The surface tensions (y) of a branched polyethylene and two side-group liquid-crystalline (lc) polyacrylates were measured in the isotropic, nematic and smectic states by the pendant-drop method. The surface tension vs. temperature characteristics of the lc polyacrylates studied show anomalous behaviour. The slope in the isotropic state is initially negative but changes its sign near the isotropic-nematic transition. The increase of y with decreasing temperature is regained in the nematic phase, until at the nematic-smectic transition the surface tension of the lc polymers discontinuously jumps to higher values and shows a very low temperature coefficient. The observed features have been found to be partly in agreement with the results of surface tension measurements on low-molar-mass liquid crystals, which indicates that the surface properties of the lc polymers are governed by the mesogenic side groups.

This paper describes the orientational behaviour of polymer blends containing a side-group liquid-crystalline polymer (LCP). The macroscopic orientation of the LC phase in these blends, and the possibility to freeze in this state are of technical interest. The orientation of LCPcontaining blends through mechanical forces depends on a variety of structural, thermal, energetical and also morphological properties, which are strongly dependent on the kinetical and thermal history. This report describes the optical-and scanning electron microscopy (SEM), X-ray diffraction and interfacial tension studies of the liquid-crystalline polyacrylate 1 a and the poly(methacry1ate) 1 b in poly(methy1 methacrylate) (PMMA) and polycarbonate matrices. 1 a droplets in thermoplastic matrices can be oriented macroscopically during fibre-drawing, but, as a result of higher interfacial tension between the components, 1 b-containing blends can not.

ZUSAMMENFASSUNG:Copolymere aus Acrylnitril und Butadien lassen sich haftfest metallisieren. Die Dauer der Ozonbehandlung hat nur geringen EinfluB auf die Polymer-Metall-Haftung. Die Haftfestigkeit nimmt mit dem Nitrilgehalt und der Molmasse des Polymeren zu. Bei Kohi3sionsbruch im Polymeren sind Werte bis etwa 150 N/25 mm gemessen worden. Die hdchsten Haftfestigkeiten wurden an Proben gemessen, deren kritische Oberflachenspannung etwa der der chemisch abgeschiedenen Nickelschicht entspricht. Kavernen, die eine mechanische Verankerung des Metalls ermdglichen Wrden, sind nicht beobachtet worden. SUMMARY:Copolymers containing acrylonitrile and butadiene can be coated with metal electroless. There is only a small influence on the metal-to-polymer-adhesion with the time of treatment with ozone. The adhesion increases with the content of acrylonitrile and with the molecular weight of the polymer. Peel strength values have been measured up to 150 N/25 mm because of the cohesive fracture inside the polymer. The highest values of adhesion have been measured on samples having nearly the same values of the critical surface tension like those of the electroless deposited nickel-layer.Caverns supporting a mechanical staying of the metal have not been observed.