Construction of Helically Oriented Syndiotactic Polypropylene/Isotactic Polypropylene Composites for Medical Interventional Tubes via Rotation Extrusion

Medical tubes are important medical devices for interventional therapy. However, current tubes suffer from poor biocompatibility due to the heterogeneity of composites. In this study, we demonstrated a syndiotactic polypropylene (sPP)/isotactic polypropylene (iPP) composite tube with reinforced hoop strength and considerable biocompatibility. Taking advantage of the same backbone structure of PP, an iPP network was constructed in situ by rotation extrusion technology, which not only promoted interfacial crystallization but also increased the orientation degree in the hoop direction. As a result, the modulus of the iPP fiber-reinforced tubes reached 4.28 MPa/rad, which is about three times than that of the sPP tube. The biocompatibility of the as-prepared tube was evaluated in vitro and in vivo, and sPP/iPP had no impact on the cell shape or proliferation. This work overcomes the current bottleneck of a lack of composite materials for medical interventional tubes and simultaneously broadens the application of the sPP matrix.