摘要:

AbstractSandy, silty, loamy, clayey, and sandy‐loamy soils were impregnated with three types of binding materials, namely, urea formaldehyde, phenol formaldehyde, and sodium silicate. Ammonium chloride, hexamethylene tetramine, and sodium fluorosilicate were used as catalysts for the previously mentioned substances, respectively. Some physico‐mechanical tests were carried out with the stabilized soils and different parameters affecting the strength, absorption and durability of stabilized soils were stud

ISSN:0003-3146    

DOI:10.1002/apmc.1981.050970101

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractExpoxy bisphenol‐A resins (A), epoxy novolac resins (B) and epoxy furfuryl alcohol resins (C) were prepared using different molar ratios of epichlorohydrin and the respective hydroxy compounds. These resins were cured with different hardeners, namely diethylenetriamine (DTA), dithioterephthalic acid (DTTPA), mercapto succinic acid (MSA), and phthalic anhydride (PA). The thermal behaviour of the cured epoxy resins was studied. From the energy of activation data and IPDT values it was concluded that DTTPA gave the highest thermal stability of all these curing agents. Dielectric constant measurements of the cured resins were also made at 30°C and at frequencies 1 kHz and 10 k

ISSN:0003-3146    

DOI:10.1002/apmc.1981.050970102

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractDurch die Reaktion von 3‐Amino‐4‐hydroxyphenylbenzoat mit vernetztem Poly(styrolsulfonsäurechlorid) wurde nach Verseifung und Oxidation ein chinongruppenhaltiger reaktiver Träger erhalten, dessen Eignung für Enzymimmobilisierungsreaktionen mit α‐Chymotrypsin getestet wurde. Mit dem Einführen von Ethylendiaminbzw. Hexamethylendiamin als Spacer zwischen dem Polystyrol‐Gerüst und der Chinonkomponente konnte das Enzymbindungsvermögen des Trägers und die Aktivität des immobilisierten α‐Chymotrypsins erhöht werden. Ausgehend von vernetztem Polyvinylalkohol wurde durch Umsetzung mit p‐Benzochinon ein reaktiver Träger hergestellt, an dem α‐Chymotrypsin immobilisiert werden konnte. Die Aktivität, das pH‐Optimum der Aktivität sowie die Lagerstabilität der unlöslichen α‐Ch

ISSN:0003-3146    

DOI:10.1002/apmc.1981.050970103

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractIn der vorliegenden Arbeit werden die Untersuchungsergebnisse über die Polymerisation des Propylenoxids in Anwesenheit von festem gepulvertem Kaliumhydroxid mit ca. 15% kristallin gebundenem Wasser dargestellt. Die Konzentration des Katalysators wurde von 0,5 bis 10 Gew.‐% und die Reaktionstemperatur von 313 bis 373 K variiert.Es konnte festgestellt werden, daß bei entsprechender Wahl der obengenannten Parameter bei praktisch hundertprozentiger Umwandlung des Propylenoxides seine Oligomeren mit einem M̄n‐Wert im Bereich von etwa 1 600 bis 4200 g/mol und mit einer Ungesättigtheit von etwa 0,5 bis 0,8 Äquivalenten C = C‐Bindungen pro mol Polypropylenoxid erhalten werden können. Das teilweise hydratisierte KOH ist ein weniger aktiver Katalysator für die Polymerisation als das wasserfreie Hydroxid, wobei der Anstieg seiner Konzentration eine Herabestzung des M̄n‐Wertes des Polypropylenoxids hervorruft, was bei wasserfreiem KOH nicht beobachtet wurde. Es wird versuchht, die gefundenen Abhängigke

ISSN:0003-3146    

DOI:10.1002/apmc.1981.050970104

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractPoly(vinyl chloride)‐dioctyl phthalate‐ethylene vinylacetate copolymer compounds of different composition were studied by combination of various computer controlled mechanical and dielectric relaxation techniques. By the high resolution (low effective frequency) quasi‐static methods multiple transitions in the glass‐rubber transition range were found which were shifted by increasing additive concentration according to the additivity rule of free volume. Transition temperatures detected by mechanical and dielectric techniques were found to coincide satisfactorily taking into account shifts due to differences of effective frequencies as well a

ISSN:0003-3146    

DOI:10.1002/apmc.1981.050970105

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractCoordination polymers of copper, nickel, cobalt, manganese, and zinc with poly(Schiff base) derived from 5,5'‐methylene‐bis‐salicylaldehyde and 4,4'‐diaminodiphenyl methane have been prepared. Elemental analysis, magnetic, spectral, and thermal properties, and electrical conductivities of the chelates have been studied and probable structures assigned to the chelates.The analytical data propose a [ML]nformula for the chelates. The site of coordination of the ligand with metal ions has been elucidated by comparing the IR spectra of the ligand and polychelates. All the polychelates are stable and insoluble in common s

ISSN:0003-3146    

DOI:10.1002/apmc.1981.050970106

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractA novel polyarylate has been synthesized from carbazole and resorcinol by low temperature solution condensation method using as an acceptor‐catalytic reagent pyridine. It has been characterized in respect of its structure, thermal stability and dielectric behaviour. The influence of the diphenol moiety on the thermal and the dielectric properties of this polyarylate and the others based on carbazole has been studie

ISSN:0003-3146    

DOI:10.1002/apmc.1981.050970107

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractAmbiguities arising in the identification of the observed dielectric loss peak with the glass transition process are described, in the light of frequency dependence of the loss‐peak‐temperature. The usefulness of the WLF equation in solving these ambiguities is explored and illustrated with the help of data on four polymers. A simplified method is described, for evaluating the parameters, reference temperature of the WLF equation and thereby the glass transition temperature from the data at two frequenc

ISSN:0003-3146    

DOI:10.1002/apmc.1981.050970108

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractGrafted samples of low‐density polyethylene were prepared by sensitizing the polyethylene with different concentrations of photosensitizer (benzophenone) and irradiation with different doses of UV‐light. These samples which differ in degree of crosslinking and in amount of active sites were grafted with methacrylic acid after different time of staying in the air after irradiation.The effect of dose of irradiation, concentration of photosensitizer and time of staying in the air after irradiation on the degree of crosslinking and graft level has been studied.Electrical resistance, pore size and tensile strength of the grafted polymers were determi

ISSN:0003-3146    

DOI:10.1002/apmc.1981.050970109

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractAn attempt has been made to prepare thermally stable resins from the condensation of anisole and 1,2‐dichloroethane. The anisole resin samples were subjected to the thermal study involving TG and DTA techniques. The kinetic parameters and the stability of the resins have been investigate

ISSN:0003-3146    

DOI:10.1002/apmc.1981.050970110

出版商:Hüthig&Wepf Verlag    

年代:1981

数据来源: WILEY