Physicochemical properties of poly (vinylidene fluoride) membrane grafted poly hydroxyethyl acrylates using radiation-induced graft admicellar polymerization

Abstract

Admicellar polymerization of hydroxyethyl acrylate onto PVDF membranes was investigated using electron beam irradiation to initiate the grafting in order to modify its inheritant physical and chemical properties. The absorbed dose and the monomer concentration controlled the amount of poly hydroxyethyl acrylate (polyHEA) grafted. The grafting degree increased from 8.35 wt% to 27.6 wt% for monomer concentration of 0.5 M and from 21.8 wt% to 48.1 wt% for monomer concentration of 1.0 M, at absorbed dose of 10–50 kGy. The TGA thermogram showed an increase in the DTG degradation peak that occurs within the range 468.35 °C–481.71 °C as the degree of grafting due to the polyHEA on the PVDF surface. Meanwhile, the surface roughness decreased from 94.97 nm for unmodified PVDF to range of 32.86 nm–65.45 nm for the grafted membrane due to the microstructure of polyHEA grafted on the membrane filled the hill and valley in the PVDF membrane. Furthermore, the PVDF membranes with polyHEA demonstrated a lower water contact angle value (45.9°–60.6°) than the unmodified PVDF membranes (75.8°). Hence, radiation-induced admicellar polymerization is a technique that can be utilised as one of the approaches to modify the surface of any membrane.