Please use this identifier to cite or link to this item:
https://hdl.handle.net/10316/3827
Title: | Phase behavior of (polyacrylamides + water) solutions: concentration, pressure and isotope effects | Authors: | Azevedo, R. Gomes de Rebelo, L. P. N. Ramos, A. M. Szydlowski, J. Sousa, H. C. de Klein, J. |
Keywords: | Liquid-liquid equilibria; Polyacrylamides; Polymeric aqueous solutions; Pressure effects; Isotope effects | Issue Date: | 2001 | Citation: | Fluid Phase Equilibria. 185:1-2 (2001) 189-198 | Abstract: | Phase diagrams of poly(N-isopropylacrylamide) (PNIPAAM) as well as of hydrophilically-modified copolymers in aqueous solution were determined. A high-accuracy He-Ne Laser scattering technique was used for the detection of operational spinodal (sp) and cloud-point (cp) curves. Polymer concentration was varied from 0.5 to 20 wt.%. In the case of copoly(PNIPAAM/vinylsaccharide) several different chain lengths were considered. Pressure (up to 400 bar) and solvent isotope effects were studied. We predict a closed-loop type phase diagram for the copolymers, which presents an estimated hypercritical point in H2O solutions at Mw~0.5×105, although only lower critical solution temperature (LCST) is experimentally accessible. At lower molecular weights, the solutions are always in the one-phase region. | URI: | https://hdl.handle.net/10316/3827 | DOI: | 10.1016/s0378-3812(01)00469-1 | Rights: | openAccess |
Appears in Collections: | FCTUC Eng.Química - Artigos em Revistas Internacionais |
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filefdcba771600e4ba8b90e27a471a8b65e.pdf | 107.49 kB | Adobe PDF | View/Open |
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