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Transport of solutes through calix[4]pyrrole-containing cellulose acetate films
Valente, A. J. M.; Jiménez, A.; Simões, A. C.; Burrows, H. D.; Polishchuk, A. Ya.; Lobo, V. M. M.Films of cellulose acetate containing different concentrations of meso-octamethyl-porphyrinogen (calix[4]pyrrole) were prepared and characterized using UV-vis and FTIR spectroscopy, DSC and SEM. Incorporation of calix[4]pyrrole into cellulose acetate leads to a decrease in the degree of hydrophilicity of the polymeric matrix. However, a slight increase in the percentage of water uptake of the polymer is found w...
Permeation of sodium dodecyl sulfate through polyaniline-modified cellulose ace...
Valente, A. J. M.; Burrows, H. D.; Polishchuk, A. Ya.; Domingues, C. P.; Borges, O. M. F.; Eusébio, M. E. S.; Maria, T. M. R.; Lobo, V. M. M.The preparation of polyaniline (PANi)-cellulose acetate (CA) blends by casting films from a suspension, is reported. Two membranes were prepared from different solvents, one with a homogeneous and the other a heterogeneous dispersion of PANi in CA matrices. The membranes were characterized by X-ray diffraction, SEM, DSC, and FTIR, and the results were compared with those obtained for pure CA and PANi films. The...
Sorption/diffusion behaviour of anionic surfactants in polyacrylamide hydrogels...
Valente, A. J. M.; Polishchuk, A. Ya.; Burrows, H. D.; Miguel, M. G.; Lobo, V. M. M.The sorption and diffusion processes of anionic surfactants with different chain length through polyacrylamide hydrogels with low swelling degree have been studied by electrical conductivity measurements. The multicomponent equilibrium equation has been used to model the sorption isotherms of different anionic surfactant in the hydrogels. Such isotherms show that initial rapid sorption of unimer surfactant into...
Diffusion coefficients of lithium chloride and potassium chloride in hydrogel m...
Valente, A. J. M.; Polishchuk, A. Ya.; Lobo, V. M. M.; Geuskens, G.http://www.sciencedirect.com/science/article/B6TWW-4459YXC-3/1/786bf7fd6f201e0f9860c7daf36e864d
Diffusion of electrolytes in hydrolyzable glassy polymers: Acetic acid in poly(...
Polishchuk, A. Ya.; Valente, A. J. M.; Camino, G.; Luda, M. P.; Madyuskin, N. N.; Lobo, V. M. M.; Zaikov, G. E.; Revellino, M.Engineering materials containing poly(vinyl acetate) (PVAc) as the key component undergo hydrolytic degradation, which must be minimized or, at least, controlled. To characterize PVAc hydrolysis quantitatively, the diffusion of acetic acid (HAc) in PVAc, poly(vinyl alcohol) (PVA), unsaturated polyester (UPE), and a UPE/PVAc blend was studied in detail. The permeability cell earlier developed by the authors was ...
Transport of non-associated electrolytes in acrylamide hydrogels
Lobo, V. M. M.; Valente, A. J. M.; Polishchuk, A. Ya.; Geuskens, G.Diffusion of non-associated electrolytes (LiCl and KCl) in different hydrogels has been studied to identify the mechanism of electrolyte interaction with the structure of hydrogels and its dependence on electrolyte concentration and thermodynamic features of the electrolyte. Hydrogel membranes have been prepared from acrylamide (AAm) using N,N'-methylene-bis-acrylamide (MBAAm) as the cross-linker. Properties of...
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