Nitroxide-mediated copolymerization of 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate: copolymerization kinetics and thermoresponsive properties.

Poly(2-hydroxyethyl acrylate) (PHEA) is an interesting biomaterial with similar biocompatibility as the widespread used poly(2-hydroxyethyl methacrylate). Poly(2-hydroxypropyl acrylate) (PHPA) is a less frequently studied polymer that exhibits thermoresponsive behavior in water. Therefore, copolymers of HEA and HPA are interesting thermoresponsive polymers to evaluate as potential biomaterials. Here, we report the copolymerization kinetics of HEA and HPA by nitroxide-mediated polymerization, employing Blocbuilder® initiator and SG-1 free nitroxide, revealing an ideal random copolymerization. Furthermore, the thermoresponsive properties of the resulting copolymers are discussed, whereby the cloud points are related to both polymer composition as well as polymer concentration.