Corundum Fillers with Variable Sizes and Shapes for Epoxy Nanocomposites as High‐Performance Chemical Anchoring and Bonding Systems

Abstract

AbstractHerein, the influence of corundum filler types and contents on the morphological, thermal, and mechanical properties of epoxy nanocomposites tailored for applications as chemical anchoring and bonding systems is investigated. Up to 65 wt% corundum particles with aspect ratios (AR) varying between 1 and 70, average particle sizes ranging from 500 nm to 48 µm, and nanoplatelet thickness varying from 40 to 300 nm, are uniformly dispersed in amine‐cured epoxy resins. At both 25 and 50 wt% filler content, the properties of corundum/epoxy composites are far superior to those of the corresponding benchmark epoxy composites containing a conventional filler such as cement, talcum, or sand. The incorporation of corundum nanoplatelets with AR of 50, length of 2 µm, and thickness of 40 nm, significantly improves Young's modulus (3.5–9.8 GPa) and fracture toughness KIc (0.83–1.24 MPa of epoxy nanocomposites at the expense of tensile strength (72–49 MPa). The pull‐out values of the corresponding chemical anchoring systems substantially improve with decreasing sub‐micrometer corundum particle sizes and correlate with tensile strength of the corundum/epoxy nanocomposites, but are much less dependent on corundum particle morphologies, filler aspect ratio, and Young's modulus of the corundum/epoxy composite.