氧化石墨烯增强磷酸钙生物水泥

为了提高磷酸钙水泥(CPCs)的强度,将纳米片状的氧化石墨烯(GO)与CPCs复合。首先,以α-Ca₃(PO₄)₂、CaHPO₄和CaCO₄物质的量之比为1:1:1的CPCs为固相、不同浓度的GO水分散液为固化液,二者按一定的固/液比混合并固化成型,制得GO/CPCs;然后,探讨GO添加量对GO/CPCs力学强度的影响,测量固化时间、在模拟体液中浸泡后的降解率及浸提液的pH,以XRD检测其物相,并通过SEM观察其显微形貌。结果显示:GO添加量对CPCs的抗压强度有显著影响,最佳添加量为0.0500wt%;随老化时间的延长,不同GO添加量的CPCs的抗压强度均明显提高,尤其是在早期阶段;与不加GO的对照组相比,老化2 h和24 h后,0.0500wt% GO/CPCs的抗压强度分别提高了200%和67%。GO/CPCs在模拟体液中的降解率升高且浸提液pH下降。GO/CPCs在同期水化反应中可获得更多的羟基磷灰石相,结晶有序、均匀且细小。所得结论表明掺加GO可以显著改善CPCs的抗压强度。 

Calcium phosphate biocements reinforced with graphene oxide

In order to improve the strength of calcium phosphate cements(CPCs), graphene oxide(GO) in nano-sheet form was composited with CPCs. CPCs whose amount ratio of substance for α-Ca₃(PO₄)₂, CaHPO₄ and CaCO₄ was 1:1:1 were used as solid phase, the aqueous dispersions of GO with different concentrations were used as solidification liquids, both of them were mixed according to certain powder/liquid ratio, set and solidified, thus the GO/CPCs were prepared firstly. Then, the effect of GO additive amount on the mechanical strength of GO/CPCs was discussed. The setting time, degradation rate after immersion in simulated body fluid and pH of extract liquids were measured, the phase was tested by XRD, and the micromorphology was observed by SEM. The results show that GO additive amount has remarkable effect on compressive strength of CPCs, the optimum additive amount is 0.0500wt%. With the aging time increasing, all of the compressive strength of CPCs with different GO additive amounts improves significantly, especially in the earlier stage. Comparing to the control group without the addition of GO, after aging for 2 h and 24 h, the compressive strength of 0.0500wt% GO/CPCs increase by 200% and 67%, respectively. The degradation rate of GO/CPCs in simulated body fluid increases, and pH of extract liquid decreases. GO/CPCs can obtain more hydroxyapatite phase in the corresponding period of hydration reaction, and the grains are well-aligned, regular and fine. The conclusions obtained indicate that the addition of GO can improve the compressive strength of CPCs significantly.