The Studies On Processibility Of Polyetherurethanes (PUs) For Intravascular Catheters And Surface Modification On The PUs With Cross-linked Coating

The process for fabricating intravascular catheters has obvious influence on the properties of catheters, such as surface smooth. maneuverability. In this article, the properties about extrusion process of four kinds of polyurehanes (PUs) for catheter materials with different hardness were investigated. TG and DSC, Rheocord system 40. melting flow rate (MFR)were employed to study the degradation temperature (Td). melting temperature (Tm). rheology behavior respectively. The results showed Tm of PUs increased with hard segment content in PUs increasing, and PUs can be extruded in a relatively large range of temperature. We also found PUs had big internal friction coefficient and small melt viscosity. With hard segment content increasing, the internal friction coefficient and melt viscosity both decreased. By tensile strength and ultimate elongation test, no remarkable decrease of mechanical properties of PUs were observed when radiopaque reagent was added up to 30%. Then. single-scre~v extruder and twin-screw extruder were adopted to extrude these PUs. The influence factors of the extrusion process were studied and proper extrusion conditions were obtained. Platelet adsorption in vitro showed the extrusion111process and radiopaque reagent had no notable influence on anti- platelet adsorption property of PUs. Additionallx~ a project of making an intravascular catheter and two extrusion molds for fabricating it were designed.Surface modification of catheters had played important role in improving hemocompatibility, lubricity, and so on. A lubricious and anti- platelet adsorption surface was achieved by cross-linked PU-PEO coatings and PU-P VP coatings. The morphology, wettability. lubricity and the ability of anti- platelet adsorption were investigated by SEM. contact angle test, friction coefficient test and evaluation of anti- platelet adsorption in vitro. respectively. The PU-PEO modified surface had better and durable lubricity, less platelet adsorption and lower platelet activation than virgin PUs surface and PU-P VP modified surface.