Graft Copolymerization of Benzyl Methacrylate onto Alginates

Homopolymerization of benzyl methacrylate has been studied by UV initiation using 25 mg DMPA with 2.5 ml BzMA and 0.5, 2.5 mL hexane for different time intervals. The maximum conversion value 99% has been obtained. Homopolymerization reaction was carried out with and without photo initiator. It was found that without photo initiator polymerization does not occur. DMPA and benzophenone were the two photo initiators tested. DMPA was found to be more effective than benzophenone, in a homopolymerization system of 50 mg DMPA or bezophenone, 2.5 mL BzMA and 0.5 mL hexane irradiated for 15 minutes, conversion resulted 61% and 11.5% respectively. Without photo initiator no polymerization occurred. Alginic acid, sodium alginate and calcium alginate have been grafted with poly(benzyl methacrylate) by the UV-irradiation method. The heterogeneous system was placed in a LZC4 photo-reactor with 15 cm distance from UV lamps (in UVA region, 350 nm) and irradiated for several different intervals of time, at room temperature (25±1◦C) and fixed power (7670 μW/cm2). Effect of irradiation time, monomer concentration and photo initiator concentration on the grafting yield was studied at room temperature. The maximum grafting yield was obtained using 0.52 g sodium alginate with 2.5 mL BzMA and 25 mg DMPA at 15 min. It was found that most vulnerable polymer to benzyl methacrylate grafting among alginic acid, sodium alginate and calcium alginate is sodium alginate with the highest grafting yields under the same conditions with others. Keywords: Alginate, Benzyl methacrylate, Graft copolymer, Photopolymerization