Qiu Xueyu, Hong Zhongkui, Hu Junli, Chen Li, Chen Xuesi, Jing Xiabin
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.
Biomacromolecules. 2005 May-Jun;6(3):1193-9. doi: 10.1021/bm049502l.
A new method of surface modification of hydroxyapatite nanoparticles (n-HA) by surface grafting reaction of l-lactic acid and ring-opening polymerization of l-lactide (LLA) was developed. Two modified HA nanoparticles were obtained: HA modified by l-lactic acid (l-HA) and HA grafting with poly(l-lactide) (PLLA; p-HA). The modified surface of n-HA was attested by Fourier transformation infrared, (31)P MAS NMR, and thermal gravimetric analysis. The results showed that l-lactic acid could be easily grafted onto the n-HA surface by forming a Ca carboxylate bond and initiated by the hydroxyl group of the grafted l-lactic acid and LLA could be graft-polymerized onto the n-HA surface in the presence of stannous octanoate. The highest grafting amounts of l-lactic acid and PLLA were about 33 and 22 wt %, respectively. The modified HA/PLLA composites showed good mechanical properties and uniform microstructure. The tensile strength and modulus of the p-HA/PLLA composite containing 15 wt % of p-HA were 67 MPa and 2.1 GPa, respectively, while those of the n-HA/PLLA composites were 45 MPa and 1.7 GPa, respectively. The elongation at the break of the l-HA/PLLA composite containing 15 wt % l-HA could reach 44%, in comparison with 6.5% of the n-HA/PLLA composites containing 15 wt % n-HA.
通过L-乳酸的表面接枝反应和L-丙交酯（LLA）的开环聚合，开发了一种羟基磷灰石纳米颗粒（n-HA）表面改性的新方法。获得了两种改性的HA纳米颗粒：L-乳酸改性的HA（L-HA）和聚（L-丙交酯）接枝的HA（PLLA；P-HA）。通过傅里叶变换红外光谱、（31）P MAS NMR和热重分析对n-HA的改性表面进行了验证。结果表明，L-乳酸可以通过形成羧酸钙键轻松接枝到n-HA表面，并由接枝的L-乳酸的羟基引发，在辛酸亚锡存在下，LLA可以接枝聚合到n-HA表面。L-乳酸和PLLA的最高接枝量分别约为33 wt%和22 wt%。改性的HA/PLLA复合材料表现出良好的力学性能和均匀的微观结构。含15 wt%P-HA的P-HA/PLLA复合材料的拉伸强度和模量分别为67 MPa和2.1 GPa，而n-HA/PLLA复合材料的拉伸强度和模量分别为45 MPa和1.7 GPa。含15 wt%L-HA的L-HA/PLLA复合材料的断裂伸长率可达44%，相比之下，含15 wt%n-HA的n-HA/PLLA复合材料的断裂伸长率为6.5%。
