Glass Flakes as Lamellar Reinforcements for Bisphenol‐A Epoxy Composites: Influence of Filler Content on Mechanical, Thermal, and Morphological Properties

This study presents a systematic investigation of the influence of glass flakes as potential lamellar reinforcements in a Bisphenol‐A epoxy matrix. Glass flakes were incorporated at concentrations of 5, 10, and 15 wt% to evaluate their effect on the rheological, mechanical, thermal, and morphological properties of the resulting composites. The viscosity of the epoxy matrix increased progressively with increasing glass‐flake content, indicating enhanced resistance to flow at higher reinforcement concentrations. The composite containing 10 wt% glass flakes exhibited the highest Shore‐D hardness of 87, whereas the highest lap shear strength of 11 MPa was achieved at 5 wt% loading. Charpy impact testing also demonstrated a significant improvement in impact strength at 5 wt% glass flakes, suggesting that moderate reinforcement levels provide an optimum balance of mechanical properties. FTIR analysis of the cured specimens confirmed the incorporation of glass flakes within the Bisphenol‐A epoxy matrix. Thermal characterization using TGA and DSC revealed enhanced thermal stability with increasing glass‐flake concentration. SEM analysis of the fractured surfaces supported the observed mechanical trends and revealed interfacial adhesion and effective reinforcement sites within the epoxy matrix. Furthermore, optical microscopy demonstrated a favorable aspect ratio of the glass flakes. Overall, the findings highlight the potential of glass flakes as effective lamellar reinforcements for tailoring the performance of Bisphenol‐A epoxy composites.