Enhancing Toughness of Low- Density Polyethylene Filaments Through Infusion of Multiwalled Carbon Nanotubes and Ultrahigh Molecular Weight Polyethylene

We report enhancement in fracture strain and toughness of low-density polyethylene by infusing multiwalled carbon nanotubes (MWCNT) and a second-phase polymer; ultrahigh molecular weight polyethylene (UHMWPE). Infusion of MWCNT improved strength and modulus by about 23 and 57%, respectively, but reduced fracture strain (∼45%) and toughness (∼36%). UHMWPE was then dispersed as a minor phase, and the resulting nanocomposites showed a 55% increase in toughness without any loss of strength or modulus. The loading of MWCNT and UHMWPE was 2 and 8% by weight, respectively. Nanocomposites were in the form of filaments and were extruded through a melt extrusion process. Differential scanning calorimetry and X-ray diffraction studies revealed increase in crystallinity and crystallite size. Scanning electron microscope micrographs showed sliding of polymer interfaces and changes in fracture process. Strain hardening experiments also showed improvement in strength and modulus but reduction in toughness.