Mechanical Activation Reinforced Porous Calcium Phosphate Cement

Abstract

Calcium phosphate cement (CPC) powder was activated by ball milling to improve the mechanical properties of porous CPC scaffolds. The mechanical activation mechanism was investigated by specific surface analyses, X-ray diffraction (XRD) and scanning electron microscopy (SEM). After ball milling, the average particle sizes of BCPC powder decreased while the specific surface area, apparent density, bulk density, and compact density increased when compared with non-activated CPC powder. The porosity and compressive strength of porous CPC scaffolds prepared from ball-milled powders (BCPC-S) were (77.98 ± 0.58)% and (4.11 ± 0.46) MPa, both significantly higher than those non-activated CPC powders (CPC-S), whose porosity and compressive strength were (64.23  2.32)% and (1.99 ± 0.43) MPa, respectively. SEM revealed that there were two types of pores in the BCPC-S: one ranged a few microns in size and the other ranged several hundred microns. XRD indicated that grain sizes and crystallinities of dicalcium phosphate dehydrate (DCPD), α-tricalcium phosphate (α-TCP), calcium carbonate (CaCO3) and hydroxyapatite (HA) in BCPC powder decreased, due to the mechanical activation compared to 第 4期 黄 萍, 等: 机械活化增强多孔磷酸钙骨水泥支架的研究 433 those of the non-activated CPC powders. In addition, the mechanical activation resulted in the conversion of DCPD to dicalcium phosphate anhydrous (DCPA), which promoted the hydration of CPC and the precipitation of HA, and improved the compressive strength of BCPC-S finally. This study provided a potential approach to improve the mechanical properties of porous CaP based scaffold to meet the clinic requirement.