The effect of reinforcement weight ratios on the mechanical properties of ZrO₂/ unsaturated polyester nanocomposites

This work aims to prepare ZrO₂/ unsaturated polyester nanocomposites with reinforcement weight percentage ratios (1, 2, 3, 4, 5, and 6) wt.% and study the effect of this reinforcement weight ratio on some mechanical properties such as hardness, impact strength, and tensile strength. The used powder has a monoclinic structure, P2/m space group, and unit cell parameters a, b, and c = 5.313Å, 5.210 Å, and 5.145 Å, receptively, and angels α, γ = 90º and β= 99.233º according to XRD data and using Dicvol 91 indexing program. The grain size of the used powder was estimated using Scherrer’s equation to be 43.2 nm. The SEM micrograph of ZrO₂ nanopowder showed the particle morphology having homogenous irregular grains and appears to be similar to a coral shape. The results of the hardness test showed that increasing the reinforcement weight ratio led to an increase in the hardness values. Impact, tensile, and flexural strength values increase with the reinforcement weight ratio and peaked at 6 wt. %, and decreased at a higher ratio.