Insight into the crystalline morphology, thermal phase transitions and static, dynamic mechanical response of polypropylene hybrid composites reinforced with nanosilica and glass fibres

The present study focuses on investigating the effects of glass fibre and nanosilica, both individually and in combination, in polypropylene matrix. The hybrid multiscale composite specimens are prepared by fixing the composition of glass fibre at 20 wt.% and the weight percentage of nanosilica was varied by 2, 4 and 6. The resultant composite was characterised by scanning electron microscopy, dynamic mechanical analysis, tensile and fracture toughness tests, thermogravimetric analysis and differential scanning calorimetry (DSC). The hybrid composite with 2 wt.% nanosilica demonstrated the greatest stiffness and better ability to bear loads and absorb energy, indicating improved mechanical performance. The improvement in storage modulus and loss factor can be attributed to the addition of nanosilica into the polypropylene/glass fibre (PPG) matrix, indicating the synergism of the two multiscale fillers involved. The hybrid samples at higher content of nanosilica (6 wt%) exhibited the highest shift in thermal decomposition temperatures, thereby referring to prominent thermal stability. The thermal analysis performed via DSC analysis revealed the nucleating ability of nanosilica, and the accelerated nucleation of PP phase owing to the dual effect of fillers which have enhanced the crystallinity.