Abstract
The effect of supercritical CO 2 on the viscosity and activation energy to viscous flow of P DLLA is investigated, using a high pressure parallel plate rheometer, over a range of temperatures (50-140 °C) and pressures (5-12 MPa). The Cross model is fitted to the data to enable calculation of the zero shear viscosity and critical shear rate. A significant decrease in the viscosity is observed on increasing both variables; however, at high temperatures, the pressure effect becomes negligible. An increase in the critical shear rate is also observed on raising the pressure, indicative of a reduction in the relaxation time of the polymer. Manipulation of the Arrhenius equation shows a reduction in the activation energy to viscous flow as the pressure is increased. Together, these results show that the melt processing temperature of P DLLA can be reduced in the presence of supercritical and high pressure CO 2.
Original language | English |
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Pages (from-to) | 1383-1393 |
Number of pages | 11 |
Journal | Journal of Polymer Science, Part B: Polymer Physics |
Volume | 50 |
Issue number | 19 |
DOIs | |
Publication status | Published - 1 Oct 2012 |
Keywords
- activation energy
- polylactide
- processing
- supercritical CO
- viscosity
ASJC Scopus subject areas
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Polymers and Plastics
- Materials Chemistry