Homogeneous polymerization of hydrophobic monomers in a bio-based dl-menthol/1-tetradecanol eutectic mixture by ATRP and RAFT polymerization†
A bio-based eutectic mixture (EM), composed of DL-menthol and 1-tetradecanol was investigated for the first time as the solvent for the homogeneous polymerization of different hydrophobic monomers, namely methyl acrylate (MA), methyl methacrylate (MMA), styrene (Sty), butyl acrylate (n-BA), vinyl chloride (VC) and vinyl acetate (VAc), by atom transfer radical polymerization (ATRP) and/or reversible addition–fragmentation chain transfer (RAFT) polymerization. Homopolymers with low dispersity (Đ = [1.05–1.4]) were obtained by both polymerization techniques. The high chain-end functionality of the polymers was confirmed by the synthesis of well-defined block copolymers: PMA-b-PBA by ATRP and PMMA-b-PMA by RAFT. ATRP could be conducted with a catalyst concentration as low as 60 ppm near room temperature, making this an attractive eco-friendly process for the synthesis of tailor-made hydrophobic polymers. In addition, due to phase separation at the end of reaction, both the EM and the catalytic system could be easily recovered and successfully reused in a new ATRP reaction. The system reported could be very attractive from both economic and environmental standpoints.