摘要:

AbstractAB block copolymers with an amorphous polybutadiene block and a polypeptide block were prepared. The method of synthesis consists in the preparation of a polybutadiene block by anionic polymerization followed by a chemical modification of its living end introducing a primary amine group which is able to intiate the polymerization of theN‐carboxy anhydride (NCA) of the chosen amino acid. By this way the block copolymers polybutadiene/poly(γ‐benzyl L‐glutamate) (14a) were prepared, in which the poly(γ‐benzyl‐L‐glutamate) block could be transformed into a poly(N5‐hydroxypropyl‐L‐glutamine) block by reaction with 3‐amino‐1‐propanol leading to the block copolymers polybutadiene/poly(N5‐hydroxypropylglutamine) (14b). By using X‐ray diffraction and electron microscopy it could be shown that the block copolymers14aand14bexhibit mesophases in different solvents and it was established that the structure of the mesophases is lamellar. Each sheet of the lamellar structure consists of the superposition of two layers: one formed by the polybutadiene chains in a more or less random coil conformation; the other formed by the polypeptide chains in an α‐helix conformation, arranged

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770901

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractGastro‐intestinal absorption in rats of poly[biguanide‐1,5‐diylhexamethylene hydrochloride] (1) amounts to only 5,6% of a single oral dose, and after chronic administration, tissue concentrations do not exceed 0,3 μg g−1. It has been shown by simple chromatographic and spectroscopic methods that urinary polymer‐related material consists of small amounts of1‐oligomers, with two cyanoguanidino end groups, as well as the trace constituents, 3,3′‐dicyano‐1,1′‐hexamethylenediguanidine (8a) and a compound which is considered to be 1‐(6‐aminohexyl)‐3‐cyanoguanidine (2) that is formed during the synthesis of1. Hence, the constituent

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770902

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe syntheses and characterizations of a series of new phosphinic acids and the zinc polymers and copolymers prepared from them are reported. These compositions are characterized by the presence of phenyl sulfone side groups. The zinc derivatives were found to be among the thermally most stable tractable poly(metal phosphinates) yet studied.

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770903

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractIn the asymmetric addition of dodecanethiol (1) to isopropenyl methyl ketone (3) catalyzed by the terminal amino group of poly(5‐benzylL‐glutamate) (PBLG) (7b) and poly(4‐benzylL‐aspartate) (PBLA) (7a), the effect of addition of ethanol was studied. In the reaction catalyzed by PBLG, the magnitude of the optical rotation of the addition product increased without changing the sign with the addition of ethanol. In the reaction catalyzed by PBLA, on the other hand, the sign of the optical rotation of the product was inverted with the addition of ethanol. The effect of ethanol was discussed in relation to the mechanism of the reaction as well as the conformation of the polymeric c

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770904

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractComplexes of acrylonitrile and of methyl methacrylate with various Lewis acids,1and2, were studied by means of IR, NMR, and UV spectroscopy. The influence of the Lewis acid strength on the induction effect and on the delocalization of π‐electrons in the complexed monomer molecule was established. As the relative acidity of the complexing agent is increased, the inductive effect of the nitrile or of the carbonyl group in the complex molecule rises, whereby the electron density on the carbon atom in β‐position in the vinyl group diminishes. Complexation of the monomer also results in increased delocalization of π‐electrons in the molecule. In the complexes with moderately strong Lewis acids like CH3AlCl2and C2H5AlCl2, delocalization of π‐electrons seems to reach its maximum. The methyl methacrylate‐C2H5AlCl2complex was found to give a charge‐transfer complex with 1,5‐cyclooctadiene. On the basis of the present spectroscopic studies and of earlier studies on copolymerization of acryl monomers with butadiene, the delocalization of π‐electrons in the complexed monomer molecule is believed to be one of the major factors controlling the rate

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770905

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe reaction of TiCl4with tungsten carbonyl carbene derivatives such as (CO)5W‐[C(OEt)R] affords catalysts which display a very high activity for the “methathetic” polymerization of cyclopentene. Thus, the equilibrium concentration of cyclopentene can be reached with a cyclopentene: W mole ratio of 106:1. The formation of the active species is thermally or photochemically assisted. A large excess of TiCl4is needed during the polymerization pr

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770906

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe photopolymerization of styrene (St) by bis(trimethylsilyl)mercury (1) was studied. Kinetic studies indicated that the rate of polymerization can be expressed by the following equation:\documentclass{article}\pagestyle{empty}\begin{document}$$ R_{\rm p} = k[1]^{1/2} [{\rm St}] $$\end{document}IR and NMR spectra of the polymer indicated that trimethylsilyl groups were incorporated. By reaction of1with an equimolar amount of St in benzene under UV irradiation a radical coupling product, 2,2,7,7‐tetramethyl‐4,5‐diphenyl‐2,7‐disilaoctane (2) was formed in 22% yield. By spin trapping technique using 2,4,6‐tri‐tert‐butylnitrosobenzene (3) as a trapping agent,N‐trimethylsiloxy‐2,4,6‐tri‐tert‐butylanilino radicals were obtained.On the basis of these results, it was concluded that the polymerization was initiated by trimethylsilyl radicals formed

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770907

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractStyrol/Divinylbenzol‐Copolymere mit funktionellen Gruppen CH2X [XH, Cl, J, OCOCH3, OH, OC2H5, NH2, NHC2H5, N(C2H5)2, CN, C(NOH)NH2, NCS, COC2H5, (CH2)3CH3] in para‐Stellung wurden qualitativ analysiert durch die Kombination von Infrarotdaten mit den Ergebnissen von Curiepyrolyse‐Gaschromatographie‐Massenspektroskopie. In allen Beispielen war eine Strukturbestimmung durch direkte oder indirekte Aussagen mindestens einer der beiden Methoden möglich. Einige Strukturbeweise wurden durch eine “Thermolyse” bei 400

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770908

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractPoly[sulfadiazineacrylamide] (5), labeled with14C in the main chain, was synthesized and its molecular weight viscosimetrically determined by comparison with unlabeled samples of poly[sulfadiazineacrylamide] with similar molecular weights which were determined by membrane osmometry.The material showed a polymer‐specific prolongation of its systemic behaviour in mice. Rates of excretion of the polymer were negligibly low, whereas the toxicity was considerable. It was concentrated in the liver during the course of the experiment, but no affinity toward the PC6 plasmacytoma in mice could be detecte

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770909

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe thermal degradation of poly(oxycarbonylpentamethylene), (poly‐ε‐caprolactone), (3), was investigated at 220°C and 80 mm Hg under nitrogen.3was found to be thermally much more stable than poly(oxycarbonylethylene), (poly‐β‐propiolactone), (1), although it decomposed faster than poly(oxycarbonyl‐1,1‐dimethylethylene), (polypivalolactone), (2). The reaction was of the first order with a rate constant ofk=6,2.10−4min−1and proceeded via a “zipper mechanism” to yield mo

ISSN:0025-116X    

DOI:10.1002/macp.1976.021770910

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY