EFFECT OF BORAX ON ACRYLAMIDE STARCH CO-POLYMERIZATION AND PROPERTIES

ABSTRACT This study investigates the synthesis and properties of an acrylamide-starch copolymer cross-linked with borax, focusing on the effect of borax concentration on the resulting material's physical, chemical, and electrochemical characteristics. Starch was successfully extracted from the Borassus nut (87 g) and subsequently used as the backbone polymer in a free-radical graft copolymerization with acrylamide, initiated by a CAN/APS redox system at 70°C, yielding a manageable, low-viscosity copolymer. The copolymer was then cross-linked using varying concentrations of borax (0.5% to 3.0%). Results showed a direct correlation between borax concentration and viscosity: the magnet drop time, a measure of viscosity, increased from 0.33 s to 0.50 s as the borax concentration was increased, confirming the effective formation of a hydrogel network via borate-diol complexation. Physical tests confirmed the material's identity (positive iodine test for starch), its insolubility in organic solvents, and its biodegradability upon exposure to amylase enzyme, which resulted in the collapse of the hydrogel structure. Electrical measurements revealed a complex, non-linear dependency on borax concentration. Conductivity initially increased, but then sharply decreased in the optimal cross-linking range (2.0 g to 2.5 g), suggesting that the highly cross-linked network restricted ion mobility. However, the highest voltage reading (0.19 V) was observed in this same region (2.5 g), indicating an optimal compromise between structural stability and electrochemical performance. The findings demonstrate that borax effectively controls the viscoelastic properties of the acrylamide-starch copolymer, offering potential for tunable viscoelastic properties of the acrylamide-starch copolymer, offering potential for tunable viscoelastic properties and polymer applications in areas requiring biodegradable, high-viscosity materials and polymer electrolyte.