中文摘要：

为改善纳米SiO2粒子在聚L-乳酸基体中的分散性,将乳酸齐聚物接枝到纳米SiO2粒子表面,通过IR,29Si MAS NMR和TGA对改性SiO2进行表征.以聚L-乳酸（PLLA）为基体,加入乳酸齐聚物接枝改性的二氧化硅（g-SiO2）粒子,采用溶液浇铸法制备PLLA/g-SiO2纳米复合材料,测试其在模拟体液（SBF）中的生物活性.通过XRD,IR,SEM和EDS表征手段,考察材料表面类骨磷灰石形成能力.结果表明,乳酸齐聚物成功地接枝到SiO2表面,当反应36 h时,g-SiO2接枝率最大（9.22%）.随着g-SiO2含量增加和浸泡时间的延长,材料表面最初形成的无定形沉积物矿化成碳酸羟基磷灰石（Carbonated hydroxyapatite,CHA）,钙磷比为1.72,类似于人骨无机质,表明g-SiO2的引入能明显加速复合材料表面CHA沉积,该复合材料有望成为骨修复填充材料和组织工程支架材料.

英文摘要：

In order to improve the dispersibility of nano-silica （SiO2 ） in the matrix of poly （L-lactide） （PLLA）, the silica nanoparticles were surface-grafted with L-lactic acid oligomer. The surface-grafting reaction is confirmed via IR, 29 Si MAS NMR and TGA analyses. The nanocomposites of surface-grafting silica （g-SiO2 ） with PLLA prepared through solvent-cast technique were immersed in simulated body fluid（SBF） to examine their bioactivity. Its apatite-forming ability was characterized by means of X-ray diffraction （ XRD）, Fourier transform infrared（FTIR） spectra, scanning electron microscopy（SEM） and energy-dispersive spectrometer（EDS）. The results show that L-lactic acid oligomer can be successfully grafted onto silica surface. The highest grafting amounts of L-lactic acid are 9.22% when the reaction time is 36 h. With the increase of filler content and soaking time, the amorphous surface coating is transformed into carbonated hydroxyapatite （ CHA）, the molar ratio of Ca to P is about 1.72, close to that of apatite. This kind of nanocomposites could be one of the best potential bioactive materials for bones substitute or as a tissue engineering scaffold.