具有优异生物稳定性氟硅聚氨酯的合成与性能研究

针对现有生物医用聚氨酯植入材料生物稳定性存在的不足，拟通过对聚氨酯分子链进行优化设计，在软段引入聚二甲基硅氧烷（PDMS）、在硬段侧链引入氟碳链制备含氟含硅聚氨酯（FSPU）。利用低表面自由能的PDMS和氟碳链向表面迁移的特点，研究氟硅协同调控聚氨酯表面结构与形态的机理， 从而构筑耐氧化降解、耐水解的表面；通过对FSPU链段的运动、松弛以及分子间相互作用进行表征，揭示PDMS、氟碳侧链与聚氨酯加工流动性和热稳定性的关系，控制加工条件减少聚氨酯在熔融加工中的降解和残余应力以提高本体稳定性。结合对FSPU生物稳定性评价，从表面和本体两个角度阐明PDMS和氟碳链在防止聚氨酯降解过程中的作用机制，实现大幅改善医用聚氨酯生物稳定性的目标。本项目的实施不仅为深化氟硅元素在医用聚氨酯改性领域的应用提供了新的思路，也为开发具有优异生物稳定性的新型医用聚氨酯、拓展其在人体长期植入材料领域的应用奠定了基础。

To deal with the biostability shortcomings of biomedical polyurethanes, the macromolecular structures of polyurethanes are optimized to prepare silicone and fluorine containing polyurethanes (SFPU) via introducing polydimethylsiloxane (PDMS) to soft segment and fluorinated side chains to hard segment. PDMS and fluorinated side chains of low surface free energies tend to migrate toward the surface to construct oxidative and hydrolytic resistant surface. The mechanism will be thoroughly investigated with regard to silicone and fluorine synergistically tuning the surface structure and morphology; Meanwhile, the segmental motion、relaxation and molecular interactions of SFPU are characterized to reveal the correlation between PDMS、fluorinated side chain and processing fluidity and thermal stability of polyurethanes. Thus the bulk stability could be improved through preventing the occurrences of degradation and residual stress during melting process. Combining the biostability evaluation of SFPU, we will try to figure out how PDMS and fluorinated side chains function to prevent degradation of polyurethanes. Eventually the goal of prominently enhance the biostability of polyurethanes will be achieved. This project not only suggests one new sight of view for deepening the application of silicone and fluorine in modifying biomedical polyurethanes, but also sets a solid foundation for developing new biomedical polyurethanes of superior biostability and expands its application in long term implantation.