Toward Biosourced Elastomer from beta-Farnesene and Styrene: Synthesis, Properties, and Mechanical Performance

Abstract

Encouraged by the growing need forsustainability inthe rubberindustry, attempts have been made to fabricate biobased elastomersto replace existing petro-derived polymers for useful applications.Here, we demonstrate a simple and sustainable route to synthesizebiobased elastomers based on beta-farnesene (FA) and styrene (STY)under a high-temperature persulfate emulsion process for tire applications.The synthesized copolymer, poly-(farnesene-co-styrene)(PFS), showed molecular weight (M (w)) of108 500 g/mol and 162 100 g/mol for 30 and 50 wt % styrenecontents. The commoner reactivity ratios showed nonideal copolymerizationbehavior, as evaluated using Fineman-Ross and Kelen-Tu''do''smethods. The macromolecular chemical structure of PFS elastomers wasconfirmed by FT-IR and NMR analyses. The copolymer showed complete1,4-cis and trans-microstructureformation. The glass-transition temperature (T (g)) values of PFS elastomers were obtained in the range of -58and -38 degrees C, depending on the styrene content. The PFSgum elastomers displayed improved thermal stability and single degradationpattern compared to the pristine polyfarnesene. Besides, carbon blackwas incorporated into the PFS elastomer matrix to prepare rubber vulcanizatesfor desired mechanical properties. The 50/50 FA/STY rubber vulcanizatesdisplayed good tensile strength (4.43 MPa), elongation at break (183%).The 80/20 and 70/30 FA/STY rubber vulcanizates exhibited good wetskid resistance compared to its pristine polyfarnesene vulcanizate.This work provides an efficient approach to using emulsion polymerizationfor developing sustainable rubbers on an industrial scale for multifacetedapplications.