High Strain Rate Compressive Behavior of Polyurethane Resin and Polyurethane/Al₂O₃ Hollow Sphere Syntactic Foams

Table 1

Existing studies on polyurethane/hollow glass microballoon syntactic foams.

Reference	Syntactic foam	Results
[17]	Polyurethane foam filled with HGM	Addition of 15% sepiolite nanofibers and 10% HGM resulted in 240% and 300% increase in the tensile and compressive strength of rigid polyurethane foam
[18]	Polyurethane foam filled with HGM	90 kg/m^3 density foam showed 12% increase in compressive modulus and 10% increase in the compressive strength with addition of 1 wt.% of HGM
[30]	Polyurethane foam filled with HGM (9.5 wt.%)	Isonate CPR-16 formulation: addition of HGM resulted in 45% increase in the compressive strength, with very little increase in the composite density.
[31]	Polyurethane foam filled with HGM (0–40 vol.%)	Flexural modulus increases by 80% with addition of 10% HGM.
[32]	Polyurethane foam filled with silane treated HGM (0–20 wt.%)	50% increase in compressive modulus was observed with addition of 10 wt.% of HGM.
[33]	Polyurethane resin filled with HGM (50 vol.%)	The polyurethane foam showed strain rate sensitivity and the collapse stress increased by 238% at a strain rate of 1185 s^−1 in comparison to quasistatic compression.