Microwave-assisted Ultrafast RAFT Miniemulsion Polymerization of Bio-based Terpenoid Acrylates
Résumé
There is a growing preference to move away from traditional petrochemical-based polymers towards bio-based alternatives. Here, we report the microwave-assisted RAFT polymerization of several terpenoid acrylates (tetrahydrogeraniol, cyclademol, nopol and citronellol). These bio-based monomers give polymers with a broad range of glass transition temperatures and are excellent candidates to substitute oil-based (meth)acrylates in applications such as coatings and adhesives. First, the process was studied in miniemulsion, finding that all terpenoid acrylates showed a substantial increase in both polymerization rate and reaction control when microwave irradiation was applied. These observations were attributed to non-thermal microwave effects, namely to changes in the kinetic coefficients under irradiation. The reactions were also carried out in solution, where an amplified non-thermal microwave effect was observed. The results indicate that non-thermal microwave effects allow RAFT polymerization of these terpenoid acrylates proceed with both improved control and at higher polymerization rates compared to using conventional heating.