Determination of coefficient thermal expansion of glass microballoon/vinyl ester syntactic foams

The coefficient thermal expansion, α (CTE) of glass microballoon/vinyl ester syntactic foam was determined using dimensional changes of a temperature gradient plot. The CTE was measured and found to be up to 53-63 % lower than the vinyl ester resin matrix when mixing with different weight percentages of the glass microballoon ranging from 2 wt.% to 10 wt.% using a thermomechanical analyzer (TMA). The results of CTE showed that it has a strong relationship with the syntactic foam density (ρ), radius ration (η), cavity porosity (ϕ_γ) and matrix porosity (ϕ_μ). Experimental results showed that the CTE decreases when glass microballoons are added into the composites measured at different temperatures ranging from 30 to 70 °C. The CTE from the experimental results were also compared with Turner’s modification model for composites for its suitability for thermal expansion of syntactic foams. The results indicate that Turner’s modification model exhibits a close correlation with the reduction up to 80 % of CTE based on experiment.