K. Cornish and H.A. Colvin
EnergyEne Inc, United States
Keywords: Advanced elastomers, all natural rubber tires, biorubber, critical materials securityIn 2018, the US imported $1.5 billion-worth of natural rubber (NR) and $13 billion-worth of tires. 13.96 million tons of NR was collected by poorly-paid workers (mostly south east Asian) – still insufficient to supply global demand. With no commercial NR production, the US depends on other nations’ productivity and political goodwill. Biodiversification of global NR is essential because NR is the only critical agricultural product which has no back up. Synthetic rubber cannot mimic NR’s unique, essential performance properties. Cooper Tire has proved that the alternative semi-arid zone rubber crop, guayule, can be used to make 100% GNR tires which outperform current requirements and have excellent cold weather performance. Furthermore, waste-derived reinforcing fillers used in combination with carbon black or bifunctionalized silica improve performance and reduce carbon footprint. A novel guayule-derived processing aid can replace petroleum-based napthenic oil processing aids in natural and synthetic rubber without lowering material performance. Dynamic X-ray diffractometry reveals that strain-induced crystallites in GNR are larger than those in imported NR and load or stretch-induced vulcanized GNR strength is enhanced. Ford truck bushings and isolators have successfully been manufactured using GNR and eggshell fillers, respectively.