MODIFICATION OF STARCH USING 2-OCTENYLSUCCINIC ANHYDRIDE (OSA) VIA GRAFT COPOLYMERIZATION METHOD AS STABILIZER FOR PICKERING EMULSION

• Main Author: Mega Lestari, Ayu
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/49305
• Institution: Institut Teknologi Bandung

Emulsions are widely applied in various industries such as food, pharmaceuticals, cosmetics, and also in crude oil recovery and catalysis. Currently, most emulsions are stabilized using synthetic surfactants which may cause irritation and allergies. One of the alternatives to stabilize emulsions without using synthetic surfactants is using Pickering emulsions. Pickering emulsion is a type of emulsification technique which utilizes solid particles as stabilizers. Pickering emulsions offer a high degree of stability and low toxicity. Starch is a good candidate as stabilizer in Pickering emulsion. Generally, starch has hydrophilic character. To increase the emulsifying capacity, it is deemed necessary to modify starch by adding hydrophobic groups. In this study, the starch was modified via graft copolymerization using cerium ammonium nitrate (CAN) as initiator and 2-octenylsuccinic anhydride (OSA) as monomer to result in starch-g-poly(OSA). Starch was isolated from cassava roots with a yield of 11.8% and amylose content of 19.6%. The graft copolymerization was carried out using two variations, namely variations in reaction time (3, 6, 12, and 24 hours) and variations in the mass ratio of starch:CAN (1:2, 2:1, and 20:1). The Fourier Transform Infra Red (FTIR) spectra of the copolymer showed new absorption peaks at a wave number of about 1700 cm-1 attributed to the vibration of C=O and around 1500 cm-1 attributed to the vibration of the -C-O- ester group. This indicated that the OSA monomer had been grafted from the starch. X-ray difractograms of the copolymers showed new reflections at 2? of around 27°, 47°, and 56°. These peaks indicated the presence of new side chains in the product originated from polymerized OSA monomers. The SEM images showed that the copolymers formed aggregates. In this case the morphology was influenced by the heating process and the amount of the grafted OSA. The Particle Size Analyzer (PSA) showed that starch-g-poly(OSA) tended to have larger diameter sizes (10.9?617.2 nm) compared to native starch (21.2 nm). The Pickering emulsion stability test was carried out by mixing water and Virgin Coconut Oil (VCO) at a 3:1 volume ratio using 2.5% (w/v) of native starch or starch-g-poly(OSA) copolymer as stabilizer. The emulsion prepared using starch-g- poly(OSA) copolymer was found to be more stable compared to the emulsion prepared by native starch after centrifugation at 4500 rpm for 20 minutes.