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  • Polymer and Materials Science  (1,153)
  • SPACE SCIENCES
  • Wiley-Blackwell  (1,153)
  • 1970-1974  (1,153)
  • 1
    Electronic Resource
    Electronic Resource
    Proof of the charging of polypeptides and polyamides in organic acids (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 661-665 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electrophoresis of poly-γ-benzyl-L-glutamate (PBLG), poly-L-alanine (PLA) and nylon dissolved in various solvents was studied in a glass cell containing three sintered glass partitions. After the passage of a measured amount of charge the concentration of PBLG remained constant in all four chambers when the helicogenic solvents dimethylformamide and ethylene dichloride were used, but in mixtures of ethylene dichloride and dichloroacetic acid and in trifluoroacetic acid, polypeptide migrated to the cathode. Electrophoresis also occurred with PLA in trifluoroacetic acid and with nylon in formic acid. Although the total charge on the polyion could not be determined, the results show beyond reasonable doubt that polypeptides and polyamides are protonated in the presence of moderately strong organic acids.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110311
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  • 2
    Electronic Resource
    Electronic Resource
    The radical initiation of vinyl polymerization by α.α.α′.α′-Tetrasubstituted dibenzyls (1972)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 157 (1972), S. 279-298 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Im Temperaturbereich von 60 bis 100°C wird die radikalische Polymerisation von Styrol, Methylmethacrylat und Acrylnitril von α.α′-Dicyanodibenzylen ausgelöst, die in α-und α′-Stellung mit Ester-, Nitril-, Amid- oder Phenylgruppen disubstituiert sind. Bei 100 bis 110°C ist auch das α.α.α′.α′-Tetracarboxymethyldibenzyl aktiv. Vinylacetat und Vinylchlorid werden durch diese Initiatoren kaum polymerisiert.Fur die Polymerisation des Styrols wurden die Bruttogeschwindigkeitskonstanten Kp, für viele Dibenzyle und fur Peroxide vergleichbarer Aktivitat dilatornetrisch bestirnrnt. Norrnalerweise sind die Zeit-Urnsatz-Kurven rnit den Dibenzylen und den Peroxiden vergleichbar; das Tetracyanodibenzyl allerdings bewirkt nur eine unvollstandige Polymerisation.Der große Einfiuß von Substituenten in α-Stellung oder in den Phenylringen der Dibenzyle auf die Polymerisation des Styrols wird diskutiert. Dabei ist auch die Stereochernie wichtig. Die meso-Form des Dinitrildiesters ergibt eine 2.5- bis 3.5 ma1 schnellere Polyrnerisation als das dl-Isornere.Die Dissoziationsgeschwindigkeitskonstanten kd der Initiatoren wurden NMR-spektroskopisch aus der Linienbreite bestirnmt. Die Dinitrildiester sind gute Initiatoren, wahrend die α.α′-Dicyanodibenzyle rnit weiteren Nitril- oder Phenylgruppen in α- und α′-Stellung wenig geeignet sind. SchlieBlich wurde die 1.2-Addition einiger der Dibenzyle an Styrol im Ternperaturbereich von 120 bis 150°C rnit der Methode der chernisch induzierten KernPolarisation (CIDNP) untersucht.
    Notes: The radical polymerization of styrene, methyl methacrylate and acrylonitrile is initiated by α.α′-dicyanodibenzyls α.α′-disubstituted with ester, nitrile, amide or phenyl groups in the temperature range 60 to 100°C and by α.α.α′.α′-tetracarboxymethyldibenzyl at 100 to 110°C. Vinylacetate and vinylchloride show a low reactivity.The overall polymerization rate constants Kp have been determined dilatometrically for styrene initiated by a large number of dibenzyls and comparable peroxides. The styrene polymerization curves are generally comparable with those of peroxides. A notable exception is tetracyanodibenzyl.The strong influence of α- and ring-substituents in the dibenzyls on the styrene polymerization rate is discussed. The stereochemistry is also important : the meso α.α′-dicyanodibenzyls α.α′-disubstituted with ester groups give a 2.5 to 3.5 fold faster polymerization than their dl isomers.The initiator efficiency is related to the kd values, determined from NMR line width measurements. The α.α′- dicyanodibenzyls α.α′-disubstituted with ester groups are good initiators, while those with phenyl groups and nitrile groups are inefficient.Relevant to initiation and termination, the 1.2-addition of some of the dimers to styrene at 120 to 150°C has been studied with chemically induced dynamic nuclear polarization (CIDNP).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1972.021570128
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  • 3
    Electronic Resource
    Electronic Resource
    Methine and α-methyl proton resonance in methyl acrylate/methacrylonitrile copolymers (1973)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 164 (1973), S. 283-294 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: In Lösung und in Emulsion bei 50°C hergestellte Copolymere aus Methylacrylat (A) und Methacrylnitril (M) wurden durch 220-MHz-NMR-Spektren charakterisiert. Die Methin- und die α-Methyl-Protonen-Resonanzen für solche Copolymere bestehen aus drei Signalen, wobei die individuellen Peakflächen Protonen in der Mitte von verschiedenen A-oder M-zentrierten Triaden zugeordnet werden. Die Triadenanteile, die aus den Methin-und den α-Methyl-Resonanzen ermittelt wurden, stimmen ausgezeichnet mit den mit Hilfe der Copolymerisationsparameter rA = 0,39 ± 0,06 und rM = 3,56 ± 0,50 für die in Emulsion und rA = 0,24 ± 0,02 und rM = 3,21 ± 0,11 für die in Lösung polymerisierten Copolymeren berechneten Werten überein.
    Notes: Methyl acrylate (A)/methacrylonitrile (M) copolymers, prepared by emulsion and solution polymerization at 50°C, were characterized by 220 MHz NMR spectroscopy. The methine and α-methyl proton resonances of such copolymers consisted of three peak patterns, individual resonance areas being assignable to protons centered in various A or M centered triads. Triad fractions determined from methine and α-methyl resonance patterns were in excellent agreement with calculated values based on reactivity ratios of rA = 0.39 ± 0.06 and rM = 3.56 ± 0.50 for copolymers prepared in emulsion and on reactivity ratios of rA = 0.24 ± 0.02 and rM = 3.21 ± 0.11 for copolymers prepared in solution.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1973.021640126
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  • 4
    Electronic Resource
    Electronic Resource
    Die Zersetzung von Polyvinylchlorid in elektrischen Glimmentladungen (1974)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 5 (1974), S. 374-381 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: The Degradation of Polyvinyl Chloride in Corona-discharges In oder to interpret the process of electrical breakdown in polyvinyl chloride cable insulations the chemical degradation of plasticized polyvinyl chloride sheets were studied under model conditions in corona discharges.The alterations of chemical structure within the sheets as well as in the gaseous phase were determined qualitatively and quantitatively.The alterations of chemical structure within the sheets as well as in the gaseous phase were determined qualitatively and quantitatively.From the composition of degradation products and their variation with time of corona discharge the mechanisms of polyvinylchloride and plasticizer degradation could be deduced.
    Notes: Zur Deutung der Vorgänge beim elektrischen Durchschlag in Polyvinylchlorid (PVC)-Kabelisolierungen wurde die chemische Zersetzung von Weich-PVC-Folien unter Modellbedingungen im elektrischen Glimmfeld untersucht. Die dabei auftretenden chemischen Veränderungen in der Folie sowie im Gasraum wurden qualitativ und quantitativ erfaßt. Aus der Zusammensetzung der Zersetzungsprodukte sowie ihrem Verlauf über der Beglimmzeit konnte auf die Abbaureaktionen des PVC und des Weichmachers bei Glimmbeanspruchung geschlossen werden.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19740050706
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  • 5
    Electronic Resource
    Electronic Resource
    Rasterelektronenmikroskopische Untersuchungen der Heißwasserkorrosion von Zink (1973)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 24 (1973), S. 1-7 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Scanning electron microscope study of the hot water corrosion of zincExperiments in 0.010m sodium sulfate solution have revealed that there is a clear temperature dependence of pitting and general corrosion. At 12 °C cratershaped corrosion is found already after a short time; pit growth is by concentric rings and plate-like corrosion products grow out of the base. At 20 °C there is a scar-type attack with annular shapes being built up by spherical amorphous ZnO. At 40 °C the attack follows the same pattern but corrosion can be recognized already after 5 min; simultaneously, there is an increase of general corrosion, the individual pits being gradually overgrown by amorphous and later plate-like corrosion product. At 50 and 60 °C this type of attack is even more pronounced and is accompanied by the formation of columnar structures. At 70 °C general corrosion predominates and at 80 and 90 °C initial pitting is stopped after a short time, so that general corrosion is practically the only type found here. At 65 °C there is a pronounced corrosion maximum.
    Notes: Bei Versuchen in 0,010m Na2SO4 zeigt sich eine deutliche Abhängigkeit der Lochfraß- und der Flächenkorrosion von der Temperatur. Bei 12 °C kommt es schon nach kurzer Zeit zu kraterförmigem Angriff, wobei das Wachstum in Form konzentrischer Ringe erfolgt und plättchenförmige Korrosionsprodukte herauswachsen. Bei 20 °C ist der Angriff narbenförmig unter Bildung von immer höher wachsenden Ringen aus kugelig-amorphem ZnO. Bei 40 °C ist der Angriff vom gleichen Typ, jedoch schon nach 5 min deutlich zu erkennen; gleichzeitig nimmt die Flächenkorrosion stark zu, wobei die einzelnen Löcher mit der Zeit von zunächst amorphem und später plättchenförmigem Korrosionsprodukt überdeckt werden. Bei 50 und 60 °C ist dieser Angriff noch deutlicher, dazu treten säulenförmige Gebilde auf. Bei 70 °C überwiegt die Flächenkorrosion und bei 80 sowie 90 °C kommt die anfänglich auftretende Lochbildung nach kurzer Zeit zum Stillstand, so daß praktisch nur noch Flächenkorrosion gefunden wird. Bei 65 °C liegt ein ausgeprägtes Korrosionsmaximum.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19730240103
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  • 6
    Electronic Resource
    Electronic Resource
    Tensile strength of polyurethane exposed to nitrogen dioxide (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 1773-1778 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polyurethane prepared from tetramethylene glycol and diisocyanate was exposed in the form of films to small pressures of NO2 and to NO2 plus air. Tensile strength was measured as a function of exposure time and temperature with an apparatus especially constructed for the purpose of measuring mechanical properties in different environmental “atmospheres.”
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180615
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  • 7
    Electronic Resource
    Electronic Resource
    New static and dynamic stiffness testers (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 2963-2972 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Instruments have been developed for the testing of stiffness of polymers in various gaseous environmental “atmospheres” over a large range of temperatures. They are based on the cantilever principle, where a small strip of a specimen is deflected statically or periodically. Changes in stiffness are measured as function of the bending force or power input, respectively. The dynamic instrument responds very sensitively to the onset of cracking in specimens due to ozone exposure. The static instrument is well suited for measuring the onset of rapidly increasing stiffness as temperatures are lowered.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070181009
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  • 8
    Electronic Resource
    Electronic Resource
    Oxidative carbon-carbon coupling. III. Oxidative polymerization of bifunctional arylcyanoacetic esters (1973)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 11 (1973), S. 345-352 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bifunctional arylcyanoacetic esters were oxidatively coupled to high molecular weight, colorless, amorphous polymers, soluble in common organic solvents. Brittle films were obtained by casting or compression molding. Thermal stability of the polymers is poor due to the weak C—C bond formed by oxidative coupling. Radical dissociation-recombination of this bond (evidenced by ESR) results in meso-dl equilibration, lowering the Tg of the polymers.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1973.170110203
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  • 9
    Electronic Resource
    Electronic Resource
    Thermal degradation of poly-p-oxybenzoate under vacuum (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 10 (1972), S. 1719-1728 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal degradation of poly-p-oxybenzoate in vacuo as function of temperature has been studied. The energy of activation of the process up to about 30% volatile formation is 59.6 kcal/mole. The degradation is preceded by induction periods, which have been shown to be due to poor heat conductivity of the polymer powder. CO, CO2, phenol, and an unknown compound of molecular weight larger than 200 are the main degradation products found by chromatographic analysis. Infrared spectra of the original polymer, the polymer residue after degradation and of a degradation product solid at room temperature are presented. The possible reactions taking place have been indicated. The heat stability of the polymer in vacuo lies between those of polytetra-fluoroethylene and polyethylene.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.150100613
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  • 10
    Electronic Resource
    Electronic Resource
    Vacuum and oxidative pyrolysis of poly-p-xylylene. II. Chromatographic analysis and kinetics of reaction productsPresented at the 161st National Meeting of the American Chemical Society, Los Angeles, March 28-April 2, 1971. (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 9 (1971), S. 2605-2615 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction products of vacuum and oxidative degradation of poly-p-xylylene have been quantitatively determined by chromatographic analysis as function of time, temperature and oxygen pressure. Respective Arrhenius parameters were also ascertained for some of the reaction products and for the sums of all products. The energies of activation for the sums agree quite satisfactorily with the energies of activation obtained previously by uninterrupted experiments in quartz-spoon reaction vessels. The results found here can be described in terms of mechanisms previously postulated on the basis of the total loss in weight (or volatile production) data. Scission of “weak” links (due to abnormal structures) takes place followed by formation of various products. The whole process is governed by the initial chain scission reaction; however, the energies of activation for each of the products do not need to be identical with that of the chain scission reaction. Each product is formed by a reaction which has its own characteristic number average kinetic chain lengths; the latter have their specific energy of activation values.Oxidative degradation produces the same organic compounds as vacuum degradation and in addition CO, CO2, and H2O. Oxidized intermediate compounds are apparently fairly rapidly decarboxylated and decarbonylated. Oxidative chain scission is appreciably faster than that in vacuum. Almost simultaneous “weak” link and “normal” chain scission are taking place initiating the formation of a number of products.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.150090915
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