【作者】 王鹏；

【导师】 闫寿科；

【作者基本信息】 北京化工大学 ， 材料科学与工程， 2016， 硕士

【摘要】 聚己内酯由于良好的生物可降解性、生物相容性等特性而被广泛的用作药物载体材料和手术短期植入物。聚己内酯的疏水性限制了其应用,通过加上亲水性的链段来弥补这个缺点。结晶性能对于生物材料最终的物理性能、机械性能、生物可降解性能及药物释放机理等有重要的影响。附生结晶体系中,附生基底对附生物的诱导结晶作用致使其产生不同寻常的结晶形态结构。在附生界面处强的相互结合作用,对材料的力学性能有很大的影响,附生基底和附生物质晶体之间的协同作用引起了人们的广泛关注。1.利用自由基活性聚合方法合成了一系列不同重量分数比的PEO-b-PCL嵌段共聚物。固定分子量PEO链段结晶性随着重量分数比不同而改变,并且当PEO重量分数小于16%时不结晶。嵌段共聚物球晶生长速率随PCL链段重量分数的增大而变大,但总体上结晶速率远小于纯组分的结晶速率。2.通过不同重量分数比嵌段共聚物等温结晶过程的研究,发现结晶过程中两链段结晶形态以及结晶形貌随重量分数比的变化规律。重量分数接近的嵌段共聚物MPEG1900-PCL2000和MPEG20000-PCL20000出现环带球晶结构。嵌段共聚物环带球晶环带周期随结晶温度的提高而增大；通过环带球晶结晶形貌的研究,解释了嵌段共聚物环带球晶生长过程。3.附生结晶体系的实验中,利用熔融拉伸法制备了高度取向PE超薄膜；偏光样品旋转消光现象说明聚合物发生了取向结晶。利用三明治夹心结构解决了聚合物的团聚问题,通过揭膜法对嵌段共聚物在取向PE基底上片晶取向结构进行了表征。取向PE基底对于嵌段共聚物中PEO链段的结晶形态影响很小,但PEO链段的加入不利于嵌段共聚物中PCL链段在取向PE上的附生结晶。更多还原

【Abstract】 Poly(ε-caprolactone) has been widely used in drug carrier material and surgery short -term implants. As we know, Poly(E-caprolactone) is hydrophobic, which restrains its applications. with poly(ethylene oxide) attached to poly(ε-caprolactone) can improve the hydrophilic defection, which is hydrophilic. the synthesis and the crystalline behavior study of poly(ethylene oxide)-b-poly(ε-caprolactone) copolymers were rapidly promoted by biocompatibility, amphiphilicity, self-assembly, permeability, and controllable biodegradability. Crystallization behavior has important implications for the final physical properties, mechanical properties, biodegradable properties and drug release mechanism of biological materials. Hetero-epitaxy of polymers has been extensively studied for it provides a useful way to control the crystalline structure of a wide variety of semi-crystalline polymeric materials. In hetero-epitaxy system, the effect of the substrate on the epitaxial substances results in the strict orientation relationship between the two, which can produce unusually morphological structure. Due to the strong physical binding of epitaxial interface has a great influence on the mechanical properties of the material, which causes widespread concerns.1. A series of different weight fraction ratio of PEO-b-PCL block copolymers were synthesized by living radical polymerization method。The crystallinity of fixed molecular weight PEO segment would change with different weight ratios.The PEO segment does not crystalline when the weight ratio of PEO is less than 16%. The spherulite growth rate of block copolymers increases with the PCL segment weight fraction larger.2. In experiment, we characterized isothermal crystallization process of different weight fraction of the block copolymers with analyzing the changes in crystallinity and crystallization process of two segments varying with the component. MPEG 1900-PCL2000 and MPEG20000-PCL20000, in which the segments have the close weight fraction, appear banded crystal structure. the band period increases with the crystallization temperature higher. The crystal morphology study of banded spherulite can explains the block copolymer banded crystal growth process.3. Oriented PE ultra-thin films were prepared by melt-drawn technique during the experiment of epitaxial orientation study, the rotated extinction phenomenon of samples shows the oriented crystalline has occurred. Sandwich structure can solve the problem of polymer agglomeration. The peeling film method was introduced to character the oriented crystalline on the substrate of highly oriented PE ultra-thin film. The effect of oriented PE substrate on the crystalline of PEO segment is very little, but with the PEO segment added, the epitaxial crystalline of PCL segment of the block copolymer on oriented PE film is affected.更多还原