摘要:

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 ba

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780101

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractSeveral acrylic esters were polymerized with radical and anionic initiators and the stereoregularity of the polymers was determined. The radical polymerization oftert‐butyl acrylate gave syndiotactic‐rich polymers at low temperatures as did isopropyl and trimethylsilyl acrylates. A radically obtained polymer of triphenylmethyl acrylate was atactic in contrast to poly(triphenylmethyl methacrylate). In the anionic polymerization with phenylmagnesium bromide or butyllithium as catalyst, the stereoregularity of the polymers was governed by the coordination of the catalyst which depends on the polarity and bulkiness of ester groups, the polarity of solvents, and the temperature in the polymerizat

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780102

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

Abstract1,4‐Polybutadien wurde mit Alkylbenzolen (Toluol, Äthylbenzol,o‐, m‐ undp‐Xylol, Mesitylen) und Dicumylperoxid in einer radikalischen Reaktion partiell aralkyliert. Die erhaltenen Polymeren wurden IR‐spektroskopisch untersucht und durch Metathese mit 4‐Octen unter Verwendung eines WCl6/Sn(CH3)4‐Katalysators abgebaut. Die niedermolekularen Abbauprodukte mit Aralkylsubstituenten wurden gaschromatographisch getrennt und massenspektrometrisch

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780103

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe effect of different additives on the aqueous polymerization of acrylamide, initiated by MnO −4‐oxalic acid redox pair, was studied at 25°C in an atmosphere of nitrogen. It was observed that the rate of polymerization increased in the presence of alkali metal (Li+to Rb+) chlorides. Cupric chloride and ferric chloride were found to be polymerization retarders. Anionic and cationic detergents showed marked influence on the rate of polymerization. Also, the presence of water‐soluble alcohols lowered the polymerization rates to a sufficien

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780104

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe structural effect of polyanions on the binding type of methylene blue (1) was investigated spectrophotometrically.1was bound to poly(potassium styrenesulfonate) (PSS) and poly(sodium 4‐vinylphenylsulfate) (SVS) in the dimeric or slightly aggregated form and to poly(sodium vinylsulfonate) (SVF) and poly(potassium vinyl sulfate) (PVS) in the highly aggregated (polymeric) form. It was found that the flexibility of polyanions plays an important rǒle in the aggregation of bound1and that the difference between SO −3and OSO −3as binding site is not a sign

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780105

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractA series of new catalytic systems: (C2H5)2Zn/polyhydric phenols was prepared and their activity in the alternating copolymerization of carbon dioxide with propylene oxide (epoxypropane) was studied. On the basis of the results obtained, the structure of organozinc compounds formed in these systems and also in others described in the literature is proposed and discussed. It is shown that the presence of an internal coordinative bond in the catalyst molecule is responsible for its activity in copolymerization.

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780106

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractNew monomers with a high content of halogens,N‐(pentachlorophenyl) maleimide (1) andN‐(2,4,6‐tribromophenyl) maleimide (2) were prepared. The products of their radical polymerization consist of oligomers. Of these, products with the degree of oligomerization, n, ranging from 1–4 and from 1 to 3 were separated on a gel chromatograph for1and2, respectively. Their structures were determined from the mass spectra. The elution volumesVnof the individual oligomers were found to be a linear function of logMn. The radical polymerization mechanism of1and2is discussed on the basis of the character of ol

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780107

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe temperature‐dependent1H 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 of1ewere calculated: ΔG≠= 16,03 kcal/mol (67,1 kJ/mol), ΔH≠= 26,1 kcal/mol (109 kJ/mol), and ΔS≠= 34 cal mol−1K−1(141 J mol−1K−1). The1H NMR spectrum of the corresponding tetraacetate2was found to be ess

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780108

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractIt was found that the reaction of 1,2‐dicyano‐1,2‐ethenedithiolate, resp. of bis(1,2‐dicyano‐1,2‐ethenedithiolato)cuprate(2‐), with Cu2+does not lead to copper bis(1,2‐dicyano‐1,2‐ethenedithiolato)cuprate(2‐) dihydrate (1a) as described in the literature but to a reaction product which has a complex structure containing mainly Cu+. This compound as well as complexes with the same ligand, but with Cu+, Cu2+or Cu3+as the central atom, were synthesized and tested with and without added cuprous chloride as catalysts for the oxidative polymerization of 2,6‐dimethylphenol. Included in this investigation were some copper complexes with the isomeric ligand 2,2‐dic

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780109

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe catalytic activities of various copper(I) clusters in the oxidation of 2,6‐dimethylphenol (XOH) in pyridine and the preparative oxidative polymerization of XOH with these complexes were investigated. It was found that the copper(I) cluster containing 1,2‐dicyano‐1,2‐ethenedithiolate ligands is more effective in the oxidative polymerization of XOH than the complex containing isomeric ligands. The electric conductivities of these Cu(I) complexes ar

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780110

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY