Mechanical and thermal investigation of high-density polyethylene/multi-walled carbon nanotube/tungsten disulfide hybrid composites

This study investigates the impact of addition of different weight percentages of tungsten disulphide (WS₂) lubricant on the thermal and mechanical properties of high density polyethylene (HDPE) hybrid composites reinforced with a multi-walled carbon nanotube (MWCNT). HDPE composites were fabricated using a twin-screw extruder process employed to add reinforcement and lubricants in different weight percentages (%, by weight). X-ray diffraction (XRD) patterns indicated the distribution and dispersion of filler materials in the HDPE matrix. The quality of the composite was investigated by measuring the mechanical properties such as impact strength, hardness, tensile strength, and flexural strength. Thermogravimetric analysis (TGA) was employed to examine the thermal stability of the composite material. Main decomposition temperatures were determined using derivative thermogravimetry (DTG) analysis. Thermal transitions and degree of crystallisation (X_c) of the polymeric materials used were investigated by using differential scanning calorimetry (DSC) technique. The lubricant was added in three varying amounts of 2%, 4% and 8% (by weight) whilst MWCNT was maintained at 1% (by weight). The experimental results revealed that the composite with 2% (by weight) of WS₂ provides better mechanical properties such as impact strength, flexural strength, tensile strength, and hardness. With an increase in lubricant percentage, agglomeration of particles is found to be dominant in the composite, and the composite with 4% (by weight) of WS₂ displays better thermal properties, as determined using TGA, DTG and DSC analytical techniques.

Graphical abstract