Elastomer-polymer blends for improving tire performance

This is a PhD research project in materials chemistry.
The challenge in improving car and truck tire performance is to reduce its rolling resistance, whilst simultaneously increasing energy dissipation during braking. It is known that blending of natural and synthetic rubbers with thermoplastic polymers can have profound effects on tire performance. However, a priori molecular level understanding and the relationship to the observed mechanical property changes are still not well understood. The overall aim of the project is therefore to understand structure-property relationships in elastomer-polymer blends in model tire compounds.

The observed property enhancements are known to be dominated by changes in molecular dynamics, and yet the correlation to either the blend structure or the continuum mechanics is not well understood. This project will therefore initially synthesize model styrene-butadiene elastomer and linear polymers (controlled MW & DPI) as the basis of the subsequent studies.

These model systems will be used to investigate the effect the polymers have on the glass transition temperature (Tg), and also temperature dependence of the dynamics and dynamic heterogeneity of the elastomers in blends. These data will be correlated with the blend morphology and chain structure and mechanical properties, including basic deformation performance, but also tire related metrics of roll resistance, wear and tribology.

The primary techniques to determine the dynamic properties over a wide frequency regime will be studied by a combination of dynamic mechanical analysis (DMA) coupled with quasi-elastic neutron scattering (QENS). Structural studies to evaluate the blend structure will exploit optical and electron microscopy coupled with X-ray and neutron scattering. These techniques will be combined with other analytical techniques incl DSC and GPC. Specialist equipment for compounding and tire testing will also be accessed at the research base at Continental Tires (Germany) as part of the collaboration and support by the company.