화학공학소재연구정보센터
Journal of Supercritical Fluids, Vol.128, 404-411, 2017
Enzymatic ring opening copolymerization of globalide and epsilon-caprolactone under supercritical conditions
The enzymatic ring opening copolymerization of globalide and epsilon-caprolactone under supercritical conditions was investigated. Samples were evaluated in terms of molecular weight, thermal properties, ratio between repeating units, and production of cyclic oligomers. For the first time, poly(globalide-co-epsilon-caprolactone) (PG1CL) was synthesized by epsilon-ROP using supercritical carbon dioxide (scCO(2)) and the mixture scCO(2) + dichloromethane (DCM) as solvents. The feed ratio between globalide and epsilon-caprolactone was evaluated. PG1CL synthesized in scCO(2) showed the highest molecular weights, while the use of cosolvent caused a decrease on molecular weight values. For both scCO(2) and scCO(2) + DCM, the increase on globalide content (relative to total monomers amount) increased molecular weight values. Thermal analysis indicated a non-isomorphic behavior, characteristic of random semi-crystalline copolymers, which is the case of the PG1CL produced. PGICL synthesized on scCO(2) + DCM presented double melting point, which is related to a greater presence of cyclic oligomers, in comparison to PG1CL synthesized using only scCO(2), being confirmed by MALDI-TOF analysis.