High-pressure rheological analysis of CO2-induced melting point depression and viscosity reduction of poly(ε-caprolactone)

Curia, Silvio and De Focatiis, Davide S.A. and Howdle, Steven M. (2015) High-pressure rheological analysis of CO2-induced melting point depression and viscosity reduction of poly(ε-caprolactone). Polymer, 69 . pp. 17-24. ISSN 0032-3861

[img]
Preview
PDF (Post-review preprint) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Available under Licence Creative Commons Attribution Non-commercial No Derivatives.
Download (1MB) | Preview

Abstract

High-pressure rheology has been used to assess the effects of supercritical carbon dioxide (scCO2) on the melting point (Tm) and viscosity of poly (ε-caprolactone) (PCL) over a range of temperatures and pressures up to 300 bar over a wide range of shear rates. Plots of the storage and loss moduli against temperature show a significant shift of Tm to lower temperatures in the presence of CO2, indicating that the polymer crystals melt at temperatures much lower than the ambient pressure Tm. Furthermore, a significant decrease in the viscosity of two PCL grades with different molecular weight (Mn ~ 10 kDa and 80 kDa) was also detected upon increasing the CO2 pressure to 300 bar. Experimental viscosity data were fitted to the Carreau model to quantify the extent of the plasticising effects on the zero-shear viscosity and relaxation time under different conditions. Similar analyses were conducted under high-pressure nitrogen, to compare the effects obtained in the presence of a non-plasticising gas.

Item Type: Article
Keywords: Poly(ε-caprolactone), Supercritical CO2, Rheology
Schools/Departments: University of Nottingham, UK > Faculty of Engineering > Department of Mechanical, Materials and Manufacturing Engineering
University of Nottingham, UK > Faculty of Science > School of Chemistry
Identification Number: 10.1016/j.polymer.2015.05.026
Depositing User: De Focatiis, Dr Davide S A
Date Deposited: 05 Sep 2017 10:16
Last Modified: 06 Sep 2017 00:03
URI: http://eprints.nottingham.ac.uk/id/eprint/45413

Actions (Archive Staff Only)

Edit View Edit View