Use, Preparation, and Characterization of Copper-Containing Silica Gel

Balkose, Devrim/0000-0002-1117-9486WOS: 000537733800019The preparation and characterization of humidity-indicating silica gel containing copper sulfate were aimed at in the present study. the equilibrium and kinetics of Cu(II) sorption were investigated by contacting 200-1600 mg dm(-3) Cu ion-containing solutions with silica hydrogel slabs having 10% silica. the diffusion coefficient of Cu(II) in silica hydrogel was determined to be on the order of 10(-10) m(2) s(-1). X-ray diffraction indicated that the gels contained mainly CuSO4 center dot 3H(2)O, CuSO4 center dot H2O, and small amounts of CuSO4 and CuSiO3 center dot 2H(2)O. the silica gel with Cu(II) can be used as a humidity indicator since its color changes from light blue to dark blue upon moisture adsorption

Characterization of poly(vinyl chloride) powder produced by emulsion polymerization

10th Conference on Calorimetry and Thermal Analysis (CCTA 10)/2nd Czech-Hungarian-Polish-Slovakian Thermoanalytical Conference -- AUG 30-SEP 03, 2009 -- Zakopane, POLANDWOS: 000281027500056The effect of emulsion process formulation ingredients on the morphology, structure, and properties of polyvinyl chloride (PVC) powder has been considered in this study. PVC powder was extracted with ethanol and films were obtained by solvent casting from tetrahydrofurane. Characterization of powders, films, and ethanol extract was performed through FTIR spectroscopy, DSC, AFM, SEM, EDX analysis, methylene blue, and nitrogen adsorption. PVC powder was composed of spheres of a large particle size range from 10 nm to 20 mu m as shown by SEM. The specific surface area of the PVC powder was determined as 16 and 12 m(2) g(-1) from methylene blue adsorption at 25 A degrees C and from N-2 adsorption at -196 A degrees C, respectively. AFM indicated the surface roughness of the films obtained by pressing the particles was 25.9 nm. Density of PVC powder was determined by helium pycnometry as 1.39 g cm(-3). FTIR spectroscopy indicated that it contained carbonyl and carboxylate groups belonging to additives such as surface active agents, plasticizers, and antioxidants used in production of PVC. These additives were 1.6% in mass of PVC as determined by ethanol extraction. EDX analysis showed PVC particles surfaces were coated with carbon-rich materials. The coatings had plasticizer effect since, glass transition temperature was lower than 25 A degrees C for PVC powder and it was 80 A degrees C for ethanol extracted powders as found by using differential scanning calorimetry. These additives from polymerization process made PVC powder more thermally stable as understood from Metrom PVC thermomat tests as well.Polish Soc Calorimetry & Thermal Ana