Fink,Udo; Cole,Mark D.; Keber,Tobias O.: Europäisches und Internationales Medienrecht. 2008

Ohne Zusammenfassung     

Chemical modification of polyester fiber surfaces by amination reactions with multifunctional amines

The feasibility of incorporating amine groups into the surface of polyester (PET) fibers by reaction with multifunctional amines was investigated. Reactions of diethylenetriamine (DETA), trethylenetetramine (TETTA), and tetraethylenepentamine (TTEPA) with PET monofilaments and with a multifilament yarn were studied. Microspectrophotometric examination of aminated fibers stained with an acid dye at low pH revealed the location and concentration of amine groups. Amination could be confined to the periphery and was found to be uniform on the fiber surface. The rate of the reaction, as revealed by acid dye staining, was characterized by an induction period followed by an autoaccelerated stage. Extent of incorporation of amine groups was found to be similar for the three amines. There is a significant improvement in water wettability due to surface amination, and the interfacial shear strength of TTEPA-treated PET monofilaments embedded in an epoxy resin matrix was almost doubled. As the amination reaction proceeds, there is a weakening of the reacted zone in the PET due to chain scission leading to a decrease in the interfacial shear strength. Scanning electron microscopy (SEM) studies revealed that failure occurred within the filament most probably between the reacted and unreacted zones. The tensile properties of the TTEPA-treated PET filaments were hardly affected at the investigated extents of amination.     

Analysis of the capillary forces between two small solid spheres binded by a convex liquid bridge

This work deals with a theoretical study of convex liquid bridges, where solid particles are partially wetted by an amount of liquid whose profile is convex. In our analysis, we adopt a two particle model assuming that the solids are spherical and with the same size and properties, and that the liquid meniscus features an arc-of-circumference contour. We analyze different parameters which govern the liquid bridge: inter-particle separation, wetting angle and liquid volume. The results are compiled in liquid volume-wetting angle diagrams in which the regions of existence of the bridge are delimited in terms of maximum and minimal inter-particle distances. The capillary force is found to present both attractive and repulsive characters for wetting angles smaller and higher than 90°. A map delimiting this force character is also presented.     

Nachweis von Kokosfett in Butter

Ohne ZusammenfassungMitteilung aus der Chemischen Untersuchungsanstalt der Stadt Leipzig.     

Die Bestimmung der Rohfaser im Kakao

Ohne ZusammenfassungMitteilung aus der Chemischen Untersuchungsanstalt der Stadt Leipzig.     

Entgegnung

Ohne Zusammenfassung VDI