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Ein Beitrag zum Einfluß des Stoffüberganges auf eine erzwungene Konvektion an einer fluiden Phasengrenze (1980)

Schwarz, E. ; Waldhelm, W. ; Linde, H.

Springer

Heat and mass transfer 13 (1980), S. 187-194

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ISSN: 1432-1181

Source: Springer Online Journal Archives 1860-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics

Description / Table of Contents: Zusammenfassung Es wird das grenzflächendynamische Verhalten eines fluiden Zweiphasensystems unter den Bedingungen einer gezielten örtlichen Beaufschlagung der Phasengrenze durch ebene Strahlen bei gleichzeitig ablaufendem Stoffübergang untersucht. Hierzu wird in einem ausgewählten Punkt die Tangentialgeschwindigkeit in der Phasengrenze bzw. in Phasengrenznähe in Abhängigkeit von der Austrittsgeschwindigkeit der Strahlen in den beiden Phasen berührungslos mit Hilfe einer Laser-Doppler-Velocimeter-Anordnung im System Luft-Wasser mit und ohne Übergang von Azeton vermessen und verglichen. Die nur bei niedrigen Strahlaustrittsgeschwindigkeiten nachweisbaren Änderungen der Strömungsgeschwindigkeiten durch grenzflächendynamische Effekte werden an Hand von Modellvorstellungen diskutiert und mit theoretischen Untersuchungen des Wärmeüberganges in einem fluiden Zweiphasensystem verglichen.

Notes: Abstract The interfacial-dynamic behaviour of a fluid two-phase-system with mass transfer was investigated under influence of forced convection in the manner of flat jets directed to the interface. The tangential velocities were measured at a characteristic point near to the interface air/water or in the interface itself using a Laser-Doppler-Velocimeter in dependence on the velocities of jets into two phases in both cases with and without transfer of acetone. The variations of velocities due to the interfacial effects are only detectable at small velocities of the jets. They are discussed by model conceptions and compared with the results of a theoretical research of heat transfer in a fluid two-phase-system (Interfacial-dynamic surface renewal model).

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01433446

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Thermal stability of the silica-aminopropylsilane-polyimide interface (1984)

Linde, H. G. ; Gleason, R. T.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 3043-3062

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ISSN: 0360-6376

Keywords: Physics ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Thermal degradation of the silica-aminopropylsilane-amic acid/imide interface was studied by modifying a high-surface-area, neutral silica gel with a number of substituted aminopropylsilanes (APS). These substrates were reacted further with phthalic anhydride or aromatic amic acid monomers and the thermal decomposition of the adsorbed/reacted materials was monitored by thermogravimetric analysis (TGA) and infrared (IR) spectroscopy. The 3-aminopropyltriethoxysilane/poly[N,N′-(p,p′-oxydiphenylene)pyromellitimide] interface was also evaluated by this method.Comparison clearly distinguishes the thermal decomposition of surface-bound APS from surface-bound alkylphthalimides, the adhesion product of alkylamines and aromatic amic acids. Alkylamine imidization with the elimination of aromatic amine (analogous to polymer scission) and the decomposition of the surface-bound imide are shown in the amic acid TGA profiles. This imidization and the accompanying aniline elimination begin at about 130°C, under nitrogen, to form the surface alkyl imide which slowly decomposes at 400°C. TGA analysis indicates that the surface-bound imide undergoes minimal degradation under nitrogen at 370 ± 10°C; temperatures above this threshold range produce changes in the APS-imide interface.

Additional Material: 21 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pol.1984.170221126

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Adhesive interface interactions between primary aliphatic amine surface conditioners and polyamic acid/polyimide resins (1982)

Linde, H. G.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 1031-1041

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ISSN: 0360-6376

Keywords: Physics ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The interface reactions of 3-aminopropyltriethoxysilane treated surfaces, with the polyamic acid/polyimide resin formed from pyromellitic dianhydride and oxydianiline, were defined in bulk reactant systems and by FTIR analysis on the surface layers of germanium internal reflection plates. Adhesion between these interfacial layers is the result of chemical bonding, which proceeds through initial carboxylate salt formation between the amino function of the silylated surface and the car-boxylic acid present in the polyamic acid. Heating results in dehydration and amide formation, which is followed by preferential incorporation of the alkyl, surface-bound amine (stronger base), over the aromatic polymer amine, in an imide linkage. Aromatic imides formed before or during thermal curing may also be preferentially opened in a modified Ing-Manske reaction and reclosed to the more stable surface-bound alkylimide. Apparently polymer scission at the aromatic amide linkages occurs in this adhesion process, preferentially bonding surface-bound alkyl amines to one end of a shortened polymer chain.

Additional Material: 7 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pol.1982.170200412

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