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  • 1
    Electronic Resource
    Electronic Resource
    Kationisierung von Zellstoff unter homogenen reaktionsbedingungen (1989)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 173 (1989), S. 213-218 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: An attempt was made to obtain cationic cellulose derivatives of highest possible degrees of substitution by treating dissolving grade pulps under homogeneous conditions with glycidyltrimethylammonium chloride in the solvent system dimethylacetamide/lithiumchloride. The influence of temperature, reaction time and molar ratio of the reagents was examined. A reaction time of 8 h and a temperature of 70°C have been found to be optimal. The cellulose content in solution and the molar ratio of the reagents have to be adapted to the used pulp.
    Notes: Es wurde der Versuch unternommen, durch Umsetzung von Zellstoffen mit Glycidyltrimethylammoniumchlorid im Lösungsmittelsystem Dimethylacetamid/Lithiumchlorid kationische Cellulosederivate mit möglichst hohen Substitutionsgraden zu erhalten. Hierzu wurden Temperaturabhängigkeit, Reaktionsdauer und Molverhältnis der Reaktanden untersucht. Als optimal erwies sich eine Reaktionsdauer von 8 h bei einer Reaktionstemperatur von 70°C. Der Cellulosegehalt in Lösung und das Molverhältnis der Reaktanden müssen dem verwendeten Zellstoff angepaßt werden.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1989.051730117
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  • 2
    Electronic Resource
    Electronic Resource
    Ester der Ferrocendithiocarbonsäure (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 850-856 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Esters of Ferrocenedithiocarboxylic AcidTwo methods were used to prepare esters of ferrocenedithiocarboxylic acid: 1. Alkylation of the ferrocenedithiocarboxylate anion in the piperidinium salt [C5H10NH2]+[Fc—CS2]- (1) by CH3I, C2H5I, and ethylene oxide gave mononuclear esters Fc—C(S)SR (R = CH3 (2), C2H5 (3), CH2CH2OH (4)), whereas the dinuclear methylene diester [Fc—C(S)S]2CH2 (9a) was formed using either CH2Cl2 or CH2I2. 2. The reaction of ferrocenecarbonyl chloride, Fc—C(O)Cl, with methanethiol, CH3SH, to give Fc—C(O)SCH3 (7) and subsequent sulfuration by P4S10 furnished Fc—C(S)SCH3 (2). The analogous reactions with dithiols, HS[CH2]nSH (n = 2 - 4), led to the dinuclear compounds [Fc—C(S)S]2[CH2]n (n = 2 (9b), 3 (9c), 4 (9d)). All the intermediates of the composition Fc—C(O)S[CH2]nSH (11b - d), [Fc—C(O)S]2[CH2]n (12b - d), and Fc—C(S)S[CH2]nSC(O) - Fc (13b - d) could be isolated. The new compounds were characterized on the basis of their 1H and 13C NMR spectra.
    Notes: Zwei Methoden wurden zur Darstellung von Estern der Ferrocendithiocarbonsäure angewandt: 1. Die Alkylierung des Ferrocendithiocarboxylat-Anions im Piperidinium-Salz [C5H10NH2]+ [Fc—CS2]- (1) mit CH3I, C2H5I und Ethylenoxid ergab einkernige Ester, Fc—C(S)SR (R = CH3 (2), C2H5 (3), CH2CH2OH (4)), während mit CH2Cl2 oder CH2I2 der zweikernige Methylendiester [Fc—C(S)S]2CH2 (9a) entstand. 2. Die Umsetzung von Ferrocencarbonsäurechlorid, Fc—C(O)Cl, mit Methanthiol, CH3SH, zu Fc—C(O)SCH3 (7) und anschließende Sulfurierung mit P4S10 lieferte Fc—C(S)SCH3 (2). Die analoge Reaktion mit Dithiolen HS[CH2]nSH (n = 2 - 4) führte zu den Zweikernverbindungen [Fc—C(S)S]2[CH2]n (n = 2 (9b), 3 (9c), 4 (9d)); alle Zwischenstufen der Zusammensetzung Fc—C(O)S[CH2]nSH (11b - d), [Fc—C(O)S]2[CH2]n (12b - d) und Fc—C(S)S-[CH2]nSC(O) - Fc (13b - d) konnten isoliert werden. Die neuen Verbindungen wurden anhand der 1H- und 13C-NMR-Spektren charakterisiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190309
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  • 3
    Electronic Resource
    Electronic Resource
    Inter- and Intramolecular Chiral Stacking of Acridine Derivatives (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 1207-1210 
    Details
    ISSN: 0009-2940
    Keywords: Circular dichroism, dependence on concentration ; Exciton interaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sugar derivatives of diaminoacridine stack in aqueous solution like the parent compound. This is shown by CD measurements which give concentration-depending CD couplets. An extraordinarily strong CD couplet is obtained around 255 nm when two units of hydroxyacridine (base changed for solubility reasons) are connected by a 6-membered chain.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220630
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  • 4
    Electronic Resource
    Electronic Resource
    Carbonylmetall-Komplexe mit Ferrocendithiocarboxylato-Liganden (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 3143-3150 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbonylmetal Complexes with Ferrocenedithiocarboxylato LigandsReaction of the carbonylmetal cations [(η5-C5H5)M(CO)nL]+ (2: M=Cr, n=3, L=CH3CN;3: M=Mo, n=3, L=CH2Cl2; 4: M=W, n=3, L=CO; 5: M=Fe, n=2, L=CH3CN) and [M(CO)5(CH3CN)]+ (6, 7: M=Mn, Re) with the ferrocenedithiocarboxylate anion (Fc - CS2-) 1 leads to the monodentate ferrocenedithiocarboxylato complexes (η5-C5H5)M(CO)n[SC(S) - Fc] (2a-5a: M=Cr, Mo, W, Fe) and M(CO)5-[SC(S) - Fc] (6a, 7a: M=Mn, Re), respectively. These can be converted to the chelate complexes (η5-C5H5)M(CO)n-1[S2C - Fc] (2b - 5b: M=Cr, Mo, W, Fe) and M(CO)4- [S2C - Fc] (6b, 7b: M=Mn, Re) by thermal decarbonylation. All the new compounds were characterized by their spectra.
    Notes: Umsetzung der Carbonylmetall-Kationen [(ηn5-C5H5)M(CO)nL]+ (2: M=Cr, n=3, L=CH3CN;3: M=Mo, n=3, L=CH2Cl2; 4: M=W, n=3, L=CO; 5: M=Fe, n=2, L=CH3CN) und [M(CO)5(CH3CN)]+ (6, 7: M=Mn, Re) mit dem Ferrocendithiocarboxylat-Anion (Fc-CS2-) 1 führt zu den Komplexen (η5-C5H5)M(CO)n[SC(S) - Fc] (2a-5a: M=Cr, Mo, W, Fe) bzw. M(CO)5[SC(S) - Fc] (6a, 7a: M=Mn, Re) mit einzähnig gebundenen Ferrocendithiocarboxylato-Liganden. Durch thermische Decarbonylierung lassen sich daraus die Chelatkomplexe (η5-C5H5)M(CO)n-1[S2C - Fc] (2b - 5b: M=Cr, Mo, W, Fe) bzw. M(CO)4[S2C - Fc] (6b, 7b: M=Mn, Re) erhalten. Alle neuen Verbindungen wurden spektroskopisch charakterisiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180813
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  • 5
    Electronic Resource
    Electronic Resource
    Copolymers obtained by means of anionic ring-opening polymerization. Poly(2,2-dimethyltrimethylene carbonate-tapered-∊-caprolactone) (1988)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 189 (1988), S. 2303-2321 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The anionic ring-opening polymerization of mixtures of 2,2-dimethyltrimethylene carbonate and ∊-caprolactone in toluene as solvent, with sec-butyllithium or potassium dihydronaphthylide as initiator, results in the formation of polymers of the (A-X-B)n type, where A represents a poly(2,2-dimethyltrimethylene carbonate) block, B represents a poly(∊-caprolactone) block and X stands for a block of the two monomers with a composition gradient; n represents the number of portions by which the monomer mixture is added to the initiator or the living system. From the time-conversion curves it follows that the reactivity of the carbonate monomer is higher than that of the lactone. This difference in reactivity of the monomers is the reason for the special polymer architecture represented by (A-X-B)n. The properties of these polymers depend upon the ratio of the monomers and the number n of additions. The polymers are characterized by spectroscopic, thermoanalytical, and thermomechanical measurements.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1988.021891010
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  • 6
    Electronic Resource
    Electronic Resource
    Entwicklung auf dem Gebiet der Lebensdauervorhersage an mehrachsig beanspruchten komplexen BauteilenHerrn Prof. Dr. rer. nat. Wolfgang Bunk zum 60. Geburtstag gewidmet (1987)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 18 (1987), S. 292-298 
    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: Developments of Fatigue Life Prediction Methods for Components with Multiaxial Stress StatesFor further reductions of the structural weight of modern light weight constructions the explicit consideration of multiaxial stress states becomes increasingly important. In the present paper a survey of prediction methods for the evaluation of the life behaviour close to the endurance limit and in the finite life range is given. A main characteristic of the prediction methods especially for the limited life range is that individual stress-strain events similar to closed hysteresis loops under uniaxial constant amplitude conditions have to be present. In order to overcome this limitation, a new fatigue life evaluation procedure has been developed. The prediction method is based on a threedimensional elastic-plastic finite element model together with the material model after Mróz to account for the elasticplastic material behaviour. The fatigue damage is evaluated on the basis of plastic work using a new incremental damage law. The new method is briefly described.
    Notes: Im Hinblick auf die Erzielung höherer Ausnutzungsgrade technischer Strukturen ist das Vorliegen mehrachsiger Beanspruchungsbedingungen im besonderen Maße zu berücksichtigen. In der vorliegenden Arbeit wird eine Übersicht über im Schrifttum mitgeteilte Vorhersagemethoden für Belastungen in der Nähe der Dauerfestigkeit und im Zeitfestigkeitsbereich gegeben. Die Anwendung der meisten Methoden besonders für den Zeitfestigkeitsbereich ist an das Vorliegen von Beanspruchungsereignissen in Form geschlossener “Schwingspiele” gebunden. Diese Beschränkung wird mit Hilfe eines neuen Schadensberechnungsverfahrens auf der Grundlage der plastischen Arbeit überwunden. Es erfolgt eine kurze Beschreibung dieser auf beliebige dreidimensionale elastisch-plastische Beanspruchungen anwendbaren Methode, die eine Finite Element Analyse in Verbindung mit dem Werkstoffmodell nach Mróz, weiterhin ein inkrementelles Schadensberechnungskonzept einschließt.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19870180906
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  • 7
    Electronic Resource
    Electronic Resource
    Struktur und eigenschaften von mehrphasenkunststoffen. Deformations- und bruchverhalten von polycarbonat/ABS-mischungenHerrn Dr. G. Fritz zum 60. Geburtstag gewidmetVortrag anläßlich des 9. Darmstädter Kunststoff-Kolloquiums über Kunststofflegierungen in Darmstadt, Oktober 1984. (1985)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 132 (1985), S. 19-42 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: PC/ABS-blends have gained growing importance as engineering plastics in numerous different application sectors by the realization of interesting property combinations. These blends are in use for a longer time, but the literature about the basic physical aspects is not very comprehensive. The here presented work examines the influence of sample composition on phase behavior, on yielding and notched impact behavior. Sample composition is changed by mixing different amounts of PC, SAN and grafted rubber (polybutadiene rubber grafted with SAN). The yielding and impact behavior is discussed in connection with the deformation mechanisms. A subsequent paper will deal with the deformation morphology of these blends.
    Notes: PC/ABS-Mischungen haben als polymere Konstruktionswerkstoffe in den verschiedensten Anwendungsbereichen zunehmend an Bedeutung gewonnen, weil sie aufgrund ihres Legierungsaufbaues günstige Eigenschaftskombinationen besitzen. Obwohl diese Legierungen bereits seit längerem im Einsatz sind, liegen in der Literatur nur vergleichsweise wenige Untersuchungen über die grundlegenden physikalischen Aspekte vor. Mit den hier vorgestellten Untersuchungen wird der Einfluß unterschiedlicher Zusammensetzungen der Mischungen aus den Einzelkomponenten PC, SAN und Pfropfpolymerisat (SAN gepfropft auf Polybutadien) auf das Phasenverhalten sowie auf das Yield- und Bruchverhalten betrachtet und mit den Deformationsmechanismen in Verbindung gebracht. Eine nachfolgende Arbeit wird sich mit der Deformationsmorphologie befassen.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1985.051320102
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  • 8
    Electronic Resource
    Electronic Resource
    Cellular morphology and distribution on a stretching blood-material interface (1988)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 22 (1988), S. 339-351 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: In order to investigate the interactions of cellular elements and protein on constantly deforming (fatiguing) blood contact surfaces, a series of ex vivo canine arteriovenous shunt experiments were conducted. While fresh blood was flowing through Silastic tubing shunts, portions of the tubing were stretched 20 to 60% at a frequency of 20 to 90 cycles per minute for 10 to 90 min. The surfaces of the tubing that were stretched were compared with control tubing surfaces taken from the arterial side of the test segment using scanning electron microscopy and interference phase contrast microscopy.Approximately the same number of platelets were deposited on the stretched as on the unstretched portions of the tubing in the ten minute experiments. On the control portions of the tubing, the platelets were deposited singly and uniformly in what appeared to be a fairly inactivated state. On the stretched tubing, more pseudopod extension and aggregation was observed. In these preliminary experiments, no differences were noted as a function of frequency of stretch. As the blood contact time and the percent stretch were increased, only nonuniform, scattered aggregations of platelets, and platelets mingled with fibrin were seen. Significant numbers of spread white blood cells were observed on many of the segments of Silastic tubing stretched 20% for as short a time as 15 min. Granulocytes have occasionally been reported on less hemocompatible biomaterials after exposure to canine blood. This helps to confirm that substrate stretching of 20-60% had an adverse effect on the blood compatibility of the Siliastic tubing.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820220407
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