摘要:

AbstractDas Quellungsverhalten von vernetzten Gelen, die auf anionischem Wege hergestellt wurden, wurde untersucht. Der Quellungsgrad der Gele im Gleichgewicht ist stark strukturabhängig und durch die Bedingungen ihrer Herstellung beeinflußt. Die experimentell erhaltenen Werte des Quellungsgrades stehen in guter Übereinstimmung mit den für ideale Gele aus den strukturellen Parametern berechneten Werten. In einigen Fällen allerdings wurden Abweichungen beobachtet, die durch die Gegenwart von freien Kettenenden oder von Kupplungen (Knoten mit Funktionalitätswert 2) oder von beiden zugleich verursacht werden. In diesen Fällen kann kein Idealmodell die Eigenschaften der Gele er

ISSN:0025-116X    

DOI:10.1002/macp.1971.021410111

出版商:Hüthig&Wepf Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractLa co‐réaction des oléfines cycliques avec les oléfines acycliques en présence des systèmes WOCl4/Al(C2H5)2Cl et WOCl4/Sn(C4H9)4conduit à une télomérisation de l'oléfine cyclique; aux extrémités des molécules de télomère sont fixés deux groupements, identiques ou différents, issus de l'oléfine acyclique par une réaction non consécutive.Ont été plus particulièrement étudiés: le cyclopentène et le cyclooctène d'une part, le pentène‐2, le pentène‐1, le butène‐2 et le propylène d'autre part.Le cyclooctadiène‐1.5 et le cyclododécatriène‐1.5.9 réagissent avec le pentène‐2, par réaction non consécutive, en tant que reste CHCH2CH2CH.La répartition des télomères obéit à une loi statistique.On propose un schéma réactionnel en accord avec les faits observés dans la réaction de disproportion des oléfines acycliques, la polymérisation des oléfines cycliques

ISSN:0025-116X    

DOI:10.1002/macp.1971.021410112

出版商:Hüthig&Wepf Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractPolyoxyethylene networks were prepared by reacting the chain ends of fractions having very low molecular weight (1200) with triisocyanate.The elastic and thermoelastic behavior of these networks in the amorphous state was investigated. Non‐gaussian behavior was indicated by the state of the stress‐strain isotherms. The value of the molecular weight between crosslinks calculated using the molecular theory of rubber elasticity was in very good agreement with the theoretical one. A positive contribution of the energy component (at constant volume) of 17% to the total retractive force was found.True thermodynamic melting temperatures, Tm, for the stretched networks were determined using the HOFFMANand WEEKSmethod. Tmwas found to increase with increasing extension ratio considerably more than theoretically expec

ISSN:0025-116X    

DOI:10.1002/macp.1971.021410113

出版商:Hüthig&Wepf Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractSingle crystal growth and chain folding behaviour of two polyalkenamers (polydecenamer and polydodecenamer) have been examined. They form chain folded lamellar single crystals in spite of the macrocyclic nature of the molecules. The fold length could be varied continuously by the crystallization temperature and by annealing. In the former case the fold length depended on the supercooling which amongst others was also determined by thecisdouble bond content in an expected manner. Incorporation ofcisdouble bonds within the lattice is inferred.

ISSN:0025-116X    

DOI:10.1002/macp.1971.021410114

出版商:Hüthig&Wepf Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe synthesis and characterization of new polymers is reported. These polymers were prepared by reaction of 3.6‐bifunctional 2.5‐diketopiperazines with aliphatic and aromatic diisocyanates. UsingD‐3.6‐bis(aminoxymethyl)‐2.5‐diketopiperazine optically active polymers have be

ISSN:0025-116X    

DOI:10.1002/macp.1971.021410115

出版商:Hüthig&Wepf Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractSources of error in the determination of the density of bulk‐crystallized polyethylene in gradient columns have been reconsidered. Preferential absorption of any one column liquid can lead to gross differences between the apparent polymer densities as determined in different columns. It is therefore important to select column liquids which have about the same swelling power for the polymer. Samples of very high specific surface should be avoided, though the threshold for significant errors of this kind is unlikely to be crossed in practice. Finally, water should not be used as a column liquid in connection with polyethylene measurements because water‐rich mixtures may not wet the polymer completely. The principles emerging from this work are likely to be of general applicat

ISSN:0025-116X    

DOI:10.1002/macp.1971.021410116

出版商:Hüthig&Wepf Verlag    

年代:1971

数据来源: WILEY

摘要:

Abstractα‐Keratose, an alkali‐soluble fraction of peracetic acid oxidised wool of low sulphur content has been partially hydrolysed under controlled conditions with acid. The mixture of low molecular weight peptides has been fractionated into two fractions. The cysteic acid rich fraction has been studied in as quantitative a manner as possible. It has been shown to contain 63% of the cysteic acid (Cya) content of α‐keratose bound in peptides. This material has been further fractionated and the structures of a number of cysteic acid peptides present have been deduced. The amounts of each present in α‐keratose have been calculated. The most common two‐residue sequences of cysteic acid identified in α‐keratose are (in descending order) Ser‐Cya, Cya‐Cya, Cya‐Gly, Cya‐Pro, Cya‐Val, Cya‐Glu, Gly‐Cya. The results have been compared with previous findings for the high sulphur fraction (γ‐keratose). Whilst the environment of half cystine in α‐keratose is more varied than in γ‐keratose,

ISSN:0025-116X    

DOI:10.1002/macp.1971.021410117

出版商:Hüthig&Wepf Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractPoly[stannylalkylene(arylene)diamines] of the below form were synthesized from dichlorostannanes and diamines using a modified nonaqueous interfacial system employing 2.5‐hexanedione or acetonitrile and liquid hydrocarbons.Possible reaction phathways are presente

ISSN:0025-116X    

DOI:10.1002/macp.1971.021410118

出版商:Hüthig&Wepf Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractPolyesters of the form below are prepared by the interfacial method. Infrared frequency band assignments are given.

ISSN:0025-116X    

DOI:10.1002/macp.1971.021410119

出版商:Hüthig&Wepf Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractSilicon containing reactants are condensed with diacid salts using the interfacial technique to give low molecular weight products. Infrared frequency band assignments are given. The following reaction variables were studied and reported on: Stirring rate, stirring time, and nature of silane.

ISSN:0025-116X    

DOI:10.1002/macp.1971.021410120

出版商:Hüthig&Wepf Verlag    

年代:1971

数据来源: WILEY