Use of glycerol as a cryoprotectant in vacuum-assisted foaming of ceramic suspension technique for improving compressive strength of porous biphasic calcium phosphate ceramics

This article reports the utility of glycerol as a cryoprotectant for improving the compressive strength of highly porous biphasic calcium phosphate (BCP) ceramics, comprised of hydroxyapatite and β-tricalcium phosphate, produced using vacuum-assisted foaming of a ceramic suspension technique. All the samples produced with various glycerol contents (0, 9, 17, and 23 wt% in relation to the water content) showed a highly porous structure with a uniform pore distribution. However, the addition of glycerol effectively suppressed the formation of microchannels in the BCP walls, accordingly leading to a considerable increase in compressive strength from 0.72 ± 0.11 to 2.36 ± 0.41 MPa with increasing glycerol content from 0 to 23 wt%.