Toward Bio‐Sourced Elastomers with Reactive/Polar Groups. Myrcene – Glycidyl Methacrylate Copolymerization: Reactivity Ratios, Properties, and Preliminary RAFT Emulsion Polymerization

Abstract

AbstractThere is a pronounced need of replacing fossil‐origin materials with sustainable ones. Myrcene (Myr) is a biobased terpene‐type monomer derived from diverse plants that is a potential substitute for diene monomers (e.g., butadiene), in the manufacture of elastomers. Here, the copolymerization of Myr with glycidyl methacrylate (GMA) is studied as a candidate route for producing functional/polar elastomers. Reactivity ratios (RR) for this system are estimated using the error‐in‐variables method resulting in rMyr = 0.519 ± 0.062 and rGMA = 0.301 ± 0.014, indicating an alternating tendency. The copolymers obtained exhibit number‐average molecular weights (Mn) in the range 42–674 kDa that markedly increase with the GMA content and dispersities in the range 1.49–1.90. The addition of Myr units predominantly results (1H‐NMR) in the 1,4 cis microstructure (94–97%) that increases with the GMA content. Differential scanning calorimetry analysis is performed in some of the copolymer samples. Additionally, preliminary emulsion copolymerizations of Myr‐GMA are carried out at 70 °C, 15% solids, with potassium persulfate as initiator and 4‐cyano‐4‐[(dodecyl sulfanylthiocarbonyl)sulfanyl] pentanoic acid as RAFT agent, yielding conversions of 74–85% in 24 h and gel contents of 17–78% that increase with increasing GMA (0–21%) fed. The GMA presence in the copolymer is demonstrated by fourier transform infrared spectroscopy (FTIR) analysis.