Determination of cloud-point temperatures for different copolymers

Abstract

This paper describes a novel system which has a great potential for use for extractions in biotechnological processes as it uses only polymers and can be operated at moderate temperatures and salt concentrations. The polymers used in this work are ethylene oxide-propylene oxide 10:90 (w/w) (EO10PO90) and ethylene oxide-propylene oxide 20:80 (w/w) (EO20PO80). The temperature required for thermoseparation decreases with increasing PO content of the copolymer and increasing buffer concentration

Density, Refractive Index, pH, and Cloud Point Temperature Measurements and Thermal Expansion Coefficient Calculation for PPG400, PE62, L64, L35, PEG400, PEG600, or PEG1000 + Water Systems

“…Similar behavior was found in the literature for block L62, L92, and random PE62 copolymers. The formation of two cloud points for PE62 was determined at different pH solutions, but the fade temperature occurrence was not shown.…”

“…Similar behavior was found in the literature for block L62, 93 L92, 94 and random PE62 56 copolymers. The formation of two cloud points for PE62 56 was determined at different pH solutions, but the fade temperature occurrence was not shown. Alred et al 38 determined cloud point equal to 291.15 K for the PE62 + water system, but the authors did not report the phase diagram.…”

“…On the other hand, considering phase transition, cloud point or lower critical solute temperature ( T cloud ) data were reported for PPG 400 + water by Malcolm and Rowlinson for polymer mass fraction from 0.05 up to 0.85. The PE62 + water system was also studied previously , for polymer mass fraction up to 0.22, while L64 + water and L35 + water were studied only up to 0.1 mass fraction. Nevertheless, none of these works reported thermophysical properties measurements during phase transition.…”

Synthesis and phase behavior of aqueous poly(N-isopropylacrylamide-co-acrylamide), poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) and poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate)

“…The cloud-point temperature T cp is the temperature at which the solution becomes turbid due to the formation of polymer-rich emulsion droplets [22]. T cp of PNINAM aqueous solution is roughly independent of molecular weight and concentration of PNIPAM [2].…”

Potential for desalination using lower critical solution temperature polymers: Concentration of salt solutions by pluronic PE6200

“…Further work by our group will look into designing LCST polymers that can absorb water and release the water by heating, not at a specific ‘cloud point’ but gradually with increase in temperature, in the range of 20–50°C. We intend to combined different monomers to vary LCST behavior12, 22, 23 and include a crosslinker13 to produce polymers with controllable water sorption/desorption properties as a function of temperature and do not dissolve. The PE 6200 pluronic polymer absorbed between 1 and 5 mL of water per 10 g of polymer, this is low and will result in inefficiency and expense, so we will investigate whether other polymers are able to absorb more water, yet yield low salt uptake.…”