摘要:

AbstractThe primary structure of theEscherichia coliserotype K‐27 capsular polysaccharide has been investigated. The capsular polysaccharide was isolated fromEscherichia colistrain E56b, serotype 08:K27(A):H‐. Using methylation analysis, characterization of oligosaccharides obtained by partial acid hydrolysis and enzymic degradation, as well as1H nuclear magnetic resonance, the primary structure of the K‐27 glycan has been elucidated. The polymer was found to consist of tetrasaccharide repeating units of the following stru

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831201

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractA copolymer (PC‐1) was synthesized from a mixture of 1,2‐and 1,3‐isomers of tricarbonyl‐(methylvinylcyclopentadienyl)manganese (1) and styrene (St) crosslinked with 1,4‐divinylbenzene, and a membrane (PM–1) consisting of the1/St copolymer. A polymer‐supported dinitrogen complex (PC‐4) was prepared from the tetrahydrofuran (THF) complex ofPC‐1and molecular nitrogen in a solid‐gas phase reaction under moderate conditions. The dinitrogen complex membrane (PM–4) was readily obtained directly fromPM‐1by a “one‐step reaction” on UV light irradiation under normal pressure of nitrogen at room temperature. A prominent feature of polymer‐supported dinitrogen complexes,PC‐4andPM‐4, is their high stability as compared with the corresponding low molecular weight analogues. The coordinated nitrogen can be substituted by carbon monoxide in aPC‐4/THF mixture. The mechanism of nitrogen co‐ordination toPC‐1andPM‐1was investigated by

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831202

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractIn the reaction of methyl methacrylate (2) with methyl 2‐sodioisobutrate (1) (a model of the active center in the anionic polymerization of2) in a mole ratio of 2:1, the concentrations of all known initial compounds and reaction products were estimated. This reaction was studied in a flow reactor with reaction times between 0,02 and 1,4 s using GLC, LC and GPC as analytical methods. At the same time, a rise in temperature of the reaction mixture by 6°C was observed (for [2] = 0,2 mol/1); at a higher concentration of2(0,6 mol/1), this rise was 27°C and hence not negligible in the interpretation of the results. The concentration changes of the individual products were in accordance with the concept of a stepwise addition of2, to the metalloesters. At the end of the reaction the mean molecular weight of the addition products corresponded roughly to the ratio2/effective1. The cyclization of Na‐trimer4ato a cyclic trimer9was shown to be an important side reaction. The Na‐tetramer5aand the higher Na‐oligomers6aprobably undergo a similar cyclization.2added1very quickly; the following approximate order of reaction rates (Scheme 1) is proposed:R1>R2,R3

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831203

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractMetalation of polyisoprene by the complexsec‐butyllithium‐N,N,N′,N′‐tetramethylethylenediamine (secBuLi‐TMEDA) is strongly affected by the conditions of reaction. In certain cases, a first order rate constant with respect to each reagent is observed. The mole ratio secBuLi/TMEDA has a preponderant effect on the rate of metalation. A maximum yield is observed when the mole ratio secBuLi/TMEDA is 1/0,5. Addition of a cocomplexing reagent, potassiumtert‐butoxide (tertBuOK), to the complex secBuLi‐TMEDA yields a higher rate of metalation. A good yield can be obtained when polysioprene is treated with the metalating complex secBuLi‐TMEDA‐tertBuOK in a mo

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831204

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractCarbon fibers containing thiol groups were produced by reacting carbon fiber oxidized by nitric acid, with excess thiirane. Then, graft polymerization with styrene was carried out in a sealed tube under nitrogen. The following order of initiating ability of the investigated initiators was found: di‐tert‐butyl peroxide>p‐cumenyl hydroperoxide (CHPO)>dodecyl peroxide>benzoyl peroxide>2,2′‐azoisobutyronitrile. When CHPO was used as initiator, the rate of graft polymerization was maximum at [CHPO] = 0,01 mol/1. Chain transfer constant and grafting efficiency, both calculated from the equations of Fox and others, were compared with the experimenta

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831205

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractLinear poly(iminoethylene) was synthetised by cationic polymerization of 2‐methyl‐2‐oxazoline using BF3O(C2H5)2, SnCl4, and CH3COBF4as initiators and in the presence or absence of CH3CN. The resulting product, poly(N‐acetyliminoethylene), was then hydrolysed in basic medium. The resulting poly(iminoethylene) was identified and characterized by1H NMR,13C NMR, X‐ray diffraction, and differential scanning calorimetry (DSC). The synthetised polymer will be used as a polymeric support in ionic‐exchange resins as well as in macromolecul

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831206

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractA series of A‐B‐A triblock copolymers consisting of poly(2‐acrylamido‐2‐methylpropanesulfonic acid) as outer blocks and polystyrene as the middle block was synthesized by polymerizing 2‐acrylamido‐2‐methylpropanesulfonic acid at the ends of a diethyldithiocarbamate‐terminated polystyrene, in which the terminal diethyldithiocarbamate groups act as the radical initiator under photo‐irradiation. The heterogeneous character of the block copolymers in solutions is discussed on the basis of the solubility behavior an

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831207

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractA new polyesterimide containg CC‐double bonds was prepared by reacting an unsaturated diacid chloride containing a cyclic imido group with ethylene glycol at low temperature. The solubility, thermal, electrical and cross‐linking properties of the polymer were studied. The polymer was found to be thermostable and soluble in highly polar solvents. X‐ray diffraction data revealed that the polymer is crystalline. The unsaturation sites of the polymer chain could be exploited for crosslinking reactions. The swelling behavior of the crosslinked polymer was studied as well as the thermal and electrical properties. The overall thermal stability of the crosslinked polymer was found to be higher than that of the uncrosslinked po

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831208

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractIt was found that three polyconjugated polymers with anthrancene repeating units slow down the thermal and thermooxidative degradation of polystyrene. This effect is explained by charge transfer complex formation between the radicals formed during the degradation of polystyrene and the polyconjugated polymers as donors.

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831209

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractHydrophobic‐hydrophilic poly(2‐vinlypyridine)/poly(ethylene oxide) block copolymers were synthesized by anionic polymerization in tetrahydrofuran in vacuum with diphenylmethylpotassium as initiator. The resulting polymers were fractionated from benzene solution by progressive precipitation with 2,2,4‐trimethylpentane at 35°C. Gel permeation chromatography, light scattering, osmometry, and1H NMR were used to characterize the fractions. The copolymers, thus prepared, were found to have a well defined structure and a low polydispersity in both molecular weight and chemical compo

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831210

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY