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

Abstract

(2015) High-pressure rheological analysis of CO2-induced melting point depression and viscosity reduction of poly(ε-caprolactone). Polymer, Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/45413/1/curia_polymer2015_preprint.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the Creative Commons Attribution Non-commercial No Derivatives licence and may be reused according to the conditions of the licence. For more details see: http://creativecommons.org/licenses/by-nc-nd/2.5/ A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Furthermore, a significant decrease in the viscosity of two PCL grades with different molecular weight (M n~1 0 kDa and 80 kDa) was also detected upon increasing the CO 2 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.

Synergy of supercritical CO2 and superheated H2O for enhanced processability of polyethersulfone towards open cell foams

“…Supercritical carbon dioxide (scCO 2 ) offers a promising green alternative for membrane preparation and polymer processing in general [7][8][9][10][11][12][13]. The scCO 2 exhibits the density of a liquid and the diffusivity like that of a gas.…”

The influence of supercritical foaming conditions on properties of polymer scaffolds for tissue engineering

“…In recent years the development of modern technologies has been mainly focused on the advancement in research of innovative, efficient, cost-effective and environmentally safe methods of the production of functional porous structures. New products may be useful for a wide range of applications, for example as biodegradable scaffolds for the culture of bone cells (Curia et al, 2015;Gualandi et al, 2010;Karimi et al, 2012;Kweon et al, 2003). There are numerous production methods of polymer porous materials applicable to biomedical practices, such as solvent casting-particle leaching, thermally induced phase separation, injection molding, extrusion, foaming and electrospinning (Guan et al, 2005).…”

“…Supercritical carbon dioxide (scCO2) is the most commonly used supercritical fluid, possessing such attributes as moderate values of critical parameters, chemical passivity, nonflammability, non-toxicity, wide availability and low cost (Nalawade et al, 2006). Its unique characteristics, such as gas like low kinematic viscosity, liquid like density, high compressibility and pressure-dependent solubility of various substances, are beneficial for applications of scCO2 in industrial technologies (Curia et al, 2015;Guan et al, 2005;Karimi et al, 2012). Carbon dioxide applied as a supercritical process medium can be easily removed from porous products simply by depressurization.…”

“…Poly(ε-caprolactone) (PCL) is a polymer commonly used in tissue regenerative engineering. It is a biodegradable aliphatic semi-crystalline polyester of a low melting temperature of about 333 K (Curia et al, 2015;Guan et al, 2005;Karimi et al, 2012;Kweon et al, 2003). In the foaming process of PCL using scCO2 one can distinguish the following stages: melting and saturating the polymeric material with scCO2 at appropriate parameters, cooling and depressurization of saturated polymer matrix, and finally nucleation and growth of gas cells which leads to formation of the final porous structure (Gualandi et al, 2010;Jacobs et al, 2007;Karimi et al, 2012;Reverchon et al, 2008).…”

Green process for green materials: viable low-temperature lipase-catalysed synthesis of renewable telechelics in supercritical CO 2

“…CO2 has been exploited as a solvent for polymerisations (36,37), as a foaming agent (32,38), for precipitation/separation (39), particle formation (40,41) and encapsulation (42). High-pressure CO2 is a good solvent for many small molecules and it is very effective at plasticising and effectively liquefying many polymers at temperatures below their glass transition temperature (Tg) and melting point (Tm) (33,41,(43)(44)(45)(46)(47)(48)(49)(50)(51)(52), therefore opening up new opportunities for polymer synthesis and modification.…”