Investigation of the Electrical Properties of Elastic Syntactic Foam

Syntactic foam is a special kind of composite material. It usually consists of a polymer matrix (called binder) and hollow spherical particles with a diameter in the range of 20 - 120 mum (microspheres) which are mixed into the binder. Due to the gas in the microspheres, the material structure of syntactic foam is similar to a foamed polymer which is the reason for its name. Foams made of a silicone-gel binder and polymer microspheres are a soft and elastic version of this material group. They also feature a high compressibility and adhesion to other solids. In the field of insulation systems, they are already used to substitute mineral oil in cable sealing ends, assuring the elimination of technical failure caused by leakages and minimizing the necessary precautions concerning fire and environmental protection. In order to characterize the influence on the electrical and mechanical properties of the material, the dielectric parameters, the short-time dielectric strength, the resistivity, the adhesion and the compressibility of elastic syntactic foams which are made of different polymer microspheres (uncoated/coated, different diameters) are measured and compared. Further tests deal with influence of temperature and applied pressure on the electrical properties named above.