Melting grafting polypropylene with hydrophilic monomers for improving hemocompatibility

Polypropylene was successfully grafted with poly (ethylene glycol) methacrylate (PEGMA) using N-vinyl pyrrolidone (NVP) as a co-grafted monomer through melting reactive grafting modification. The grafting degree of PEGMA could be obviously enhanced by the introduction of NVP at the NVP/PEGMA molar feeding ratio of 1.3. To improve the surface hydrophilicity further, hydrophilic monomers were enriched onto the surface by solvent inducement. The water contact angle of the copolymers decreased obviously and X-ray photoelectron spectroscopy (XPS) showed that the surface energy and the polar component of the modified films depended on the PEGMA grafting degree. The hemocompatibility of copolymers films were improved by increasing the PEGMA grafting degree and deteriorated by augmenting the NVP grafting degree. It was found that the balance of PEGMA grafting degree and NVP crosslinking was significant to the blood compatibility of the modified films. The biomaterial PP-g-(NVP-co-PEGMA) with the largest PEGMA grafting degree (up to 3.22 wt.%) and moderate NVP grafting degree (1.76 wt.%) could effectively resist to protein adsorption and suppress platelet adhesion.