bluuebunny/crossref_metadata_2025 huggingface dataset:
Einfluß der kristallstruktur und der überstruktur auf einige eigenschaften von polypropylen
Authors: Leugering Von Hans Joachim
Published: April 2003

Isotaktisches Polypropylen bildet bei der Kristallisation vier verschiedene Typen von Sphärolithen, die nach PADDEN und KEITH als Typ I bis IV bezeichnet werden. Die Typen I und II zeigen eine monokline Kristallstruktur, während die Typen III und IV pseudohexagonal kristallisieren. Die Sphärolithe vom Typ III und IV sind weniger leicht deformierbar als die normalerweise gebildeten Typen I und II. Durch Ausbildung submikroskopischer Risse werden sie bei der Dehnung, im Durchlicht betrachtet, undurchsichtig. Sie werden von Lösungsmittel sowie von heißer HNO3 stärker angegriffen als die Typen I und II. Durch Zusätze sehr geringer Mengen von kristallkeimbildenden Stoffen wird bei der Kristallisation nicht nur die Zahl der Sphärolithe pro Volumeneinheit vermehrt, sondern es tritt eine bevorzugte Ausbildung einer bestimmten Kristallstruktur ein. Ein Zusatz von 10−4 bis 10−5 Gew.‐% Permanentrot E3B (Chinacridon‐Farbstoff) führt bei Kristallisationstemperaturen unter 130°C zu einer bevorzugten Bildung der pseudohexagonalen Form, während der kristallkeimbildende Zusatz von p‐tert‐Butylbenzoesäure ausschließlich zur Bildung der monoklinen Modifikation führt. Zum Nachweis der Effekte werden mikroskopische Methoden, röntgenographische Messungen, DTA‐ und dilatometrische Untersuchungen herangezogen.
Über die trennschärfe der gelchromatographie im vergleich zur fällungschromatographie
Authors: Scholtan Von W. , Kranz D.
Published: April 2003

Die Molekulargewichtsabhängigkeit des Elutionsvolumens von Polypropylenglykolen wird mittels der Gelchromatographie in verschiedenen Lösungsmitteln bestimmt. Die beim Übergang zu einem anderen Lösungsmittel auftretende Änderung des Elutionsvolumens eines polymeren Stoffes kann nicht durch die Änderung seiner Knäueldimensionen erklärt werden.

Die grundlegenden Größen wie spezifisches Elutionsvolumen Vp, Änderung des Elutionsvolumens mit dem Polymerisationsgrad dV/dP werden ermittelt. Der Einfluß dieser Größen auf die Trennschärfe der Gelchromatographie wird untersucht.

Die Polymerisationsgradverteilung eines Polypropylenglykols wird durch Gelchromatographie und Fällungschromatographie bestimmt. Die nach beiden Verfahren berechneten Verteilungskurven und die entsprechenden Mittelwerte des Molekulargewichtes stimmen gut miteinander überein, vor allem, wenn die Dispersionskoeffizienten der Komponenten berücksichtigt werden.

Die Uneinheitlichkeit der nach beiden Verfahren erhaltenen Fraktionen wird nach der von SCHULZ et al. angegebenen Gleichung berechnet und durch Gelchromatographie bestimmt. Dabei ergibt sich, daß die Fällungschromatographie Fraktionen liefert, die nur wenig einheitlicher sind als die durch Gelchromatographie erhaltenen Fraktionen.
Thermally‐induced cross‐linking of poly[2.2‐propane‐bis‐(4‐phenyl carbonate)]
Authors: Davis A. , Golden J. H.
Published: April 2003

The cross‐linking of poly [2.2‐propane‐bis‐(4‐phenyl carbonate)] by heating in a continuously evacuated system has been examined at various temperatures (295‐382°C). The effect of time and temperature on the viscosity of the polymer and the gel content is discussed.
Polyethylmethacrylate in dilute solution
Authors: Karunakaran K. , Santappa M.
Published: April 2003

Polyethylmethacrylate (PEM) was prepared by bulk polymerization and fractionated using acetone/acetone‐water (2:1 V/V) mixture. The solution properties of fractionated as well as unfractionated polymers were investigated in various solvents (ethylacetabte, toluene, ethylacetate‐ethanol) by light scattering and viscosity at 35°C. Osmotic pressure measurements were also carried out on selected polymer samples for the evaluation of width of distribution. [η]–Mw and (r2)1/2–Mw relationships for these systems were established. Ethylacetate was found to be a bad solvent compared to toluene and methylethyketone. In the case of unfractionated PEM, the parameters like [η]2/3M1/3, Mw/[η], and Φ were corrected for molecular weight heterogeneity assuming SCHULZ‐ZIMM distribution. For the evaluation of FLORY's constant K, and the unperturbed dimension (r)1/2 of the polymer, FLORY‐FOX, KURATA‐STOCKMAYER, and STOCKMAYER‐FIXMAN methods were employed. The K and (r)1/2 values evaluated from the FLORY‐FOX method were almost similar to those measured in a Θ solvent, while the other two methods yielded higher values. A comparison of the measured (r2) and that calculated from KIRKWOOD‐RISEMAN and DEBYE‐BUECHE theories indicated the polymer coil as conforming to a statistical chain. The molecular weight dependence of A2, the second virial coefficient, for PEM/ethylacetate was established and the value of A2 compared well with that calculated from OROFINO‐FLORY equation.
Polyradikale mit verdazyl‐gruppen
Authors: Kinoshita Von Masayoshi , Schulz Rolf C.
Published: April 2003

Um Polyradikale mit Verdazylgruppen zu gewinnen, wurden verschiedene Wege erprobt. Die Methylierung von Polyacrolein‐formazan führte nicht zum Ziel. Herstellung und Eigenschaften von 1.5‐Diphenyl‐3‐(p‐vinylphenyl)‐verdazyl werden beschrieben; eine radikalische Polymerisation dieser Verbindung war nicht möglich. Ausgehend von Poly‐p‐vinylbenzaldehyd gelang es aber, durch polymeranaloge Umsetzungen Polymere mit Verdazylgruppen darzustellen. Diese Polyradikale enthalten in jedem zweiten Grundbaustein ein ungepaartes Elektron.
Isolierung und charakterisierung von cyclischen oligomeren des formaldehyds
Authors: Burg Von K. H. , Hermann H. D. , Rehling H.
Published: April 2003

Bei der Aufarbeitung von Rückständen aus der Polymerisation von Trioxan konnten neben Trioxan und Tetroxan auch höhere cyclische Oligomere des Formaldehyds isoliert werden. Das Pentamere wurde dabei mit Hilfe der präparativen Gaschromatographie gewonnen, während zur Isolierung eines Ringes mit 15 Formaldehydeinheiten die Methode des Zonenschmelzens geeignet war. Die durch saure Agentien katalysierte Pyrolyse von Polytrioxan führt ebenfalls zu höheren cyclischen Oligomeren des Formaldehyds. Durch pyrolse‐gaschromatographische Untersuchungen wurde die Bildung von Pentoxan sichergestellt und das Entstehen von Hexoxan wahrscheinlich gemacht. Zur Charakterisierung der isolierten ringfömigen Acetale wurden ihre Polymerisierbarkeit, ihre Schmelzpunkte und ihre IR‐, Kernresonanz‐ und Massenspektren herangezogen.
Polymerization of styrene oxide and butadiene monoxide by organozinc compounds
Authors: Tsuruta Teiji , Inoue Shohei , Tsubaki Kazumi
Published: April 2003

The reaction of styrene oxide with organozinc compounds was studied to clarify the polymerization mechanism of styrene oxide. In the reaction with diethylzine ring scission of styrene oxide was observed to occur almost exclusively at the CH(C6H5)O‐bond to form ethylzinc monoalkoxide. In the second step zinc dialkoxide was formed by the reaction of the ethylzinc monoalkoxide with styrene oxide and the dialkoxide was found to be active species for the polymerization of styrene oxide. In the reaction of styrene oxide with zinc dialkoxide both α‐scission and β‐scission occurred. Studies were also made for butadiene monoxide.
The thermal degradation of polyoxymethylene
Authors: Grassie N. , Roche R. S.
Published: April 2003

The thermal degradation of polyoxymethylene has been studied in the dynamic molecular still. The energy of activation for the degradation of hydroxyl group terminated polymer increases from 5–7 kcal/mole in the early stages to 50–52 kcal/mole from about 40% volatilisation onwards. There is an inverse relationship between molecular weight and initial rate and this, together with the changes in molecular weight which occur during the course of the reaction and the fact that acetylation of the chain terminal hydroxyl groups inhibits the reaction, indicates a very close similarity between the overall reaction mechanism and that for the thermal degradation of poly(methyl methacrylate).

From the shape of the rate curve obtained during the course of the reaction and the fact that the density of the residual polymer increases during the reaction it has been concluded that reaction occurs preferentially in the amorphous regions of the polymer.

Molecular, free radical and ionic mechanisms have been considered in detail. An examination of minor reaction products and the effect of catalysts and inhibitors positively eliminates the possibility that a radical process is involved. In the presence of basic catalysts the reaction is undoubtedly anionic but the anionic and molecular mechanisms are virtually indistinguishable in the uncatalysed reaction although the molecular mechanism is preferred on energetic grounds.
Quantitative IR‐spektroskopische untersuchungen der mikrostruktur von polyvinylchlorid
Authors: Pohl Von H. U. , Hummel D. O.
Published: April 2003

Die durch graphische Auftrennung des ν(CCI)‐Bandenkomplexes gewonnenen relativen integralen Extinktionen von ν(CCI)‐Schwingungen wurden in Abhängigkeit von der Polymerisationstemperatur des PVC untersucht. Der Grad der Syndiotaxie der Proben wurde ohne Erhitzung aus der relativen Intensität der ν(CCI)‐Schwingungen bestimint. Aus der Intensität der A1‐ und Bi‐Schwingungen bei 639 und 603 cm−l wurde die intramolekulare Ordnung der Ketten (Regalarität) und die für die Aufspaltung notwendige Mindestlänge der syndiotaktischen Zickzack‐Kette bestimint. Sic beträgt für Harnstoffeinschluß‐PVC 8 und für alle übrigen Proben 5 Monomer‐Einheiten.
Structural studies of polyesters. I. Crystal structure of polyglycolide
Authors: Chatani Yôzô , Suehiro Kazuaki , Ôkita Yasuo , Tadokoro Hiroyuki , Chujo Kiyoshi
Published: April 2003

In the course of structural study of aliphatic polyesters, the crystal structure of polyglycolide, the simplest polyester of the type [(CH2)zCOO]n was determined by interpretation of the X‐ray diffraction patterns of the fibers. The crystallographic data are: a = 5.22 Å, b = 6.19 Å, c (fiber axis) = 7.02 Å, the orthorhombic spacegroup, Pcmn‐D. Two molecular chains pass through the unit cell. The crystal structure was determined by the help of two dimensional and three dimensional FOURIER syntheses. The planar zig‐zag chain molecules form a sheet structure parallel to the ac plane and have not the polyethylene type arrangement. High density of the crystallite, 1.69 g/cm3, namely the tight molecular packing and the close approach of the ester groups might stabilize the crystal lattice and contribute to the high melting point of this polymer.
Thermal degradation of polymethylmethacrylate. Energies of activation
Authors: Jellinek H. H. G. , Luh Ming Dean
Published: April 2003

Rate constants of the thermal degradation of polymethylmethacrylate fractions have been measured over a range of temperatures, and the ARRHENIUS equations have been derived. There are two degradation reactions for this polymer; one “fast” reaction, which is chain‐end initiated, due to double‐bonded chain‐end polymer molecules and one “slow” reaction, which is initiated at random. The energy of activation for the fast reaction is much smaller than that of the slow reaction. Both show two levels of energies of activation proceeding from long to short chains. These energies of activation increase with decreasing chain length of the polymer as expected from theory. Whereas the differences in energies for the fast reaction are in agreement with a mechanism consisting of chain‐end initiation, depropagation, and second‐order termination, a reasonable value for the overall energy for the slow reaction is only obtained for a first‐order termination process. Such a reaction is not unlikely, as the polymer film contains appreciable amounts of monomer at this stage of degradation. The energies of activation for the slow reaction increase with percentage conversion as long as some double‐bonded chain ends are still in the system. It has to be concluded that the degradation of isotactic and syndiotactic polymethylmethacrylate, which degrade by random initiation, also have a first‐order termination reaction. On the basis of the results reported here, the confusion in the literature concerning energies of activation for the thermal degradation of polymethylmethacrylate can be understood. These energies do not only depend on chain length but also on the mechanism of the degradation process, range of conversion, and percentage of double‐bonded chain ends in the system.
Synthesis and properties of some poly(methyl)methacrylate stereoisomers
Authors: Berghmans H. , Smets G.
Published: April 2003

The synthesis of some new stereoisomer poly(methyl methacrylates) is described, and their structure discussed.

In the polymerization of methyl methacrylate, initiated by phenyl magnesium bromide and anhydrous cobaltous chloride, polymers with a stereoblock structure are formed. On the basis of NMR spectra, a model can be proposed in which the polymer chains are composed of an isotactic sequency followed by a statistical one. An initiation and propagation mechanism are presented in order to interprete these data.

The results of the study of the viscoelastic behaviour of the stereoisomers reported elsewhere are briefly summarized.
Phosphororganische Verbindungen. 60. Mitt. Aufbau und Eigenschaften eines optisch aktiven Anionenaustauschers mit identischem Chiralitäts‐ und Ladungszentrum
Authors: Horner Von Leopold , Balzer Wolf‐Dieter
Published: April 2003

Chlormethyliertes Polystyrol (vernetzt mit 0,5% Divinylbenzol) wird mit (+)‐Methyl‐ n‐propyl‐phenyl‐phosphin quartärisiert. Der entstehende Austauscher besitzt eine Kapazität von 2,68 mVal/g. Mandelsäure, Atrolactinsäure und Traubensäure konnten an diesem Material nicht in die Antipoden gespalten werden.
The Compressibility of Crosslinked Polymers
Authors: Warfield R. W.
Published: April 2003

Bulk compressibilities of seven crosslinked polymers have been measured at pressures as high as 20,000 atmospheres and over the temperature range 25 to 250°C. Volume changes of up to 20% were observed. In most cases the pressure vs. change in volume isotherms were nonlinear and the coefficients of compressibility at one atmosphere increased with increasing temperature. For many of the polymers, pressure‐induced glass transitions are observed. From data on the pressure and temperature dependence of the glass transition, glass‐rubber phase diagrams have been prepared. The nature of the compressibility process is qualitatively discussed in terms of the BUECHE theory. It is shown that the EHRENFEST relationship dTg/dP ≃ TVΔα/ΔCp holds for crosslinked polymers.
NMR studies of polymer solutions. VI. Molecular weight determination of poly(ethylene glycol) by NMR analysis of near‐end groups
Authors: Liu Kang‐Jen
Published: April 2003

We have used the chemically identical “near‐end” groups of poly(ethylene glycols) (PEG) for molecular weight determinations. High resolution NMR technique was used for all measurements. The number average molecular weight of the polymer can be calculated by measuring the ratio of NMR absorptions of chain segments in a polymeric structure to those of non‐polymeric segments (“near‐end” groups). Two and four internal ethylene groups of PEG can be used as the “near‐end” groups respectively in pyridine on the one hand, and benzene or α‐chloronaphthalene solutions on the other. It is clearly shown that the NMR absorption of the “near‐end” groups of PEG is a much better choice than that of the “end” group for molecular weight determination. We have also discussed the significance of realizing the effect of the “near‐end” groups on polymer NMR spectroscopy.
Condensation polymers and copolymers of N.N′‐bis(2.3‐epoxypropyl)piperazine
Authors: Canonica L. , Cappuccio V. , Caldo C. , Bonvicini A. , Cantatore G. , Maltese P. , Cicchetti O.
Published: April 2003

Condensation polymers and copolymers are obtained by reaction of N.N′‐bis(2.3‐epoxypropyl)piperazine with primary aliphatic and aromatic amines, and with aliphatic, aromatic, cycloaliphatic, heterocyclic disecondary diamines.

The reaction rates of the polycondensations of N.N′‐bis(2.3‐epoxypropyl)piperazine with primary amines rise with decreasing the chain length.

In hydrocarbon solvents polycondensation reactions proceed slowly whereas in alcohols they are accelerated.

Activation energies are 11.6 kcal/mole in the polycondensation with trans 2.5‐dimethylpiperazine, 12.6 kcal/mole with n‐dodecylamine, 16.5 kcal/mole with piperazine.
Viscosity‐molecular weight relationships for poly p‐chlorostyrene
Authors: Mohite R. B. , Gundiah S. , Kapur S. L.
Published: April 2003

Viscosity, osmotic pressure and light scattering measurements have been carried out on fractions of poly p‐chlorostyrene. The viscosity‐molecular weight relationships have been established. The KUHN‐HOUWINK constants obtained by different workers show wide divergence. However, the constant KΘ obtained by different workers from different extrapolation methods, is in good agreement with the value of 5.2·10−4. The same value is obtained using [η]R, the ordinate at the common point of intersection of the In ηr/c vs. c Plots for the same polymer in different solvents.
Participation of the depropagation reaction in the cationic copolymerization of 3.3‐bischloromethyl oxacyclobutane and tetrahydrofuran
Authors: Yamashita Yuya , Kasahara Hideo , Suyama Katsuhiko , Okada Masahiko
Published: April 2003

A copolymer composition equation including the depropagation reaction was derived and applied to the cationic copolymerization of 3.3‐bischloromethyl oxacyclobutane and tetrahydrofuran. The observed decrease of the number of tetrahydrofuran units incoroporated in the copolymer with increase of the polymerization temperature or with decease of the monomer concentration was well explained by the equation. Differences between the catalyst systems, BF3·Et2O, Et3OBF4,PhN2PF6, and AlEt3H2O were also observed.
Ein automatisches viskosimeter zur flüssigkeitschromatographie
Authors: Meyerhoff Von G.
Published: April 2003

Eine Viskosimeterapparatur wird beschrieben, die ein automatisches sukzessives Einfüllen und Meessen von Flüssigkeiten erlaubt. Bei chromatographischen Prozessen ermöglicht es das Gerät, außer der bisher üblichen Verfolgung der Konzentration auch das Molekulargewicht des gelösten Stoffes im Eluat zu bestimmen. Für eine Elutionsgeschwindigkeit von 1 ml/min ist es möglich, das mittlere viskosimetrische Molekulargewicht in Intervallen von jeweils 2 ml oder auch 1 ml für den gesamten Elutionsvorgang anzugeben.
Kinetics and mechanism of the alkali‐catalysed addition of formaldehyde to phenol and substituted phenols
Authors: Eapen K. C. , Yeddanapalli L. M.
Published: April 2003

In view of the differences in the positional reactivities, reported by different authors, in phenol and methylol phenols, an exhaustive kinetic study using quantitative paper chromatography has been carried out not only on phenol and methylol phenols but also on phenols with methyl group and chlorine atom substituents.

The o‐position is less reactive than the p‐position in phenol and substituted phenols for the addition of formaldehyde in the presence of alkali catalyst, with a correspondingly higher activation energy. The effect of the methylol group appears to be intermediate between the activating effect of the electron repelling methyl group and the deactivating effect of the electron attracting chlorine atom. But the marked activating effect of the methyl and methylol group in the o‐position is tried to be accounted for by intra‐molecular hydrogen bonding. The activating effect of chlorine atom in the o‐position is explained in terms of the electron repulsion between chlorine atom and the phenoxide anion.

The few characteristic differences in the positional reactivities observed in the results of earlier workers are not found in the results obtained in the present investigation.
Kinetics and mechanism of the alkali‐catalysed addition of formaldehyde to dihydroxydiphenyl methanes
Authors: Francis D. Joseph , Yeddanapalli L. M.
Published: April 2003

The kinetics of the alkali‐catalysed addition of formaldehyde to dihydroxydiphenyl methanes (DPMs) has been studied by quantitative paper chromatography. The order of reactivity of the three DPMs is found to be o.p′‐ > p.p′‐ > o.o′‐DPM. The low reactivity of o.o′‐DPM is explained on the basis of formation of a chelate ring in its singly ionised form, resulting in the fixation of the negative charge on the O.

Equimolecular quantities of p.p′‐DPM and formaldehyde (concentrations 0.04 M) react in presence of NaOH (0.006 M) to give 3‐methylol‐4.4′‐DPM. Under similar conditions o.p′‐DPM gave 3‐methylol‐2.4′‐DPM, 5‐methylol‐2.4′‐DPM and 3‐methylol‐2′.4‐DPM and o.o′‐DPM gave 3‐methylol‐2.2′‐DPM and 5‐methylol‐2.2′‐DPM. The individual rate of formation of each of the products is determined. These rates are compared with those of other reactions in the phenol‐formaldehyde reaction, and their relative importance in the overall reaction is discussed.
Graft polymerization in solution of methyl acrylate on atactic polypropylene
Authors: Natta G. , Severini F. , Pegoraro M. , Tavazzani C.
Published: April 2003

The polymerization of methyl acrylate in an atactic polypropylene solution in the presence of radical initiators (benzoylperoxide, tert‐butylperpivalte, α.α′‐azoisobutyronitrile, Iauroylperoxide) yields a mixture of grafted polymethylacrylate/polypropylene copolymer and a methyl acrylate homopolymer.

The crude polymers are fractionated and the influence of the concentration of both monomer and initiator, and of the type ofsolvent used on the percentage of grafting was studied.

The concentration of active macroradicals in the grafting reaction is measured with the of a slinplified kinetic scheme.
The decomposition of potassium peroxydisulphate in polymerization systems
Authors: Morris Carolyn E. M. , Parts Adolf Gustav
Published: April 2003

The influence of various soaps and monomers on the rate of thermal decomposition of potassium peroxydisulphate has been investigated. It was found that all investigated compounds, except a fully fluorinated soap caused marked increases in the rate or peroxydisulphate disappearance. This finding should be considered in studies on the kinetics of polymerization in which peroxydisulphate is the initiator.
Die chemische heterogenität von copolymerisaten. 4. Experimentelle untersuchungen zur verträglichkeit
Authors: Kollinsky Von Fritz , Markert Gerhard
Published: April 2003

Zwei chemisch einheitliche Methylmethacrylat/Butylacrylat‐Copolymerisate bilden in Substanz nur dann optisch homogene, d. h. klare Gemische, wenn der Unterschied im Methylmethacrylat‐Anteil 10–20 Mol‐% nicht übersteigt.

Wie Torsionsschwingungsversuche zeigen, liegt die Grenze der mechanischen Homogenität bei der gleichen Differenz im Methylmethacrylat‐Anteil. Bei inhomogenen Systemen aus zwei einheitlichen Copolymerisaten werden zwei diesen entsprechende Dämpfungsmaxima gefunden.

Elektronenmikroskopische Aufnahmen lassen zum Teil auch in optisch order mechanisch homogenen Systemen Strukturen noch in der Größenordnung von 30 Å erkennen. In der Nähe der Trübungsgrenze steigt die Phasengröße sprunghaft an. Bei Mischungen aus drei Komponenten übt das hinsichtlich seiner Zusammensetzung in der Mitte liegende Copolymerisat keine Verträglichkeitsvermittlung aus.

In Copolymerisaten mit breiter, lückenloser chemischer Verteilung bilden sich Mikrophasen aus jeweils miteinander verträglichen Makromolekülen. Optische und mechanische Homogenität oder Inhomogenität ist dann eine Frage der Größe der einzelnen Mikrophasen. Unterdrückung bzw. Begünstigung der Übertragungsreaktion am Polymeren hat eine Vergröberung bzw. Verfeinerung der Mikrophasen zur Folge. In Übereinstimmung damit wirken Pfropfcopolymerisate homogenisierend.

Orientierende Versuche an Copolymerisaten aus anderen Monomeren lassen darauf schließen, daß diese Feststellungen allgemeine Gültigkeit besitzen.
Darstellung und eigenschaften von poly‐4‐vinyltriarylmethylradikalen
Authors: Braun Von Dietrich , Faust Raimund Josef
Published: April 2003

Als Ausgangsverbindungen für die Darstellung von Poly‐4‐vinyltriarylmethylradikalen werden die aus Poly‐4‐vinyltriarylcarbinolen zugänglichen Poly‐4‐vinyltriarylmethylchloride verwendt. Die Umsetzung der Poly‐4‐vinyltriarylmethylchloride mit Zinkpulver führt nur bei vollständigem Wasserausschluß zu den entsprechenden Poly‐Kohlenstoffradikalen; bei Anwesenheit von Spuren Wasser Entstehen Dagegen Poly‐4‐vinyltriarylmethylkationen.

Die dargestellten Poly‐4‐vinyltriarylmethylradikale enthalten nach ESR‐spektroskopischen Untersuchungen bis zu 100 Radikalstellen pro Markomolekül. Sie reagieren mit Sauerstoff zu vernetzten Poly‐Peroxiden, wobei als Zwischenstufe ESR‐spektroskopisch instabile Peroxyradikale nachgewiesen werden können. Mit Alkalimetallen bilden die Poly‐4‐vinyltriarylmethylradikale Polyanionen und im Falle von Polymeren mit Biphenylgruppen außerdem Polyradikalanionen.
Triazin‐polymere. I. Poly(vinylenphenylentriazine)
Authors: Elias Von Hans‐Georg , Greth Erich
Published: April 2003

Bei der Kondensation von Methyl‐s‐triazinen mit aromatischen Aldehyden in konz. Schwefelsäure zwischen 25 und 60°C wurden Styryltriazine mit Ausbeuten bis zu 99% erhalten, darunter folgende neue Verbindungen: 2‐Methyl‐4.6‐distyryl‐s‐triazin, 2.4‐Dimetyl‐6‐styryl‐s‐triazin, 2.4‐Diphenyl‐6‐styryl‐s‐triazin, 2‐Methyl‐4‐phenyl‐6‐styryl‐s‐triazin, β.β'‐Bis(diphenyl‐s‐triazinyl)‐p‐divinylbenzol, 2‐(4‐Formylstyryl)‐4.6‐diphenyl‐s‐triazin, 2.4‐Diphenyl‐6‐(4‐nitrostyryl)‐s‐triazin 2.4‐Diphenyl‐6‐(4‐dimethylarminostyryl)‐s‐triazin, 2.4‐Diphenyl‐6‐(4‐chlorstyryl)‐s‐triazin und 2.4‐Diphenyl‐6‐(4‐methoxystyryl)‐s‐triazin. Kondensationstemperaturen von 100°C führten ‐ vermutlich durch Sulfurierungzu laugenlöslichen Produkten. Durch Polykondensation von Terephthalaldehyd mit 2.4‐Dimethyl‐6‐phenyl‐s‐triazin wurden in konz. Schwefelsäure lösliche, mit 2.4.6‐Trimethyl‐s‐triazin unlösliche Polymere erhalten. Die Polymeren sind nach ultraviolettspektroskopischen Messungen nicht durchgehend konjugiert. Die Geschwindigkeitskonstanten der Kondensation verschiedener s‐Triazine mit aromatischen Aldehyden wurden bestimmt. Die höchsten inhärenten Viskositäten betrugen ca. 130 ml/g (25°C, konz. Schwefelsäure), was Zahlenmitteln des Polymerisationsgrades von ca. 11 entspricht. Höhere Polymerisationsgrade konnten wegen Nebenreaktionen der Methylendgruppen nicht erreicht werden.
Radical reactions initiated by chelate complexes of transition metals. II. Radical polymerization of styrene
Authors: Bartoň J. , Lazár M.
Published: April 2003

Bis‐(–)ephedrine copper(II) chelate initiates styrene polymerization in the presence of halogen compounds. Among the halogen compounds examined, the highest rate of Polymerization was found in the system bis‐(–)ephedrine copper(II) chelate‐carbon tetrachloride. The polymerization rate for constant carbon tetrachloride concentration can be described by the equation Rp = k [chelate]n with the exponent n = 0.26. For molar ratios of chelate over carbon tetrachloride equal to, or smaller than one, the rate of polymerization is practically independent of carbon tetrachloride concentration. In the case that [CCl4] < [Chelate] the dependence of the polymerization rate of the concentration of carbon tetrachloride can be expressed by the equation Rp = k[CCl4]n where n = 0.30. While bis‐(–)‐ephedrine copper(II) chelate acts as a retarder in styrene polymerization initiated with 2.2′‐azobisisobutyronitrile, it has a rate increasing effect in the dibenzoylperoxide initiated polymerization. In the first case the decrease of polymerization rate was attributed to the reaction of radicals with the chelate, while this is outdone by the catalytic effect of bis‐(–)ephedrine copper(II) chelate on benzoylperoxide decomposition in the second case.
Radical reactions initiated by chelate complexes of transition metals. III. Grafting of polymers containing halogen atoms
Authors: Bartoň J. , Lazár M. , Nemček J. , Maňásek Z.
Published: April 2003

Polymerization of styrene is initiated by bis‐(–)ephedrine copper(II) chelate in presence of halopolymers and telomers containing terminal halogen atoms. The rate of polymerization at constant concentration of the chelate depends on the specific halopolymer used and its concentration i.e. on the concentration of halogen atoms in the polymerization system. It is suggested that initiation results from interaction of the chelate with the halogen atoms of the halopolymer leading to formation of reactive centres at the halopolymer. These centres are able to give rise to formation of graft and block copolymers in presence of suitable vinyl monomers.
Effects of aminoalcohol and alkoxyalcohol on the n‐butyllithium‐initiated polymerization of methyl methacrylate
Authors: Maruhashi Motokazu , Takida Hiroshi
Published: April 2003

The effects of the addition of aminoalcohols or alkoxyalcohols on the n‐butyllithium initiated polymerization of methyl methacrylate in toluene were studied. Stereoregulating behavior in the polymerization was affected remarkably by these additives. The addition of 2‐diethylaminoethanol, 2‐ethoxyethanol or tetrahydrofurfurylalcohol favored formation of syndiotactic type polymer in the polymerization at −78°C. On the other hand, isotactic type polymer was obtained by the addition of 3‐diethylainino‐1‐propanol or 1‐diethylamino‐2‐propanol.

The influences of polymerization temperature and solvent were also investigated. In the polymerization with n‐butyllithium‐tetrahydrofurfurylalcohol system, these varibles affected scarcely on the stereoregularity of polymers, and considerably syndiotactic‐rich polymer was prepared even at 0°C, both in toluene and in tetrahydrofuran.

It is confirmed by gas‐chromatographic analysis, electronic spectra, and the results of polymerization that the catalyst system consists of n‐butyllithium and lithium alkoxide of aminoalcohols or of alkoxyalcohols.
The solution properties of poly‐o‐chlorostyrene
Authors: Matsumura Kimiyoshi
Published: April 2003

The solution properties of poly‐o‐chlorostyrene in toluene were measured by means of light‐scattering and viscosity method, and the results were compared with those obtained from other polystyrene derivatives.

The dependence of the intrinsic viscosity, the second virial coefficient and the end‐to‐end distance of the polymer chain on the molecular weight is follows:

These relationships do not differ substantially from those of other polystyrene derivatives.

The unperturbed dimension of poly‐o‐chlorostyrene was calculated. Results showed that the polymer chain of poly‐o‐chlorostyrene at the theta state, {o/f}1/2 = 2.42, was more extended than that of poly‐p‐chlorostyrene, {o/f}1/2 = 2.15 to 2.30.
Vinyl compounds of nucleic acid bases. III. Polymerization and copolymerization of N‐vinyl and β‐methacryloyloxyethyl compounds of nucleic acid bases and their polymer‐polymer interactions
Authors: Kondo Koichi , Iwasaki Hiroshi , Nakatani Koichi , Ueda Nasuo , Takemoto Kiichi , Imoto Minoru
Published: April 2003

9‐Vinyladenine, 1‐vinyluracil, 1‐vinylthymine, and β‐methacryloyloxyethyl derivatives of uracil, thymine and adenine were polymerized and copolymerized with acrylamide, maleic anhydride, and vinylpyrrolidone in different solvents. The polymer‐polymer interactions were measured by a spectrophotometric method. Poly(9‐vinyladenine) gave a hypochromic effect with ribonucleic acid in aqueous solution.
Investigations of the structure of ethylene‐propylene and ethylene‐butene copolymer crystals using fuming nitric acid. Part I. The molecular weight distribution of degraded copolymer crystals
Authors: Holdsworth P. J. , Keller A. , Ward I. M. , Williams T.
Published: April 2003

The effect of fuming nitric acid on single crystals of random ethylene‐propylene and ethylene‐butene copolymers has been investigated. In this paper changes in the molecular weight distributions which occur when such copolymer crystals are treated with fuming nitric acid will be described. The changes were examined using Gel Permeation Chromatography. It is shown that in all cases the changes in molecular weight distribution are similar to those observed when crystals of linear polyethylene are treated correspondingly. It is concluded that the copolymer crystals have a chain folded structure very similar to that of single crystals of linear polyethylene.

A qualitative correlation between the changes in molecular weight distribution and changes in the melting behaviour of degraded polymer crystals will also be described.
Investigations of the structure of ethylene‐propylene and ethylene‐butene copolymer crystals using fuming nitric acid. Part III. The effects of nitric acid on the physical properties of single crystal mats of ethylene copolymers
Authors: Holdsworth P. J. , Keller A.
Published: April 2003

The structure of crystals of random ethylene‐propylene and ethylene‐butene copolymers has been investigated using fuming nitric acid. This paper is concerned with the effect of nitric acid on crystals grown from a series of copolymers. The weight losses and changes in long period, heats of fusion and unit cell spacings which result from acid treatment are reported. From these results and using the results reported in the earlier papers of this series it is concluded that crystals grown from both ethylene‐propylene and ethylene‐butene copolymers are very similar in structure to linear polyethylene single crystals apart from the fact that branches are contained within the crystalline cores of the copolymer crystals. It is shown that there are some differences between the way that ethylene‐butene and ethylenepropylene crystals are attacked by nitric acid, and a possible reason for this is suggested.
Kinetics and mechanism of the alkali‐catalysed condensations of di‐ and tri‐ methylol phenols by themselves and with phenol
Authors: Francis D. Joseph , Yeddanapalli L. M.
Published: April 2003

The kinetics of the alkali‐catalysed condensations of 2.4‐ and 2.6‐dimethylol phenol and 2.4.6‐trimethylol phenol by themselves and with phenol has been studied under various experimental conditions. The observed higher rates of self‐condensation of the methylol phenols have been explained on the basis of the relative reactivities of ortho and para methylol groups and the reactivities of the free nuclear positions in methylol phenols and phenol. A mechanism of the condensation reactions is also proposed.
Metal‐containing initiator systems. XII. Vinyl polymerization by pentacyanobenzylcobaltate(III) and by the binary systems of pentacyanocobaltate(II) and organic halides
Authors: Aoki Shuzo , Shirafuji Chiaki , Otsu Takayuki
Published: April 2003

Pentacyanobenzylcobaltate(III) acts as an effective initiator for the polymerization of methyl methacrylate (MMA), styrene, acrylonitrile, and vinyl acetate, and the initiating radical is assumed to be the benzyl radical produced from homolysis of the Carbon‐cobalt bond. The binary systems of pentacyanocobaltate(II) and some organic halides were also found to serve as initiators for the MMA polymerization. The initiating activity of these systems increased with decreasing dissociation energy of the carbon‐halogen bond in the halides. The polymerization of MMA and styrene by pentacyanobenzylcobaltate(III) was accelerated in the presence of benzyl bromide.
Permeability of solutes through hydrated polymer membranes. Part III. Theoretical background for the selectivity of dialysis membranes
Authors: Yasuda H. , Peterlin A. , Colton C. K. , Smith K. A. , Merrill E. W.
Published: April 2003

The diffusional transport of aqueous solutes through water swollen polymer membranes is examined by the concept of the free volume of the water‐polymer systems, Vf,13. The relative diffusivity (D in membrane/D in water) can be expressed by the product of the probability factor of finding holes of equal or larger cross section, q, than the cross section of solute, q2, (sieve mechanism) and the free volume factor. An analysis of experimental data indicates that within the range of solute size investigated (up to albumin) the sieve mechanism is not yet playing a role in homogeneous cellulosic membranes. The main reduction of permeability of larger solutes is caused by the free volume term which is an exponential function of the negative cross section of the solute, q2, exp (–Bq2/Vf,13). In porous membranes, however, the sieve mechanism alone is responsible for the selectivity.
Alternating copolymerization of phthalic anhydride and propylene oxide by dialkylzinc
Authors: Inoue Shohei , Kitamura Kazuyuki , Tsuruta Teiji
Published: April 2003

The mechanism of alternating copolymerization of propylene oxide with phthalic anhydride catalyzed by dialkylzinc is discussed. Dialkylzinc and phthalic anhydride form a complex which exhibits reactivity with propylene oxide to form alkylzinc alkoxide. Alkylzinc alkoxide thus formed reacts preferentially with phthalic anhydride in the presence of propylene oxide, giving alkylzinc carboxylate. Alkylzinc carboxylate then reacts selectively with propylene oxide to reproduce alkylzinc alkoxide. Repetition of these two reaction steps results in the formation of highly alternating polyester‐copolymer.
Considerations about the possibility of determining [η] and K by means of the „one point measurement”︁ method
Authors: Solomon O. F. , Gottesman B. S.
Published: April 2003

A method is presented permitting to calculate values for [η] and K for every pair of experimental values c and ηsp.

In this context several equations are offered and discussed.
Bis‐trimethylchinon‐1.4‐yl‐alkane als modellsubstanzen für polymere hydrochinon‐chinon‐redoxysysteme. VI. Synthese und untersuchung des redoxverhaltens durch potentiometrische titration und polarographie
Authors: Förster Von H. J. , Manecke G.
Published: April 2003

Es wurden das Bis‐trimethylchinon‐1.4‐yl‐methan, ‐äthan und ‐propan als symmetrisch aufgebaute, tetravalente Modellsubstanzen für polymere Hydrochinon‐Chinon‐Redox‐systeme synthetisiert. Die Verbindungen wurden durch potentiometrische Titration und Polarographie untersucht. Die Titrationskurven und Polarogramme werden theoretisch gedeutet. Die gegenseitige Beeinflussung der bivalenten Redoxeinheiten wird mit Hilfe eines induktiven Modells diskutiert.
Über oligomere und polymere 2.5‐dimethoxyphenylen‐vinylene
Authors: Manecke Von G. , Zerpner D.
Published: April 2003

Poly‐2.5‐dimethoxyphenylen‐(1.4)‐vinylen und eine Reihe oligomerer 1.4‐verknüpfter Modellsubstanzen der Formel 2.5‐(CH3O)2‐4‐RC6H2CHCH[2.5‐(CH3O)2C6H2CHCH]n2.5‐(CH3O)2‐4‐R (n = 0 bis 4; R  CH3, H, CHO) wurden synthetisiert. Poly‐2.5‐dimethoxyphenylen‐(1.3)‐vinylen und die 1.3‐verknüpften Oligomeren (n = 0, 1; R  H, CHO) wurden ebenfalls erhalten. Die Darstellung der Verbindungen erfolgte mit Hilfe der WITTIGschen Reaktion aus Triphenylphosphoniumsalzen wie 2.5‐(CH3O)2C6H3CH2P(C6H5)3Br, 2.5‐(CH3O)2C6H21.3‐[CH2P(C6H5)3Br]2 oder 2.5‐(CH3O)2‐4‐CH3C6H2CHCH2.5‐(CH3O)2C6H2‐4‐CH2P(C6H5)3Br und Aldehyden wie 2.5‐Dimethoxyisophthalaldehyd, 4.4′‐Diformyl‐2.2′.5.5′‐tetramethoxystilben oder 4‐Formyl‐4′‐methyl‐2.2′.5.5′‐tetramethoxystilben. Hydrierung der Vinylen‐Brücken bei den Verbindungen mit n = 1 ergab die zu erwartenden 2.5‐Dimethoxyphenylenäthylene. Die Entmethylierung der 2.5‐Dimethoxyphenylenvinylene bzw. ‐äthylene (n = 1) führte in den meisten Fällen zu den entsprechenden Hydroxy‐Verbindungen.
Über aromatische polyamide mit heterocyclischen ringsystemen
Authors: Künzel Von H.‐E. , Wolf G. D. , Bentz F. , Blankenstein G. , Nischk G. E.
Published: April 2003

Zur Herstellung von hochmolekularen aromatischen Polyamiden, die in polaren Lösungsmitteln löslich sind, wurden neue aromatische Diamine mit Oxdiazol‐, Triazol‐, Thiadiazol‐, Thiazol‐, Hydantoin‐, Chinazolon‐ und Chinazolindion‐Ringsystemen, die zum Teil auch noch Äther‐ oder Sulfongruppen enthalten, mit aromatischen Dicarbonsäuredichloriden (z. B. Iso‐ oder Terephthaloyldichlorid) in polaren organischen Lösungsmitteln (z. B. N.N‐Dimethylacetamid oder N‐Methylpyrrolidon) umgesetzt.

Es konnten Fäden und Fasern hergestellt werden, die eine sehr gute Festigkeit und eine hohe Temperaturbeständigkeit aufweisen. Polyamide aus Diaminen mit Chinazolindion‐Ringsystemen waren thermisch am beständigsten und zeichnen sich außerdem durch eine sehr geringe Brennbarkeit aus.

Aus ihren Lösungen in polaren Lösungsmitteln lassen sich die neuen Polyamide auch zu geschmeidigen, hochtemperaturbeständigen Filmen verarbeiten.
Polymérisation anionique du sulfure d'isobutène. Préparation de copolymères statistiques et séquencés
Authors: Boileau Par Sylvie , Sigwalt Pierre
Published: April 2003

Des homopolymères cristallins du sulfure d'isobutène (épithio isobutane) ont été obtenus par polymérisation anionique, ainsi que des copolymères statistiques et séquencés avec le sulfure de propylène. Les copolymères solubles ont des masses moléculaires en accord avec les masses théoriques, ce qui montre que la polymérisation se produit sans réaction de terminaison.

Les amorceurs conduisant à des polymères bifonctionnels (renfermant deux centres actifs) comme le naphthalène‐sodium ou le naphthalène‐potassium, ont donné des copolymères à trois séquences, dont deux séquences cristallines de polysulfure d'isobutène. Ces copolymères sont insolubles dans le toluène à 37°C, alors que des copolymères de même masse moléculaire et de même composition, mais renfermant seulement deux séquences, sont solubles. Ceci montre l'influence sensible sur les propriétés physiques des différents types d'association intermoléculaire par l'intermédiaire de réseau cristallin.
Über polyenarylene und polyenheteroarylene. 2. Mitt.: Poly‐[thienylen‐(2.5)‐äthenamer‐alt‐phenylen‐(p,m,o)‐äthenamer] und einige oligomere. Synthese, spektrales verhalten und elektrische leitfähigkeit
Authors: Kossmehl Von Gerhard , Härtel Manfred , Manecke Georg
Published: April 2003

Bei der WITTIG‐Reaktion von 2.5‐Bis‐(triphenylphosphoniomethyl)‐thiophen‐dichlorid mit Terephthalaldehyd, Isophthalaldehyd und Phthalaldehyd wurden die Poly‐[thienylen‐(2.5)‐äthenamer‐alt‐phenylen‐(p,m,o)‐äthenamere] erhalten. Diese Polymeren enthalten endständige Aldehydgruppen. Analog wurden die Poly‐[phenylen‐p‐äthenamer‐alt‐phenylen‐(p,m,o)‐äthenamere] hergestellt sowie einige Oligomere mit 3 Aromatenbausteinen und 2 Vinylengruppen sowie 5 Aromatenbausteinen und 4 Vinylengruppen. Diese Polymeren und Oligomeren sowie das Poly‐[thienylen‐(2.5)‐äthenamer] wurden durch UV‐Spektren, Spektren des sichtbaren Bereiches, IR‐Spektren und Massenspektren charakterisiert. Es wurden auch Untersuchungen mit Röntgenstrahlen zur Ermittlung des Festkörperaufbaus angestellt. Alle Oligomeren und Polymeren wurden auf ihre elektrische Leitfähigkeit untersucht.
Poly‐p‐xylyliden. Synthesen und beziehungen zwischen struktur und elektrophysikalischen eigenschaften
Authors: Hörhold Von Hans‐Heinrich , Opfermann Johannes
Published: April 2003

Poly‐p‐xylyliden (I) wird durch bifunktionelle Carbonylolefinierung von Terephthalaldehyd nach der WITTIGschen Reaktion und mitp‐Xylylen‐bis‐[phosphonsäurediäthylester] sowie durch Dehydrochlorierung vonp‐Xylylendichlorid mit Natriumhydrid in Dimethylformamid und mit Kaliumamid in flüssigem Ammoniak hergestellt und vergleichend untersucht. Methyl‐ und methoxysubstituierte Poly‐p‐xylylidene (II) und (III) werden aus 2.5‐Bis‐[chlormethyl]‐p‐xylol und ‐hydrochinondimethyläther erhalten. I—III werden durch IR‐ und Reflexionsspektren und durch Thermogravimetrie analysiert.magnified imageDie Polyxylylidene I—III besitzen Halbleitereigenschaften und Photoleitfähigkeit. Typische Werte für die Dunkelleitfähigkeit und Aktivierungsenergie von I sind σ400°K ≈ 10−15Ohm−1cm−1und ED= 2,4 eV.

Absorptions‐ und Leitfähigkeitsspektren fallen in den gleichen Spektralbereich, wobei die Photoleitfähigkeit an der langwelligen Kante der Absorption ein Maximum besitzt. Die Anregungsenergie für die Grenze der Photoleitung von I, E0= 2,35 eV, besitzt dieselbe Größe wie EDund ist annähernd in Übereinstimmung mit dem theoretisch berechneten Wert für den π–π*‐Übergang des isolierten Makromoleküls. Bei den substituierten Polyxylylidenen II und III ergeben sich entsprechende Beziehungen.

Ferner wird zur näheren Charakterisierung der Leitungsphänomene die Abhängigkeit des Photostromes und dessen Relaxationszeit von der Spannung, der Temperatur und der Bestrahlungsstärke gemessen sowie die Photoleitfähigkeit bei kombinierter optischer Anregung und der Einfluß von Sauerstoff auf die Photoleitung untersucht.
Free radical polymerization of unconjugated dienes. IX. Kinetic evidence of formation of five and six membered rings in the free radical polymerization of divinylether
Authors: Guaita Marino , Camino Giovanni , Trossarelli Luigi
Published: April 2003

Some kinetic relationships between the monomer concentration and the composition of the polymers from 1.4‐dienes, in terms of monomeric and structural units, are derived taking into account all the cyclization reactions which can occur in the course of the chain growth. These relationships are applied to the results of the analytical determination of the residual unsaturations in the products of the free radical polymerization at 70°C of divinylether in benzene solutions. It is shown that the chain growth takes place exclusively by addition of cyclic radicals onto monomer molecules. Evidence is given that both five and six membered rings are formed in the cyclization steps.
Structure of solution grafted polybutadiene
Authors: Wetton R. E. , Moore J. D. , Fox B. E.
Published: April 2003

Three different polybutadienes possessing widely different vinyl and cis monomer structures have been grafted with methyl methacrylate in solution using both benzoyl peroxide and azobisisobutyronitrile catalysts. Careful fractionation and backbone degradation techniques together with molecular weight determinations lead to the conclusions that both catalysts gave graft copolymer in the 10% rubber solutions used. Benzoyl peroxide always gave better graft efficiencies, (as did high vinyl and to a lesser extent high cis polybutadiene). The molecular weight of the polymethylmethacrylate grafts are slightly lower than those of homopolymers polymerized under the same conditions indicating < 20% grafting by chain transfer and termination mainly by disproportionation.
Molecular weight distribution of crystalline polypropylene
Authors: Yamaguchi Kinya
Published: April 2003

The molecular weight distribution of several polypropylene samples was studied by the column elution method. With the exception of a lower molecular weight sample, the molecular weight distribution curves were found to be well described by a revised log‐normal function presented by DAVIS et al. The molecular weights Mw and Mn observed by direct measurements for the whole polymers were in good agreement with the corresponding ones calculated from their molecular weight distribution curves according to this function. Moreover, no anomalous relation was found between the solution viscosity and the molecular weight for several unfractionated polymers and their high molecular weight fractions. These results reveal that there exists no long chain branch even in the high molecular weight region, and that the approximation of the distribution pattern by this revised lognormal function sufficiently characterizes polypropylene samples. The values of Mw/Mn of all samples studied were within a narrow range from 6 to 9, and no distinct dependency of the molecular weight distribution on the average molecular weight was observed.