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 20wt.%. In the case of copoly(PNIPAAM/vinylsaccharide) several different chain lengths were considered. Pressure (up to 400bar) 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.
Original language | English |
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Pages (from-to) | 189-198 |
Number of pages | 10 |
Journal | Fluid Phase Equilibria |
Volume | 185 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 30 Jul 2001 |
Event | 14th Symposium on Thermophysical Properties - Boulder, United States Duration: 25 Jun 2000 → 30 Jun 2000 |
Keywords
- Data
- Isotope effects
- Liquid-liquid equilibria
- Polyacrylamides
- Polymeric aqueous solutions
- Pressure effects