New cosolvents effects. Solubility behavior

Cosolvent effect of alkyl acrylates on the phase behaviour of poly(alkyl acrylate)supercriti-cal CO2 mixtures has been reported. Cloud-point data to 220 and 2000 bar are presented for ternary mixtures of poly(butyl acrylate)-C02-butyl acrylate (BA) and poly(ethylhexyl acrylate)-C02-ethylhexyl acrylate) (EHA). The addition of either BA or EHA to the respective polymer-solvent mixtures decreases the cloud-point pressures by as much as 1000 bar and changes the pressure-temperature slope of the cloud-point curves from negative to positive, which significantly increases the single-phase region. 

The literature presents many studies on coil dimensions of synthetic polymers in mixed solvents. Most investigations involve liquid mixtures composed of a good and a poor solvents for the polymer. The action of mixed solvents has been reported to change coil dimensions, not only because of excluded volume effect or due to the interactions existing between the two liquids but also due to the preferential adsorption of one of the solvent by the polymer. 

Recently, the behavior of polysiloxanes with amino end-groups in tolu-ene/nitromethane mixtures has been reported. This mixture is solvent/non-solvent for the 

The transition concentrations separating the concentration domain chain flexibility aspects, excluded volume effects and total and preferential adsorption coefficients of the same system have been discussed. 

Anoflier interesting effects are flie changes of a polyelectrolyte in binary solvents. The complex inter and intramolecular interactions that take place due to the presence of hydrophilic and hydrophobic structural units in the macroion can modify the balance of the interactions and for this reason can change flie solubility.  

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