Innovative BIO-Sourced Compatibilizers for Carbon and White Fillers in Rubber Compounds

Elastomers are fascinating materials, but they are not able to fulfill the requirements of demanding applications such as, for example, the one in tyre compounds.

Mechanical reinforcement of elastomeric materials is obtained with reinforcing fillers. Evolution of tyre technology has been for many decades based on carbon black. Silica is nowadays the preferred filler for achieving improved balance among key tyre performances such as low rolling resistance, high abrasion resistance and good wet traction. Nano-fillers are expected to bring discontinuities in rubber compounds performances. Clay minerals have been mostly investigated and the interest is nowadays mainly on carbon fillers such as carbon nanotubes, graphene, nanographite. The high surface area and aspect ratio of nano-fillers lead to establish high interfacial area with the polymer matrix and, thus, remarkable improvements of physical-mechanical properties. Even dispersion of white and carbon fillers and their intimate interaction with the polymer chains are pursued with coupling agents and functionalized polymers.

This contribution presents innovative bio-sourced compatibilizers suitable for both carbon and white fillers, nano- and nano-structured. Glycerol and glycerol derivatives were selected as the starting building blocks and the work was focused on molecules endowed with chemoselectivity. The synthesis, optimized to be green and atom economic, led to products with low and high molecular masses. The same molecules are able to promote the compatibilization with elastomers of either carbon or white fillers as well as the formation of hybrid filler systems. Synthetic aspects, preparation and characterization of elastomer composites, comparison with traditional compound formulations are discussed.