Thermal and electrical properties of acrylic acid grafted onto starch by ceric ammonium nitrate and potassium permanganate initiator

Abstract

Graft copolymerization of acrylic acid (AA) onto corn starch (Starch) in aqueous media via a redox initiator system of ceric ammonium nitrate and potassium permanganate has been studied gravimetrically under nitrogen atmosphere. The grade of graft copolymers were synthesized under the effect of reaction variables such as redox initiator concentration, monomer concentration, reaction temperature and polymerization time on the grafting were studied in terms of percent grafting ratio (% G) and percent grafting efficiency (% E). The graft copolymers obtained were characterized by fourier transform infrared (FTIR), scanning electron microscope (SEM), and thermogravimetry analysis (TGA). SEM morphology shows that the surface of the grafted starch is highly rough in comparison with ungrafted starch which is attributed to the high graft density. The starch surface was dispersed heterogeneously among the polyacrylic matrix and rugged surface was observed that all fragments of these surfaces are rough, spherical, rod in shape. The FTIR shows characterized peak in the region 1722.28 cm⁻¹ which attributed to the shift in the position of C = O group deriving grafting of AA with starch. TGA shows the graft copolymer degrades at higher temperature and electrical conductivity indicates conductivities lies between 10⁻⁷ and 10⁻⁵ S/cm.