Bond strength of epoxy-based composites at the interface with surface deposited metal layer: A comparative study with different dimensional fillers

Abstract

With the complexity of the working environment, pure epoxy resin can no longer meet the requirements, and the weak interfacial bonding between metal layer and epoxy-based composites limits its development. In this work, we propose a novel molecular grafting modification technique by using the active functional groups of polymers, which can apply to epoxy-based composites with various fillers to improve the adhesive strength of the interface between the metal film and matrix. 3D surface profile and surface wettability were used to characterize the effect of fillers on the surface of epoxy composites. Scanning electron microscope (SEM) and Raman spectroscopy were utilized to judge the interface failure modes of the composites. Peeling test and surface-enhanced Raman scattering (SERS) were conducted to examine how fillers affected adhesion. The results showed that silane grafting substantially improved the bonding between the epoxy-based composite matrix and the metal layer without the need for alkaline washing and palladium (Pd) activation steps on the substrate. The average adhesive strength can reach a maximum of 17.76 N/cm. The study also revealed the effect of filler size on the interfacial adhesive strength. The interfacial adhesive strength was increased by two dimensional lamellar materials, decreased by one-dimensional tubular materials, and remained unaffected by zero-dimensional spherical materials. This study may have positive implications for improving interfacial bonding between metal and polymer composite surfaces.