65. Sisal Fiber/Fly Ash-Reinforced Hybrid Polypropylene Composite: An Investigation into the Thermal, Rheological, and Crystallographic Properties

The current work aims to develop fly ash (FA) and sisal fiber-reinforced (SSL) polypropylene (PP) composites via injection molding. X-ray diffraction (XRD), differential scanning calorimetry (DSC), and rheology test were performed for evaluating crystallography, crystallinity, and melt viscosity. XRD study reveals the increase in β phase of the PP due to the addition of styrene-(ethylene-co-butylene)-styrene (SEBS) and maleic anhydride-grafted SEBS. This induced β phase increased further upon the addition of FA to the composite systems. β phase improved toughness and impact strength of the composites. DSC investigation revealed highest and lowest crystallinity of 43.46 and 17.49% for PP and composite made of 30 wt% of FA to the base matrix (BM). A decrease in crystallization temperature was observed for the BM and all the composites compared to PP. Rheological properties showed that at lower frequencies (rad/s), melt viscosity was governed by reinforcements (FA/SSL), and highest storage modulus of 297 MPa was recorded for 30 wt% SSL-reinforced BM composite. However, at higher frequencies (100 rad/s), BM recorded higher value of storage modulus than 30 wt% reinforced SSL/BM composites.