Preparation And Characterization Of Magnetic Fe₃O₄/PCU Composite Microspheres

With the development of endovascular interventional treatment technology, therequirements of endovascular embolic materials have become more and more strict. Inorder to improve some shortcomings of embolic material, this paper designed andsynthesized a series of PCU microspheres and Fe3O4/PCU composite microspheres.Then their chemical properties and biocompatibility were investigated.In this study, polycarbonate diol (PCDL2000) was used as soft segment, isophor-one diisocyanate (IPDI), hexamethylene diisocyanate (HDI) and1,4-butanediol (BDO)were chosen as hard segment, these materials were synthesized to produce PCU microspheres by prepolymerization and suspension polymerization. Then by conjugatingPCU microspheres with iron oxide, Fe3O4/PCU microspheres with different massratios were prepared. The structure and properties of microspheres were characterizedand analyzed by infrared spectroscopy and differential scanning calorimetry.Moreover,the shape memory performance was characterized by compression test.The structure of PCU was analyzed by infrared spectroscopy, the resultsindicated that PCU had the structure of IPDI, HDI and PCDL2000respectively,andthe amido formyl ester in polyurethanes. DSC and TGA were used to characterize thethermal properties and the microphase separated structure. With the increase of thecontent of hard segment in PCU, the limitation of the soft segment crystalline will beenhanced. Thus, the crystalline of soft segment and the crystalline melting tempera-ture of material will gradually decrease. All PCU microspheres with different ratios ofthe soft segment and hard segment exhibited shape fixture rate and shape recoveryrate above90%and thus had excellent shape memory performance. But with theincrease of hard segment content, the shape recovery ratio will increase firstly andthen decrease. However, the shape fixture rate will reduce gradually. In addition, dueto the presence of stress, the minimum temperature of deformation recovery is usuallylower than the shape memory temperature.The Fe3O4/PCU was successfully synthesized by in-situ suspension polymerize-tion. The study indicated that the effect of Fe3O4on shape memory property andthermal properties was less than that of hard segment. With the increase of the contentof Fe3O4, the shape memory property of composite microspheres decreased. TheFe3O4/PCU composite microspheres with different ratios exhibited shape fixture rateand shape recovery rate above90%and thus had excellent shape memory performance. The effect of Fe3O4on shape memory property and thermal propertieswas less than that of hard segment. With the increasing content of Fe3O4, the shapememory property of composite microspheres decreased.Moreover, the results of the biocompatibility evaluation showed that Fe3O4/PCUhad a good biocompatibility. Thus, Fe3O4/PCU could be used as implant material.