bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymere ester von säuren des phosphors, 4. Polymerisation des 2‐äthoxy‐2‐oxo‐4,5‐dihydro‐1,3,2‐dioxaphosphorins
Authors: Vogt Walter , Siegfried Robert 
Published: April 2003

AbstractDie ringöffnende Polymerisation des 2‐Äthoxy‐2‐oxo‐4,5‐dihydro‐1,3,2‐dioxaphosphorins (1) mit Alkoholaten als Initiatoren, ist durch folgende Merkmale gekennzeichnet: (a) Zur Polymerisation sind Temperaturen von über 100°C und Reaktionszeiten von vielen Tagen erforderlich. (b) Es stellt sich ein Polymerisations‐Depolymerisations‐Gleichgewicht ein. Für 125°C liegt der maximale Umsatz bei der Polymerisation in Substanz bei 70%. (c) Die Polymerisationsenthalpie hat den Wert 0±12,6 kJ mol—1 (0±3 kcal mol—1). (d) Es werden nur Oligomere gebildet. Die Ausbeute an Substanz mit Pn > 5 liegt um 3%. Die Oligomeren mit Pn = 1 bis 5 werden durch Dünnschichtchromatographie getrennt und durch Massenspektrometrie charakterisiert.
Pharmacologically active polymers, 11. Polymeric sulfonamides as potential antibacterials and carriers for antitumor agents
Authors: Hofmann Volker , Przybylski Michael , Ringsdorf Helmut , Ritter Helmut 
Published: April 2003

AbstractA number of acryl and methacryl derivatives of different sulfanilamides (1a—I) were prepared and polymerized. The fixation of the sulfonamide to the polymerizable group was carried out directly, using the acryl‐ and methacrylamides, and by means of spacer groups, to favour the enzymatic or hydrolytic release of the drug moiety. Selected sulfonamide types of different pKA values were used, and the pH‐dependant solubility of the corresponding polymers was studied.The monomeric acryloyl and methacryloyl sulfonamides were homopolymerized radically by AIBN. For distribution studies polysulfadiazineacrylamide, 14C‐labelled in the main chain (2e'), was synthesized. Copolymerization with 2‐methylsulfinylethyl methacrylate (5a) yielded water soluble polymers of lower toxicity. Eventually biodegradable polymers containing sulfonamide units in the backbone were obtained by anionic polymerization of acryloyl and methacryloyl sulfanilamide.The new monomers and polymers were characterized by elemental analysis, IR‐ and NMR‐spectroscopy, pyrolysis mass spectrometry, and hydrolytic degradation.
Über poly[1‐N‐(4‐isothiocyanatophenyl)carbamoyloxy‐methyläthylen‐co‐1‐hydroxymethyläthylen]e als träger zur immobilisierung von papain
Authors: Manecke Georg , Pohl Robert 
Published: April 2003

AbstractDurch Reaktion von Poly(allylalkohol) (2) mit 4‐Isothiocyanatophenylisocyanat (3) wurden Poly[1‐N‐(4‐isothiocyanatophenyl)carbamoyloxymethyläthylen‐co‐1‐hydroxymethyläthylen]e (5a–c) hergestellt, die in einigen Fällen durch Umsetzung mit 1,4‐Phenylendiisocyanat (4) zu 5d oder 5e vernetzt werden konnten. Diese reaktiven Träger ließen sich zur Immobilisierung von Enzymen mittels kovalenter Bindung verwenden. Das Bindungsvermögen dieser Polymeren 5a–e für Butylamin, 3,4‐Dichloranilin, Pepton (aus Lactalbumin) und Papain wurde untersucht. Vom immobilisierten Papain wurden die Enzymaktivitäten, das pH‐Optimum, die scheinbare Michaelis‐Konstante KM(app) und die Abhängigkeit der Aktivität von der Temperatur bestimmt.
The formation of oligomers in the thermal copolymerisation of the styrene/acrylonitrile‐system
Authors: Kirchner Kurt , Schlapkohl Heinz 
Published: April 2003

AbstractIn the thermal copolymerisation of styrene with acrylonitrile, a Dields‐Alder addition of the two monomers first takes place. The adduct reacts with a further monomer molecule, forming trimers and initiator radicals. This results from the structure of the trimers and the kinetics of their formation. The initiating step is, therefore, analogous to the polymerisation of pure styrene.
The adiabatic compressibility of polyelectrolytes: Binding of Na+ ions on the multivalent site of polymer chains
Authors: Dewhare Anil R. , Roy‐Chowdhury Phanibhusan 
Published: April 2003

AbstractThe adiabatic compressibility of a 1:0,35 acrylic acid/maleic acid copolymer (AA/MA) and of its three “sodium salts” obtained by neutralizing (25%, 50% and 100%) with sodium hydroxide was studied. In 100% neutralized AA/MA copolymer, the dissociation of the counter ions was complete so that the limiting values of the apparent molal compressibility δK and apparent molal volume δV were found to be lowest with values of −83,0·10−4 cm3 bar−1 mol−1 and 52,9 cm3/mol respectively. This showed a decrease of 89,0·10−4 cm3 bar−1 mol−1 and 20,9 cm3 mol−1 from that of the unneutralized acid copolymer. The δK and δV values were resolved into the ionic components, δK and δV. The electrostriction caused in the copolymer by an increase of the negative charge from 0 to −0,425, from −0,425 to −0,85 and from −0,85 to −1,7 produced a decrease of 3,9.10−4, 6,9.10−4, and 5,7.10−4 cm3 bar−1 mol−1 in δK and 3,7,4,5 and 10,2 cm3 mol−1 in δV. Contrary to the volume change, the compressibility data showed a disproportionate decrease for the neutralized products. The reduced viscosity for the sodium salts was also found to have reduced values. A notable point emerging from this study is that the apparent ion binding on the multivalent site of the polymer chain, as obtained by the two methods—the adiabatic compressibility and density determinations—shows an appreciable variation.
Strukturuntersuchungen an adsorptionsschichten makromolekularer stoffe, 3. Untersuchung der struktur von adsorptionsschichten unverzweigter polyester an siliciumdioxidoberflächen
Authors: Dietz Erwin 
Published: April 2003

AbstractDie Adsorptionsstruktur von Polyestern an verschiedenen Aerosiloberflächen in CHCl3 wird durch Aufnahme von Adsorptionsisothermen und IR‐spektroskopische Bestimmung der Adsorptionswechselwirkung untersucht. Vergleiche zwischen den Bruchteilen gebundener Kettencarbonylgruppen der Polyester und der entsprechenden Abnahme an oberflächenständigen, freien SiOH‐Gruppen zeigen, daß die Ausbildung von Wasserstoffbrückenbindungen zwischen Carbonyl‐ und SiOH‐Gruppen nicht in einem stöchiometrischen Verhältnis erfolgt. Bei niedriger Oberflächenbelegung werden Carbonylgruppen bevorzugt an freie (geminale) Silanolgruppenpaare adsorbiert. Mit zunehmender adsorbierter Menge nimmt bei allen Polyestern die Haftstellenzahl ab. Die Größe der bei der Adsorption ausgebildeten Schlaufen hängt im wesentlichen von der Anordnung der Adsorptionsplätze auf der Aerosiloberfläche und von der Verteilung der adsorbierbaren Gruppen im Makromolekül ab. Die Bildungswärme der bei der Adsorption ausgebildeten Wasserstoffbrückenbindung wird mit Hilfe einer empirischen Formel aus der Verschiebung der IR‐Absorptionsbanden der SiOH‐Gruppen berechnet und beträgt je nach Polyester zwischen 21 und 26kJ mol−1.
Some observations on the interpretation of ESCA spectra of fluorine containing polymers and their relation to the degree of crystallinity, to the surface tension, and to the content of adsorbed gas
Authors: Adams David , Clark David , Dilks Alan , Peeling James , Thomas Herbert Ronald 
Published: April 2003

AbstractAn analysis is presented of recently published data concerning the ESCA spectra of some fluorine containing polymers. The claim that the ESCA data may be directly related to degree of crystallinity and to surface tension and content of adsorbed gas is examined and shown to be incorrect.
Solution polymerization of 1,3,5‐trioxane and 1,3,5,7‐tetroxocane, 1. Rate of polymerization, characterization and melting behaviour of as‐polymerized poly(oxymethylene)
Authors: Muñoz‐Escalona Antonio , Guerrero Saul J. 
Published: April 2003

AbstractA relationship between the rate of polymerization and the structure of the as‐polymerized crystals is investigated in the cationic polymerization in solution of 1,3,5‐trioxane and 1,3,5,7‐tetroxocane. The monomer/solvent reaction systems chosen were: 1,3,5,7‐tetroxocane/nitrobenzene (I); 1,3,5,7‐tetroxocane/l,2‐dichloroethane (II), 1,3,5‐trioxane/chlorinated parafin (III), and 1,3,5,7‐trioxane/normal paraffin (IV). The poly(oxymethylene), (POM), obtained in each case was characterized as to molecular weight, X‐ray cristallinity and by differential scanning calorimetry (DSC). The data from the DSC curves indicated a folded chain structure for systems I and II, where the rate pf polymerization was very high. However in system II at high polymer conversion a fraction of POM appears with a melting behaviour characteristic of an extended chain structure. For systems III and IV, where the rate of polymerization was very low, the DSC curves indicated the presence of two crystal forms. One of these forms shows a clear response to overheating and annealing treatments, which indicates the presence of an extended chain structure. The second form shows ambiguous melting behaviour and by thermal data alone it is impossible to determine its structure.
Die Bestimmung der Molekulargewichtsverteilung von Poly(methylmethacrylat)en durch Gegenstromverteilung in flüssigen Phasenpaaren
Authors: v. Tavel Peter , Rüfenacht Hans Jakob 
Published: April 2003

AbstractDrei polydisperse Poly(methylmethacrylat)e werden mittels Gegenstromverteilung fraktioniert und ihre Molekulargewichtsverteilungen bestimmt. Ihre mittleren Molekulargewichte M̄w betragen ca. 30 000, 130 000 und 540 000. Als Phasenpaare dienen fast kritische Gemische von Aceton (ca. 70. Vol.‐%), Hexan (ca. 22%) und Wasser (ca. 8%) mit einem Phasendichteunterschied von 0,03 bis 0,05g/cm3, denen zur Einstellung eines günstigen mittleren Verteilungskoeffizienten wenig Benzol zugesetzt wird. Die gemessene Molekulargewichtsverteilung von Präparat 130 000 stimmt mit derjenigen, die in der Ultrazentrifuge bestimmt wurde, überein. Die Gelpermeationschromatographie liefert wesentlich breitere Verteilungen. Die aus den Verteilungen berechneten Uneinheitlichkeiten Mw/Mn betragen für die Gegenstromverteilung 1,45, die Ultrazentrifugierung 1,46 und die Gelpermeationschromatographie 1,98, diejenige typischer Fraktionen 1,02 bis 1,05.
Formation of polyglycine crystals in the course of polymerization of glycine N‐carboxy anhydride initiated by primary diamines
Authors: Khair B. M. Abo‐El , Kōmoto Tadashi , Kawai Tohru 
Published: April 2003

AbstractThe heterogeneous polymerization of glycine N‐carboxy anhydride (2,5‐dioxo‐1‐oxa‐3‐azacyclopentane) was carried out in acetonitrile using various kinds of primary diamines as initiators such as ethylene diamine (ED), hexamethylenediamine (HM) and bis(4‐aminophenyl) ether (AP) comparing with butylamine previously reported. Electron microscopic observations revealed that most of the precipitates were spherulites. The conformation of polyglycine obtained from all the initiators used, was in the form of polyglycine I. The apparent crystallinity of the resultant polymer was low in the case of AP‐as compared with ED‐or HM‐initiated polymerizations. A growth mechanism of polyglycine crystals formed in the course of polymerization has been proposed.
Branching in free radical polymerization due to chain transfer. Application to poly(vinyl acetate)
Authors: Wolf Christine , Burchard Walther 
Published: April 2003

AbstractA general statistical theory in direct relation to the kinetics of polymerization is developed for free radical polymerization with chain transfer. In the present paper this relationship is displayed in detail; analytical expressions are derived for the probabilities of reaction as functions of the reaction rates and the monomer conversion. The statistical treatment (cascade theory) of the polyreaction allows the calculation of the weight average degree of polymerization Pw, the z‐average mean square radius of gyration 〈S2〉z, and the particle scattering factor Pz(θ). While for linear chains the mentioned averages are determined by a single link probability, in the branched system these averages are characterized by a stochastic matrix whose elements are the various link probabilities. The theory is applied to poly(vinyl acetate). A good agreement is obtained with the experimental results of D. J. Stein for this polymer.
Inorganic coordination polymers, 20. Zinc(II) phosphinate polymers and copolymers containing phenyl sulfone side groups
Authors: Nannelli Piero , Gillman H. D. , Monsimer Harold G. , Advani Shyam B. 
Published: April 2003

AbstractThe syntheses and characterizations of a series of new phosphinic acids and the zinc polymers and copolymers prepared from them are reported. These compositions are characterized by the presence of phenyl sulfone side groups. The zinc derivatives were found to be among the thermally most stable tractable poly(metal phosphinates) yet studied.
Carbon‐13 and proton magnetic resonance studies of poly(N‐vinylcarbazole) in solution
Authors: Tsuchihashi Nobuaki , Hatano Masahiro , Sohma Junkichi 
Published: April 2003

AbstractSpin‐lattice relaxation times T1 of individual carbons and protons were measured by the partially relaxed Fourier transform (PRFT) method for poly(N‐vinylcarbazole) in solution. The 13C‐T1 value of the methylene carbon is about one‐half of that of the methine carbon, and the carbazolyl CH carbons have T1 values close to that of the skeletal CH carbons. The effective correlation time for the skeletal carbon is estimated as ca. 0,95 ns on the basis of the measured T1 and 13C‐1H nuclear Overhauser effect (NOE) factor. Moreover, the 13C normal Fourier transformation (NFT) spectrum and proton T1 indicate strong steric interactions between the pendant carbazolyl groups in the polymer. The results demonstrate that the polymer in solution has a rigid local structure with hindered internal rotation of the bulky side‐chain groups.
Neue 8‐chinolinol‐haltige polykondensate und polymerisate
Authors: Idel Karsten , Freitag Dieter , Vernaleken Hugo 
Published: April 2003

AbstractDurch Friedel‐Crafts‐Alkylierung aromatischer Systeme mit komplexbildenden Zentren gelangt man direkt zu funktionell einkondensierbaren und nach Modifizierung zu polymerisierbaren Komplexbildnern.Die Alkylierung von 8‐Chinolinol mit p‐Isopropenylphenol oder p‐Isopropenylanilin führt zu neuen funktionellen 8‐Chinolinolen, (8a, b), die bei Polykondensationen als Kettenabbrecher reagieren und hochmolekulare, thermoplastische Polykondensate mit 8‐Chinolinolendgruppen erstmals leicht zugänglich machen. Bei der Umsetzung von Metallverbindungen mit den komplexbildenden Polykondensaten werden kettenverlängerte Polymere mit koordinativen Metallbrücken erhalten.Die Acylierung der funktionellen 8‐Chinolinole mit Methacrylsäurechlorid ergibt neue Vinylmonomere mit 8‐Chinolinolgruppen, (9a, b), die leicht zu Homo‐ und Copolymerisaten mit seitenständigen 8‐Chinolinolgruppen weiterverarbeitet werden können. Diese komplexbildenden Polymerisate zeigen insbesondere für Schwermetalle gute reversible Austauschereigenschaften. Die metallhaltigen Polymerisate besitzen vielfache Anwendungsmöglichkeiten und können z. B. als Depotdünger oder elektronenmikroskopische Kontrastierungsmittel eingesetzt werden.
Untersuchungen zur kettenbewegung von cis‐1,4‐ und cis‐trans‐1,4‐polybutadien durch 13C‐relaxationsmessungen
Authors: Gronski Wolfram , Murayama Nobumichi 
Published: April 2003

AbstractAus 13C‐NMR‐Spektren von cis‐1,4‐Polybutadien wurden Spin‐Gitter‐Relaxationszeiten (T1), Spin‐Spin‐Relaxationszeiten (T2) und Kernoverhauserverstärkungsfaktoren (NOEF) in Lösung und temperaturabhängig im festen Zustand ermittelt. Das konstante hohe T1/T2‐Verhältnis und der konstante reduzierte NOEF weisen darauf hin, daß die Kettenbewegung sich mit abnehmenden Restriktionen nicht der inkohärenten Mikrobrownschen Bewegung niedermolekularer Flüssigkeiten annähert. 13C‐T1‐Messungen an festem cis‐trans‐1,4‐Polybutadien zeigen verschiedene Temperaturabhängigkeiten für cis‐ und trans‐Einheiten. Mit zunehmender Verdünnung bleibt das Verhältnis der T1‐Werte von Methin‐ und Methylen‐C‐Atomen (T1,CH/T) der cis‐Einheiten konstant, während das entsprechende Verhältnis der trans‐Einheiten zunimmt. Es wird geschlossen, daß die mittlere Zahl der Struktureinheiten in voneinander unabhängig sich bewegenden Kettensegmenten stark reduziert ist. Das unterschiedliche Relaxationsverhalten von cis‐ und trans‐Struktureinheiten wird als Folge unterschiedlicher Rotationsbarrieren der Einfachbindungen zwischen Methin‐ und Methylen‐C‐Atomen in diesen Einheiten gedeutet.
Pharmakologisch aktive Polymere, 14. Modellsysteme zur Untersuchung der Abspaltung niedermolekularer Komponenten von polymeren Pharmaka
Authors: Netter Karl Joachim , Ringsdorf Helmut , Wilk Hans‐Christof 
Published: April 2003

AbstractEs wurden Polymere dargestellt, in denen 4‐Biphenylylamino‐, N‐(4‐Sulfamoylphenylazophenyl)amino‐ und 4‐Sulfamoylphenylazophenyloxy‐Gruppen entweder direkt oder über eine ionische Spacergruppe kovalent an die Polymerkette gebunden sind. Die polymeren 4‐Biphenylylamino‐Derivate wurden als Modellsubstanzen zur Messung der Abspaltungsgeschwindigkeit von Pharmaka in vitro und nach intraperitonealer Applikation bei Ratten pharmakologisch untersucht.
The limitations of the paracrystalline model of disorder
Authors: Brämer Rainer , Ruland Wilhelm 
Published: April 2003

AbstractThe basic concept of the paracrystalline disorder model is revised and its applicability to disordered structures, notably liquids and amorphous materials, is examined.The concept of the ideal paracrystal can be considered useful provided its application is restricted to a semi‐quantitative interpretation of anisotropic disorder structures; its applicability to liquid structures and amorphous structures with homogenous density fluctuations is very limited.The concept of the real paracrystal does not appear to be an improvement over that of the ideal paracrystal.
Etherification of poly(oxymethylene)‐diol [α‐hydro‐ω‐hydroxypoly(oxymethylene)] with orthoesters in the presence of Lewis acids
Authors: Colombo Paolo , Radici Pierino , Custro Sergio , Ermoni Mario 
Published: April 2003

AbstractAttempts were made to elucidate experimentally the behaviour of poly(oxymethylene)‐diol [α‐hydro‐ω‐hydroxypoly(oxymethylene)] in the etherification reaction in order to explain the decrease of the polymer molecular weight compared with that of the starting product and in order to determine the type of terminal groups and how the thermal resistance and alkali stability can be affected. In fact one finds that, in addition to the wanted terminal ether groups, formyl and orthoformyl (dialkoxymethyl) groups are formed having a different chemical resistance in comparison to that of the pure ethers, particularly in basic media.
Ring inversion in a p‐alkylphenol‐formaldehyde cyclic tetracondensate
Authors: Munch John H. 
Published: April 2003

AbstractThe temperature‐dependent 1H NMR spectrum of cyclo{tetrakis[(2‐hydroxy‐5‐(1,1,3,3‐tetramethylbutyl)‐1,3‐phenylene)methylene]} 1e, a 4‐(1,1,3,3‐tetramethylbutyl)phenolformaldehyde cyclic tetracondensate, is described. From this the activation parameters in chloroform at 25°C for ring inversion (turning the pyramid inside out) of the truncated pyramid conformation of 1e were calculated: ΔG≠ = 16,03 kcal/mol (67,1 kJ/mol), ΔH≠ = 26,1 kcal/mol (109 kJ/mol), and ΔS≠ = 34 cal mol−1 K−1 (141 J mol−1 K−1). The 1H NMR spectrum of the corresponding tetraacetate 2 was found to be essentially independent of temperature.
Free radical polymerization of unconjugated dienes, 16. Temperature dependence of the cyclization ratio of the cyclopolymerization of methacrylic anhydride
Authors: Chiantore Oscar , Camino Giovanni , Chiorino Anna , Guaita Marino 
Published: April 2003

AbstractThe temperature dependence of the cyclization ratio of the free radical cyclopolymerization of methacrylic anhydride in chloroform solutions was investigated. The experimental difference between the activation entropy of the intramolecular cyclization and the activation entropy of the intermolecular addition of the growing chain radical onto a monomer molecule was found to agree satisfactorily with the difference calculated on the basis of a semiempirical method. It came out that, even in the present case, the intramolecular cyclizations are favoured over the intermolecular additions by a smaller entropy decrease.
Polymerization of styrene catalyzed by trifluoromethanesulfonic acid. Conductivity, spectroscopic, and kinetic measurements
Authors: Chmelir M. , Cardona N. , Schulz G. V. 
Published: April 2003

AbstractThe solution polymerization of styrene in methylene dichloride catalysed by trifluoromethanesulfonic acid takes place at a high rate even at low catalyst concentration. The S‐shaped course of the conversion curves is explained by a reaction mechanism, in which the catalyst rapidly forms an inactive complex with one monomer molecule, and this monomer‐acid complex is in equilibrium with the free catalyst molecule from which the propagating species are formed. Therefore, the formation of active initiating species becomes a slow process which depends also on the change of monomer concentration during polymerization. It is assumed that the active initiating species are formed from two or three molecules of acid and this process is supposed to be a determining step in the mechanism of the styrene polymerization.The conductivity of the polymerizing system is caused probably by at least two species: firstly by the 1‐aralkyl‐3‐phenylindanyl cation which was found by means of UV spectroscopy and which is formed during and after the polymerization as product of termination reaction; secondly by another species, which takes part, as we assume, in the propagating process, probably as polystyryl carbcation.
Terpolymerization of vinyl compounds in the presence of lewis acids
Authors: Kuran Witold , Pasynkiewicz Stanisław , Nadir Riad 
Published: April 2003

AbstractThe terpolymerization of polar vinyl monomers, such as acrylonitrile or methacrylonitrile and methyl acrylate or methyl methacrylate with butadiene or styrene in the presence of ethylaluminium, aluminium, zinc(II), or stannum(IV) chlorides has been investigated. The yield and composition of the terpolymers as well as the yield of the Diels‐Alder reaction by‐products were determined. The copolymerization between two polar vinyl monomers in the presence of ethylaluminium dichloride or zinc(II) chloride was also carried out and the yield and composition of the copolymers produced were determined. The effect of the complexation of polar vinyl monomers by Lewis acids on the yield and monomer composition of the terpolymers produced in the investigated ternary systems is discussed in terms of the reactivities of these monomers (complexed by Lewis acids in alternating copolymerization) and competitive Diels‐Alder reactions with butadiene, as well as in terms of the copolymerization reactions between them.
Effect of metal ion on the radical polymerization of methyl methacrylate
Authors: Sugiyama Kazuo , Lee Show‐Wei 
Published: April 2003

AbstractThe polymerization of methyl methacrylate (MMA) initiated by azoisobutyronitrile (AIBN) in the presence of various metal chlorides and water was investigated in N,N‐dimethylformamide (DMF). The order of catalytic activity of the metal chlorides for the polymerization of MMA is as follows:

A complex formation between poly(methyl methacrylate) (PMMA) and the metal ions was observed from the measurement of the solution viscosity of PMMA in the presence of the same metal ions in DMF.