C.T.S.G. Alembic

Circular tires: Strengthening styrene butadiene rubber (SBR) by non-covalent interactions

All cars of the world produce a billion used tires every year. Their replacement requires a lot of resources and energy. It would be of enormous value to become able to recycle car tires, not only for new tires, but also for other materials and applications.

Elastomers are three-dimensional networks of polymers with special properties such as elasticity or damping, durability, and for some polymers high strength due to strain crystallization. The largest application for elastomers is tires: the majority of natural and synthetic rubber is consumed by the tire industry. Recycling is a major challenge because of the crosslinked nature of these materials.

Blocked styrene butadiene rubber (SBR) is intrinsically better recyclable than random SBR. However, it is too weak for the purpose of tires, therefore, it has to be strengthened for use in a tire. Implementing non-covalent interactions between subunits of the SBR components may strengthen the material while maintaining easier recyclability.

This MSc assignment aims to explore different methods for implementing non-covalent interactions between SBR monomers.

The first is the use of cations (administered as salt) to introduce cation-pi interactions between the styrene subunits. Typical cations will be Li+ and Na+. Key will be to use lipophilic, weakly coordinating counter-anions in order to achieve solubilization and liberate the cation for interaction with the styrene subunits.

The second is the design and synthesis of small, oligomeric additives with electron-poor aromatics to create charge-transfer interaction pairs with the, relatively electron-rich, styrene subunits. Precursors will hook these up to a platform molecule (a divalent linker or a tri- or tetravalent template). Some of these will be synthesized, and the produced molecules will be implemented in the SBR formulation as an additive. Assessment of mechanical properties will be performed to compare the properties of the functionalized SBRs with the native one.

Contact info:

Supervisors:
Jurriaan Huskens, j.huskens@utwente.nl;
Jean-Paul Lange, j.p.lange@utwente.nl

Daily Supervisor:
T.B.D.