Enhancements of epoxy resin based syntactic foam by inner interface and matrix modifications

The present study focuses on inner interface modifications and matrix modifications to improve the electrical and mechanical properties of epoxy resin based syntactic foam during production process and lifetime. Silane-coated hollow microspheres are used to modify the interfaces between microspheres and epoxy resin, and SiO₂ nanofiller is used to modify the matrix. Electrical investigations show a positive impact of the silane-coating on the ac and dc breakdown field strength. Mechanical investigations show an increased mechanical strength of the material due to an improved adhesion quality between microspheres and epoxy resin. The nanofillers show no significant influence on the properties of the cured syntactic foam. However, it is verified that nanofillers reduce the viscosity of the uncured, liquid material. This provides a better production quality of the material at high microspheres´ filling degrees.