Blood compatibility is the most important property required for biomedical materials. There are many basic concepts for development of blood compatible polymers. But it is known that the perfect nonthrombogenic materials have never been obtained. It may be difficult to regulate blood-materials interactions by simple molecular design of polymeric materials. The future trend is toward a combination of concepts and hybridization of artificial materials and biological molecules.
Our research group has investigated the blood compatibility of PU/PS IPN with hydrophilic-hydrophobic microphase separated structure and PEO- grafted PU/PS IPN. In this study, the effect of incorporation of ions into PU/PS IPN on blood compatibility was investigated. The series of PU/PS IPN, PEO-grafted PU/PS IPN were synthesized and ionization was accomplished by quaternizing the tertiary amine of MDEA with (-propane sultone. Their physical, thermal and mechanical properties were examined by a number of different techniques such as SEM, AFM, DMTA, ESCA, ATR-IR, NMR, contact angle measurement, Instron tensile tester.
The fractured surface and surface of PU/PS IPNs all exhibited microphase separated structures with dispersed PS domains in the continuous PU matrix. The PS domain size decreased with increasing MDEA and increasing the content of PEO side chains. PU/PS IPNs exhibited two transition temperatures, each corresponding to the component polymers due to the phase separated structure. Sulfonated PU/PS IPNs with ionic sulfonate group were more hydrophilic than the corresponding nonionized materials. PU/PS IPNs have an excellent mechanical property compared with PU and PS.
In the blood compatibility test, the amount of platelets adsorbed, activated upon the PU/PS IPNs were reduced compared with PU and PS. Sulfonated PU/PS IPNs with ionic sulfonate group showed enhanced blood compatibility compared with the corresponding nonionized PU/PS IPNs due to synergistic effect of microphase separated structure, mobility of PEO side chains and negatively charged sulfonate groups.