摘要:

AbstractEthylene/propene copolymerizations were carried out in the presence of the catalyst system Cp2Ti(CH3)2/Al(CH3)3/H2O (Cp = cyclopentadienyl group), and the reactivity ratiosr1,r2were determined through the Fineman and Ross equation and via13C NMR. A nearly alternating copolymer structure was pointed out. The yields as well as the molecular weights of the copolymers strongly decrease with increasing propene mole fraction in the copolymers.

ISSN:0025-116X    

DOI:10.1002/macp.1983.021841101

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe study of the initiation step in the hydrolytic polymerization of 12‐dodecanelactam showed the prominent role of chain‐ends in the monomer consumption and especially that of amino end groups. Different initiators, dodecylamine hydrochloride, 12‐aminododecanoic acid, or lauric acid, where employed and in some experiments water was added. This led to the formation of new end groups and thus to an enhancement of the monomer consumption rate. It could be shown that during this process large changes in the polymer chain length distribution

ISSN:0025-116X    

DOI:10.1002/macp.1983.021841102

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractCopolymerization of potassium Λ‐ and Δ‐bis[N‐(5‐methacryloylamino)salicylidene‐(S)‐norvalinato]‐cobaltate(III) (1and2) with acrylamide andN,N′‐methylenediacrylamide gives crosslinked gels. The behaviour of the amino acid moiety in the gel obtained from the isomer with the Δ(S,S) configuration does not differ from that of the monomeric model compound4.The Λ(S,S) isomer gives gels, in which a part of the complex proves to be attached by both phenyl moieties to one polymeric chain forming a macrocycle. Deuterium exchange in such complexes proceeds with full retention of the configurat

ISSN:0025-116X    

DOI:10.1002/macp.1983.021841103

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractPolyamides containing azo groups were prepared by the phosphorylation method from 4,4′‐diaminoazobenzene and malonic, succinic, glutaric, adipic, azelaic, sebacic, or chlorosuccinic acid. The polymers were characterized by their viscosity and solubility, and by UV‐visible and IR spectroscopy, TG, an

ISSN:0025-116X    

DOI:10.1002/macp.1983.021841104

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe visible light‐induced photolysis of trityl salts with anions such as PF⊖6, FeCl⊖4, BF⊖4or AsF⊖6was investigated in an inert atmosphere. The rates of decoloration of the dichloroethane solutions of the trityl cation (10−5mol · 1−1) in the presence of different anions are compared. The results indicate that the order of photostability is (C6H5)3C⊕PF⊖6.>(C6H5)3C⊕FeCl⊖4≥ (C6H5)3C⊕BF⊖4>(C6H5)3C⊕AsF⊖6≥ (C6H5)3C⊕SbCl⊖6. A comparison of the overall rate of photolysis of (C6H5)3C⊕SbCl⊖6in argon and oxygen suggests that the photo‐induced reactions are both of radical and ionic type. The composition of the react

ISSN:0025-116X    

DOI:10.1002/macp.1983.021841105

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractPoly(p‐phenylene), poly(2,6‐naphthylene), poly(2,7‐naphthylene), poly(1,5‐naphthylene), and poly(1,4‐naphthylene) were prepared by nickel‐catalyzed polycondensation of Grignard reagents from the corresponding dibromides. The polymers were annealed in vacuo. Doping with SbF5markedly increase the conductivity of the polymers. Annealed poly(2,6‐naphthylene) is the most conductive among the four isomers after SbF5doping. The conductivity of doped poly(2,6‐naphthylene) and poly(p‐phenylene) is about 10−1S · cm−1. Annealed poly(p‐phenylene) shows a broad single line ESR signal which changes to a narrow single line upon doping. Superposition of the two signals is observed at the initial stage of doping. Simultaneous conductivity and ESR measurements indicate that the narrow signal is closely

ISSN:0025-116X    

DOI:10.1002/macp.1983.021841106

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractCompounds with the structure R1NNR2decompose either thermally or photochemically to yield nitrogen and the radicals\documentclass{article}\pagestyle{empty}\begin{document}${\rm R}^{1 \atop {^\bullet}}\hbox{and}\ {\rm R}^{2\atop ^\bullet}$\end{document}. These radicals, under appropriate conditions, can either act as polymerization initiators or can be trapped by radical scavengers such as iodine. In the presence of suitable reagents the title compounds behave like diazonium salts and thus, since they are relatively stable, may provide a safe and readily available diazonium ion s

ISSN:0025-116X    

DOI:10.1002/macp.1983.021841107

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractEnd groups in a low molecular weight fraction of a commercial suspension poly(vinylchloride) were analysed by means of1H NMR and IR spectroscopy and by size exclusion chromatography. The following groups were identified and quantified: ethoxycarbonyloxy(1), 1,2‐dichloroethyl (2),trans‐ andcis‐4‐chloro‐2‐butenyl (3and4), 2‐chloroethyl (5), and 2‐chloroethylidene (6). The influence of these groups on the degradation at 180°

ISSN:0025-116X    

DOI:10.1002/macp.1983.021841108

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractStudies of various tetrahydrofuran and tetrahydropyran derivatives as modifiers of Zieglertype propylene polymerization catalysts are reported. Among methyl derivatives, ethers containing two methyl substituents on carbon atoms adjacent to the etheric oxygen provied the best activity‐stereospecificity combinations (e.g. 2,5‐dimethyltetrahydrofuran (1c) and 2,2,4,4‐tetramethyltetrahydrofuran) (4). Significantly better stereospecificity with some loss in activity is realized when bulkier ethers such as isochroman (5) or 2‐(tetrahydrofurfuryloxy)tetrahydropyran (6) are used. On the other hand, combination of one of the preceding ethers with a second modifier (bis(tributyltin) sulfide, tributyl phosphite, or triethyl thiosphosphate) results in catalyst systems characterized by very attractive activity‐stereospecificity combinations. Systems of this type, containing1cor4, exhibit higher activity and about equal or better stereospecificity than the systems modified only with the second modifier; whereas5and6depress somewhat the activity of the latter systems but provide substantially improved stereospecificity. The steric and electronic effects introduced by the ether modifiers in the single and binary modifier systems investigated are

ISSN:0025-116X    

DOI:10.1002/macp.1983.021841109

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

Abstract1‐Methyl‐1‐(3‐vinylphenylazo)ethyl acetate (1a), diphenyl‐(3‐vinylphenylazo)methyl acetate (1b), and α‐phenylazo‐α‐(4‐vinylphenyl)benzyl acetate (2) were prepared and copolymerized with styrene using AIBN as initiator at 50°C. The azo functions of the monomers remain unaltered during the polymerization process at this temperature. The resulting copolymers3a, 3b, and4were used as initiators for the polymerization of methacrylonitrile (MAN). The grafted copolymers of styrene andMANwere separated from polystyrene and poly(methacrylonitrile). The different rates of polymerization ofMAN, initiated by the azo group containing polymer3bor4or by diphenylphenylazomethyl acetate, a low molecular model initiator, and the different molar masses obtained allow a discussion of

ISSN:0025-116X    

DOI:10.1002/macp.1983.021841110

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY