摘要:

AbstractDuring the thermal polymerization of styrene small quantities of dimeric and trimeric styrenes are formed which affect essential properties of the polymer. The kinetics of the oligomer formation are investigated under industrially important reaction conditions and the concentrations of the intermediates formed during the initiation reaction are determined by UV‐spectroscopy. The results show that no gel effect occurs in the reactions investigated. Using the kinetic fomulae and reaction rate constants obtained it is possible to describe the formation of oligomers and intermediates at temperatures of 137°C and 180°C up to 97% monomer convers

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051110101

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractAromatic polyamides with imide pendent groups were prepared from 4,4′‐diaminodiphenylether and imide‐diacid chlorides by solution polycondensation. Imidediacid chlorides used included the diacid chlorides of 5‐maleimidoisophthalic, 5‐dichloromaleimidoisophthalic, 5‐tetrahydrophthalimidoisophthalic, 5‐chlorendimidoisophthalic, 5‐nadimidoisophthalic, 5‐methylnadimidoisophthalic and 5‐phthalimidoisophthalic acid. The pure aromatic polyamide from 4,4′‐diaminodiphenylether and isophthaloyl chloride was also prepared for comparative reasons.Polyamide‐imides are soluble in polar organic solvents and show good thermal resistance. They are film‐forming and the films have good mechanical properties. Those polyamide‐imides which contain unsaturated carbon‐carbon bonds may be crosslinked by heating to 220°C, giving rise to insoluble materials wit

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051110102

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractNous avons préparé des réseaux polyuréthannes à partir de polyéthers ou de polybutadiénes α‐ω diols, de diphényl méthane diisocyanate et en présence d'un catalyseur basique (triethyl mine au dibutyle dilaurate d'étain). Il se forme des cycles isocyanurates que nous avons mis en évidence par IR. Ces cycles sont très stables á haute température. Nous avons des polymères qui présentent un plateau caoutchoutique dont le module E′ est constant entre Tget 160°C. La valeur de ce module dépend de la formulation, de la nature du prépolymère, de sa masse molaire, des proportions de diisocyanate et de catalyseur. Il est également possible d'introduire du butanediol dans la formulation ce qui permet d'augmenter la valeur du modul

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051110103

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractCalcium carbonate modified with 1,2‐polybutadiene using aluminum chloride as the catalyst is described. The polybutadiene‐modified surface is shown to be sufficiently hydrophobic by a wettability test and by the measurement of adsorptive capacity for benzene. The polybutadiene modification is capable of performing a desired protective function from water penetration and of reacting with the polymer matrix on curing. The availability as a reinforcing filler for SBR is sh

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051110104

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effect of molecular weight in a narrow range on some rheological properties of acrylic solutions during Newtonian flow at different temperatures and concentrations was investigated. The results showed that the change in viscosity with temperature and concentration was dependent on the molecular weight. It was found that the molecular weight in a closer range influenced the activation entropy and the free energy of activation during Newtonian flow.

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051110105

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractScoured ply cotton yarn (substrate I) was slack mercerized (substrate II) and slack mercerized followed by stretching to 94% (substrate III) and 103% of original length (substrate IV). These substrates were given an acid pretreatment (0.5 N HCl, 60°C, 15 min). The four substrates and their corresponding HCl‐treated substrates (substrates I‐H, II‐H, III‐H and IV‐H) were reacted under similar conditions with N,N‐diethylaziridinium chloride to yield diethylaminoethyl (DEAE)‐cottons. In addition, DEAE‐cottons of substrates I, I‐H, II and II‐H were hydrolyzed with 0.5 N HCl at 80°C for 0.5, 1, 2, 3, 5 and 7 h and the ratio of substituents in the D‐glucopyranosyl units of these DEAE‐cottons as well as in those of DEAE‐hydrocelluloses were determined. It was found that there is a considerable difference between the reactivity of scoured cotton and slack mercerized‐restretched cottons. This was interpreted in terms of differences in the microstructure between the substrates in question, which in turn, are reflected on availability, accessibility and state of order of the cellulose hydroxyls in the scoured and mercerized cottons. Nitrogen‐, chemical, microscopical and X‐ray analyses were used to assess the structural

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051110106

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractSwelling and sorption equilibria for Nafion membranes in concentrated solutions of sodium chloride and sodium hydroxide have been studied at 293–363 K. It has been stated that at increased temperature deswelling changes the state of the membranes. The Donnan equation modified for the description of the sorption equilibria in nonuniform gel has been applied for the interpretation of the experimental data. The calculated structural parameter β shows that at deswelling the nonuniformity of the membranes diminishes, i. e. water is removed mainly from the volume elements of low concentration of fixed charges. Further confirmation of the applicability of the equation S̄ = k1(N̄0—N̄m)bto the description of the relation between sorption (S̄) and hydration of the membranes (N̄0,N̄m) has been

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051110107

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractIn this paper a new type of porous polymeric sorbents of 4,4′‐di(methacryloyloxymethyl)diphenyl ether (DME) and styrene as a GPC column packing material has been investigated. The tested DME‐styrene copolymers had molecular sieve properties and separation and elution was in accordance with the exclusion mechanism. The applied preparative procedure gives packings which do not vary considerably in their por

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051110108

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe proportion of various collagen types in calf skin, placenta and aorta are compared. It has been found that calf skin provides a good source for type I collagen; while placenta and aorta are the best sources for type III collagen. Type IV and V collagens are found mainly in placenta and aorta. Appreciable amounts of the new cysteinerich high molecular weight collagen was found mainly in placenta. The various collagen types were characeterized by SDS‐Gel electrophoresis, amino acid analysis, cyanogen bromide peptides and electron microscopy. Localization of type IV and V collagens in placental membranes were achieved by immunological methods. Further, the functional significance of various collagen types together with the diseases of the collagen molecule are discusse

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051110109

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractIn der Tribologie werden Makromoleküle als Viskositäts‐Index‐Verbesserer dem Basisöl zugesetzt. Dadurch kann eine Anhebung und Verflachung der Viskositäts‐Temperatur‐Kurve des Schmieröls erreicht werden.Zwei Ursachen sind im wesentlichen für diesen Effekt zu nennen:1Übergang auf eine relativ niedrigviskose Basisflüssigkeit mit kleinem Absolutwert des Temperaturkoeffizienten TK der Viskosität und damit geringere Aktivierungsenergie des viskosen Fließens Aη.Anhebung der Viskosität in den Arbeitsbereich durch Zugabe von Polymeren.2Expansion der gelösten Polymermoleküle mit steigender Temperatur (Knäuel‐Kontraktion ist ebenfalls möglich).Untersuchungen haben ergeben, daß beim System Poly‐n‐butylmethacrylat (PBMA)/Isopropanol (schlechtes Lösungsmittel) Aηmit steigender Konzentration des PBMA abnimmt. Die Grenzviskositätszahl [η] als Maß für die Knäuelaufweitung verläuft mit der Temperatur über ein Maximum.Dagegen steigt Aηbei PBMA in Chloroform (gutes Lösungsmittel) leicht an. [η] erreicht im angegebenen Temperaturb

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051110110

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY