Polymer / Montmorillonite Nano-anticoagulant Composites

Polymeric biomaterials, which could be used in biological environment, played an important role in biomedical application, and were widely used in biomedical fields for artificial organ and other medical devices. When polymeric materials come into contact with living organisms, significant responses such as thrombus formation and unfavorable immunoresponses occur. Biocompatibility, especially blood compatibility, is the most important property with regard to biomedical materials. Therefore, improving blood compatibility of biomaterials is an essential research task for biomaterials research and development.Polymer nanocomposites containing an equivalent volume fraction of inorganic filler have attracted substantial attention from academic and industrial researchers because of their superior mechanical, barrier properties and blood compatibility. In this work, three novel classes of intercalation-benzalkonium chloride-heparin (C12-hep),cetyltrimethylammonium bromide-heparin (C16-hep) andoctadecyldimethyl-2-ethoxylammonium bromide-heparin (C18-hep)-were prepared and used as intercalation for montmorillonite (MMT) to form modified montmorillonite (MMT-C12-hep, MMT-C16-hep, MMT-C18-hep). The three kinds of modified montmorillonite(O-MMT) were characterized by XRD,FTIR and TGA. The preparation process and the technical conditions of modified montmorillonite were studied and optimized.A series of novel exfoliated PDMS/O-MMT nanocomposites with different structures and properties were synthesized with PDMS and different modified montmorillonite through intercalated polymerization. The results indicated that there were very good compatibilities between O-MMT and PDMS. Nanoscale dispersion of modified montmorillonite was analyzed by FTIR, XRD, SEM and water contact angle. Mechanical properties were measured to assess reinforcement effect. TGA was also employed to determine the thermal stability. From the experimental results, the thermo-decomposition dynamic mechanism of the nanocomposites was discussed. Moreover, the blood compatibility of PDMS/O-MMT nanocomposites was evaluated by hemolysis test, recalcification time and platelet adhesion test. The hemolysis rate of PDMS/O-MMT nanocomposites accorded with the international standard and there was little platelet adhered on the antithrombogenic nanocomposites surface. The results indicated that PDMS/O-MMT nanocomposites had long-term blood compatibility, which could be expected to find wide application in the medical treatment in future.