Stabilization of carbon black with ionic-hydrophobic polyelectrolytes

The mode of action and efficiency of amphipolar copolymers of different molecular architectures with copolymers consisting of ionic (acrylic acid) and hydrophobic (styrene) constitutional units and sequences (segments, blocks, grafts) as stabilizers of carbon black dispersion are discussed. The pigment-copolymer interactions were investigated by the ESA method as well as lumifuge and rheological measurements. The results indicate that there are distinctive differences in the stabilization behavior depending on the molecular architecture with better results being achieved for block and graft copolymers.     

The influence of HF on the incorporation of silicon into the erionite-like AlPO4-17 molecular sieve

The synthesis of SAPO-17 with high silicon content (up to 18 weight-%) succeeded with the addition of HF to the reaction mixtures. The characterization of the samples with chemical analysis, XRD, and adsorption measurements show the incorporation of silicon into tetrahedrally coordinated framework positions. Spectroscopic methods (IR, ¹⁹F MAS NMR) demonstrate the presence of fluorine in the as-synthesized samples. The effect of the fluorine consists in (i) the improvement of the silicon incorporation into framwork positions, (ii) the stabilization of the as-synthesized samples and (iii) the charge compensation of the template ion by F⁻.