SYNTHESIS OF POLYASPARTIC ACID/ CHITOSAN (PASP/CS) GRAFT COPOLYMER AS CORROSION INHIBITOR FOR CARBON STEEL AND SCALE INHIBITOR

• Main Author: TANIA ARTHA (NIM: 20515033), WIDYA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31593
• Institution: Institut Teknologi Bandung

<p align="justify">Consideration of the industrial and environmental facilities’s maintenance for cooling water systems has led to the searching for environmentally friendly corrosion inhibitors and scale inhibitors. PASP has been known to have inhibition power toward corrosion and slag, and it is pretty soluble in water as well as environmentally friendly. In order to improve PASP inhibition power toward, this research conducted PASP copolymerization by using chitosan that is enviromentally friendly and has ability to inhibit slag. The PASP/CS copolymer was synthesized by polysuccinimide copolymerized with chitosan. Polysuccinimide was acquired from the synthesis of maleic anhydride and urea. On the other hand, chitosan is resulted from the isolation of chitin using shrimp skin through three stages: deproteination stage, demineralization stage and deacetylation stage. Chitin from demineralization, polysuccinimide, deacethylation of chitosan and copolymerization of PASP/CS were characterized using Infrared Spectroscopy. The effect of chitosan composition variations (1, 5, 10 and 15%) on the PASP/CS copolymer was characterized using Infrared Spectroscopy and TGA. Polysuccinimide showed absorption peaks at 1717 cm-1 wave numbers (five-ring imid groups), 1400 cm-1 (vibration of bending N-H and stretching of C-N) and 1666 cm-1 (-CO-NH-R-secondary amide). The chitosan for PASP/CS copolymerization was the result of chitosan deacetylation on the third stage with deacetylation degree 72.50% calculated based on the FT-IR spectrum using baseline Domzy & Robert method. The success of chitin deacethylation became chitosan were shown by the decrease of absorption intensity of carbonyl functional groups and the increase of absorption intensity of N-H vibration on the FT-IR spectrum. In the FT-IR spectrum of PASP/CS copolymer, there was a wide peak at a wave number 3500 cm-1 which indicated a carboxylate group in the copolymer. As the chitosan composition increased, the absorption peak of thhe carboxylate group would decrease and the absorption of C=O chitosan would arise. The testing on PASP/CS 1% and PASP/CS 5% copolymer as scale inhibitor resulted in inhibition efficiency of 70.37% and 87.50% respectively at 100 ppm concentration. The testing on corrosion inhibition ability PASP/CS 1% and 5% copolymer using EIS method in 0.1 M HCl environment at 55°C temperature yielded highest inhibition efficiency on 125 ppm concentration of 60.21% and 68.58% respectively. Meanwhile, the testing on corrosion inhibition ability PASP/CS 1% and 5% copolymer using Tafel method in 0.1 M HCl environment at 55°C temperature yielded highest inhibition efficiency on 125 ppm concentration of 55.49% and 42.00% respectively. On the Tafel measurement, the PASP/ CS 1% and 5% copolymer can be said as the mixed inhibitors. The testing on corrosion inhibition ability PASP/CS 1% and 5% copolymer using Wheel Test Corrosion method in 0.1 M HCl environment at 55°C temperature showed highest inhibition efficiency on 100 ppm concentration of 70.84% and 77.95%.<p align="justify">