摘要:

AbstractPolypropylene (PP) prepared with a MgCl2/TiCl4‐Et3Al/Ph2Si(OMe)2catalyst system was fractionated by temperature rising elution fractionation method in order to investigate the effect of Ph2Si(OMe)2as an external donor (ED). This PP had a broad and continuous distribution of tacticity. In comparison to the system without donor, however, ED brought a decrease of lower isotactic portions and an increase of higher isotactic ones simultaneously to the resulting polymer. The latter portions were eluted at higher temperature than the corresponding component obtained without donor, showing that the higher isotactic PP was newly produced by E

ISSN:1022-1360    

DOI:10.1002/masy.19940840103

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe polymerization of acetylene and its derivatives by rare earth coordination catalysts and the characterization of the polymers so obtained in our laboratory are reviewed.Because of the metallic conductivity possessed by doped polyacetylene and the unique properties such as conductivity (semiconductivity), paramagnetism, migration and transfer of energy and chemical reactivity and complex formation ability often shown by acetylenic polymers, which seem promising as specialty polymers, there has been considerable interest in the polymers of acetylene and its derivatives. A wide variety of catalyst systems have been developed for the polymerization of acetylenes. But there has been no information concerning the use of rare earth compounds as catalysts in the polymerization of acetylene and its derivatives. We for the first time in 1981 have succeeded in the polymerization of acetylene with rare earth coordination catalysts, which in turn is a development based upon earlier work on the diene polymerization using rare earth coordination catalysts(Ref. 1). Using rare earth catalysts, acetylene can be polymerized conveniently into high cis polyacetylene films with metallic sheen at room temperature and phenylacetylene can also be polymerized into high molecular weight, high cis polyphenylacetylene films at ambient temperature. Thus new varieties of polyacetylenes have been developed and a novel family of coordination catalysts consisting of a rare earth compound plus trialkyl aluminum for the polymerization of acetylenes has been exploited. This article reviews our studies on the polymerization of acetylene and its derivatives with rare earth coordination catalysts and on the characterization of the polyacetylenes prepared.

ISSN:1022-1360    

DOI:10.1002/masy.19940840104

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe spontaneous thermal reactions of electron‐rich dienes with electrophilic olefins lead to both [4+2] cycloadducts and copolymers. The mechanism proposed for the initiation of the copolymerization involves the formation of a 2‐hexene‐1,6‐diradical. Structure‐reactivity relationships are

ISSN:1022-1360    

DOI:10.1002/masy.19940840105

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe results on radical polymerization and copolymerization of alkyl bromide salts of 2‐dimethylaminoethyl methacrylate having a different alkyl chain length in various solvents giving micellar and isotropic solutions are summarized to obtain an insight into micellar polymerization. The monomer micellization of the cationic surface‐active monomers at concentrations far above their critical micelle concentration (cmc) leads to great increases in the rate of polymerization and the molecular weight of the resulting polymers for both aqueous and inverse micellar systems and the tendency toward alternation of the copolymerization for aqueous micellar systems, whereas it has little influence on the tacticity of the resulting polymers. Applications of the polimerization and the copolymerization of the surface‐active monomer to the polymer encapsulation of silica particles are also rep

ISSN:1022-1360    

DOI:10.1002/masy.19940840106

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe anthracene–9, 10–bisketene compound 9, 10‐dicarbonyl‐9, 10–dihydroanthracene (1) was found to react spontaneously with a variety of benzoquinones and benzoquinone diimines to give aromatic polyesters and polyamides, respectively. These addition reactions are regarded as a novel preparative route to polyarylate and po

ISSN:1022-1360    

DOI:10.1002/masy.19940840107

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractTelechelic acrylic oligomers possessing terminal carboxylic acid, ketone, aldehyde or hydroxy groups can be synthesised in good yields by the ozonolysis of free radical copolymers of the appropriate acrylic monomer with a small amount of a 1,3‐diene, such as butadiene, 2,3‐dimethyl‐butadiene or 2,3‐diphenyl‐butadiene. The oligomers so‐prepared have high end‐functionalities (>98%), controllable average molecular weights, relatively narrow molecular weight distributions, and can be chain extended by a variety of means to give back high molecular weight polymers. Oligomers with perfect α‐phenyl ketone‐ω‐carboxylic acid functionality can be prepared by ozonolysing copolymers containing low concentrations of units derived from phenyl acetylene. Photolysis of copolymers of an alkyl vinyl ketone with monomers such as styrene yield, directly, oligomers with polymerisable unsaturated end‐gro

ISSN:1022-1360    

DOI:10.1002/masy.19940840108

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractPolyisopeptides are non‐peptidic polymers formed by α,ω‐polycondensation of tri‐ or multi‐functional α‐amino acids. They are expected to possess physical and mechanical properties of synthetic polyamides (or polyesters) and to be biodegradable. In the present paper, the methods of polyisopeptide synthesis are reviewed. Many of them are specific to a given α‐amino acid (and sometimes its derivatives, too). We discuss here about two methods giving satisfactory results. One is the polymerization of L‐aspartic β‐lactam α‐esters, in which the structure of a resulting polymer varies according to the solvent used. A new interpretation on the basis of the nature of catalyst anion species (free ion, ion pair) is presented. The other subject is the active ester polycondensation method applied to the amino‐ and carboxyl‐ protected L‐cystine polyisopeptide and its selective deprotection successively until total deprotection to free amino‐ and free carboxylic groups. The final polymer is the first poly‐L‐cyst

ISSN:1022-1360    

DOI:10.1002/masy.19940840109

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractMetal butyl methacrylate colloids were obtained by codeposition at 77K of the monomer with several metals such as Au, Pd, Cu, Ag, Zn, Cd, Ga, In, Ge, Sn, Sb and Bi. Au and Pd colloids are stable tor months at room temperature. The colloids were polymerized with different amounts of initiator benzoyl peroxide at 65°C for 25 min and a wide range of viscosity‐average molecular weights (103

ISSN:1022-1360    

DOI:10.1002/masy.19940840110

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper describes our recent work dealing with novel polymerization methods of allene and propargyl derivatives. By the radical, cationic, and living coordination polymerizations, polymers bearing exomethylene moieties in the side chain could be obtained. The polymers obtained could undergo the cationic crosslinking reaction. As step‐growth polymerizations, spontaneous copolymerizations, polyadditions with dithiols, and coupling polymerizations using palladium catalyst are also describe

ISSN:1022-1360    

DOI:10.1002/masy.19940840111

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractTriple‐layer‐type organic electroluminescent devices were fabricated using charge‐transporting poly(N‐vinylcarbazole) (PVK) as a hole‐transporting emitter layer. Electron‐transporting layers consisting of a triazole derivative (TAZ) and an aluminum complex (Alq) layer were used to maximize the carrier recombination efficiency. The EL device with a structure of glass substrate/indium‐tinoxide/PVK/TAZ/AIq/Mg:Ag showed bright blue emission from the PVK layer with a luminance of over 700 cd/m2. The emission color was tuned to a desirable color in the visible region through doping the PVK layer with fluorescent dyes. Bright white emission, in particular, was obtained for the first time at a high luminance level of over 3000 cd/m2by using three kinds of fluorescent dyes each emitting red,

ISSN:1022-1360    

DOI:10.1002/masy.19940840112

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY