Elastically effective devulcanized ground tyre rubber (GTR) for high recyclate content rubber blends, and their compatibility with nanofillers

This paper demonstrates that mechanical devulcanization techniques, such as solid-state shear milling (S3M), can produce a recycled rubber powder that is elastically effective when blended into a virgin rubber matrix. Furthermore, blends produced via this route match the equivalent virgin rubber modulus, despite high recyclate loadings (30/70 vNR/GTR blend). The addition of nanofillers (carbon black and graphene nanoplatelets) to these blends was evaluated to see how their impact differed from a virgin matrix and how they compared with filler reinforcement theories. Stiffness of the filled blend could be related to the aspect ratio of graphene nanoplatelets or shape factor for carbon black. Results pointed to differences between standard vulcanization of a virgin material and revulcanization of a recycled blend, highlighting scope for further development of recycled rubbers. This process may allow for incorporation of devulcanized rubber into existing engineering products, promoting a circular economy for rubber.