28 Synthesis and Characterisation of Guar Gum-g-Poly(Acrylamidoglycolic acid) by Redox Initiator S. Siva Prasad 1 , K. Madhusudhana Rao 2 , P. Rama Subba Reddy 1 , N. Sivagangi Reddy 1 , K.S.V. Krishna Rao 1 *, M.C.S. Subha 2 1 Department of Chemistry, Yogi Vemana University, Andhra Pradesh, India-516003. 2 Department of Chemistry, S.K. University, Andhra Pradesh, India-515003 Received 20 September 2012; Accepted 1 st October 2012; available on line December 2012. ABSTRACT Graft copolymer of acrylamidoglycolic acid with guar gum was synthesized and its reaction conditions were optimized for better yield using potassium persulphate as initiators. The effect initiator, guar gum, and monomer along with reaction time and temperature were studied by determining the grafting parameters: % grafting ratio, % efficiency. The graft copolymer was characterized by Fourier transform infrared spectroscopy and thermal analysis. It was observed that the maximum yield occurred at which time of 2h at temperature 60 o C. Key words: guargum, graft copolymer, polysaccharide, acrylamidoglycolic acid, FTIR, thermal analysis . 1. INTRODUCTION Modification of natural polymers by grafting has drawn much attention in recent years [1]. Guargum is a seed gum obtained from the seeds of cyamopsis tetragonalobus, it is leguminase plant, which is native to north western parts of India. Guargum is high molecular weight carbohydrate polymer, has the characteristic of being rigid and non-ionic [1,2]. It consists of (1→4)-β-D-manno-pyranosyl units with α-D-galacto-pyranosyl units attached by 1→6 linkages. It forms colloidal dispersions with water at room temperature and imparts extraordinary viscosity, because of this property, native guargum as well as its derivatives are commercially impart and find use in such diverse applications like oil well drilling, paper and textile sizing, as a binding agent for explosives, and is widely used in food industry [3]. Guargum crosslinked with borax was investigated for water retention applications [4]. Although guargum has wide industrial applications, it suffers from some draw backs like biodegradability [5], which limits its uses considerably. These drawbacks can be improved through the grafting of vinyl monomer, which imparts new properties to the polymeric backbone. Acrylamidoglycolic acid (AGA) refers to a class of acrylamides containing -OH, -COOH and -CONH- functional groups that shows excellent hydrophilic as well as responsitivity in biological fluids [6]. In this present work we report synthesis and characterisation of Guar gum grafted poly (acrylamidoglycolic acid). 2. EXPERIMENTAL 2.1 Materials Guargum (GG) was purchased from Merk Limited, Mumbai. Acrylamidoglycolic acid (AGA) was purchased from Alfa Acer (Japan). Potassium persulphate (KPS) was purchased from s.d. fine chem limited Mumbai, and were all used without further purification. Double-distilled water was used in all experiments. 2.2 Graft copolymerisation Graft copolymer of GG and AGA was synthesised by free radical polymerization. 0.25 g of GG was dispersed in 30 ml (1.66 mole) of AGA dissolved in a 250 ml round-bottom flask. Then 0.0015- 0.0091 mole of AGA dissolved in 10ml (0.55 mole) of water, added to GG solution and the mixture was stirred overnight. A quantity of redox initiator (K 2 S 2 O 8 ) equivalent to 0.0002-0.0016 mole was dissolved in 10 ml of water and added to the above solution. Polymerization was carried out at 40-70 o C under continuous nitrogen atmosphere for 60-240 mins in a thermostatic water bath under constant stirring. After complete polymerization, the product was cooled by running under tap water and poured into excess of acetone to induce precipitation. The graft (GG-g-AGA) solid polymer was washed several times with methanol:water (80:20 v/v) mixture [7] to remove the *Corresponding Author: Email: drksvkrishna@yahoo.com Phone: +91 9704278890 Available online at www.ijacskros.com Indian Journal of Advances in Chemical Science Indian Journal of Advances in Chemical Science 1 (2012) 28-32 I