Effect of different microcapsule types on the wear mechanism of PTFE/aramid fiber composite liners

In this study, three different methods based on vacuum adsorption, solvent volatilization, and Pickering emulsion were utilized to prepare microcapsules with the core material of PAO40 and the wall materials of SiO2, polysulfone (PSF), and PSF/SiO2 composites, respectively. PTFE/Kevlar fabric liners were modified by PAO40/SiO2 microcapsules (PSMS), PAO40/PSF microcapsules (PPMS), and PAO40/PSF/SiO2 microcapsules (PPSMS). The effect of microcapsules based on different wall materials on the tribological properties of liners was investigated by friction and wear tester under low‐speed and heavy‐load conditions. The anti‐friction and anti‐wear mechanisms of several microcapsule types on the liners were systematically investigated. The results showed that PPMS induced the most significant enhancement in anti‐friction properties of liners when compared to pure liner resulting in a 19.4% reduction in coefficient of friction (COF). PSMS was found to reveal much better wear resistance of liners, as evidenced by 75% increase in wear rate. PSMS and PPSMS not only release lubricating oil after the break of microcapsules under the friction action to lubricate, but also generate a cavity to store abrasive debris for liner wear reduction. Nonetheless, PPMS only released the oil onto the friction surfaces for lubrication. PSF as the microcapsule wall material could not contribute to the formation and promote wear resistance of transfer films. SiO2 as a microcapsule wall material participates in the formation and enhances the wear resistance of transfer films. The findings obtained are anticipated to improve the reliability and broaden the range of applications of liners in aerospace and other industrial fields. Highlights Three microcapsules all improve the tribological properties of the liners. Anti‐friction and wear‐resisting mechanism of three microcapsules in liners. SiO2 as wall material can increase the wear resistance of transfer films. PAO40 in microcapsules has antifriction effect at the friction interface. (A–C) SEM images of three kinds of liners before wear: (A) liner‐1, (B) liner‐2, and (C) liner‐3; (A1–C1) SEM images of three kinds of liners after wear: (A) liner‐1, (B) liner‐2, and (C) liner‐3. (A2, C3) are EDS distributions of S elements on the liner surfaces, (B2, C2) are EDS distributions of Si elements on the liner surfaces respectively.