurs de ZIEGLER‐NATTA conduit à des polymères formés d'un enchainement de motifs monocyclohexbniques, comparables à ceux qui sont obtenus par cyclisation du polyisoprbne‐1,4. Les températures d'amorçage peuvent être relativement faibles et les taux de conversion presentent un maximum pour les temperatures voisines de 50°C. Aux temperatures plus Clevees, les taux de conversion dhcroissent du fait même de la nature du monomere. Le mecanisme de polymerisation prockde par ouverture des deux cyclopropanes, suivie d'une riaction de cyclisation entre deux unitis monomères.En presence du couple TiCl4/Et3Al, la polymerisation s'effectue en partie par ouverture d'un seul cyclopropane : un polymhre lineaire possedant des groupements cyclopropaniques en chafne laterale est alors obtenu.
Polymérisation de diènes conjugués aux hautes pressions. IX. Polymerisation de l'isoprène en presence de HI
Authors: Abdi‐Oskoui Hossein , Jenner Gérard , Brun Claude 
Published: April 2003

AbstractL'action de HI dans la polymérisation de lisoprbne est très sensible sous pression et dépend de la concentration en eau dans le milieu rCactionnel. En l'absence d'eau, on observe une dimerisation cyclique (formation de limonbne). La présence d'eau augmente la vitesse de rdaction au profit du polymbre. La structure des polymbres n'est pas affectée par les variations de concentration en eau, seule la pression apporte des modifications à la structure en rdduisant l'addition en 1,4 cis et en favorisant de ce fait les unitds 1,4 trans. La dimCrisation et la polymdrisation se font probablement selon d e w mdcanismes differents.
On the bulk polymerization of vinyl chloride
Authors: Ugelstad J. , Fløgstad H. , Hertzberg T. , Sund E. 
Published: April 2003

AbstractIn continuation of our investigations on the kinetics and mechanism of bulk and emulsion polymerization of vinylchloride, the mechanism of bulk polymerization is still further elucidated. A simple approximative method which in the preceding paper was only suggested but not evaluated in detail is given a more comprehensive discussion and it is shown that the method may describe the significant experimental results obtained in bulk polymerization of vinyl chloride. A correction to the more elaborate methods applied in the preceding paper is given.
On the orthorhombic to hexagonal phase transformation in polyethylene single crystals
Authors: Thomas E. L. , Sass S. L. 
Published: April 2003

AbstractThe orthorhombic to hexagonal transformation in polyethylene single crystals was examined at room temperature and 110°C using electron diffraction. The transformation involves an anisotropic lattice expansion and the formation of a projected 6‐fold symmetric atomic potential on a plane normal to the chain axis. The continuous transformation to the hexagonal phase at low temperatures was shown to occur primarily by crosslinks formed between chains during irradiation. At high temperatures, following nucleation of the hexagonal phase by an initial electron dose, further growth of the hexagonal phase without irradiation is believed to occur by the introduction of chain ends (which provides for easy chain rotation) into the crystal interior during annealing.
Solvent effects in radical copolymerization. IV. N‐methyl acrylamide
Authors: Leoni Alvaro , Franco Simone , Saini Guido 
Published: April 2003

AbstractThe influence of different solvents on the copolymerization behaviour of N‐methyl acrylamide with styrene and methyl methacrylate has been investigated. The calculated relative reactivities of N‐methyl acrylamide towards both the polystyryl and poly(methyl methacrylyl) radicals (1/r2) are practically unaffected by the reaction medium; on the contrary, the relative reactivities of both styrene and methyl methacrylate monomers towards the poly(N‐methyl acrylamide) radical (1/r1) are remarkably influenced by the reaction solvents. A comparison both with unsubstituted and disubstituted acrylamides polymerized under the same conditions has been made.
Vinyl polymerization. 294. Decomposition of tetramethyltetrazene in the presence of p‐substituted benzyl chlorides
Authors: Sugiyama Kazuo , Hatanaka Hideo , Nakaya Tadao , Imoto Minoru 
Published: April 2003

AbstractA study was made of the polymerization of acrylonitrile in dimethylformamide (DMF) initiated by the binary systems of tetramethyltetrazene (TMT) and p‐substituted benzyl chlorides. The polymerization rate increased linearly with the σ‐constants of substituents as electron‐releasing groups were introduced to the phenyl ring of benzyl chloride. In order to elucidate the initiation mechanism of the polymerization, a kinetic investigation was also undertaken of the decomposition of TMT in the presence of p‐substituted benzyl chlorides in DMF. The decomposition rate was first‐order in TMT and first‐order in p‐substituents benzyl chloride. The decomposition rate also increased with the σ constants of substituents as electron‐releasing groups were introduced. On the basis of the results, the initiation mechanism for the polymerization was discussed.
Aqueous polymerization of methacrylamide initiated by the redox system K2S2O8/ascorbic acid
Authors: Misra G. S. , Gupta C. V. 
Published: April 2003

AbstractThe polymerization of methacrylamide initiated by the redox system K2S2O8/ascorbic acid has been studied at 35 ± 0,2°C under the influence of atmospheric oxygen. The molecular oxygen autocatalyses the polymerization rate. The rate of polymerization is independent of the activator (ascorbic acid) concentration within the range 2,83 · 10−3 to 11,3 · 10−3 mol · l−1, this does not hold below or above the given concentration range. The rate varies linearly at low monomer concentration (up to 17,76 · 10−2 mol · l−1). The catalyst exponent decreases from nearly unity (0,94) to 0,57 with increasing concentration of the catalyst probably due to participation of primary radicals in the termination of growing chain. The initial rate is not changed by the addition of a strong acid (H2SO4) within the range 15 · 10−5 to 30 · 10−5 mol · l−1. With the activator (ascorbic acid) alone, an optimum is observed within the pH range 2,9–3,5. The initial rate and the limiting conversion increases with increasing polymerization temperature. The overall energy of activation as calculated from the ARRHENIUS plot has been found to be 16,0 kcal.mol−1 within the temperature range 30–45°C.Organic solvents (water miscible only) and small amounts of neutral salts, (KCl, Na2SO4) depress the initial rate and the maximum conversion. The addition of small amounts of catalysts like Cu2⊕, Mn2⊕, Agoplus; increases the initial rate but no appreciable increase in the limiting conversion is observed.
Lösungseigenschaften von äthylcellulose. Vergleichende bestimmungen von molekulargewichten und zweiten virialkoeffizienten mittels osmose, lichtstreuung und sedimentation/diffusion
Authors: Sütterlin N. , Meyerhoff G. 
Published: April 2003

AbstractEs wurden osmotische und Lichtstreuungsmessungen an Äthylcellulose in Aceton, Äthylacetat, Butanol‐(2), n‐Butylchlorid und Benzol (nur Osmose) ausgeführt und die Ergebnisse in einigen Fällen mit Hilfe der Sedimentation/Diffusion kontrolliert. Durch Vergleich der verschiedenen Meßmethoden konnten die von Gelen unbeeinflußten Meßergebnisse gegen die durch Gele verfälschten Werte abgegrenzt werden.Die osmotisch und hydrodynamisch bestimmten A2‐Werte sind hoch im Vergleich zu denen von Vinylpolymeren. Im Gegensatz dazu steht der niedrige Exponent ε der Trägheitsradius‐Molekulargewichtsbeziehung

der sich für negative Exponenten ε nur durch Geleinfluß deuten läßt. für die zweiten Virialkoeffizienten wurde eine nur wenig ausgeprägte Lösungsmittelabhängigkeit beobachtet.
Study of organized structures of polystyrene/polybutadiene/polystyrene block copolymers
Authors: Douy André , Gallot Bernard 
Published: April 2003

AbstractUsing both monochromatic low angle X‐ray scattering and electron microscopy, we have shown that polystyrene/polybutadiene/polystyrene (SBS) block copolymers exhibit, in the presence of a preferential solvent for one block, liquid crystalline structures, before and after polymerization of the solvent. These structures are of three types: hexagonal, lamellar and reversed hexagonal.We have shown that the structural type adopted by SBS copolymers is governed by the composition of the copolymer. Inside the domain of stability of each structure, we have studied the variation of the structural parameters with different factors: concentration and nature of the solvent, composition and molecular weight of the copolymer, temperature, polymerization of the solvent.The properties of SBS and BSB copolymers are compared.
The direct conversion of 6‐aminocaproic acid vapor into polymer single crystals
Authors: Macchi E. M. 
Published: April 2003

AbstractSpecimens of Nylon 6 obtained by reaction of the monomer in the vapor phase onto surfaces of crystalline substrates are investigated by electron microscopy and electron diffraction.The specimen is found to consist of lamellar spherulites of Nylon 6, as it was already reported, and a small proportion of single crystals displaying the structure known as the Gamma‐form.
Über die polykondensation von isothiocyanatocarbonsäuren, DTE‐aminosäuren und 5‐oxo‐2‐thioxo‐oxazolidinen (2‐thioxo‐oxazolidonen‐(5))
Authors: Kricheldorf Hans R. 
Published: April 2003

AbstractAliphatische wie aromatische Isothiocyanatocarbonsäuren werden in hoher Reinheit und guten Ausbeuten aus ihren Trimethylsilylestern gewonnen; dabei cyclisieren die 2‐Isothiocyanatocarbonsäuren sofrt zu den isomeren in 4‐Stellung substituierten 5‐Oxo‐2‐thioxo‐oxazolidinen (2‐Thioxo‐oxazolidonen‐(5)). Aliphatische und aromatische Isothiocyanatocarbonsäuren lassen sich über 150°C polykondensieren, in Gegenwart basischer Katalysatoren bereits bei Raumtemperatur, wobei unter Abspaltung von COS Polyamide entstehen. Bei 3‐ und 4‐Isothiocyanatocarbonsäuren verhindert die Cyclisierung der Isothiocyanat‐Endgruppe bzw. die Bildung von γ‐lactamen das Zustandekommen höherer Polymerisationsgrade. 5‐Oxo‐2‐thioxo‐oxazolidine lassen sich ebenfalls, thermisch oder basisch katalysiert, durch ionische, ringöffnende Polymerisation in Polypeptide überführen. DTE‐Aminosäuren bilden primär die entsprechenden Isothiocyanatocarbonsäuren, deren Verhalten den weiteren Reaktionsverlauf bestimmt.
Polymerization of methyl methacrylate with alkyllithium in the presence of N,N,N′,N′‐tetramethylalkylenediamines or ω‐dimethylaminoalcohols as catalysts
Authors: Matsuzaki Kei , Nishida Yoshiki , Kumahara Hiromi , Miyabayashi Toshio , Yasukawa Tamio 
Published: April 2003

AbstractMethyl methacrylate was polymerized with alkyllithium in the presence of N,N,N′,N′‐tetramethylalkylenediamines or ω‐dimethylaminoalcohols as catalysts. The effects of the catalysts on the stereoregularity and the yield of the polymers were investigated. The presence of N,N,N′,N′‐tetramethylethylenediamine or 2‐dimethylaminoethanol resulted in a decrease of yield and isotacticity of the polymers, especially in toluene. The decrease was attributed to the formation of stable five‐membered ring chelates in the reaction of alkyllithium with N,N,N′,N′‐tetramethylethylenediamine or 2‐dimethylaminoethanol.
Kinetic effects of surfactants on a polymer reaction in a nonaqueous system: Nucleophilic substitution of poly(vinyl chloride) with the azide ion
Authors: Takeishi Makoto , Kawashima Riichiro , Okawara Makoto 
Published: April 2003

AbstractCationic surfactants such as laurylpyridinium chloride and tetrabutylammonium chloride catalyze the nucleophilic substitution of poly(vinyl chloride) with sodium azide in tetrahydrofuran, dioxane and cyclohexanone in which sodium azide is insoluble. An anionic surfactant, sodium laurylbenzenesulfonate, does not catalyze the reaction. It was assumed that a quarternary cation exchanges a chloride ion for an azide ion and then transfers it to the reaction site of poly(vinyl chloride) through the solvent. The reaction of poly(vinyl chloride) with laurylpyridinium azide was also investigated, and a saturation phenomenon in the relationship between the rates and the concentrations of laurylpyridinium azide was observed. The kinetic data are discussed in terms of an “adsorption” of the quarternary salts on a poly(vinyl chloride) chain.
Methods for treating data of excluded volume effects in dilute polymer solutions
Authors: Nakata Mitsuo 
Published: April 2003

AbstractA method for estimating the free‐energy parameter B appearing in the excluded volume parameter z defined by z=(4π)−3/2B(M/〈s20〉)3/2M1/2 was proposed based on the semiempirical equation of STOCKMAYER N0B/2A2 = 1 + Sz/a3 (S = 2,865) for the second virial coefficient A2, where N0 is the AVOGADRO number and a is the expansion factor. When the temperature dependence of B is given by B = B0(1−Ω/T) the definition of z and the STOCKMAYER equation yield the relation

The plot of (1−Ω/T)/A2 versus M2(1−Ω/T)〈s2〉−3/2 due to this equation was made for the existing experimental data on the theta solvent and was found to give a straight line. The values of B0 and S obtained by this plot agreed with the value determined by BERRY's method and the theoretical value S = 2,865 respectively. In order to investigate the behaviour of a at small z, the data of a near the theta temperature were analyzed with an approximate equation a5 ‐ a2 = 1,914z which fits to the perturbation theory and to the YAMAKAWA‐TANAKA equation of a in the region 0<z<5.
Korrektur der kollimationseinflüsse bei röntgenweitwinkelmessungen
Authors: Glatter Otto 
Published: April 2003

AbstractDie bei Röntgenweitwinkelmessungen mit Lochblendensystem, zylindrischem Präparathalter und spaltförmigem Detektor entstehenden Kollimationseinflüsse werden mathematisch erfaßt. Die so erhaltene Integralgleichung wird unter Verwendung orthonormierter Funktionensysteme gelöst. Die Lösungskurve wird zur Fehlerkontrolle nach einer getrennten und von dem Lösungsverfahren unabhängigen Methode rückintegriert. An Hand einer experimentell bestimmten Streukurve wird die Leistungsfähigkeit des Verfahrens gezeigt. Sämtliche Rechnungen wurden mit einem eigens erstellten FORTRAN‐IV‐Programm durchgeführt.
Thermal degradation of copolymers of methyl methacrylate and butyl acrylate, 2. Identification and analysis of volatile products
Authors: Grassie N. , Fortune J. D. 
Published: April 2003

AbstractThe volatile products of thermal degradation of copolymers of methyl methacrylate and butyl acrylate covering the entire composition range have been identified. 1‐Butene and carbon dioxide are the main gaseous products. Other products, methane, ethane, propane, butane, ethylene, propylene, cis and trans 2‐butene, hydrogen and carbon monoxide are also present in very small amounts which tend to increase with the butyl acrylate content of the copolymer. The liquid products are butanol, methyl methacrylate, butyl acrylate and butyl methacrylate.Products have been estimated quantitatively for all the copolymers at intervals during the course of the reaction and detailed mass balance tables drawn up.The yields of carbon dioxide and 1‐butene and the molar ratio of carbon dioxide to 1‐butene all increase with increasing acrylate content of the copolymer. Methyl methacrylate is the only liquid product from high methacrylate copolymers. Butyl acrylate and methacrylate begin to appear in 16,3 mole‐% butyl acrylate copolymer although butanol is still absent. From high acrylate copolymers butanol is the only liquid product.
Addition of chlorine and nitrogen dioxide to linear polybutadienes reaction mechanism
Authors: Royo Joaquín , González Luis , Ibarra Luis , Barbero Miguel 
Published: April 2003

AbstractThe reaction of chlorine or nitrogen dioxide with polybutadienes consists mainly in their addition to the double bonds of the polymer, but it is often followed by a number of secondary reactions, such as crosslinking and cis‐trans isomerization.The effects of polymer microstructure, nature of the solvent, solution concentration, temperature, and various additives, are studied. To explain the experimental facts several reaction mechanisms are proposed.The chlorination reaction is thought to follow an ionic and radical mechanism simultaneously. The former, which is always predominant, gives only soluble addition products without secondary reactions, whereas the latter can give rise to crosslinked and isomerized products, besides the addition product. Under certain experimental conditions the radical reaction can be avoided and only soluble addition products are obtained.The reaction with nitrogen dioxide is predominantly of radical character, and consequently it is always followed by isomerization and crosslinking reactions. Only under special conditions these ancillary reactions can be avoided.
The interaction between polymerization initiators and inhibitors in solution. III. The reaction of benzoyl peroxide with 2,5‐dichloro‐1,4‐benzoquinone and 2,3,5,6‐tetrachloro‐1,4‐benzoquinone (chloranil) in chlorobenzene
Authors: Yassin A. A. , Rizk N. A. , Ghanem N. A. 
Published: April 2003

AbstractThe reaction of benzoyl peroxide with 2,5‐dichloro‐1,4‐benzoquinone and 2,3,5,6‐tetrachloro‐1,4‐benzoquinone (chloranil) in chlorobenzene was studied by isolation and identification of the reaction products.In dilute solution (0,02 mol peroxide/dm3), both phenyl and benzoyloxy radicals interact with 2,5‐dichloro‐1,4‐benzoquinone to form the corresponding quinonoid derivatives by substitution of hydrogen atoms in the quinone nucleus. Chloranil does not react under these conditions.In concentrated solution (0,5 mol peroxide/dm3), both 2,5‐dichloro‐1,4‐benzoquinone and chloranil are attacked by radicals of the spontaneous as well as the induced decomposition of the peroxide. Aryl radicals (but not benzoyloxy radicals) can substitute only one chlorine atom of the chloranil molecule. The difficulty is due to the steric hindrance of the chlorine atoms and the instability of the radical intermediate. This probably accounts for the tendency of chloranil to react with polymeric radicals through O‐ rather than C‐atoms.
Reaktionskinetik und gleichgewichtsumsätze bei der PF5‐initiierten homopolymerisation von tetrahydrofuran in 1,2‐dichloräthan
Authors: Hoene Richard , Reichert Karl‐Heinz W. 
Published: April 2003

AbstractDie kationische Polymerisation von Tetrahydrofuran in 1,2‐Dichloräthan mit Phosphorpentafluorid also Initiator wurde mittels gaschromatographischer Bestimmung des Monomergehaltes unter reaktionskinetischen und thermodynamischen Gesichtspunkten untersucht.Kinetische Versuche ergaben, daß die Polymerisationsgeschwindigkeit nicht linear mit der Initiatorkonzentration zunimmt. Der Einfluß der Initiatorkonzentration auf die Polymerisationsgeschwindigkeit nimmt vielmehr mit wachsender Initiatorkonzentration ab, was auf die Anwesenheit von Solvatationsgleichgewichten der aktiven Spezies zurückgeführt wird. Die Aktivierungsenergie der Polymerisation in Lösung wurde nach ARRHENIUS zu 15,2 kcal/mol bestimmt.Durch Messung der Temperaturabhängigkeit der Gleichgewichts‐Monomerkonzentrationen wurden die thermodynamischen Größen ΔHp und ΔS0p und die Ceiling‐Temperaturen bei zwei verschiedenen Ausgangs‐Monomerkonzentrationen ermittelt. Die Gleichgewichts‐Monomerkonzentrationen liegen in Lösung höher als bei der Polymerisation in Substanz. Infolgedessen werden für die gewählten Ausgangs‐Monomerkonzentrationen in Lösung Ceiling‐Temperaturen beobachtet, die um 20–25°C tiefer liegen als die diesen Gleichgewichts‐Monomerkonzentrationen entsprechenden Temperaturen der Substanzpolymerisation. Für die Abhängigkeit der thermodynamischen Größen vom verwendeten Lösungsmittel werden Solvatationseffekte verantwortlich gemacht.Weiterhin kann aus den Ergebnissen entnommen werden, daß im Bereich der Ceiling‐Temperatur die thermodynamischen Größen geringfügig vom Polymerisationsgrad abhängen.
The crystal structure of polylauryllactam (nylon 12)
Authors: Cojazzi Gianna , Fichera Annamaria , Garbuglio Carmine , Malta Viscardo , Zannetti Roberto 
Published: April 2003

AbstractThe crystal structure of nylon 12 was determined from the X‐ray diffraction patterns of uniaxially oriented specimens. The unit cell is monoclinic (pseudo‐hexagonal) with the following dimensions: a = 4,79 Å, b = 31,9 Å (fiber axis), c = 9,58 Å, β = 120°. There are four monomeric units in the unit cell and the space group is P21/c. The structure presents a distortion of the amide group from the planar chain conformation and it is rather similar to γ‐nylon 6. The hydrogen bond length is about 2,80 Å and the molecular packing is characterized by alternate, “up and down”, highly disordered sheets of parallel chains, linked by hydrogen bonds. The agreement between observed and calculated intensities has been improved by introducing a statistical disorder.
Polyethylene ionomers. The effect of annealing
Authors: Marx Curtis L. , Cooper Stuart L. 
Published: April 2003

AbstractThe effect of annealing on the morphological structure and properties of a poly(ethylene‐co‐methacrylic acid) ionomer is discussed. The density of samples annealed at different temperatures was measured and compared with densities calculated from calorimetry measurements assuming additivity of component volumes. At intermediate annealing temperatures, densities calculated from calorimetry are higher than densities experimentally measured. Also, at intermediate annealing conditions the X‐ray scattering associated with separation of ionic groups changes, and the multiple DSC melting endotherms merge into a single endotherm. These effects are thought to be caused by a thickening of polyethylene lamellae to a uniformly large fold distance which causes strain of the non crystallizable polymer segments and void formation.