The Chemical Modification of Graphite with Dopamine and Silane to Enhance Tribological Properties of PEK‐C Matrix Composite Material

ABSTRACT The compatibility between PEK‐C and graphite has a significant impact on the ultimate composites performance. In this work, an effective and low‐cost technique, combing bio‐inspired dopamine polymerization and silane coupling agents grafting, was presented to improve the interfacial strength of graphite with PEK‐C. As a result, the bonding strength of the composite was obviously superior to that of the non‐treated and polydopamine‐coated only, which was confirmed by SEM, DHR, and DSC experiments. Other characterizations indicated that the chemically modified graphite played the role of a toughening agent to improve the toughness of PEK‐C/ graphite composites. Moreover, friction tests also displayed that the modified PEK‐C/graphite composites exhibited enhanced tribological properties under different test conditions. When the linear velocity was 2.24 m/s, the dry friction coefficient of CS‐6 was 0.1757, which was about 42% lower than the friction coefficient of the pure graphite‐filled composite. In addition, the mass wear ratio of CS‐6 composite was 0.054 wt.% under dry friction, which was 74% lower than CS‐3. To sum up, the research not only proved the importance of interfacial strength to the frictional properties but also proposed a method to modify the interfacial interaction force of composites.