Poly Acrylic Acid Particles Research Articles

Characterization of Palladium Nanoparticles Adsorpt on Polyacrylic Acid Particles as Hydrogenation Catalyst

Palladium particles can be prepared in sizes of a few nanometers from Pd(OAc)2in the presence of a block copolymer in aromatic unpolar solvents with suitable reducing agents like NaBH4 or LiAlH4. After mixing the organic metal solution with a polyacrylic acid (PAA) dispersion of defined concentration and following a crosslinking process with an epoxide, reactive membranes with a well-defined pore diameter were obtained. The catalytic activity of the prepared palladium particles incorporated in the crosslinked PAA network has been proven by the gas phase hydrogenation of propyne in a special membrane reactor.

Complexation studies of Eu(III) with polyacrylic acid either free in solution or adsorbed onto alumina

SummaryThe complexation of Eu(III) with Polyacrylic acid (PAA) and alumina-bound polyacrylic acid (PAA-Al2O3) was studied at pH 5 in 0.1 M NaClO4. The experiments were carried out for two polyelectrolytes at 5000 Da and 50000 Da. The quantitative description of the interaction of Eu and PAA showed the formation of a 1:1 Eu:PAA complex and the existence of similar binding modes ("sites") of Eu with both polymers. Interaction studies of Eu(III) with alumina-bound PAA particles were carried out in conditions where their overall surface charge were equal to 0. The description of the data indicated the existence of a similar site in binary and ternary systems for high Eu loading. For low Eu loading, the existence of a new site on PAA-Al2O3particles resulting from the PAA-Al2O3interaction was suggested.

Persistence and Selectivity of the Immune Phagocytosis Inhibition by Major Histocompatibility Complex Antibodies

Major histocompatibility complex (MHC) antibodies induce immune phagocytosis inhibition (IPI) which lasts for at least 7 days. IPI-inducing antibodies do not inhibit the phagocytosis mediated by the beta-glucan receptor. This corresponds well to recent findings that these antibodies do not interfere with the phagocytosis of deactivated saccharomyces, mediated by the mannose-fucose receptor, or polyacrylic acid particles, also mediated by non-Fc receptors. Substances that interact with certain MHC antigens or with Fc receptors, certain toxins that inhibit surface molecule mobility, and ciclosporin do not cause IPI and do not suppress the induction of IPI by MHC antibodies. These substances are: opioid peptides, insulin, penicillin G, immune complexes, aggregated IgG, Fc fragments, ciclosporin, botulinum C2 toxin, sodium azide. Some lectins and EDTA are inhibitory in a non-selective fashion, since the Fc receptor independent phagocytosis is also abrogated.