Combined effects of interface modification and micro-filler reinforcements on the thermal and tribological performances of fabric composites

The high specific‐strength of glass fibers and exceptional self‐lubrication of polytetrafluoroethylene(PTFE)fibers promote the potential application of hybrid PTFE/glass fabric composites in the tribological field,but their weak interfacial adhesion and inferior thermal properties significantly inhibit their tribological performance and reliability.Herein,a hybrid of polydopamine/silicon carbide/polyethyleneimine(PDA/SiC/PEI)functional coating was co‐deposited onto the hybrid PTFE/glass fabric surface through a one‐step impregnation method,leading to increased surface roughness and abundant amine groups.Tensile and peeling tests showed that this functional coating offered 47.8%enhancement in the fabric/matrix interfacial adhesion without compromising the strength of the pristine fabric.Moreover,the additional incorporation of WS_(2),and aluminum nitride(AlN)micro‐fillers contributed to the development of a high‐quality tribofilm and improved the thermal properties of fabric composites.The results of wear tests proved that the hybrid‐fabric composites,after the introduction of functional coating and micro‐fillers,exhibited outstanding tribological performance,which was attributed to the superior interfacial adhesion as well as the synergistic enhancement effects between WS2 and AlN micro‐fillers.

Fabrication of PTFE/Nomex fabric/phenolic composites using a layer-by-layer self-assembly method for tribology field application

Fabric composites are widely applied as self-lubricating liner for radial spherical plain bearings owing to their excellent mechanical and tribological properties.Nevertheless,the poor interfacial strength between fibers and the resin matrix limits the performance of composites utilized as tribomaterials.To overcome this drawback,a mild layer-by-layer(LbL)self-assembly method was successfully used to construct hybrid fabric composites in the present work.In addition,this investigation addressed the effect of self-assembly cycles on the friction and wear behaviors of hybrid fabric composites under dry sliding condition.The results demonstrate that fabric composites with three or more self-assembly cycles have significantly enhanced surface activities and anti-wear performances.The results obtained in this work can provide guidance in the preparation of self-lubricating liner composites and highlight how the LbL self-assembly techniques could influence the properties of hybrid fabric composites.

Surface modification of YS-20 with polydopamine for improving the tribological properties of polyimide composites

Recently,great effort has been devoted to prepare various reinforce fillers to improve polymer performances,but ignoring the importance of raw polymer powders which are indispensable parts of hot-pressed polymer composites.Herein,we engineer raw polyimide(PI)powders with the assistance of polydopamine(PDA)in aqueous solutions.After the modification,polymer powders change from hydrophobic to hydrophilic,which makes it is possible to further modification of polymer powders in liquid phase.During the curing process of modified polymer powders,the partial dehydration of the catechol groups and crosslinking of PDA via C–O–C bonds are confirmed.Based on the features of PDA,a non-destructive mixing method is utilized to realize homogeneous dispersion of multi-walled carbon nanotubes(MWCNTs)in polymer matrix.In comparison with ball milling method,this way can preserve the integrated innate structure of MWCNTs effectively.Besides,by taking full advantage of the reducing and metal-coordination capability of PDA,Cu2+is successfully loaded onto the surfaces of polymer powders.The related characterizations demonstrate that Cu2+in situ converts to metallic copper rather than copper oxide during the hot pressing process.The tribological properties of corresponding polymer composites are also studied.These results indicate that modifying polymer powders with PDA is multi-profit and presents practical application prospect.