ABSTRACT The graft polymerization of hydrophilic monomers on the surface of hydrophobic PMMA was performed using an electron beam (e-beam). The dose of e-beam irradiation, reaction concentration, temperature, and reaction time were used to study the effect of variables on the graft density of poly (ethylene glycol)-methacrylate. The results demonstrated that the weight percentage of graft polymer increased with increasing temperature, time and monomer concentration. However, the weight of the graft polymer did not increase with the increasing dose of e-beam irradiation. The change of the contact angle of the water droplet on the PMMA surface was monitored as a function of a reaction time. The results showed that the contact angle decreased up until a specific time and then leveled off to an approximately constant value after a certain reaction time of the graft polymerization. Transmission electron microscopy proved that the constant value of the contact angle was due to the local survival of surface radicals followed by the perpendicular diffusion of monomers only into the bulk of the surface-modified area on the sheet surface.
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