Ultralow friction polymer composites containing highly dispersed and thermally robust microcapsules

The heat-resisting property of microcapsules as additives directly determine the selection of matrix materials and the molding process of composite materials, which greatly affect the comprehensive properties of materials. In this research, thermally robust polyimide (PI) was used as shell material to synthesize microcapsules by solvent evaporation method, and the synthesized microcapsules were treated by soaking them in dopamine hydrochloride solution for improving their dispersion property in the matrix. The SEM and infrared spectra results showed that the PAO (Poly alpha olefins)@PI microcapsules with the dimeter of similar to 20 mu m and the oil content of 60 wt% were successfully coated with polydopamine (PDA) shells. It was demonstrated that the strong electrostatic repulsion of PDA structure made the microcapsules better dispersed in the epoxy resin, so as to play a better role in lubrication, thus resulting in a COF (Coefficient of friction) decrease of composite from 0.108 to 0.038. The high temperature lubrication performance of composites was also investigated and the experimental results shown that the PAO@PI/PDA microcapsules could provide high lubrication performance with a low COF (0.074) at 190 degrees C.