本研究采用球磨对磷酸钙骨水泥(CPC)起始粉末进行机械活化处理,以期改善 CPC 力学性能,并探讨了其影响机理。采用激光粒度仪、比表面积测量仪和X射线衍射仪(XRD)表征球磨后的CPC粉末(Ball milling CPC, BCPC)。利用发泡法制备多孔BCPC支架,采用万能力学试验机、XRD和扫描电子显微镜(SEM)表征多孔BCPC支架。结果显示,球磨后的BCPC粉末平均粒径减小,比表面积增大,表观密度、堆积密度及紧密密度减小。BCPC支架孔隙率为(77.98±0.58)%,抗压强度为(4.11±0.46) MPa,相比CPC支架的(64.23±2.32)%和(1.99±0.43) MPa有显著提高。SEM结果显示BCPC支架具有数微米和数百微米的两种孔隙结构。XRD结果表明机械活化作用降低了DCPD、a-TCP、CaCO3和HA的晶粒尺寸和结晶度,促使DCPD向DCPA转化,促进了各相磷酸钙盐的水化和HA的沉积,提高了BCPC支架的力学性能,为增强CaP基多孔材料的力学性能和扩展其临床应用提供了新途径。
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 den-sity 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 car-bonate (CaCO3) and hydroxyapatite (HA) in BCPC powder decreased, due to the mechanical activation compared to 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.
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