摘要:

AbstractEs wurde der Einfluß einigern‐Alkylhalogenide (n‐Butylfluorid,n‐Butylchlorid undn‐Butylbromid) und einiger Benzylhalogenide (Benzylfluorid, Benzylchlorid und Benzylbromid) auf die durch Aluminiumjodid katalysierte Polymerisation des Isobutylens in Heptan studiert. Dabei wurde festgestellt, daß dasn‐Butylfluorid und die Benzylhalogenide die Polymerisationsgeschwindigkeit wesentlich erhöhen. Aus der Abhängigkeit der Polymerisationsgeschwindigkeit und der Molekulargewichte der gewonnenen Polymeren von der Konzentration der Alkylhalogenide und des Aluminiumjodids geht hervor, daß die Alkylhalogenide nicht als Cokatalysatoren wirken, sondern daß die Erhöhung der Polymerisationsgeschwindigkeit durch katalytisch aktive Produkte verursacht wird, die durch Halogenaustausch zwischen dem Aluminiumjodid und den Alkylhalogeniden gebildet werden. Die Ergebnisse der vorliegenden Arbeit werden im Zusammenhang mit den Erkenntnissen diskutiert, die über die Polymerisation des Isobutylens mit den aus zwei FRIEDEL‐CRAFTS‐Halogeniden bestehenden Katalysatorsys

ISSN:0025-116X    

DOI:10.1002/macp.1972.021510111

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractEs wird der Einfluß der Kettenlänge dern‐Alkylamine auf die morphologische Beschaffenheit und die innere Anordnung der übermolekularen Strukturen untersucht, die sich aus wäßrigen undn‐Butanollösungen ihrer Salze mit ataktischer Polymethacrylsäure bilden. Alle im Licht‐ und Elektronenmikroskop beobachteten Strukturen zeichnen sich durch eine vollkommene morphologische Beschaffenheit aus. Die Salze höherern‐Alkylamine (C4, C6, C12und C17) sind optisch anisotrop. Dasn‐Butylaminsalz weist ein kristallines Elektronenbeugungsbild auf. Die Salze der höherenn‐Alkylamine schmelzen in einem engen Temperaturbereich. Auf Grund dieser Angaben wird vermutet, daß die beobachteten übermolekularen Strukturen der Salze von ataktischer Polymethacrylsäure mit niedrigenn‐Alkylaminen (bis C4) aus der Hauptpolymerkette gebildet werden. Die optisch anisotropen Strukturen mit kristallähnlichem innerem Bau der Salze höherern‐Alkylamine (mehr als C4) sind dagegen auf dien‐aliphati

ISSN:0025-116X    

DOI:10.1002/macp.1972.021510112

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe annealing behaviour of samples of melt crystallisedtrans‐1.4‐polyisoprene, containing different percentages of the two solid modifications, was examined. The plots of long‐spacingsversusthe annealing temperature show a discontinuity at a temperature that has been identified with the melting temperature of the low‐melting modification.The equilibrium melting point Tm0and the surface free energy σeof the crystallites of the low‐melting modification oftrans‐1.4‐polyisoprene has been calculated thermodynamically using the slope method. A value of 78°C and 102 erg·cm−2is found for Tm0an

ISSN:0025-116X    

DOI:10.1002/macp.1972.021510113

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractAs part of an enquiry on the fold structure of crystals from unsaturated chains and on the relation between crystal morphology and degradation, single crystals of two polyalkenamers were subjected to oxidative attack by ozone, and to a lesser extent by nitric acid, and the resulting changes in the concentration of double bonds and the distribution of molecular lengths were followed. It was found that double bonds were attacked deep within the crystal without a clear distinction between the fold surface and the crystal interior in contrast to the analogous studies involving the severance of single bonds in polyethylene. Nevertheless, the attack does not follow a random pattern but leads to a crystalline dimeric residue which remains highly resistant in spite of containing double bonds. The implications of this unexpected finding, which include the possibility of a highly perfect crystalline subunit much smaller than involved in the much argued models of chain folded crystals, are discussed. It is reconfirmed that the occasional intrachain double bonds in polyethylene are largely shielded from ozone while in the lattice in contrast to the high accessibility of these bonds in the present polyalkenamers of closely similar crystal structure. In view of similar results on guttapercha7it appears that the latter property may be a feature common to polymer crystals where the unsaturation is intrinsic to the molecule.

ISSN:0025-116X    

DOI:10.1002/macp.1972.021510114

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractGuttapercha (trans‐1.4‐polyisoprene) was crystallized from solution and its single crystal habit and chain folding characteristics were examined. The two polymorphic forms, known from previous studies, could now be assigned to two different single crystal habits by means of electron diffraction patterns, and conditions of their formation could be circumscribed. Similarly, the melting and annealing behaviour could be associated with the two forms and a transition between them observed at temperatures where the two phases can still coexist by present evidence. The fold length and its variations were also defined.Single crystals were exposed to the degrading effect of ozone, and changes in IR‐spectra and molecular weight distribution were followed. It was observed that, as expected, double bonds were severed; nevertheless a sizeable portion of them remained intact. At the same time the chain was broken down into a sharply defined fragment length which was identified as a trimer or tetramer oftrans‐1.4‐polyisoprene with carboxylic and carbonylic termination. No appreciable selectivity as regards fold traverses analogous to the degradation products in polyethylene was observed. It is pointed out that appreciable accessibility of double bonds within the crystals, coupled with oxidation resistance of small oligomeric lengths, seems to be characteristic of chain folded crystals of unsaturated compounds with possible implications for studies on the crystal structure and on degradation behaviour i

ISSN:0025-116X    

DOI:10.1002/macp.1972.021510115

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractWhenp‐xylylenedichloride (XDC) and α.ω‐tert‐diamines are present in equimolar amounts in dimethylformamide (DMF), fairly fast polymerization occurs to form the polycation polymers of integral type owing to the structural characteristic of XDC to stabilize the transition state with delocalization. The reactivities based on the structures of monomers are as follows: Diamines:Dihalogren compounds:The reactivity of XDC is remarkable.The reaction of TED and XDC proceeds by nucleophilic bimolecular substitution (SN2), thus the rate Eq. is, v = k · [XDC][TED]. The fact that this polymerization is considerably faster than the normal MENSCHUTKIN reaction may be attributed to the structure of XDC above mentioned and the solvent effect of DMF that solvates cations only. The activation energy and log of the frequency factor of this polymerization are 9.6 and 5.61 kcal/mole, resp

ISSN:0025-116X    

DOI:10.1002/macp.1972.021510116

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractIt was found that the oxidative polymerization of 2.6‐xylenol with a copper‐amine complex proceedsviaa mechanism similar to that of a MICHAELIS‐MENTEN‐type reaction, the steady state being maintained during the polymerization; the kinetics were studied. The LINEWEAVER‐BURK plots showed linear relationships, supporting this mechanism. From the comparison of the kinetic constants it was concluded that oxygen not only takes part in the recycling step of the catalyst, but also promotes the catalytic action of the cuprous complex by being coordinated to the intermediate complex. K1values (the reciprocal of the MICHAELIS constant, Km) vary with the amine‐ligand species, but the reaction‐rate constants (k2) do not change, regardless of the ligands used. According to the kinetic formula, K1is proportional to the product of the formation constant of the complex between the copper‐amine catalyst and the monomer (K′1) by the rate constant of electron transfer (ke). It is because of the K′1values that the apparent polymerization rate varies with the amine ligands in the region of relatively low monomer concentrations. It was found that, as the ligand ratio ([pyridine]/[Cu]) increases,i.e., as the selectivity for CO coupling increases, the K1values become larger. The mechanism for the coupling selectivity is discussed in rel

ISSN:0025-116X    

DOI:10.1002/macp.1972.021510117

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe role of oxygen in the oxidative polymerization of 2.6‐xylenol by copper‐amine complexes was studied. It was found that using an excess of a copper‐pyridine (Py) complex the polymerization proceeds even in the absence of oxygen, but that with an excess of a copper‐aliphatic amine (n‐butylamine or diethylamine) complex, oxygen is indispensable for the coupling to occur. It is concluded that oxygen promotes the electron transfer from the coordinated monomer to the metal ion or the dissociation reaction of the activated monomer, probably by forming a complex with the intermediate. Due to the π electron‐accepting property of the Py ring the Py‐copper complex is active even in the absence of oxygen. On the other hand, the aliphatic amine‐copper complex is active only when oxygen, which has an electron‐accepting ability, is coordinated. According to the kinetic equation derived on the basis of complex formation between oxygen and the catalyst, the reciprocal of the reaction rate constant (k2) is proportional to the reciprocal of the partial pressure of oxygen in the system; this is in agreement with the experimental results. The effect of the solvent (Py ando‐dichlorob

ISSN:0025-116X    

DOI:10.1002/macp.1972.021510118

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe contributions of the charge‐transfer complexes to the alternating copolymerizations (e.g., the styrene/maleic anhydride system) were studied. From the facts that the complex concentrations changed in various solvents and the rates of copolymerization depended on the solvent species, the behavior of the alternating copolymerization was considered to be controlled by the quantities of the reactive monomer complexes.In relatively strong donor solvents such as acetone and tetrahydrofuran, the concentrations of the monomer complexes were low because acceptor monomers also form complexes with the solvents. Therefore, the contributions of the monomer complexes to the copolymerization were neglectable. On the other hand, in benzene and carbon tetrachloride, which interact with acceptor monomers relatively weakly, the concentrations of the monomer complexes were relatively high. Then the copolymerizations were mainly controlled by the reactive monomer complexes.After all, it was suggested that the uncomplexed monomers as well as the complexed monomers should be taken into account on discussing the mechanisms of the alternating copolymerization between donor and acceptor monomers. In addition, the equilibrium constants or the complex concentrations could be determined inn‐hexane by the use of NMR spec

ISSN:0025-116X    

DOI:10.1002/macp.1972.021510119

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractPolymerizations ofo‐diethinylbenzene were conducted with ZIEGLER‐type and other catalysts. Polymers were readily obtained withas catalysts. Combinations of alkylaluminium compounds with other transition metal acetylacetonates were much less effective as catalysts. The polymers obtained with these catalysts are pale brown to brown powders with a mol. wt. of 2000 to 3500, which do not melt nor decompose up to 300°C. Small amounts of polymers were also obtained with cationic catalysts and with azobisisobutyronitrile as initiator.From NMR and IR spectroscopic data, the polymers obtained with coordination catalysts were shown to contain 30–50% of the unreacted second ethinyl group. The methyleneindene unit probably is involved as cyclic structure, although other structural units formed by head‐to‐head addition could not be excluded from the data

ISSN:0025-116X    

DOI:10.1002/macp.1972.021510120

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY