Tensile and compressive properties of epoxy syntactic foams reinforced by short glass fiber

The hollow glass microsphere/epoxy resin syntactic foams reinforced by short glass fibers are fabricated. The microsphere is constant 5% weight ratio to the epoxy resin matrix and the fibers with weight ratio to the resin matrix are 5%, 10%, 20% and 30%. Their mechanical properties are studied by uniaxial compression test and tension test. The compressive deformation morphology and tensile fracture surfaces of syntactic foams are investigated. It is obtained that the compressive and tensile strength of syntactic foams are enhanced by adding fibers, and the 10% fiber weight ratio is found to be much more efficient, which shows 70% and 49% higher compressive strength and tensile strength respectively than that of syntactic foams without fiber content. However, the strength decreases with further addition of glass fiber beyond 10% weight ratio. The reason of strength enhancements is discussed. The compressive and tensile moduli are also enhanced by adding fibers. The ductility of composites is found to decrease with larger fiber filling.