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

• Published in: Composites. Part A, Applied science and manufacturing Applied science and manufacturing, 2023-10, Vol.173, p.107701, Article 107701
• Main Authors: Azam, Muhammad Umar, Schiffer, Andreas, Kumar, S
• Format: Article
• Language: English
• Subjects: 3D printing; Polymer-matrix composites (PMCs); Sintering; Strain sensing
• ISSN: 1359-835X; 1878-5840
• DOI: 10.1016/j.compositesa.2023.107701

[Display omitted] •MWCNTs promote sintering, leading to reduced porosity and improved mechanical properties of MWCNT/UHMWPE composites.•The composites show an increase of 50% and 34% in tensile and flexural strength, respectively.•0.5 wt% MWCNT/UHMWPE shows a gauge factor (in tension) of 0.6 and 2.6 in the elastic and inelastic regime, respectively.•MWCNT/UHMWPE 2D lattice structures show a gauge factor of 1.0 under monotonic loading.•MWCNT/UHMWPE 2D lattice structures show a stable strain sensing performance over 100 cycles. 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.