Papers by Keyword: Aqueous

Abstract: Cyclic carbonate emulsion was prepared by means of polymerization technology using DOMA (which was synthesized by glycidyl methacrylate and carbon dioxide) and acrylic monomers. Effect of temperature, amount of emulsifier, initiator, DOMA and acrylic acid on properties of the emulsion and the film were studied. It was found that with 4% emulsifier, of which the ratio of OP-10 and SDS was 2:1, and 0.4% initiator, 3.5% acrylic acid, 13.3% DOMA, the temperature was 78°C. Under this condition the performance was the best, and then the aqueous non-isocyanate polyurethane was synthesized by cyclic carbonate emulsion and diethylenetriamine as curing agent. The structure of emulsion and aqueous non-isocyanate polyurethane was characterized by FTIR.

Abstract: Hydrolysis and dispersing behavior of aqueous ZrB2 slurry were investigated. The isoelectric point (IEP) of ZrB2 slurry was measured to be pH 6.3. The acid and base slurry underwent rather rapid change of pH after fabrication for one and three hours, respectively. The oxygen content of the boride powder increased slowly with static ageing time in acid and neutral slurries, while the value decreased in base slurry. Application of poly(ethyleneimine) changed IEP of the boride slurry to pH 10.4. Sedimentation test informed that stability of the slurry was improved when increasing the molecular weight of poly(ethyleneimine) to 70,000 and in acid slurry (pH 3).

Abstract: Porous piezoelectric ceramics are of interest for hydrophones and medical imaging because of their enhanced coupling with water or biological tissue due to acoustic impedance matching. Multilayer lead zirconate titanate (PZT) substrates with dense and porous interlayers were produced by tape casting of aqueous PZT slips with high solids contents. The use of latex binders with low viscosity enabled addition of starch as a fugitive additive to create air/ceramic composites with ´3-3´connectivity. Microstructures, piezoelectric and mechanical properties of sintered, poled laminates were evaluated. The relative permittivity, ε33, decreased by 40% for laminates with porous interlayers compared to dense ones, whereas the relative decrease in piezoelectric longitudinal coefficient, d33, was 35%. Laminates with porous interlayers maintained 72% of their bending strength compared to dense ones.

Abstract: Two specifically determined dispersants and three binders have been investigated with respect to their influence on the rheological flow behavior of aqueous BaTiO3 slurries for tape casting and the properties of cast green tapes. Depending on the additive combinations, shear thinning and unique Newtonian flow behaviors could be achieved. Hereby the respective flow behavior must be based on specific additive interaction and determines the microstructural properties of the green tapes.

Abstract: This paper aims at a simple preparation method of nanocrystalline copper powders through copper sulfate reduction by potassium borohydride in aqueous solution. The product powders obtained in various conditions were investigated by X-ray powder diffraction, transmission electron microscope and particle size distribution analyzer. The parameters that influence the preparation process of copper crystalline were researched, such as the effect of complexing agent, the molar ratio of copper sulfate to potassium borohydride and the quantity of protective polymer. Finally, the preferable reaction conditions were determined, and well-dispersed nanocrystalline copper powders with average diameter of 28.4nm were obtained.