| Polyurethanes are one of the most important thermoplastic elastomers and have been widely used in medical-device manufacturing as well as in other applications. However, their long-term performances in biological environment are not acceptable to date. Particularly, they are known to degrade in vivo by hostile substances (enzymes, super oxide anion, hydroxyl radical, H2O2 and acids, etc.) released by macrophages and foreign body giant cells during inflammatory response stimulated by the foreign materials. In addition, fluoropolymers, such as polytetrafluoroethylene, have good chemical stability but poor mechanical properties. So, introducing fluorinated chains into the backbones of polyurethanes maybe will produce novel polyurethanes having good mechanical properties, acceptable biocompatibility and long-term biostability. In this dissertation, a fluorinated alcohol, 2,2, 3, 3,4,4, 5, 5,6, 6, 7, 7, 8, 8, 8-pentadecafluoro-l-octanol (PDFOL) was used as an end-capping reagent to polycarborate urethanes during synthesis these polyurethanes through bulk polymerization. And its hemocompatibility and biostability were also investigated in this thesis.As the starting materials for polycarbonate urethanes and fluorocarbon end-capped polycarbonate urethanes, a series of aliphatic polycarbonate diols were synthesized by carbonate interchange reaction of aliphatic diols with diethyl carbonate (DEC). Gas Chromatogram Analysis revealed that there were about 2.54% (by weight) tetrahydrofuran and very lillte (0.154%, by area) tetrahydropyran in the distillations of 1,4-butanediol/DEC and 1,5-pentanediol/DEC reaction systems, respectively. A "cycloalkylene carbonate-decarboxylation" mechanism was proposed for interpretation the formation of the side products. X-ray diffraction and DSC demonstrated that homopolycarbonate diols from 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol were semicrystalline polymers while copolycarbonate diol from 1,6-hexanediol and 1,5-pentanediols (3:2, mole ratio), PHPC, was an amorphous polymer. It was a pale-yellow liquid at room temperature.Polycarbonate urethanes (PCU) were synthesized from aliphatic polycarbonate diols as soft segments and MDI/BDO as hard segments. IR spectra, DSC analysis and X-ray diffraction revealed that all polycarbonate urethanes had microphase separation structures and the two phases in bulk polymers were amorphous. The degree ofmicrophase separation increased with the increasing of molecular weights of the soft segments. All polycarbonate urethanes had high tensile strength (30-60MPa) and moderate elongation at break (300-450%). Particularly, the polycarbonate urethane from copolycarbonatediol, PHPC, exhibited improved flexibility and elastic recovery as compared to those from homopolycarbonatediols.PDFOL end-capped polycarbonate urethanes (PCU-1058F) were synthesized from PHPC as soft segment and MDI/BDO as hard segment. About 2% w/w PDFOL in the total reactants generated a polymer with nonwettable surface. Bulk elemental analysis and X-ray photoelectron spectrum (XPS) showed that the atom percents of fluorine at outermost surfaces were as much as 90 - 100 times of those in the bulk. Because of the high surface activity of fluorocarbon tails, PCU-1058F formed three different layers from outermost surfaces into the bulk materials, that is, firstly fiuorocarbon-dominated (about 0A-50A), then hard-segments dominated (about 50A-100 A) and finally the bulk-dominated (about >100 A), which were called "Sandwich Structure".The in vitro biostability of polycarbonate urethanes and fluorocarbon-terminated polycarbonate urethanes were test by Zhao's "Glass wool-H2O2/CoCl2" test system and PBS (0.1M, PH=3.4) test system. After 100 days in both tests, no stress cracks were observed on both materials. GPC analysis demonstrated that fluorocarbon-terminated polyurethane exhibited slower molecular weight decrease than fluorocarbon non-terminated ones. In the case of "Glass wool-H2O2/CoCl2" test, the content of C-O sharply increased as for polycarbonate ureth...
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