Mechanical and piezoresistive behavior of selectively laser sintered MWCNT/UHMWPE nanocomposites

Herein, we present the mechanical and piezoresistive behavior of MWCNT/UHMWPE nanocomposites processed via selective laser sintering (SLS) under tensile, flexural and cyclic loadings. We show that the uniform dispersion of MWCNTs in UHMWPE enhances crystallinity (+10% for 0.5 wt% MWCNT) and decreases porosity (as evidenced by μCT images), evincing the lowest porosity (∼1%) and the highest tensile strength of 20.3 MPa which is ∼ 45% higher than the maximum tensile strength of extant SLS processed UHMWPE and UHMWPE-based composites. The nanocomposite also exhibits superior piezoresistive characteristics, showing a sensitivity factor (in tension) of 0.6 and 2.6 in the elastic and inelastic regime, respectively. Furthermore, 2D-hexagonal nanocomposite lattices with a relative density of 50% reveal a linear piezoresistive response with a gauge factor of 1 and show consistent and stable strain sensing capability over 100 repeated load cycles. The results demonstrate the potential of MWCNT/UHMWPE nanocomposites for the development of smart biomedical devices.