Oligo-b-Alanine b-Sheets As Crosslinker and Filler

The present project aims to use oligo-b-alanines covalently attached to rubbers as the crosslinker and filler.  The oligo-b-alaninemotifs self-associate into b-sheets through cooperative multiple intermolecular hydrogen bonds to achieve physical crosslink .The self-associatedoligo-b-alaninesb-sheets phase separate from hydrocarbon polymers even at a few percent of the total weight to form crystalline b-sheet domains. The crystalline domains further act as fillers.The oligo-b-alanine domains are covalently linked to the hydrocarbon polymers and hence have the strongest filler-polymer interaction possible. They are expected to compensate for the carbon black network under a low-frequency stress and a low-amplitude strain to delay and reduce the loss of storage modulus, known as the Fletcher-Gent effect or Payne effect.At high frequency and high amplitude, the sheets may slide against each other, and/or the hydrogen bonds can break and re-form. Each serves as an energy dissipation mechanism. The above design of novel supramolecularcrosslinker/filler system is expected to produce the following practical results: reduced rolling resistance, improved wet-skid resistance, and improved strength and crack resistance. Consequently, the tires produced with this technology are expected to be fuel efficient without compromising safety.

We have been able to demonstrate that the supramolecularoligo-b-alanine filler is able to increase the ultimate tensile strength by at least 40% and reduce the loss factor tand at 60 °C to almost half while maintaining tandat 0 °C about the same. The delay and reduction of Payne effect has also been observed.