Molecular Rebar Design, LLC (MRD) has been awarded a Small Business Innovation Research (SBIR) Phase I award from the U.S. Environmental Protection Agency (EPA) to use MOLECULAR REBAR® (MR) carbon nanotubes to reduce or replace 6PPD in tire compounds, targeting similar/better lifetime of tires with less environmental impact.
MR imparts significant abrasion, tear, and crack propagation resistance properties to elastomers. With the use of MR, ozonation-related microcrack propagation will be lessened, preventing coalescence of microcracks, and thus reducing larger crack occurrence. With this additional reinforcement in a tire compound, the quantity of 6PPD used can be reduced, or 6PPD can be replaced with a less effective, but environmentally safer antiozonant- like 77PD. Treating the effects of polymer ozonation, rather than preventing the initial ozone degradation, is a unique approach that can be implemented commercially more quickly than the evaluation of a new small-molecule antiozonant- which may require exhaustive environmental testing, in addition to the rubber compound tests.
In Phase I, Molecular Rebar Design, LLC will determine what type of carbon nanotube surface functionality is most effective at preventing crack propagation, and then formulate tire sidewall elastomer compounds with those nanotubes while varying the type and quantity of antiozonant present in the sidewall compounds. These rubber compounds will undergo ozone aging to simulate real-world conditions, whereafter the aged samples will be tested for differences in crack resistance, lifetime, tear strength, and intrinsic strength. These experiments will culminate in a sidewall compound formulation that is less environmentally damaging than incumbent compounds that utilize a full loading of 6PPD. The resultant experimental compound will be designed to have the same, or better, expected lifetime as an incumbent sidewall compound.
This Phase I award, contract no. 68HERC24C0030, will be performed over 6 months from 12/01/2023 to 05/31/2024 by Molecular Rebar Design, LLC in Austin, TX. This contract was awarded after MRD’s response to solicitation number 68HERC23R0249, and more information related to the award itself can be found here.