Grantee Research Project Results

Recycle & Reuse for Superelastic SMA Tires via Intermediate Thermal Annealing

EPA Contract Number: 68HERC24C0029
Title: Recycle & Reuse for Superelastic SMA Tires via Intermediate Thermal Annealing
Investigators: Weinberg, Charles
Small Business: The SMART Tire Company, Inc.
EPA Contact: Richards, April
Phase: I
Project Period: December 1, 2023 through May 30, 2024
Project Amount: $99,903
RFA: Small Business Innovation Research (SBIR) - Phase I (2024) RFA Text |  Recipients Lists
Research Category: Small Business Innovation Research (SBIR)

Description:

The Smart Tire Company (STC) tires utilize large deformational recovery of superelastic shape memory alloys (SMA), eliminating the need for pneumatics, and enabling stronger, lighter, environmentally friendly solutions to the innovation-starved and wasteful global tire market. STC seeks to develop an innovative and safe process for the reuse and recycling of SMA components to bolster the already beneficial environmental impacts of non-pneumatic, never-flat tires. The limiting factors on the lifetime of these tires are 1) the wear on the rubber treads and 2) the lifetime of the SMA components. While retreads are already an established process in the tire industry, SMA components are primarily used in the medical industry where reuse & recycling is not considered an acceptable approach. While there has been some research on fatigue life, crack propagation, and stress-relieving SMA through thermal annealing, this would be the first investigation and development of a product-specific reuse program for SMA. STC seeks funding to develop methods for extending the functional lifetime of superelastic SMA components to be a part of its recycling program, potentially extending the lifetime of their tires beyond the lifetime of their connected vehicles. It should be imminently feasible to perform the proposed experiments: durability testing of tires and characterization of SMA are independently understood processes that have not previously been performed together.

The commercial impact of high performance airless tires in general is well understood and demand is high; however, cost is a primary factor in buying decisions, and supply of shape memory alloys is limited compared to other more popular alloys. As such, the ability to recycle and reuse the materials has a large direct impact on future adoption. Extending life decreases the effective cost per mile of the technology, and also relieves pressure from the supply chain for new first-time use material.

Tire waste is a significant and growing global problem, which produces over 50B lbs of end of life tires annually. Much of this waste is due to the inherently disposable nature of tires. Airless solutions address the problem through increased durability, but are typically lacking in some key areas such as performance. Micro-plastic contamination is another significant problem for which airless tires may have at least a partial solution. Eliminating the risk of under-inflation limits the occurrence of uneven, accelerated tread wear.

Progress and Final Reports:

Final Report