Surface modification of hybrid-fabric composites with amino silane and polydopamine for enhanced mechanical and tribological behaviors

The poor interfacial adhesion between hybrid Nomex/PTFE fabric surfaces and polymer materials caused intrinsically by chemical inertness of Nomex and PTFE fibers severely inhibits the further application of hybrid Nomex/PTFE fabric composites. In this study, amino functionalized silane layer (KH550) was immobilized covalently onto hybrid Nomex/PTFE fabric surfaces using bio-inspired polydopamine (PDA) as a bridge to introduce substantial amino groups onto the fabric surfaces. The successful grafting of KH550 on the PDA-coated hybrid fabric surfaces was confirmed by FTIR, XPS and SEM. As a result, the tensile and bonding strength of the amino-functionalized fabric composite were obviously superior to those of the non-treated and polydopamine-coated only, which indicated that the introduction of amino functional layer brought about considerable improvement in interfacial compatibility of hybrid Nomex/PTFE fabric with the phenolic resin matrix. Besides, wear tests also showed the modified fabric composite exhibited the optimal tribological properties under varied test conditions. Most significantly, the strategy presented in this study is substrate-independent along with considerable flexibility to introduce various functional groups, suggesting promising applications for easily improving the interfacial compatibility of reinforcements with polymer matrix.