新型改性聚乳酸材料的制备及性能研究

发布时间：2018-07-01 16:40

  本文选题：聚乳酸 + 胶原蛋白　； 参考：《山东轻工业学院》2012年硕士论文

【摘要】：聚乳酸由于具有良好的生物相容性、生物可降解性以及良好的力学性能和加工性能，已成为生物降解医用材料领域中最受重视的材料之一。但是单纯的PLA材料存在以下性质缺陷：PLA表面的疏水性强，降低了它的生物相容性；在人体内的降解时间长，降解周期难以控制；易出现局部酸度过大导致非感染性炎症等。为克服聚乳酸的上述缺陷，人们对PLA进行了大量的改性研究工作。利用蛋白质或多肽对聚乳酸进行共价修饰改性，可以改善聚乳酸的性能缺陷。本文利用胶原蛋白对聚乳酸进行了改性研究，并研究了改性聚乳酸的主要性能，为聚乳酸的改性研究和应用研究作出探索。 本文以DL-乳酸为原料，以氯化亚锡为催化剂，采用直接缩聚法合成得到聚乳酸，采用红外光谱、核磁共振等方法证明了其结构，经过测定其粘均分子量为1万左右。以自制聚乳酸为原料，选用二环己基碳二亚胺（DCC）为缩合剂，用胶原蛋白对聚乳酸进行改性，在聚乳酸链中引入胶原蛋白，得到改性聚乳酸（CPLA），采用FT-IR、荧光光谱、茚三酮显色以及DSC测定等方法对改性聚乳酸进行了表征，证明了胶原蛋白与聚乳酸发生作用并且已成功接入到聚乳酸中。DSC分析表明，PLA的玻璃化转变温度为56.0℃，而CPLA的玻璃化转变温度只有一个为41.7℃，从而证明CPLA中成功接入了胶原蛋白，且已完全纯化。 研究发现，CPLA的水接触角小于PLA而其吸水率大于PLA，表明CPLA的亲水性要明显高于未改性的PLA。降解性研究表明，CPLA在降解的前两周降解速率较高，然后降解速率比较均匀，没有酸催化的自加速降解过程，而PLA在降解过程中存在明显的酸催化的自加速降解现象。细胞相容性研究结果显示，3T3纤维原细胞在CPLA材料表面上的粘附、铺展以及生长情况都要好于未改性的PLA，表明采用胶原蛋白改性聚乳酸后，可以明显提高其细胞相容性。 本文采用O/W型溶剂挥发法，通过优化制备工艺条件，制备得到胶原改性聚乳酸微球。SEM和粒度分析表明，微球的表面光滑、成球圆整、分散性好、大小均匀，平均粒径为3.10μm，跨度为0.6548。红外分析结果表明，微球的制备过程没有改变CPLA的化学结构，只是改变了其形态。利用差热分析对微球的热稳定性进行了研究，，结果显示PLA接枝上胶原蛋白后其玻璃化温度下降了10.06℃，冷结晶温度下降了12.45℃。
[Abstract]:Polylactic acid (PLA) has become one of the most important biomaterials in the field of biodegradable medical materials due to its good biocompatibility, biodegradability, good mechanical properties and processability. However, the simple PLA material has the following properties: the hydrophobicity of the surface of the PLA is strong, which reduces its biocompatibility; the degradation time in human body is long, the degradation cycle is difficult to control, and the local acidity is too large to lead to non-infectious inflammation and so on. In order to overcome the above defects of PLA, a lot of research work has been done on the modification of PLA. The performance defects of polylactic acid can be improved by covalent modification of polylactic acid with protein or polypeptide. In this paper, the modification of polylactic acid by collagen was studied, and the main properties of modified PLA were studied. Poly (lactic acid) was synthesized by direct Polycondensation with DL-lactic acid as raw material and stannous chloride as catalyst. Its structure was proved by IR and NMR. Its viscosity average molecular weight was about 10,000. Polylactic acid (CPLA) was prepared by using self-made polylactic acid (PLA) as raw material and dicyclohexyl carbodiimide (DCC) as shrinkage agent. Collagen was introduced into the chain of polylactic acid to obtain modified polylactic acid (CPLA). The modified polylactic acid was characterized by indenhydrin color development and DSC measurement. It was proved that collagen acted with polylactic acid and was successfully inserted into polylactic acid. DSC analysis showed that the glass transition temperature of PLA was 56.0 鈩

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