【作者】 张中明；

【导师】 胡巧玲；

【作者基本信息】 浙江大学 ， 高分子化学与物理， 2004， 硕士

【摘要】 壳聚糖已经能够采用原位沉析法三维成型，但壳聚糖棒材在作为骨折内固定材料的实用化以及成型工艺的理论方面还存在一些问题，主要有：棒材的高吸水速率和吸水率导致棒材在湿态环境中力学性能损失过快；棒材成型机理尚不十分明确等。本文采用了表面乙酰化和涂覆生物酯防水层的工艺对棒材进行了疏水化改性尝试，并对原位沉析法进行了一定的改进，进一步明确了棒材成型机理。 1、针对壳聚糖棒材在湿态环境下力学性能衰减速率过快的原因进行了深入分析，参考纤维素的酰化工艺，采用“乙酸酐+浓硫酸”在常温下对壳聚糖棒材表面进行乙酰化疏水改性；制定并优化了工艺；对酰化效果进行了红外、接触角表征和吸水速率测试。表面乙酰化4h能有效的增大壳聚糖棒材的接触角，降低其亲水性，但只能有限延缓棒材的吸水速度，无法降低其吸水率。 2、采用壳聚糖棒材外表面涂覆物理防水层的思路，对各种生物相容的疏水材料进行了选择和比较。尝试了一种天然生物酯；对其涂覆工艺进行了优化；并通过模拟体液环境下壳聚糖棒材力学性能衰减实验对涂层防水效果进行了检验；结果表明该生物酯涂层结构致密，粘附性强，疏水效果极佳，结合棒材表面的乙酰化改性能有效地延缓棒材在湿态环境下力学性能的衰减。对其应用前景及改进方法进行了初步的分析。 3、在树木年轮结构的启发下，对原位沉析法进行了一定的改进，变连续的沉析过程为间歇可控的沉析过程，制备出横截面具有类似树木年轮状圈层结构，分层清晰可见壳聚糖棒材；该成型工艺的改进有利于进一步明确原位沉析法的成型机理。更多还原

【Abstract】 In-situ precipitation method has been developed to prepare chitosan rod (CR). But, high water penetrating rate and large amount of water absorption of CR block its practical application as internal fixation of bone fracture, the preparation mechanism of CR is not very clear as well. In this thesis, surface acetylating and bio-ester coating were tried for surface hydroprobization of CR, and an improved preparation method was studied for clarifying in-situ precipitation mechanism further.1. The facts influencing the mechanical properties attenuation of CR in wet situation were studied. Acetic anhydride catalyzed by sulfuric acid was used to CR surface acetylation, the acetylation processing was optimized, and the final waterproof effect was characterized by FTIR, contact angle and water absorption rate also. Surface acetylation can increase contact angle of CR effective but works a little in delaying water penetrating.2. For coating a waterproof layer on the CR surface, comparison and selection have been made among several biocompatible materials. One kind of bio-ester was applied as coat finally for a trial. The coating progressing was studied. As shown in the result of experiment on mechanical properties attenuation of CR in artificial body fluid, the bio-ester lay with compact structure and strong adhesive ability has very good waterproof effect combined with surface acetylation method. Its prospective use and improvement measures were also discussed.3. Illumined by annual ring of wood, in-situ precipitation method was improved by changing uninterrupted precipitation into intermittent and controllable process, which produced a kind of CR with layered structure similar to annual ring on their cross section. The improvement is help to clarify the preparation mechanism of CR.更多还原