Grafting of Methyl Methacrylate onto Starch Initiated by Ceric Ion as an Initiator in Presence of Nitric Acid as Activator

Abdurahman Abuabdalla Khalifa

Abstract

Natural polymers with improved structure have been securing increasing value in the industry as theyare abundant, cheap, and biodegradable. Graft copolymerization is one of the effective ways toenhance the properties of natural polymers. Starch based graft copolymers are becoming increasinglyimportant due to their remarkable adhesion, high water absorbency, and biodegradability. Methylmethacrylate (MMA) grafted onto starch by using the ceric ammonium nitrate (CAN) as a redoxinitiator in the presence of nitric acid in aqueous medium to form grafted copolymer (Starch-g-PMMA) was investigated. The grafting reaction was carried out under stream of nitrogen gas. Theimpact of different reaction parameters to achieve the highest percent grafting (%G) has been studiedby determining the initiator concentration, monomer concentration, time (hours), nitric acidconcentration, and polymerization temperature. The % G was found to be 97%. Evidence of graftingwas characterized and confirmed by Fourier transform infrared spectroscopy (FTIR). The peaks at1736.70 cm-1 and 3449.78 cm-1 indicates that MMA has been successfully grafted to starch. %G wasfound to be decreased at higher than 70°C, after 2 hours of reaction time, with an increase of MMAmonomer concentration, initiator concentration, and with HNO3 concentration. The highest percentgrafting was obtained at the parameters of 1 g starch, 70°C, 2 hours, 2 mmol CAN, 140 mmol MMAand 0.4 mmol HNO3.

Abstract

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