|Appears in Collections:||eTheses from Faculty of Natural Sciences legacy departments|
|Title:||Multiple phase equilibria in polar polymer solutions containing poly (acrylic acid)|
|Author(s):||Swinyard, Brian Trevor|
|Publisher:||University of Stirling|
|Abstract:||The cloud-point curves for solutions of poly(acrylic acid) in 1,4-dloxane, 1,4-dloxane/water mixtures, tetrahydrofuran and tetrahydrofuran/water mixtures as a function of molecular weight and solvent composition were determined. These systems are unusual in that they exhibit three phase separation boundaries on raising the temperature from room temperature to 500K designated as pseudo-LCST (p-LCST), UCST and LCST behaviour respectively in order of Increasing temperature. Systems consisting of poly(acrylic acid) together with small chain poly(ethylene glycol)s and poly(propylene glycol)s In 1,4-dioxane were also studied and, in general, they exhibited simple LCST behaviour. Critical points for the pseudo-LCST phase separation boundary were determined for the higher molecular weight poly(acrylic acid)s in 1,4-dloxane, using the phase volume ratio method. The variation of the intrinsic viscosity of solutions below the pseudo-LCST was measured as a function of temperature increasing towards the phase separation boundary. The structure and possible complex formation in the system at temperatures below the pseudo-LCST were determined using laser raman spectroscopy. Preferential solvation studies, using light scattering techniques, were also made on the mixed solvent system 1,4-dioxane/water, from which data were obtained which could be compared with those derived from solution viscosity. The variation of the enthalpic interaction parameter, Xh, was determined from heat of dilution data derived from microcalorimetry experiments. The cloud-point curves for the poly(acrylic acid) In 1,4-dloxane system were compared to poly(N-isopropylacrylamide) in water, which exhibited simple LCST behaviour and aqueous solutions of poly(vinyl alcohol) which formed a closed-loop of immiscibility.|
|Type:||Thesis or Dissertation|
This item is protected by original copyright
Items in the Repository are protected by copyright, with all rights reserved, unless otherwise indicated.
The metadata of the records in the Repository are available under the CC0 public domain dedication: No Rights Reserved https://creativecommons.org/publicdomain/zero/1.0/
If you believe that any material held in STORRE infringes copyright, please contact firstname.lastname@example.org providing details and we will remove the Work from public display in STORRE and investigate your claim.