【作者】 舒晓军；

【导师】 杨青芳；

【作者基本信息】 西北工业大学 ， 生物医学工程， 2007， 硕士

【摘要】 聚乳酸(PLA)具有优良的生物相容性、生物降解性，但PLA为疏水性物质，降解速度较慢，分子链上缺乏可反应性官能基团。这些性质限制了其在生物医药等领域的实际应用。聚氨基酸具有良好的生物相容性和降解性，并含有羟基、羧基、氨基、巯基等反应活性基团。但因大分子链的分子内和分子间易形成氢键，所以不宜溶于许多有机溶剂，加工成型性能较差。通过丙交酯(LA)和氨基酸共聚，可望获得具有良好的生物相容性、降解速率可调控、含有一定密度的反应活性基团、具有良好加工成型性能的共聚物。通过改变组分及共聚物合成工艺，可以调整其降解周期和亲水性能。 本文在不添加任何催化剂或溶剂的情况下，由天冬氨酸(Asp)和丙交酯(LA)混合加热合成了聚(天冬氨酸-丙交酯)(PAL)。通过改变单体组分比例以及不同的合成工艺条件，合成出了不同分子量的共聚物。通过红外光谱(IR)和核磁共振光谱(NMR)可以发现PAL具有独特的琥珀酰亚胺和聚乳酸分枝体系结构。通过差示扫描量热法(DSC)研究了其热性能，凝胶色谱(GPC)测定了其分子量及其分布。PAL可溶解于很多有机溶剂，具有良好的加工成型性能。PAL及其与PLA的共混物的亲水性能随组分的不同而发生变化。 PAL能有效加快PLA的水解速率。通过制备不同比例的PLA／PAL试样，观察力学性能、结晶度和外观形貌的变化，计算重量损失、分子量损失。得出结论：PAL的亲水成分能大大加快PLA的水解速度。同时，PAL能加快大多数脂肪族聚酯的水解速率。PLA／PAL共混膜在复合肥中的降解速率比纯PLA膜快，也表明PAL不仅能加快PLA的水降解率，而且能加快其生物降解率。更多还原

【Abstract】 Poly (lactic acid) (PLA) has fine biological compatibility and biological degradability, but PLA is a kind of hydrophobic material, degrades slowly, and lacks reactivity function groups on the molecular chain. These properties have limited it in applications of biological and medicine fields. Poly (amino acids) have good biological compatibility and degradability, and includes responsable active groups such as the hydroxyl, the carboxyl group, the amino group etc. Because there are many hydrogen bonds between intramolecular and intermolecular chains, they cannot dissolve in many organic solvents, and their processing performance is poor. Copolymerization of lactic acid(LA) and amino acid could obtain copolymers with good biological compatibility, adjustable degeneration speed, reactive active groups, and good processing performa nce. The copolymers’ degeneration speeds and hydrophilic properties can be adjusted by changing the raw material’s formulae and copolymerization conditions.Poly(aspartic acid-lactide) (PAL) was synthesized by simply heating a mixture of aspartic acid (Asp) and lactic acid(LA) without additional any catalyst or solvent. The copolymerization conditions of the there formulae had determined respectively, which are including Asp solution temperature, copolymerization temperature and reaction time. The unique branched architecture comprising succinimide units and lactic acid units was confirmed by infrared spectrum (IR) and nuclear magnetic resonance spectrum (NMR). The thermal properties are determined by differential scanning calorimetry (DSC), and the molecular weight and the distribution was determined by gelatin chromatograph (GPC). The PAL was soluble in many organic solvents, and has the good processing formation performance. PAL and the blends with PLA have different hydrophilic properties which are changing along with the component.PAL can make PLA hydrolysis faster.Through making PLA/PAL samples in various proportions,we can observe the change of the samples’ mechanical properties, crystallization and surface topography;calculate the samples’ loss of quality and molecular weight. Arrival at a conclusion:PAL can make PLA hydrolysis more effectively. At the same time,PAL could make the most Polyeaster hydrolysis faster.The degradation of blending films made by PLA/PAL is faster than pure PLA films.We could conclude that PAL dose not only make the hydrolysis of PLA faster,but also the degradation.更多还原