Terpene Based Sustainable Elastomer for Low Rolling Resistance and Improved Wet Grip Application: Synthesis, Characterization and Properties of Poly(styrene-co-myrcene)

Incited by the unprecedented surge of developing sustainable polymers, we demonstrate herein a green emulsion polymerization route toward the development of sustainable rubbery materials based on β-myrcene (MY) and styrene (ST) for low rolling resistance and improved wet grip applications. The microstructure of the synthesized copolymers was found to be governed by the ST weight percent. For example, the copolymers having less than 40 wt % of ST had 1,2 vinyl and 3,4 addition products along with 1,4-cis and -trans microstructure of the polymyrcene unit, whereas the copolymers having higher weight percent of ST had only 1,4-cis and -trans microstructure of the polymyrcene unit. The copolymers displayed improved onset degradation temperature and subambient glass transition temperatures. The copolymer having a 70/30 weight/weight ratio of MY/ST displayed a molecular weight of 51 500 Da and a glass transition temperature of −35.2 °C. The 70/30 rubber vulcanizate exhibited satisfactory mechanical properties (tensile strength of 6.4 MPa and elongation at break of 395%). Dynamic mechanical analysis of the vulcanizate reveals improved traction and low rolling loss over a standard tire tread compound, thereby making it a promising material for tires.