取向性纳米片状HAp/PLA结构仿生复合材料的制备科学及性能研究

人骨中的主要无机相为呈均匀且定向排列的纳米片状羟基磷灰石（HAp），而人工合成的HAp多为纳米颗粒，其在基体中的可控分布以及与基体的良好界面结合一直是HAp复合材料发展的瓶颈。本项目在模板法合成片层HAp的基础上，拟充分利用插层复合材料的优点（即均匀分散和强界面结合），率先将“插层”概念引入到HAp生物复合材料领域，提出取向性纳米片状HAp/聚乳酸（PLA）结构仿生复合材料的制备方案。本项目拟先对HAp的几何结构进行调控，同时在其表面接枝低聚乳酸，进而研究HAp几何形态与表面接枝对PLA熔体“类插层”过程、HAp-PLA界面结合及HAp在PLA基体中分散与取向的调控机制，并重点研究HAp/PLA复合材料结构学参数（HAp尺度与形态、取向、分散等）与其力学性能、生物相容性及生物学功能（骨修复）的关联规律，为设计和制备高性能结构仿生的新型生物复合材料提供新的科学依据。

Human bone is a hard tissue mainly consisting of nano-hydroxyapatite (HAp) with defined alignment. Finding a synthetic pathway to artificial analogs of bone represents a fundamental milestone in the development of high-performance composite materials for biomedical applications. Based upon our previous work on successful preparation of lamellar HAp using template synthesis, herein we propose a new approach to make the artificial bone-like biocomposite that makes use of the advantages of intercalation technique in favor of physically controlled alignment of HAp nano-platelet in polylactic acid (PLA). This results in a biocomposite, which will reproduce not only the oriented arrangement of the HAps in natural bones, but also the strong interfacial interactions with matrix in conventional intercalated composites. To this end, the physical morphology of nano-platelet HAp will be tuned by adjusting the template synthesis process. In addition, low molecular PLA will be grafted on the surface of the nano-HAp to allow PLA intercalate into the layered HAp galleries. The melt intercalation technique that has become a main stream for the preparation of intercalated nanocomposites and shows many advantages over solution intercalation will be employed to fabricate the HAp/PLA biocomposites with highly oriented and well-dispersed HAp and strong HAp-PLA interactions. The effects of the morphology of the nano-platelet HAp and its grafting on the melt intercalation processes, HAp-PLA bonding, and HAp distribution and arrangement in the PLA matrix will be investigated. The special emphasis will be given to correlating the structural parameters (including dimension, orientation, and distribution) with the mechanical properties, biocompatibility, and biomedical functions (bone formation) of the HAp/PLA biocomposites. This work is expected to open a new way of designing and fabricating a new type of novel sophisticated composites with structural resemblance to natural bones.