Multifunctional Carbon Nanotube Film/Epoxy Composites With Nanofiller Tuned For High-Performance Applications

Multifunctional thin and flexible carbon nanotubes(CNTs)thin films demonstrate excellent mechanical,thermal and electrical properties.These properties can further be enhanced with the incorporation of high-performance polymers,such as epoxy resin,in the form of composites for high-performance materials.However,the resultant performance is highly dictated by the compatibility of CNTs within the polymer matrix.Whereas,to date,such anticipated properties are hardly achieved due to a number of factors.For example,the weak bonding of CNT films(CNTf)with epoxy resin at interface causing peeling-off and delamination and the poor conductivity contributed by the insulating epoxy resin.Herein,we report a detailed strategy to solve the named quandary which in brief involved first modification of the epoxy resin with CNTs then manufacturing composites by immersing CNTf in CNT-modified epoxy resin so as to create a new CNT-to-CNT bonding and also to improve the conductivity of the epoxy solution.The CNTs reinforced epoxy when employed with CNTf via vacuum assisted resin transfer method(VARTM),the resultant composites showed significant bonding improvements between CNTf and epoxy with peeling strength enhancement of atmost 74.38% with 0.1 wt% CNTs/epoxy solution when compared to the unmodified CNTf/epoxy composite.Moreover,the tensile strength of CNT/Ep-CNTf composite was increased 164.76% than the reference composite.Not only mechanical properties but the strain sensing properties,thermal stability and electric heating behavior of the composites were also greatly improved.The synergistic effect of the improved bonding on the mechanical,electrical,thermal,strain sensing,and electric heating properties was also investigated.These improvements are attributed to the enhanced bonding of CNT films with CNT-modified epoxy resin which was confirmed by the bridging and interlocking of CNTs from epoxy resin to CNTf with scanning electron microscopy(SEM)analysis showing no apparent delamination even after tensile testing.More still,the observation worth noting,is that controlled CNT reinforcements is paramount as higher concentrations of CNTs in epoxy consequently resulted into the mechanical properties as well as strain sensing behaviors of the modified composites decreasing due to the agglomeration of CNT bundles in epoxy causing poor bonding between CNTf and CNTs-based epoxy resin.In the nutshell,this work provides an approach to fabricating high-performance CNT-based composites with the required durability,flexibility,strength and conductivity.