Silvio Curia
University of Nottingham, UK
Title: Low temperature lipase-catalysed synthesis of renewable functional telechelic polyesters in supercritical CO2
Biography
Biography: Silvio Curia
Abstract
The use of green monomers for the replacement of fossil-based raw materials is an attractive research subject of modern polymer science . To achieve a completely green process, enzymes have been investigated as polymerisation catalysts . Unfortunately, the high melting point (>105 °C) of some diacids and their insolubility in non-polar solvents necessitate the use of their esters and limits the range of natural monomers that could be used without pre-modification . Moreover, the use of high temperature is expensive and can lead to side reactions and enzyme deactivation . Here we show that scCO2 can overcome these issues. In recent years the interest on the use of scCO2 as a medium for polymer synthesis and processing has increased steeply . ScCO2 is able to plasticise many polymers at temperatures below their glass-transition temperature and melting point, therefore opening new opportunities for polymer synthesis and modification . Here we investigate the poly-condensation of bio-based commercially available long-chain diacids and diols under scCO2. Telechelic polyesters with targeted molecular weight were synthesised by end-capping the chains with functional molecules. The use of scCO2 as a reaction medium allowed for the use of Candida Antarctica Lipase B (CaLB) as a catalyst at a temperature as low as 35 °C. Thus, easily preserving the functionality of the end-capper and the enzyme activity, so that it can be then recycled. The products, obtained with good yields, have been characterised to assess their structural and thermal properties. Finally, the telechelic chains were cross-linked to form useful naturally derived films.