An Overview on the Effects of Fillers on Properties of Epoxy Resins

The present review gives an overview of a vast selection of fillers—natural, metallic, carbon fillers— incorporated in ER matrices to enhance or to meet the requirements for a desired application, such as the increase in the final adhesive toughness. One of the most common types of resins used as structural adhesives is epoxy resin (ER); however, ERs have certain drawbacks, mostly because of their highly cross-linked network following the curing process. The main shortcomings of these kinds of materials include low electrical and thermal conductivity and low fracture toughness, though attempts have been made in recent years to address these issues. A critical survey regarding the use of different fillers in ERs systems and the outcome is highlighted and discussed in the present review. One of the most successfully investigated methods for enhancing ERs' characteristics is the addition of fillers to the matrix. Although ER composites have been extensively studied, it is important to note that very few studies have concentrated on a list of the most pertinent fillers and the primary modifications on the performance of ER composites. The combination of the top characteristics of fillers and polymers is accomplished, leading to high-performance composites. Among the most promising fillers, carbon nanomaterials, biofillers and metallic and ceramic fillers are described which have the ones having higher application potential.