Abstract
The critical degree of polymerization (Jcrit) at which polymer chains become insoluble in the continuous medium and particle formation commences has been estimated under a variety of experimental conditions for the nitroxide-mediated precipitation polymerizations of styrene (St) at 110 C and tert-butylacrylate (t-BA) at 118 C in supercritical carbon dioxide (scCO2) mediated by N-tert-butyl-N-[1-diethylphosphono(2,2-dimethylpropyl)]oxy (SG1). The value of Jcrit increases with increasing target molecular weight, initial monomer loading, and pressure. Under the conditions investigated, Jcrit fort-BA is higher than that for St, which is consistent with greater solubility of poly(acrylates) in neat scCO2. A simple graphical approach has been developed and successfully employed, whereby Jcrit can be predicted as a function of both target molecular weight and initial monomer loading on the basis of a data set of Jcrit versus initial monomer
loading.
loading.
| Original language | English |
|---|---|
| Pages (from-to) | 914-919 |
| Number of pages | 6 |
| Journal | Macromolecules |
| Volume | 43 |
| Issue number | 2 |
| Early online date | 18 Nov 2009 |
| DOIs | |
| Publication status | Published - 26 Jan 2010 |
| Externally published | Yes |
Keywords
- Mixtures
- Monomers
- Polymerization
- Polymers
- Radical Polymerization