Crush behaviour and vibration damping properties of syntactic foam incorporating waste tyre-derived crumb rubber

Syntactic foams, containing up to 23 wt% of untreated waste tyre-derived rubber particles mixed with hollow glass microspheres (HGMs) and epoxy, were produced via compressed air-assisted injection moulding. This study investigated the effect of rubber particles on the through-the-thickness compression properties and the vibration-damping response of the ternary syntactic foams. The interaction between foam constituents was investigated using SEM, with the objective to establish a microstructure-compression property relationship for rubber-incorporated foam. The effect of rubber particles on the energy absorbed by the foam under compression deformation was also studied. The substitution of epoxy for rubber particles did not alter the compression properties (crush behaviour) of the foam. A laser Doppler vibrometer was used to measure the vibration-damping response and natural resonance frequency. The vibration-damping ratio of the rubber-incorporated foam increased by up to 75% upon the addition of 23 vol % rubber particles.