The preparation and characterization of surface-grafted plastic materials designed for the evaluation of their tissue and blood compatibility

With the objective to develop both characterization methods and test systems for blood and tissue compatibility, some polymers, e.g., polyethylene (PE), polypropylene (PP), and ethylene/propylene/diene‐ter‐polymer (EPDM) of different shapes, e.g., beads, films, tubes, fibers, tubings, and microtome slices, were grafted with a variety of 15 monomers in order to introduce hydrophobic, hydrophilic, and ionizable groups. The grafted surface was characterized morphologically by the surface area (Brunauer‐Emmett‐Teller: BET value), by scanning electron microscopy (SEM), and by profilographic measurements. Surface grafting was controlled by frustrated multiple internal reflexion (FMIR)–ir measurements, by determination of the critical surface tension, and by energy‐dispersive x‐ray analysis (EDXA) combined with SEM. The EDXA–SEM method was found to be a helpful tool to characterize the homogeneity and penetration profile of surface grafting. The tissue compatibility was tested by implanting test samples under the skin of rats. Blood compatibility was determined via in vitro test systems based on the determination of single clotting factors.