Lipase-catalyzed synthesis of poly(e-caprolactone) in supercritical carbon dioxide

In this study, the synthesis of poly(ε-caprolactone) by lipase-catalyzed reactions in supercritical carbon dioxide was performed in a batch reactor in order to evaluate the influence of the operating conditions on polymer chain size and on polydispersity index. Firstly, a fractional 24−1 factorial design was performed to evaluate the effect of temperature, concentration of enzyme, water content and agitation. Then, a full 23 experimental design was carried out to evaluate the effects of pressure, enzyme concentration and water content. The best result was a polymer chain size of 7419.6 g/gmol, obtained in a reaction conducted at 145 bar, 65 °C, 200 rpm, 10 wt% enzyme concentration and at the lowest water content.