HA-g-PDLA与左旋聚乳酸的共混研究

发布时间：2018-01-10 22:14

本文关键词：HA-g-PDLA与左旋聚乳酸的共混研究　出处：《北京化工大学》2016年硕士论文　论文类型：学位论文

【摘要】：羟基磷灰石(HA)在人体某些硬组织(牙齿、骨骼等)中的含量将近七成,是近年来临床上公认的优秀骨替代材料,但强度低、脆性大、易疲劳等缺点导致HA难以单独作为骨支撑材料,通常选择将其与聚合物进行共混来提升其机械性能。其中,聚乳酸(PLA)是一种具备优良生物相容性和生物可降解性的聚合物,将其与HA共混制备成复合材料,一方面PLA可以改善HA易碎,韧性低等缺陷,另一方面HA对PLA降解后的酸性产物能起到缓冲的作用。然而HA纳米粒子本身易团聚,在PLA中的分散性较差,选择右旋聚乳酸(PDLA)接枝改性后的HA(HA-g-PDLA)不仅可以有效的改善与PLA的相容性,还可与左旋聚乳酸(PLLA)形成立构复合晶(sc),通过调控复合材料的结晶性能,从而提升HA/PLA复合材料的机械性能,拥有广阔的应用前景。本课题主要围绕接枝共聚物HA-g-PDLA与PLLA共混产物的结晶行为展开了一系列研究,具体工作如下：1、为了改善HA纳米粒子在PLLA基质中存在分散性较差的缺点,通过开环聚合的方法成功制备出HA-g-PDLA接枝聚合物。并研究了HA与DLA不同的反应投料比与产物接枝率之间的关系,优化了反应条件,实验结果证明改性后HA在PLLA中的分散情况得到明显改善；2、研究了HA-g-PDLA与PLLA在不同共混比例下复合材料的结晶能力,阐明了复合材料中HA-g-PDLA的含量变化对PLLA结晶性能的影响规律；3、研究对比HA-g-PDLA/PLLA与PLLA、HA/PLLA、PDLA/PLLA、 HA/PDLA/PLLA、HA-g-PLLA/PLLA等五组共混样品的结晶行为,实验结果表明HA-g-PDLA/PLLA共混产物的结晶效果最好,分析了产生这种结果的原因；4、分别以HA和HA-g-PDLA作为PDLA/PLLA共混样品的添加剂,研究共混产物中不同晶体的结晶行为,对比并分析了HA和HA-g-PDLA对PLA均聚物晶体和立构复合晶形成的影响,阐释了HA-g-PDLA/PLLA复合材料的结晶机理。
[Abstract]:Hydroxyapatite (HA) in some human hard tissues (teeth, bones, etc.) content of nearly 70%, is clinically recognized in recent years as an excellent bone substitute materials, but low strength, brittle. It is difficult for HA to be used as bone support material alone because of its weakness such as easy fatigue. It is usually chosen to blend it with polymer to improve its mechanical properties. Polylactic acid (PLA) is a kind of polymer with good biocompatibility and biodegradability. It is blended with HA to form composite material. On the one hand, PLA can improve the fragility and toughness of HA. On the other hand, HA can buffer the acidic product after PLA degradation. However, HA nanoparticles are easy to reunite and have poor dispersion in PLA. The modified Ha-HA-g-PDLA can not only improve the compatibility with PLA effectively. The composite crystal can be formed with L-polylactic acid (PLLA), and the mechanical properties of HA/PLA composites can be improved by controlling the crystalline properties of the composites. This paper focuses on the crystallization behavior of graft copolymer (HA-g-PDLA) and PLLA blends. The main work is as follows: 1. In order to improve the dispersion of HA nanoparticles in PLLA matrix, there is a disadvantage of poor dispersion. HA-g-PDLA grafted polymers were successfully prepared by ring-opening polymerization. The relationship between the different feed ratio of HA and DLA and the grafting rate of the product was studied, and the reaction conditions were optimized. The results show that the dispersion of modified HA in PLLA is improved obviously. 2. The crystallinity of HA-g-PDLA / PLLA composites with different blending ratios was studied. The effect of the content of HA-g-PDLA on the crystallization properties of PLLA was clarified. 3. The study compared HA-g-PDLA/PLLA with PLLAA / PA / PLLA / PLLA, HA/PDLA/PLLA. The crystallization behavior of HA-g-PLLA/PLLA and other five groups of blend samples, the experimental results show that the crystallization effect of HA-g-PDLA/PLLA blends is the best. The reasons for this result are analyzed. (4) HA and HA-g-PDLA were used as additives of PDLA/PLLA blends to study the crystallization behavior of different crystals in the blends. The effects of HA and HA-g-PDLA on the formation of PLA homopolymer crystals and orthotropic composite crystals were compared and analyzed, and the crystallization mechanism of HA-g-PDLA/PLLA composites was explained.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB332;R318.08

【参考文献】