Tribological properties of oil impregnated carbon nanocapsules modified with polydopamine-polyethyleneimine

Self-lubricating microcapsules can reduce the coefficient of friction/wear and improve the tribological properties of polymer composites. Impregnation of prefabricated shell with core substances is a versatile and applicable route to obtain the microcapsules. In this work, double shell nanocapsules (PA@C HSM) with particle size of 448 nm, shell thickness of 65 nm are obtained by incorporating paraffin wax (PA) into the pre-synthesized hollow carbon nanospheres (PHCs)and then packaged by co-depositing with polydopamine (PDA) and polyethylenimine (PEI). The PDA/PEI transition shell increase the surface roughness of the nanocapsule and enhance the compatibility with the polymer matrix which will contribute to the improved oil storage ability and thermal stability of the nanocapsules as well. The distinguished mechanical interlocking and chemical interface bonding between PDA/PEI layer and EP matrix effectively facilitates mitigating the unfavorable impact of PA@C HSM on the mechanical properties of the composite with the modulus of the 7.5 wt% PA@C HSM/EP composites increased by 17.44 %. As for the tribological performance of PA@C HSM/EP composite, the tribological properties are boosted remarkably and the friction coefficient and wear rate of 7.5 %PA@C HSM/EP composite are reduced by 77.69 % and 98.79 % compared with pure EP material.