Enhanced miscibility of low-molecular-weight polystyrene/polyisoprene blends in supercritical CO{sub 2}
- North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemical Engineering
- Procter and Gamble Co., Cincinnati, OH (United States). Corporate Research Div.
- Oak Ridge National Lab., TN (United States)
While ongoing efforts continue to explore the high-pressure phase equilibria of polymer blends, few studies have attempted to address the impact of a supercritical (sc) fluid on such equilibria. In this work, the authors report on the phase behavior of an upper critical solution temperature (UCST) polymer blend in the presence of supercritical carbon dioxide (scCO{sub 2}), a nonselective plasticizing agent. Blends composed of low-molecular-weight polystyrene and polyisoprene have been examined as a function of temperature in scCO{sub 2} by visual inspection, small-angle neutron scattering, and spectrophotometry. In the presence of scCO{sub 2}, the cloud point temperature is depressed by as much as 28 C, depending on both blend composition and CO{sub 2} pressure. Complementary studies performed with nitrogen decouple the plasticization efficacy of CO{sub 2} from free-volume compression due to hydrostatic pressure. Existence of a pressure yielding a maximum in CO{sub 2}-induced cloud point depression is established. These results provide evidence for enhanced polymer miscibility as a result of the plasticizing effectiveness and tunable solubility of scCO{sub 2}.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 682078
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Vol. 103, Issue 26; Other Information: PBD: 1 Jul 1999
- Country of Publication:
- United States
- Language:
- English
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