Stabilization of Aqueous Dispersions of Inorganic Microparticles Under Mechanical Activation

The stability of aqueous dispersed systems of TiO2 and Fe2O3 microparticles in the presence of a water-soluble polymer - ethylhydroxyethylcellulose (EHEC) - has been studied under the condition of using two methods of mechanoactivation of the pigment surface - processing them in a disintegrator and in an ultrasonic field. It is shown that in the absence of a polymer stabilizer, an intense effect on aqueous dispersed systems of pigments leads to rapid coagulation of particles. In the presence of EHEC, a small stabilizing effect is observed, which is significantly enhanced when processing dispersed systems in a disintegrator and in an ultrasonic field. In this case, the stability of dispersed systems depends little on the method of mechanoactivation of their surface, but significantly depends on the duration of the intense exposure.

Exploration of Amphipolar Copolymer Adsorption on the Hydrophobic Surface

The data on thicknesses of the adsorbed polymer layer as obtained for the CuPc pigment dispersions under conditions of ultrasonic treatment in comparison to the systems without ultrasonic treatment are reported. The thicker adsorption layers observed for the ultrasonically treated systems confirm that an activation of the pigment surface occurs by the action of ultrasonic power.

Surface Modification of Titanium Dioxide under Ultrasonic Treatment

The surface modification of titanium dioxide in aqueous dispersions of specially tailor-made periodic acrylic acid/isobutylene copolymers by ultrasonic treatment was studied. The pigment surface modification by the above copolymers was comparatively investigated regarding conventional adsorption as contrasted to an ultrasonic treatment assisted procedure. The course and efficiency of the polymer adsorption onto the pigment surface was quantified by electrokinetic sonic amplitude measurements. The higher efficiency of the pigment surface coating by the copolymers as achieved by ultrasonic treatment and is a consequence of ultrasonically induced pigment surface activation.

SURFACE MODIFICATION OF TITANIUM DIOXIDE NANOPARTICLES WITH ACRYLIC ACID/ISOBUTYLENE COPOLYMER UNDER ULTRASONIC TREATMENT

The influence of the ultrasonic treatment of block copolymer solution on its solid-liquid interface behavior was investigated in detail. The surface modification of titanium dioxide nanoparticles in aqueous dispersions of specially tailor-made periodic acrylic acid/isobutylene copolymer by ultrasonic treatment was studied in order to get new approaches for the creation of hybrid composite materials or polymer coatings. The pigment surface modification by the above copolymer was comparatively investigated regarding conventional adsorption as contrasted to an ultrasonic treatment assisted procedure. The course and efficiency of the polymer adsorption onto the pigment surface were quantified by electrokinetic sonic amplitude measurements. The higher efficiency of the pigment surface coating by the copolymer as achieved by ultrasonic treatment in comparison to conventional adsorption is a consequence of ultrasonically induced pigment surface activation. Two perspective avenues of the utilization of the discovered effects for creation of organic-inorganic composite materials are anticipated: the nanoparticles could first be treated by ultrasound in the presence of polymers and so create a surface modifying coating and the second option is an entrainment of the nanoparticles into the monomer matrix which can be polymerized afterward yielding a polymer with immobilized nanoparticles.

INVESTIGATION OF AN AMPHIPOLAR COPOLYMER ADSORPTION ON THE HYDROPHOBIC SURFACE OF COPPER PHTHALOCYANINE NANOPARTICLES

It was presented the data on the thicknesses of the adsorbed polymer layer, which were obtained for copper phthalocyanine (CuPc) pigment dispersions under ultrasonic processing conditions. The thicker adsorption layers, which are observed in ultrasound systems, confirm the fact that the activation of the surface of the pigment occurs under the action of ultrasonic energy. The course and efficiency of adsorption of the polymer onto the pigment surface were quantified by electrokinetic measurements of the amplitude of sound (EIAZ). It became possible to obtain a more detailed picture of the pigment-polymer interactions and the adsorption mechanism of the copolymer based on the data on the dynamic mobility, obtained as a result of electrokinetic measurements of the amplitude of the sound. For aqueous dispersions of CuPc, stabilized with a copolymer of poly (acrylic acid) -poly (isobornyl acrylate) (PiBA-PAA), it was established the saturation concentrations of polymeric surfactant. Thus, the ultrasonic treatment allows to obtain stable, highly dispersed pigment suspensions with a modified pigment surface, which opens up new prospects for a more effective change in the surface of the pigment.

Ultrasonic Treatment Enhanced Surface Modification of Titanium Oxide by Tailor-Made Surface-Active Polymers

The surface modification of titanium dioxide in aqueous dispersions of specially tailor-made periodic acrylic acid/isobutylene copolymers, poly(acrylic acid)/polystyrene graft copolymers, and hydrophobically modified polyethyleneoxide urethane (HEUR) by ultrasonic treatment was studied. The pigment surface modification by the above copolymers was comparatively investigated regarding conventional adsorption as contrasted to an ultrasonic treatment assisted procedure. The course and efficiency of the polymer adsorpption onto the pigment surface was quantified by electrokinetic sonic amplitude measurements. The higher efficiency of the pigment surface coating by the copolymers as achieved by ultrasonic treatment varies with the copolymer architecture and is a consequence of ultrasonically induced pigment surface activation.