Compressive properties of expandable rigid polyurethane foam for use in an analogue spine

Abstract

This study examines the potential of expandable polyurethane foam to replicate trabecular bone in spinal testing. The research is intended to determine whether an expandable polyurethane foam as substitute to the rigid block foam may be used to replace the trabecular bone in biomechanical testing. Static compression test were performed on two different densities of foam (0.16 g/cm3 and 0.24 g/cm3) with 7.5 mm in diameter and 6.5 mm in length. The results indicated that the compressive modulus for 0.16 g/cm3 was varied from 19 to 23 MPa and the yield stress values were from 1.2 to 1.8 MPa. As for 0.24 g/cm3, the compressive modulus and the yield stress were from 17 to 88 MPa and 2.4 to 4.8 MPa respectively. Based on these results, it can be summarised that the 0.16 g/cm3 was not valid to be used in biomechanical testing because of its compressive modulus values were off reached to the human data. However with the 0.24 g/cm3, the compressive modulus obtained were fallen within the human data range. This may be proved to have the potential to substitute the trabecular bone. Further investigation is necessary for higher density values to obtain the most suitable expendable foam.