学校代码***** 学号************分类号O63 密级
硕士学位论文
纳米羟基磷灰石表面改性及其增强PCL复合材料性能研究
学位申请人曾亮
指导教师张雪飞副教授
学院名称化学学院
学科专业高分子化学与物理
研究方向功能高分子
二0一0年六月
Surface Modification of Hydroxyapatite Nanoparticles and Performance Study of its Reinforced PCL Composites
Candidate Liang Zeng
Supervisor Xuefei Zhang
College Chemistry
Program Polymer Chemistry & Physics
Specialization Functional Polymer
Degree Master of Science
University Xiangtan University
Date June, 2010
湘潭大学
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摘要
近年来，骨修复材料的制备逐渐成为化学、医学以及材料学中的一项热点。为综合各种材料性能，研究人员进行了大量的研究，其中提出的复合材料的理念已经被广泛接受。由于羟基磷灰石（HAP）与聚合物基质之间差的界面相容性，生物复合材料的应用受到了很大的限制。因此，如何提高磷灰石/有机复合材料中无机相与有机相间的界面相容性是骨修复材料领域中一个重要课题。为解决这些问题，可对磷灰石进行接枝改性，使其与有机相间形成过渡相以增强相容性。目前，骨修复材料领域中，接枝改性并不理想，低的接枝量及接枝率不能控制等因素制约了其进一步的应用和发展。
原子转移自由基聚合（ATRP）是一种很有价值的聚合方式，能很容易的在材料表面接枝上结构明确的均聚物或共聚物来改善材料的表面性能。此外，由于ATRP聚合方法具有可控的链增长以及可聚合单体多样等优点，在制备具有分子量可控、分子量分布窄的聚合物方面得到了广泛应用。
本文中，我们设计了一种结合了原子转移自由基聚合和开环聚合的羟基磷灰石纳米粒子表面改性方法。该方法利用ATRP方法将一定数量的官能团引入HAP 纳米粒子表面，并能通过调节引发剂和单体投料比对接枝量进行控制。论文对HAP以及接枝改性的HAP纳米粒子进行了研究。具体内容摘要如下：
1、采用化学沉淀法合成HAP纳米粒子，并利用α-溴代异丁酰溴与其表面羟基反应，得到用于ATRP聚合的引发剂（HAP-Br）。采用了傅里叶变换红外光谱仪（FT-IR）、热失重分析（TGA）、x射线衍射（XRD）及透射电镜（TEM）对HAP及HAP-Br进行了表征。
2、利用HAP-Br引发甲基丙烯酸羟乙酯（HEMA）的ATRP聚合，得到羟基化的HAP纳米粒子（HAP-PHEMA）。然后利用HAP-PHMEA引发己内酯（CL）的开环聚合，得到具有高接枝率的改性纳米羟基磷灰石。所得产品采用了13C固体核磁（13C CP/MAS）、FT-IR、TGA、XRD及TEM进行了表征。
3、利用溶液共混法将改性HAP与聚己内酯（PCL）进行共混制备复合材料。采用了差示扫描量热仪（DSC）及扫描电镜（SEM）以及其他测试设备对材料性能进行了表征。
关键词：纳米羟基磷灰石；原子转移自由基聚合；开环聚合；化学接枝改性；复合材料。
Abstract
In recent years, the preparation of bone repairing materials has been gradually become one of the m
ost important tasks in chemical, medical and materials field. In order to integrate the performance of variety materials, great progress has been made and the idea of composites materials has been accepted widely in recently years. Due to the weak interfacial compatibility between hydroxyapatite and polymer matrix, the application of biocomposites also has been limited. To solve this problem, chemic grafting modification strategy has been developed. However, becau of the low grafted amount and uncontrollable grafting efficiency,the application of hydroxyapatite has been limited in more fields.
Atom transfer radical polymerization (ATRP) is a uful polymerization method for constructing well-defined block and graft copolymers on material surface to modify their surface properties. Furthermore, ATRP is widely applied to prepare polymers with predictable molecular weights and narrow molecular weight distribution for its advantage of controlled chain growth and multiplicity of monomers.
In this paper, a novel strategy to modify hydroxyapatite nanoparticles (HAP) surface has been developed by combination of ATRP and ring opening polymerization (ROP). In this method, definite functional groups were introduced onto the HAP surface and the amount of the functional groups could be controlled by adjusting the initiator/monomer ratio. The preparation and characterization of
HAP and modified HAP were studied. The main contents were as follows:
1．HAP nanoparticles were synthesized via chemical precipitation firstly. Then, 2-bromoisobuturyl bromide (BIBB) was coupled to the surface of HAP nanoparticles directly to obtain ATRP initiator (HAP-Br). FT-IR, TGA, XRD and TEM were ud to investigate the nanoparticles of HAP and HAP-Br.
2．HAP-Br was ud to initiate the ATRP of 2-hydroxyethyl methacrylate (HEMA) to get functionalized HAP (HAP-PHEMA). The ROP of ε-caprolactone (CL) was initiated by HAP-PHEMA to obtain high grafting ratio modified HAP. The products were characterized by 13C CP/MAS, FT-IR, TGA, XRD and TEM.
3．Composite materials of polycaprolactone (PCL) reinforced by modified HAP nanoparticles were prepared via solvent blending. DSC, SEM and other instruments
