Insight into the mechanical properties and thermal expansion behavior of epoxy nanocomposites reinforced with multi-walled carbon nanotube solvent-free nanofluids

Epoxy resin (EP) is a promising material that exhibits great potential in the fields of packaging and adhesion. However, reducing its brittleness and coefficient of thermal expansion (CTE) at low filler content is still a challenge. To address this problem, three types of MWCNTs nanofluids (MWCNTs NFs) with different shell structures were designed to modify epoxy resin. With the addition of 1 wt% MWCNTs-M1, the compression, impact, and lap shear strength of the composites increased to 88.97 MPa, 81.39 kJ/m², 12.69 MPa, respectively, which are 21.7%, 66.1%, and 58.0% higher than pure epoxy. Meanwhile, incorporating MWCNTs NFs also improved the CTE and thermal conductivity, with a 19.7% decrease in CTE and a 40% improvement in thermal conductivity at 2 wt% NFs content. Particularly, the effect of MWCNTs NFs structure on the composite properties was explored, which can be an available reference for designing specific NFs epoxy composites. Highlights: Three types of MWCNTs nanofluids with different structures were designed. The MWCNTs NFs were used in packaging materials for the first time. The impact performance of composite has been improved by 66%. The CTE of composite is 19.7% lower than pure EP. The thermal conductivity of the composite increased by 40%.