Effects of nickel shell microcapsules and short fibers on polyamide 6‐matrix composites: Thermal, surface wetting, mechanical, and tribological properties

Abstract

The excellent lubricating properties of microcapsules have been well recognized in modified polymers though very few reports have mentioned the practical application for engineering parts. In this study, different short fibers and nickel shell microcapsules (NMS) synergistically modify PA6 and injection molded to prepare bearings. With 10 wt% NMS, the COF could be reduced from 0.45 to 0.1. Fibers can effectively overcome bearing failure resulting from crushing the matrix under high loads or rapid peeling wear at high swing frequencies, which can warrant the effective lubrication of NMS and the formation of high‐quality transfer film. The bearing long‐life test shows very stable and low COF and wear with the feasibility to utilize microcapsules modified polymers in journal bearings.

Research on polyamide based self‐lubricating composites: A review

“…[102] The unique "core-shell" structure of microcapsules allows the lubricant to be better dispersed in the matrix and the lubricant to escape from the wall under the action of shear during friction, thus improving the tribological properties of the composite. [103][104][105][106] Gao et al [63] added lubricant-containing microcapsules to MC PA6 to make a composite coating, and the coefficient of friction and mechanical properties of the material decreased as the microcapsule content continued to increase. When the microcapsule content was too high, the composite did not bind tightly enough, and the specific wear rate increased instead; a microcapsule content of 20 wt% was most reasonable, and the friction coefficient and wear rate decreased by $57% and 92%.…”

The sustainable recycling of polyvinylidene fluoride membrane for tribological application

“…The microcapsule technology allows the liquid lubricant to be wrapped in a solid shell by enabling the combination of solid lubrication and liquid lubrication 33–36 . At this case, microcapsules containing lubricating oil are well known as a novel core‐shell additive that enables the incorporation of lubricating oil into polymer matrices.…”

“…32 The microcapsule technology allows the liquid lubricant to be wrapped in a solid shell by enabling the combination of solid lubrication and liquid lubrication. [33][34][35][36] At this case, microcapsules containing lubricating oil are well known as a novel core-shell additive that enables the incorporation of lubricating oil into polymer matrices. Various related studies have reported amazing effects of the microcapsules in enhancing the tribological properties of different polymers, such as epoxy, 37,38 polyamide 6, 39,40 and polypropylene.…”

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

“…The properties of polymeric materials modified by microencapsulation technology not only combine the merits of solid lubricants and lubricating oil, but also prevent the direct contact between lubricating oil and polymers to influence mechanical properties and binding properties of polymeric materials 15,16 . Meanwhile, microcapsules containing oil also enable to significantly improve tribological properties of polymers 17–19 . Li et al 20–22 prepared microcapsules with lubricating or tung oil as a core material and PSF or PSF/SiO 2 as a wall material by solvent volatilization and sol–gel methods respectively.…”

“…15,16 Meanwhile, microcapsules containing oil also enable to significantly improve tribological properties of polymers. [17][18][19] Li et al [20][21][22] prepared microcapsules with lubricating or tung oil as a core material and PSF or PSF/SiO 2 as a wall material by solvent volatilization and sol-gel methods respectively. The microcapsules were added to low-density linear polyethylene or epoxy resin in order to modify their tribological properties.…”