Takahara A, Tashita J, Kajiyama T, Takayanagi M
J Biomed Mater Res. 1985 Jan;19(1):13-34. doi: 10.1002/jbm.820190104.
Characterization of microphase separated structure, interaction with blood components, such as lipids, and fatigue behavior after immersion in blood components were carried out for segmented poly(urethaneureas). The materials studied were Biomer and segmented poly(urethaneurea) (TU-Mn) composed of hard segment with 4,4'-diphenylmethane diisocyanate (MDI)-ethylenediamine (EDA) or 4,4'-diaminodiphenylmethane (DAM) and soft segment with MDI-polytetramethylene glycol (PTMG) [Mn of 856, 1350, and 2000]. Small-angle x-ray scattering, wide-angle x-ray diffraction, and dynamic viscoelastic measurements revealed that these materials showed the state of microphase separation. TU-Mn with PtMG of Mn = 856 shows the partial phase mixing between hard and soft segments, and phase separation was improved with an increase of Mn of PTMG. Biomer has the characteristics of stronger aggregation of hard segment than that of TU-Mn. All the specimen showed lipid absorption, but the amount of absorption decreased remarkably after precoating on the specimen surface with serum albumin. Lipid absorption of the specimen was confirmed by dynamic viscoelastic and IR measurements. In the case of segmented poly(urethaneurea) which did not immersed in lipids solution, their fatigue strength are sufficient for application to artificial heart systems. However, fatigue strength of the TU-Mn series was decreased drastically after absorption of lipids. On the other hand, Biomer did not show a decrease of fatigue strength after lipid absorption. The reduction of fatigue strength in the TU-Mn series after lipid absorption will be attributed to the weak aggregation of hard segment domain. This reduction of fatigue strength in the TU-Mn series is characterized by formation of microcrack and mirror zone in fatigue fractured specimen. As the precoating of the specimen surface with serum albumin inhibits the absorption of lipids, the reduction of fatigue strength was not observed for the specimen precoated with serum albumin even after immersing the TU-Mn series in lipids solution for 96 days.
对嵌段聚（聚氨酯脲）进行了微相分离结构的表征、与血液成分（如脂质）的相互作用以及浸入血液成分后的疲劳行为研究。所研究的材料包括Biomer和由4,4'-二苯基甲烷二异氰酸酯（MDI）-乙二胺（EDA）或4,4'-二氨基二苯甲烷（DAM）组成的硬段以及由MDI-聚四亚甲基二醇（PTMG）[Mn分别为856、1350和2000]组成的软段的嵌段聚（聚氨酯脲）（TU-Mn）。小角X射线散射、广角X射线衍射和动态粘弹性测量表明，这些材料呈现出微相分离状态。Mn = 856的PTMG的TU-Mn在硬段和软段之间表现出部分相混合，并且随着PTMG的Mn增加，相分离得到改善。Biomer具有比TU-Mn更强的硬段聚集特性。所有样品均表现出脂质吸收，但在用血清白蛋白预涂样品表面后，吸收量显著降低。通过动态粘弹性和红外测量证实了样品的脂质吸收。对于未浸入脂质溶液的嵌段聚（聚氨酯脲），其疲劳强度足以应用于人工心脏系统。然而，TU-Mn系列在吸收脂质后疲劳强度急剧下降。另一方面，Biomer在吸收脂质后未表现出疲劳强度降低。TU-Mn系列在吸收脂质后疲劳强度的降低将归因于硬段域的弱聚集。TU-Mn系列中这种疲劳强度的降低表现为疲劳断裂样品中微裂纹和镜面区的形成。由于用血清白蛋白预涂样品表面可抑制脂质吸收，即使将TU-Mn系列浸入脂质溶液96天后，预涂有血清白蛋白的样品也未观察到疲劳强度降低。
