Friction and wear characteristics of additive manufactured CNT reinforced HDPE composites in dry contact

AbstractThe tribological properties of 3D-printed polymeric composites is often less explored due to the complexity involved related to their softness, poor mechanical properties, and lower thermal conductivities. Keeping this in view, this work reports the influence of carbon nanotubes (CNT) on the tribological properties of High-Density Polyethylene (HDPE) composites. Fused deposition modeling was adopted to develop the composites with varying CNT contents from 0.5 wt% to 2 wt%. The tribological properties were studied by subjecting them to friction-on-wear test using a pin-on-disc setup. The tests were conducted with varying applied loads (5 to 20 N) and sliding speeds (0.262 to 1.048 m/s). A Scanning Electron Microscope (SEM) was employed to study the morphology of the filaments and to analyze the worn surfaces after testing. The printed composite parts displayed a good dispersion of CNTs, showed a good print quality, and were free from warpage or shrinkage defects. With the increase in load and sliding velocity, both the wear rate and coefficient of friction of all the developed samples tend to increase. Out of all the developed samples, some showed poor wear resistance, while composites with the highest CNT of 2 wt% showed significant resistance to material loss, which is attributed to the reduced contact area and the CNT acting as an anchor to prevent the polymer chain from being detached. The worn surface analysis revealed adhesive wear as the dominant mechanism for pure HDPE and abrasive wear as the primary mechanism for HDPE composites. Overall, this work showed that CNT can be used as an effective filler for reducing the friction coefficient and increasing the wear resistance.Keywords: High density polyethylene (HDPE)Carbon nanotubes (CNTs)Fused deposition modellingWearFrictionDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also.