LAUSR

A biorenewable polymer was synthesized via a green process using the RAFT principle for the first time in supercritical CO2 at 300 bar and 80°C. α-Methylene-γ-butyrolactone polymers of various chain lengths and molecular weights were obtained. The molecular weights varied from 10000 up to 20000 with low polydispersity indexes (PDI <1.5). Furthermore, the monomer conversion in supercritical CO2 was substantially higher, respectively 85+ % for ScCO2 compared to around 65% for polymerizations conducted in dimethyl formamide (DMF) solvent. Chain extensions were carried out to confirm the livingness of the formed polymers in ScCO2. This opens up future possibilities of the formation of different polymer architectures in ScCO2. The polymers synthesized in ScCO2 have glass transition temperature (Tg) values ranging from 155°C up to 190°C. However, the presence of residual monomer encapsulated inside the formed polymer matrix affected the glass transition of the polymer which was lowered by increasing monomer concentrations. Hence, additional research is required to eliminate the remaining monomer concentration in the polymer matrix in order to arrive at the optimal Tg. This article is protected by copyright. All rights reserved.