The properties of SBS-g-VP copolymer membrane prepared by UV photografting without degassing

The grafting of 4-vinylpyridine (VP) onto styrene-butadiene-styrene triblock copolymer membrane (SBS) was induced by UV-radiation without degassing to obtain the SBS-g-VP copolymer membrane. The graft copolymer membrane was characterized by electron spectroscopy for chemical analysis (ESCA) and scanning electron microscope (SEM). The tensile strengths and elongations of dry and wet SBS-g-VP copolymer membranes were measured. The contact angle of dry and wet SBS-g-VP graft copolymer membranes with different amount of grafting were determined. By using Kaelble's equation and the contact angle data, the surface energy of dry and wet SBS-g-VP graft copolymer membranes were determined. The protein absorption of fibrinogen and albumin on the SBS-g-VP membranes were evaluated. It was found that the oxygen content in the SBS-g-VP copolymer membrane increased with increasing grafting degree which resulted from the UV photografting without degassing. The tensile strength of dry SBS-g-VP membrane increased with increasing degree of grafting but the elongation decreased. The tensile strengths and elongations of wet SBS-g-VP were significantly lower than those of SBS. The surface energy of dry and wet SBS-g-VP were determined by using Kaelble's equation and the contact angle data. It was found that the surface energy of SBS-g-VP membrane increased. The surface energy of wet SBS-g-VP was higher than that of dry SBS-g-VP. The absorption of albumin and fibrinogen decreased with increasing grafting degree and then levelled off.