摘要:

AbstractDie ungestörten Dimensionen von Polytetramethylenadipat, Polyoctamethylensebacat und Poly‐ε‐caprolacton wurden nach fünf verschiedenen Methoden im Temperaturbereich zwischen 18 und 35°C ermittelt. Sie erwiesen sich für jede Probe als unabhängig von der verwendeten Methode. Mit steigendem Gehalt der Polyester an Methylengruppen nimmt die charakteristische Konstante C∞zu und daher die Flexibilität der

ISSN:0025-116X    

DOI:10.1002/macp.1972.021570101

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

Abstract2.4‐Diphenyl‐6‐styryl‐s‐triazin (P2ST), 2.4‐Diphenyl‐6‐(p‐dimethylaminostyryl)‐s‐triazin (P2AT) und 2.4‐Diphenyl‐6‐(p‐nitrostyryl)‐s‐triazin (P2NT) gehen beim Belichten mit UV‐Licht in siedender toluolischer Lösung in Dimere mit Cyclobutanstruktur über. Die Geschwindigkeit der Dimerisierung nimmt in der Reihenfolge Toluol>Äthylacetat>Chloroform ab. Die Belichtung von 2‐Phenyl‐4.6‐distyryl‐s‐triazin (PS2T), 2‐Phenyl‐4.6‐bis‐(p‐dimethylaminostyryl)‐s‐triazin (PA2T) und 2‐Phenyl‐4.6‐bis‐(p‐nitrostyryl)‐s‐triazin (PN2T) führte zu Polymeren. In Toluol, nicht aber in Benzol, wurde dabei viskosimetr

ISSN:0025-116X    

DOI:10.1002/macp.1972.021570102

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe compositions of copolymers formed by reacting styrene or α‐methylstyrene (M) with lithium in tetrahydrofuran in the presence of varying amounts of alkyl dibromides (RX2) have been studied. Regular copolymers of structure are formed at 2:1 monomer to dibromidemolarstoichiometry, but they become less regular and richer in monomer as the proportion of dihalide decreases. α‐Methylstyrene copolymers change systematically with reactant ratios and a series of materials can be prepared with different glass transition temperatures which can be related to the copolymer compositions. The fast rate of anionic homopropagation of styrene after consumption of the dihalide prevented pure copolymer from being prepared free of homopolystyrene. However, it is shown that the composition of the styrene copolymers is much more sensitive to the initial reactant ratios than is that of the α‐methylstyrene co

ISSN:0025-116X    

DOI:10.1002/macp.1972.021570103

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe compositions of copolymers formed by reacting butadiene or isoprene (M) with lithium in tetrahydrofuran in the presence of varying amounts of alkyl dihalides have been studied. When butadiene was reacted with dibromo‐p‐xylene, it was found that the dihalide predominantly dimerised by a WURTZ condensation mechanism before reacting with butadiene thus giving a copolymer of general formthe value of q depending on the initial reactant ratio.Isoprene was reacted with bis(2‐chloroethyl)ether and with dibromodecane. With the former reagent, and to a lesser extent with the latter, there is evidence that some initiation takes place by direct reaction of the halide with lithium. Only very low molecular weight materials were obtained with this monomer and bis(2‐chloroethyl)ether. The reasons for this are di

ISSN:0025-116X    

DOI:10.1002/macp.1972.021570104

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

Abstract1.5‐Diphenyl‐3‐(p‐methacryloyloxymethylphenyl) verdazyl (I), 1.5‐diphenyl‐3‐(p‐methacryloyloxyphenyl) verdazyl (II), and 1.5‐diphenyl‐3‐(p‐acryloyloxymethylphenyl) verdazyl (III) were synthesized and anionically polymerized withn‐butylmagnesium bromide or sodium naphthalene as an initiator to dark green polymers of a molecular weight of about 2300. III was polymerized with a catalytic amount of initiator, while I needed more initiator than the molar equivalent of the monomers suggesting the formation of intermediate metal salts of monomers and subsequent polymerization of the salts. More reactive double bond of III polymerized directly without the formation of the salt between stable free radical and organometallic compounds. Polymeric verdazyls contained up t

ISSN:0025-116X    

DOI:10.1002/macp.1972.021570105

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe reaction ofp‐substituted benzyl carbamates (BC) with formaldehyde (F) was carried out in dioxane/water solution in the presence of potassium hydroxide yielding N‐methylol derivatives. Their structures were identified by elementary analysis, IR, and NMR spectra. The kinetic study was carried out using potassium hydroxide as a catalyst resulting the following rate equation.\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm R}_{\rm 0} {\rm = - }\frac{{{\rm d[F]}}}{{{\rm dt}}}{\rm = K[BC]}_{\rm 0} {\rm [KOH]}_{\rm 0} {\rm [F]}_{\rm 0}^{{\rm 0} \sim {\rm 1}} $$\end{document}The rate constants for the reaction ofp‐substituted benzyl carbamates with formaldehyde fit HAMMETT's equation and the values of ρ were estimated to be +0.6 and +0.3 for lower and higher formaldehyde concentrations, respectively. The kinetics and the mechanism of the reaction are dis

ISSN:0025-116X    

DOI:10.1002/macp.1972.021570106

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractPolymerizations of ethinylferrocene were carried out with ZIEGLER‐type catalysts. AlR3‐TiCl4catalysts gave predominantly cyclic trimers,i.e., 1.2.4‐ and 1.3.5‐triferrocenylbenzene, and AlR3‐Ti(OBu)4catalysts gave linear polymers of comparatively low molecular weight (1000‐3500). Basic organic additives like pyridine or triethylamine showed limited influence on the yield and the product distribution. The polyene may contain some irregular structures. On the other hand, polyethinylferrocene obtained by dehydrative condensation of acetylferrocene was shown by NMR spectroscopy to contain considerable amounts of aliphat

ISSN:0025-116X    

DOI:10.1002/macp.1972.021570107

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe kinetics of cumene hydroperoxide (CHP) decomposition in benzene in the presence of bis‐(‐)‐ephedrine copper(II) chelate (Cueph), copper acetylacetonate (Cuac), and copper oxinate (Cuox) was studied by chemical analysis, UV, and ESR measurements. It was found that only Cueph markedly accelerated the CHP decomposition. The course of the CHP decomposition in presence of Cueph may be described by the kinetic equation for bimolecular reactions. From the temperature dependence an activation energy of 17.3 kcal· mole−1for CHP decomposition has been calculated. For the decay of paramagnetic Cu2⊕particles concentration during CHP decomposition in the presence of Cueph a reaction order of 1.1 with respect to [CHP] and 0.35 order kinetics for [Cueph]as well as an activation energy of 13.2 kcal·mole−1were established. It was found on the basis of UV spectroscopy that during CHP decomposition in the presence of Cueph a complex between CHP and Cueph as an intermediate product was formed. Thus for the equilibrium constant of complex formation a value of 32 1 · mole−1was estimated. The kinetic results obtained have been explained on the basis of supposition that a regeneration cycle for cupric species is operative. The disagreement between the supposed existence of the regeneration cycle and the observed decay of paramagnetic Cu2⊕particles in the course of CHP decomposition in the presence of Cuep

ISSN:0025-116X    

DOI:10.1002/macp.1972.021570108

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractESR studies of γ‐irradiated polysulphone (prepared from 2.2′‐bis(4‐hydroxyphenyl)‐propane and 4.4′‐dichlorodiphenyl sulphone) and its model compounds (diphenyl sulphone, 2.2′‐diphenyl propane, diphenyl ether), suggest that the majority of radicals produced in the polymer are formed by the subsequent reactions of hydrogen atoms released from the pendant methyl groups by the action of the γ‐radiation. Cyclohexadienyl‐type radicals are produced in quantity together with phenoxy and ArṠO2radicals. Supporting evidence for the mechanism is obtained from studies of the hydrogen atom b

ISSN:0025-116X    

DOI:10.1002/macp.1972.021570109

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe temperature independent factor of the cyclization parameters in the free radical cyclopolymerization of symmetrical unconjugated dienes is calculated through the evaluation of the entropy change occurring in the intramolecular cyclization reactions and in the intermolecular additions of cyclizable chain radicals onto monomer molecules. The agreement between the calculated and the experimental values for the free radical cyclopolymerization of acrylic anhydride and of divinyl ether is highly satisfactory. The decrease in entropy is found to be consistently smaller in the intramolecular than in the intermolecular reactions. Since, on the other hand, the activation energy for the intramolecular reactions is equal to, or slightly higher than that for the intermolecular additions, the high fractions of cyclic structural units in the cyclopolymers from symmetrical unconjugated dienes should be thermodynamically accounted for on the basis of an entropic effect largely exceeding the energetic one.

ISSN:0025-116X    

DOI:10.1002/macp.1972.021570110

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY