The development of the high-performance resin for medical use by using the multi-block copolymer of aramid and silicone

在整个项目中，我们一直在研究芳族聚酰胺-硅树脂（PAS）作为生物医学聚合物的可能用途。在这一年中，通过研究力学性能、热机械性能、氧渗透性和血液相容性，对PAS的表征和功能进行了详细的研究。结果如下。采用气-液体系研究了PAS膜的透氧性能。结果表明，PAS膜的界面层阻力受流体力学参数的影响大于其有机硅含量的影响。PAS膜的界面层电阻比硅橡胶低。PAS膜的低界面层阻力和相当高的拉伸强度使得能够在实际应用中提供高透氧性膜，例如人工肺。PAS膜的表面结构，其特征在于角依赖的X射线光电子能谱（XPS），静态二次离子质谱（SSIMS），和透射电子显微镜（TEM）。XPS测试结果表明，有机硅链段的表面浓度远高于体相浓度。特别地，包含超过24wt%硅酮的PAS膜的最外表面的化学组成几乎与硅橡胶的相同。SSIMS测量和TEM观察的结果显示了相同的结果。很明显，发现所有PAS膜的最外表面完全被硅酮链段覆盖，即使硅酮含量在本体中非常低（8wt%）。通过TEM观察以及本体中的微区结构，可以证实有机硅链段的表面富集。从这些结果可以得出结论，PAS有能力成为高性能的医用树脂，如人工肺，抗血栓涂层，和硅橡胶的替代用途。

We have been studying the possible use of aramid-silicone resins (PAS) as a biomedical polymer throughout this project. In this year, the detailed investigation of the characterization and functionality of PAS were done by studying mechanical properties, thermo-mechanical properties, oxygen permeability, and blood compatibility. The results are as follows. The oxygen permeation properties of PAS membranes were investigated using the gas-liquid system. It became clear that the boundary layr resistance of the PAS membrane was effected by the hydrodynamic parameter rater than its silicone content. PAS mambrane showed the very low boundary layr resistance than silicone rubber. The low boundary layr resistance and the fairly high tensile strength of the PAS membrane enables to provide the high oxygen permeable membranes in practical applications such as an artificial lung. The surface structures of PAS membranes were characterized by angular-dependent X-ray photoelectron spectroscopy (XPS), static secondary ion mass spectrometry (SSIMS), and transmission electron microscopy (TEM). The results of XPS measurement showed that the surface concentration of the silicone segment was much higher than that in bulk. In particular, the chemical composition of the outer-most surface of the PAS films that contained over 24 wt% silicone were almost the same as that of silicone rubber. The results of SSIMS measurement and TEM observation showed the same results. It comes clear that the outermost surfaces of all of the PAS films were found to be completely covered with silicone segment even the silicone content was very low (8 wt%) in bulk. The surface enrichment of the silicone segment could be confirmed by TEM observation as well as the micro-domain stuctures in bulk. From these results, we would conclude that PAS has ability to become a high perfomance resin for medical use such as artificial lung, antithrombogenic coating, and alternative use of silicone rubber.