Molybdenum disulfide of modified in situ as a nanofiller for enhanced mechanical properties and thermal properties of polypropylene composites

Few-layer molybdenum disulfide (MoS2) was prepared by liquid phase exfoliation with in-situ modification as a nanofiller for polypropylene (PP). Scanning and transmission electron microscopies (SEM, TEM) showed uniform dispersion and excellent adhesion of MoS2 within the PP matrix. When MoS2 was centrifuged at 1000rpm, the mechanical properties of the composite were greatly improved by adding only 0.5 wt.% of MoS2. The yield strength, bending modulus, and impact strength increased by 2.3%, 8.9%, and 44.03%, respectively. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) showed that the enhanced mechanical properties of the composites were related to PP crystallographic transformation. Thermogravimetric analysis (TGA) showed that the incorporation of 2 wt.% MoS2 increased the maximum weight-loss temperature of the composites by approximately 30 degrees C. The mechanisms for increasing thermal stability have been thoroughly demonstrated by band energy analysis. MoS2 nanosheets have high aspect ratios and strong insulation with a change in band gap width compared to bulk MoS2, which is resulting in the stronger interactions at the MoS2/PP substrate interface. Furthermore, due to the outstanding carrier for rigid and thermally stable materials, MoS2 composites displayed excellent mechanical and thermal properties. In addition, unlike PP, the melt flow rate (MFR) of composite materials is more conducive to downstream product processing. This will further promote the application scope of MoS2/PP composites.