Construction Of Surface Microstructure On Styrenic Thermoplastic Elastomer And Its Properties

Styrenic thermoplastic elastomer(STPE)is currently the fastest growing thermoplastic rubber.STPE possesses outstanding physical and chemical properties,especially ozone resistance,oxidation resistance,ultraviolet resistance,and low toxicity.Just because of these properties,STPE is edging out PVC gradually in biomedical fields.However,when contacting with SEBS,red blood cells(RBC)will be hemolyzed inevitably.So STPE should be physically or chemically modified in advance to make it have more favorable biochemical properties,especially in the blood contacting materials field,thus further expand its application in biomedical field.By electrospinning,a hydrophilic,3D hierarchical architecture is constructed on the surface of SEBS with high molecular weight poly(ethylene oxide)(PEO)nano/micro fibers.The adhension between PEO and SEBS is investigated,and influence factors of the adhension are discussed.Poly(ethylene oxide)(PEO)/lecithin(LE)nano/microfibers are fabricated on SEBS by electrospinning.The properties of the PEO/LE nano/microfibers,e.g.,surface morphology,wettability,hemocompatibility etc,are investigated.A nano/microfibers membrane with PEO/lecithin(LE)-ascorbic acid(AA)is fabricated on the surface of SEBS by coaxial electrospinning,and the surface morphology of PEO/LE-AA is investigated.Firstly,Poly(ethylene glycol)methyl ether methacrylate(PEGMEMA)are grafted on the surface of SEBS by UV photo-grafting.PEO electrospun meshes are fabricated on the grafted surface of SEBS by electrospinning,the PEO electrospun meshes and PEGMEMA brushes are crosslinked.The surface morphology of PEO electrospun meshes on SEBS is observed by SEM and AFM,and the adhension between PEO and SEBS is measured with a weight method.Through analysis,four kinds of surface interactions are found to control the adhension between electrospun fibers and SEBS,i.e.hydrophobic-hydrophilic interaction,hydrophilic interaction,chain entanglement and crosslinking.And it is proved that,without crossking,hydrophilic interaction,chain entanglement are the main factors for the adhension of PEO electrospun meshes andSEBS.In addition,the effect of PEO/LE electrospun meshes on RBC preservation is investigated.In this part,the PEO/LE electrospun meshes are constructed on SEBS by electrospinning.The SEM images show that the surface morphology of the meshes is smooth without beads.The controlled release of lecithin is measured by HPLC.The discussions of the released lecithin demonstrate that the controlled release of lecithin is helpful for the decrease of RBC hemolysis.At last,another electrospun meshes(PEO/LE-AA nano/micro fibers)which are fabricated on grafted SEBS by coaxial electrospinningare proved to be core-shell structure by transmission electron microscope(TEM).The binary release of LE and AA from PEO/LE-AA nano/micro fibersis in a controlled manner and it is conducive to improve the blood compatibility of grafted SEBS.