Hard nanodiamonds in soft rubbers: Past, present and future - A review

Conventional fillers used in rubber matrices include carbon black (CB), silica, and clay. However, the new demands on reinforced rubbers, especially the need to significantly enhance the overall performance while reducing the amount of filler, is currently expected to be met only through intelligent use of nano-sized fillers. Among carbon-based nanomaterials, such as fullerenes, carbon nanotubes (CNTs), graphene and nanodiamonds (NDs), nanodiamonds are a good candidate due to their nano-scale size, stable diamond core, highly reactive outer shell, biocompatibility, and potential for chemical functionalization. Here we review the state of the art and current research on nanodiamonds produced by laser ablation and detonation techniques with a special focus on their application in elastomers. The current understanding about structure and synthesis of nanodiamonds indicates some possible methods for their functionalization and dispersion in soft rubber matrix. We also discuss the effect of nanodiamonds on the various properties of elastomeric materials.