This study seeks to examine the mechanical properties of epoxy composites reinforced with natural fibers derived from hybrid palmyra palm fruit waste and jackfruit (Artocarpus heterophyllus) peel waste fibers, as well as to evaluate the impact of varying zirconia (ZrO2) nano filler loadings on their physical and mechanical attributes. A 5% NaOH solution was utilized to mercerize the fibers of the palmyra palm fruit, and X-ray diffraction (XRD) analysis verified the crystallinity of the treated fibers and ZrO2 nanofillers. Three distinct loadings of ZrO2 nano fillers (2.5 wt. %, 5 wt. %, and 7.5 wt. %) and three fiber fractions (20 wt. %, 25 wt. %, and 30 wt. %) were employed. Composites were manufactured via hand lay-up techniques, and evaluations were conducted in accordance with ASTM standards. The findings indicated that the incorporation of nZrO2 markedly improved tensile strength (up to ~32 MPa), tensile modulus (up to ~1555 MPa), flexural strength (up to ~78 MPa), impact resistance (up to ~1.8 J), hardness (up to ~64 HV), and interlaminar shear strength (up to ~82 MPa) relative to unfilled composites, with optimal performance achieved at 25 wt. % fiber loading and moderate filler content (2.5–5 wt %). Excessive fiber or filler loadings (30 wt % fiber or ≥7.5 wt % filler) led to diminished characteristics due to agglomeration and an increase in voids (up to about 7 wt. %).
Sivasamy et al. (Fri,) studied this question.