  We demonstrate the large scale exfoliation of bulk black phosphorus into
few-layers black phosphorus. We use wet-jet mill (WJM) as an industrially
scalable exfoliation technique. In order to avoid the degradation by oxidation
of the exfoliated flakes, the few-layers black phosphorus is protected by
functionalisation (with 4-bromobenzene-diazonium tetrafluoroborate) during the
exfoliation process. We used the exfoliated and functionalised flakes as
fillers in a polymethyl methacrylate matrix to test the mechanical endurance,
obtaining an improvement in the Young modulus of 106% compared to the bare
polymer. These data support the development of black phosphorus materials as
2D-polymer fillers and performance-enhancers.
