摘要:

AbstractControlled cyclization of cis‐1,4‐polybutadiene‐rubber (BR) was achieved with the aid of cationic catalyst systems based on alkyl aluminium chloride and organic halide and by working in xylene solution at high temperature (T>100°C). Different catalysts based on some Lewis acids and the main parameters of the cyclization process were investigated. Interesting gel‐free elastomers were obtained when 35–40% of the initial unsaturations disappeared.Physical and technological properties of cyclized BR revealed that a new class of elastomers was obtained displaying skid resistance and tensile properties better than those of the parent polymer. The results were accounted for in terms of polycyclic sequences randomly formed in BR chains during the cyclizati

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050880101

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractInformation on the structure of cyclized cis‐1,4‐polybutadiene (CBR) was obtained by means of extensive physico‐chemical investigations.Fractionation of typical samples of CBR showed a constant distribution of unsaturations in all fractions. No presence of co‐catalyst (aromatic) moiety and conjugated double bonds was found in CBR having a degree of cyclization lower than 40%. Combined IR and13C‐NMR analysis allowed to calculate the average length of the polycyclic sequences postulated by the cyclization process.The average length was found to range between three and four cyclohexane rings for a cyclization extent ranging from 15 to 60%.Direct evidence of polycyclic sequences having up to three rings was collected by vapour‐phase‐chromatograph‐mass‐spectroscopy (VPC‐MS) analysis of the products coming from the pyrolysis of CBR: fragments having higher molecular weight were not detected by our work.Ozonolysis experiments, performed under both reducing and oxidizing conditions, showed only the formation of very large fragments(about 18 butadiene units).The collected data support the cyclization mechanism proposed and account for the technologica

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050880102

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractMit Polyvinylalkohol‐haltigem Synthesepulp wurden Derivatisierungsreaktionen durchgeführt, die die Einführung folgender reaktiver Gruppen gestatten: Der Isothiocyanat‐, Imidocarbonat‐ und der Dichlor‐s‐triazin‐Gruppe. Weiterhin ließen sich gemischte Disulfide mit 2‐Thiopyridin‐Resten als reaktiver Komponente herstellen. Die Glutardialdehyd‐Methode wurde zur Aktivierung des unmodifizierten Synthesepulps und auch von Aminogruppen‐haltigen Derivaten dieses Polymeren herangezogen. An allen hier beschriebenen reaktiven Trägern ließen sich Enzyme immobilisieren. Als Enzyme wurden Trypsin, Esterase (aus Bacillus subtilis), Glucose‐Oxydase, Urease, Katalase, Hexokinase und Glucose‐6‐phosphat‐dehydrogenase eingesetzt und die Immobili

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050880103

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe initial polymerization rate of ethyl, butyl, and 2‐ethylhexyl acrylate was studied in a thermally insulated polymerization reactor. Monomers were continuously added into the reactor and the effect of variables in emulsifier and initiator concentrations was investigated. Ethyl and butyl acrylate polymerized even in absence of emulsifier. This indicated a homogeneous nucleation of particles. Ethoxylated nonyl‐phenols containing 20 and more oxyethylene units were effective in emulsion polymerization of the studied acrylic monom

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050880104

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe initial polymerization rate of ethyl, butyl, and 2‐ethylhexyl acrylate was studied in a thermally insulated polymerization reactor. The monomers were continuously added into the reactor and the effect of concentration of anionic emulsifiers on the temperature increase was investigated.Alkyl(aryl)polyethylenglykolethersulfate were found to be most effective in promoting the initial polymerization rate. An inhibition action of some emulsifiers was foun

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050880105

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractPolyurethanes were synthesized by polyaddition reaction of betulinol isolated from birch bark and linear extended aromatic polyisocyanate Desmodur E 22. The reactions were carried out in solvents such as toluene and cyclohexanone, and the polymers with molecular weights of up to 7200 g/mol were obtained. The kinetics of the reaction was studied and the formation of polyurethanes was shown by IR‐spectroscopy. The structure of the polymers was determined from the molecular characteristics of the building unit

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050880106

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractSemi continuous and continuous methods were described for grafting of acrylamide to partially carboxymethylated cotton (PCMC). In essence, PCMC previously treated with ferrous sulphate was padded in a solution containing acrylamide and H2O2followed by drying and baking. Incorporation of N‐methylol finishing agent to the polymerization solution brought about easy care cotton with improved strength properties and good fabric performancy as measured by crease recover

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050880107

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractIt was demonstrated that non‐homopolymerizing derivatives of 6‐caprolactam: 7‐cyclohexyl‐1‐aza‐2‐cycloheptanone (I) and 7‐isopropyl‐5‐methyl‐1‐aza‐2‐cycloheptanone (II) were polymerizing with 6‐caprolactam under conditions of the socalled hydrolytic polymerization. With its increasing content in the initial reaction mixture the copolymerization rate, the equilibrium content of the copolymer, and the reduced viscosity decreased. Lactam (I) was a more reactive comonomer i

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050880108

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractDie Kinetik der Perlcopolymerisation des Acrylsäureethylester‐Acrylnitril‐Divinylbenzol‐Systems wurde untersucht und mit Hilfe der Zeitabhängigkeiten des Umsatzgrades α und der momentanen Polymerisationsgeschwindigkeit Rpbeschrieben. Der charakteristische Zug dieser Copolymerisation macht sich durch den Trommsdorff Effekt schon im Bereich ab α = 0,02 bemerkbar. Die Abhängigkeit der Copolymerisationsgeschwindigkeit von der Temperatur am Anfang der Copolymerisation und von der Anfangskonzentration des Initiators wurde numerisch ausgedrückt. Aus diesen Angaben wurde die Größe der Aktivierungsenergie der Copolymerisation bestimmt, E = 1

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050880109

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractEin Dichtemeßsystem nach der Biegeschwingermethode erweist sich als geeignetes Gerät für die schnelle und genaue Bestimmung des Umsatzes bei radikalischen Polymerisationen in verdünnten Lösungen, wie durch Vergleich mit chromatographischen und gravimetrischen Methoden gezeigt

ISSN:0003-3146    

DOI:10.1002/apmc.1980.050880110

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY