摘要:

AbstractAlkali lignin was successfully converted to chemical derivatives which could be used as synthetic tannins for leather production. The prepared lignin derivatives were: nitrolignin, aminolignin and chlorolignin. their affinity to chromed hide powder and polyamide powder as model substances for collagen was tested by column chromatography.Aminolignin showed a higher percentage adsorption on chromed hide powder than nitrolignin and chlorolignin, indicating strong irreversible bonding.Measurements of the shrinkage temperature (Ts) of the pelts tanned with those compounds showed that the tanning effect of aminolignin on delimed pelts was satisfactory, and almost similar to the tanning effect of vegetable tannins, followed by nitrolignin, whereas chlorolignin showed a slight increase in the Ts values of tanned pelts, i.e. weak tannage properties.

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050920101

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractIn order to get direct information about polymer retention in Enhanced Oil Recovery and a more detailed picture about the influence of polymer retention in the mode of action of polymers as mobility reducing agents, static adsorption measurements have been carried out in a practice‐oriented model system.Valentin‐Busch‐Quarz was found to be a suitable model adsorbent, and polyacrylamides as well as a biologically synthesized polysaccharide were used as adsorbing agents. Adsorption isothermes of these polymers have been determined as a function of ionic strength, temperature of adsorption, and molecular weight. Performance of the adsorption‐ and desorption measurements required a new analytical technique employing a gel permeation chromatograph. The following results were found:Polyacrylamides are adsorbed irreversibly and the saturation amount of adsorption increases with increasing molecular weight, increasing ionic strength, and decreasing temperature. The adsorption of the polysaccharide is reversible to some degree, the amount of saturation again increasing with increasing ionic strength and decreasing temperature. With salt concentration below 15 g · dm−3no polysaccaride is bein

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050920102

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractDas Verhalten von verdünnten Lösungen eines Polycaprolacton‐Polyurethans wird hinsichtlich viskosimetrischer Messungen, Fraktionierung, Molekülgrößenverteilung und Bestimmung einiger thermodynamischer Parameter besch

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050920103

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractSome alkenyl‐ and alkinyl‐2‐cyanoacrylate monomers, possessing adhesive properties were synthesized. The ease of esterification of cyanoacetic acid, the first step of the synthesis, with some alcohols was in the following order:After condensation of the cyanoacetates with formaldehyde to low molecular weight polymers and depolymerization in vacuum, allyl‐2‐cyanoacrylate, propargyl‐2‐cyanoacrylate, 1‐methyl‐2‐propinyl‐2‐cyanoacrylate and 1‐propyl‐2‐propinyl‐2‐cyanoacrylate were obtained, the last two for the first time. It was found that the strength of the adhesive bonds of these monomers depends primarily on the number of C atoms in the ester group of the molecule, i.e.The introduction of double and triple bonds increases the tensile strength properties. The unsaturated cyanoacrylates also have a better heat‐resistance of their bonds: CH2CHCH2>CHCCH2>CHCC(CH3)H>CHCC(C3H7)H>alkyl. This result is explained with the formation of cross‐links in the adhes

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050920104

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractTransformations of N,N′‐disubstituted 1,4‐benzoquinonediimines have been investigated as a means for the elucidation of processes occurring in hydrocarbon polymers stabilized with amine antidegradants and of transformations accompanying the analyses of extracts of aged rubbers. N‐Phenyl‐N′‐isopropyl‐1,4‐benzoquinonediimine (1b) is quickly hydrolyzed on a silicagel surface, giving rise to N‐phenyl‐1,4‐benzoquinoneimine (3). The hydrolysis of N,N′‐diphenyl‐1,4‐benzoquinonediimine (1a) proceeds more slowly under the same conditions, but the released aniline quickly reacts with the initial (1a), giving rise to N,N′‐diphenyl‐1,4‐phenylenediamine(2a), 2‐(phenylamino)‐N,N′‐diphenyl‐1,4‐benzoquinonediimine (4) and azophenine (5). The Reaction is catalyzed by the weakly acid surface of silicagel. Compound (4) is readily disproportionated thermally to 1,2,4‐tris(phenylamino)‐benzene (8) and 2, 10‐dihydro‐10‐phenyl‐2‐(phenylimino)phenazine (9), even in the absence of a catalyst. A mechanism of the formation of compounds arising in the reaction has been suggested. Diimine (1a) possesses a higher oxidation potential than all the products derived from it, so that it is quickly reduced by these products to (2a). The gradual formation of (2a) may explain the retardati

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050920105

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractAromatische und aliphatische Amide der Brenzcatechylphosphorsäure wurden auf ihre Wirksamkeit als Antioxidantien überprüft. Es wurde der Einfluß dieser Verbindungen auf die AIBN‐initiierte Oxidation von Tetralin bei 60°C sowie auf die Oxidation von isotaktischem Polypropylen bei 180°C untersucht. Eine Aktivität der untersuchten Verbindungen als kettenabbrechende Antioxidantien tritt nur bei Phosphorsäureamiden, die sich von primären Aminen ableiten, auf. Gegenüber Derivaten der phosphorigen Säure ist die antioxidative Aktivität wesentlich erniedrigt. Es wird ein Wirkungsmechanismus von Esteramiden der Phosphor‐ bzw. phosphorigen Säure als radikalkettenabbrechende Antioxida

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050920106

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractMechanical energy which is released by vibratory grinding is able to initiate polymerization reactions of some vinylic monomers. On this way it was possible to obtain poly(acrylonitrile) without any initiator or classical catalyst. The paper presents the physico‐chemical properties of the products obtained by vibratory grinding of acrylonitrile. For the characterization of the obtained polymers, IR‐, ESR‐, and Mössbauer‐spectra were used, together with X‐ray diffraction. Based on the chemical composition and spectral analysis a reaction mechanism and the polymer structure wer

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050920107

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractDer linear thermische Ausdehungskoeffizient α von Polyethylen hoher Dichte wurde für Temperaturen von etwa −15 bis +50°C bestimmt. Bei isotropen Proben erhält man für T0= 20°C Werte um 120 · 10−6K−1, die sich je nach Kristallisationsgrad aus den Ausdehnungskoeffizienten αam= 230 · 10−6K−1der amorphen und α;kr= 90 · 10−6K−1der kristallinen Phase ergeben. Proben mit Verstreckungsgraden λ = 8 bis 16 haben in Faserrichtung α = −24 · 10−6K−1, während man für Kristallite in Richtung der c‐Achse αc= −12 · 10−6K−1findet. Ausgehend von einem Zweiphasen‐Modell erhält man für die orientierte amorphe Phase etwa αam= −52 · 10−6K−1. Dies wird auf entropieelastisches Verhalten der gespannten tie‐molecules zurückgeführt. Dagegen ist die Volu

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050920108

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractKinetics of the catalyzed decomposition of hydrogen peroxide in the presence of BF3etherate were investigated, and the basic kinetic parameters used in the discussion of the mechanism of this reaction were determined. The system hydrogen peroxide‐BF3etherate was used in the initiation of the radical polymerization and copolymerization of butadiene. The parameter φ was determined using an analysis of the kinetics of copolymerization of butadiene with acrylonitrile and the Simha‐Branson equation; the dependence of φ on the composition of the copolymerization mixture was interpreted in terms of Arlman's equation. The cross‐termination reaction occuring in the copolymerization of butadiene with acrylonitrile was characterized by comparing theoretical and experimental fu

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050920109

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThis work deals with some features of the reaction of organic acid chlorides with poly(vinyl alcohol). The structure of the modified polymers was determined by means of IR, UV and NMR spectroscopy as well as by chemical analysis. Vinyl alcohol‐vinyl butyrate copolymers were obtained by reaction of poly(vinyl alcohol) with n‐butyryl chloride without any catalyst. The reaction appeared to satisfy a second order kinetics for conversions no higher than 50%. The activation energy found was of 9.9 kcal/mol. The use of pyridine as a catalyst involved a noticeable increase of the reaction rate, but this effect was found to be independent of the acid chloride used. When triethylamine was used as a catalyst, β‐keto ester groups were found to be grafted onto the polymer chain. The steric hindrance of these groups were thought to be sufficiently important for the conversion to reach a limit of about 30%. The observed swelling in water of vinyl alcohol‐vinyl butyrate copolymers made it reasonable to conclude that the hydrophilic character of the copolymers decreased progressively when the ester group content i

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050920110

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY