摘要:

AbstractSchlagfeste Polystyrole auf der Basis von Polybutadienkautschuk als Elastomerkomponente besitzen im Vergleich zu Standard‐Polystyrolen eine deutlich reduzierte Witterungsbeständigkeit. Einer wirkungsvollen Stabilisierung dieser Werkstoffe mit feinverteiltem Ruß steht die Tatsache entgegen, daß infolge einer mangelnden Ruß‐Polymer‐Verträglichkeit das Pigment eine Kerbwirkung zeigt, die den Hauptvorteil des schlagfesten Polystyrols — seine hervorragende Zähigkeit — deutlich vermindert. In dieser Arbeit wird über Versuche berichtet, durch Aufpfropfen von Polystyrolketten auf die Rußoberflache eine Verbesserung der Ruß‐Polymer‐Verträglichkeit und damit der technologischen Eig

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051200101

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe polycondensation reaction between telechelic poly(dimethylsiloxanes) and α,ω‐difunctional polystyrenes (or substituted polystyrenes) in toluene solution is very fast, in spite of the heterogeneous nature of the reaction medium. In the first part of the article is reported a qualitative approach of the condensation reaction in relation to the microscopic structure of the reaction medium. The second part is devoted to an investigation of the mechanical and thermomechanical behaviour of the multiblock copolymers which results from intramolecular phase separat

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051200102

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractAmbient dielectric effects were studied by the short‐circuited waveguide method at 9.375 GHz microwave frequency in foams from copolymers of styrene and methyl methacrylate of varying compositions, generated under identical conditions of solvent‐nonsolvent ratio, impregnation time and steaming period. The results were correlated with foam‐density, porosity and composition and were interpreted in terms of dipole‐dipole interactions and the applicability of Wiener's inequalities, logarithmic law of Lichtenecker and Rother with an empirical factor of 0.64 in the index based on the additive law of mixtures and the Böttcher‐Bruggeman's relation. Scanning electron micrography on copper‐coated fractured surfaces of the samples was done in order to examine the degree of foamability, cell‐size distribution and the mechanism of failure. Microhardness, compressive and flexural strength were also measured. Loss characteristics were similarly ascribed to copolymer foamability and dipoleorientability. A prudent choice in the monomer reactivity ratio might therefore yield an optimum reinforcement and a proper dielectric requirement suitable for electronic and radar device

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051200103

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe new third generation Ziegler‐Natta catalysts give extremely high yield and produce highly stereoregular polypropylene of controlled morphology and size. The role of Lewis bases and MgCl2is underlined and their mechanisms of action is discussed in the light of the most significant experimental data. Furthermore, technological and economical advantages are emphasize

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051200104

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractFür die Bestimmung der Grenzviskositatszahl [η] von nitroso‐oxydierter Cellulose in verdünnter Losung wurde die EWNN Methode (alkalische Lösung eines Eisen‐Weinsäure‐Natrium‐Komplexes) angewandt. Die bisher bekannten Berechnungsmethoden von [η]mit Hilfe der Polynome für verschiedene Arten von Polymeren, verschiedene Lösungsmittel und Meßsysteme sowie auch für reine Cellulose erwiesen sich als unbrauchbar. Es wurde eine empirische Berechnungsformel in expliziter Form\documentclass{article}\pagestyle{empty}\begin{document}$$[\eta ] = \frac{{\eta _{{\rm sp}} }}{{\rm c}} + {\rm c}^2 + {\rm A}_1 \eta _{{\rm sp}} {\rm c} - \eta _{{\rm sp}}^2 {\rm c} + {\rm A}_2 \eta _{{\rm sp}}^3 {\rm c} + {\rm A}_3$$\end{document}mit A1= −2,348, A2= 3,584 und A3= 0,006 (ηsp: spezifische Viskosität, c: Konzentration g/100 ml) vorgeschlagen, die die Berechnung von [η] bei Oxycellulose aus einer bei einer einzigen Konzentration der Probe durchgeführten Messung ermöglicht. Für die Berechnung eines Mittelwertes für den Polymerisationsgrad nach der Staudinger‐Mark‐Houwink‐Gleichung war es möglich, die für nichtoxydierte Cellulo

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051200105

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractIn einer vorausgegangenen Arbeit wurden Verfahren vorgeschlagen, die die Zeit‐Umsatz‐Kurven der chemischen Reaktion zwischen dem flüssigen Reaktanten und dem vernetzten makromolekularen Stoff auszuwerten ermöglichen. In dieser Arbeit werden die angeführten Verfahren an einem Beispiel der alkalischen Hydrolyse des Perlcopolymeren aus Acrylsäureethylester, Acrylnitril und Divinylbenzol beschrieben, weiterentwickelt und untereinander ver

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051200106

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractConditions were established to introduce almost equal and reproduciple amounts of diethylaminoethyl (DEAE) substituents into the molecular structure of scoured cotton (substrate I), slack mercerized cotton (substrate II), slack mercerized‐stretched (94%, substrate III), and slack mercerized‐stretched (103%, substrate IV) cotton. Similarities between the original structures of these substrates before and after the chemical modification were assessed by X‐ray analysis. Comparison between the DEAE cottons and the corresponding unmodified cottons upon acid hydrolysis with respect to moisture regain, loss in weight and degree of polymerization was also made. Chemical analysis was used to study the compositions and structures of the hydrolyzates (i.e., hydrocelluloses and solublized fractions) resulting from hydrolysis of the modified cottons with 2.5 N HCl under reflux for different lengths of time. Studies of rates of hydrolysis of the cellulose, rates of removal of substituted glucoses and rates of removal of individual types of substituted glucose units were considered as means to provide information regarding: (a) distribution of DEAE substitutents throughout the structure of cellulose, (b) nature of accessible regions where the DEAE substituents are developed, and (c) selective availability of the hydroxyl groups at C‐2, C‐3 and C‐6 of the D‐glucopyranosyl units in the cellulose elem

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051200107

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe influence of UV‐radiation on thermal stability of PVC films, depending on the type and quantity of modifying copolymers, was studied. It was found that UV radiation can induce various changes in thermal stability of PVC decreasing its dehydrochlorination temperature T01while increasing temperature of decomposition T02.Particularly distinct changes in sampels containing VC/VAC indicate that even 1% of this copolymer accelerates the photodehydrochlorination and the processes which decrease the temperature of decomposition of PVC.Smaller changes than in pure PVC in thermal parameters in samples containing ABS after irradiation show that this copolymer increases the PVC resistance to UV radiation.Films containing MBS, ABS, MMA/MA reveal the largest changes in T01after irradiation in the case of a content of 1% of these copolymers in the samples. In the case of bigger quantity (3 to 10%) the changes are smaller and may even diversify their direction. These copolymers, contrary to VC/VAC, make PVC films a little turbid indicating the limited compatibility of both components. Hence, the conclution is that the structure of a film, depending on compatibility of components and changing with their differing concentration, has decisive influence on the thermal and photochemical processe

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051200108

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractEs wird das Prinzip einer Meßanordnung zur Bestimmung von Zetapotentialen an plattenförmigen Polymeren vorgestellt. An Platten aus Polytetrafluorethen und Homopolystyrol wurden charakteristische Unterschiede des Zetapotentials nach der Adsorption von 3‐N‐Alkylaminopropan‐1‐olen und Dodecylpropylamin aus wäßriger Lösung nachgewiesen. Der Einfluß von pH‐Wert, Konzentration und C‐Kettenlänge der Tensid

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051200109

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractPyrolysis field desorption mass spectrometry has been performed from various polyamides such as nylon 6, 8, 12, and nylon 66. The pyrolytic behaviour of these compounds depends strongly on the solvent and the temperature program employed. Using formic acid as solvent strong thermal fragmentation is observed, while with 1,1,1,3,3,3‐hexafluoro‐2‐propanol almost exclusively molecular ions or cationized molecules of the monomer building block M are produced. With increasing temperature larger clusters of polymeric subunits (Mn+ Na)+are generated, but thermal fragmentation on the emitter surface also increases. The cationized molecules dominate all spectra. They are found from M3to M5or M15depending on the chain length of the polymer subunit. With increasing temperature, the base peak of the spectrum is shifted to the higher mass end and small signals up to m/z 2000 and above are recorded. Thermal products are mainly formed by water elimination (−18 mu), loss of the acid amide group (−44 mu) after rearrangement and from longer polyamides by loss of the methylene groups (− 42 or 56 mu) by cis‐elimination.These thermal fragmentations of the polymeric substances on the emitter surface can be controlled by appropriate emitter heating and correlate directly with the common chemical knowledge of these materials in the liquid or solid phase. Together with the options of integrating recording, high mass resolution and direct isotope determination, the combination of pyrolysis and field desorption mass spectrometry offers a unique tool for characterization of building blocks and high mass sequences in synth

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051200110

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY