Abstract
The effects of compressed carbon dioxide at slightly subcritical temperatures on solutions of a chloro-substituted, para-linked aromatic polyamide (PPTA-Cl) in dimethylacetamide were investigated by depolarized light spectroscopy. Pressurization of isotropic solutions resulted in polymer precipitation at a sharply defined pressure. Pressurization of nematic solutions resulted in an increase in the intensity of scattered light with no evidence of precipitation. A plausible interpretation of this observation is the occurrence of liquid-liquid phase separation into polymer-rich (anisotropic) and polymer-lean (isotropic) phases induced by the compressed carbon dioxide. The results suggest that compressed, near-critical antisolvents can be used to control the degree of anisotropy in liquid-crystalline polymeric systems.
Original language | English (US) |
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Pages (from-to) | 4904-4909 |
Number of pages | 6 |
Journal | Macromolecules |
Volume | 29 |
Issue number | 14 |
DOIs | |
State | Published - Jul 1 1996 |
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry