Anticorrosion potentials of derived chitosan and polyaspartic acid modified with organic compounds on steel in acidizing environment
Date
2023-09
Authors
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Publisher
Federal University of Technology, Owerri
Abstract
The anticorrosion potentials of derived chitosan and polyaspartic acid modified with organic compounds on steel in an acidizing environment were investigated using gravimetric and electrochemical methods. Chitosan (CTS) and polyaspartic acid (PAA) were synthesized from oyster shells and L-aspartic acid respectively. The oyster shell synthesized chitosan was modified using polyaspartic acid and nicotinic acid hydrazide (NAHD) respectively. The modified polymers (CTS-PAA) and (CTS-NAHD) obtained were used to investigate corrosion inhibition of mild steel in 1.0 M HCl solution.The synthesized chitosan, polyaspartic acid, and modified polymers were characterized using FT-IR and UV-vis respectively. Corrosion studies were performed using gravimetric (weight loss), electrochemical (electrochemical impedance spectroscope, EIS, and potentiodynamic polarization, PDP), and computational techniques respectively. Gravimetric results obtained revealed that inhibitor efficiency of the modified polymers increased with the rise in inhibitor concentration at room temperature (CTS-PAA and CTS-NAHD had an efficiency of 96.5% and 86.6% at a concentration of 200mg/L) at room whereas their response with time (24hrs, 72hrs, 120hrs & 168hrs) and temperature (40- 60oC) variations respectively showed reversed cases. The electrochemical test, EIS, and PDP showed that CTS-PAA gave the highest inhibition efficiency than CTS-NAHD at 86.3% and 89% respectively. The adsorption isotherms results confirmed that adsorption of CTS-PAA and CTS-NAHD on the mild steel surface followed Langmuir adsorption isotherm. Surface analysis carried out on the mild steel using X-ray photoelectron spectroscopy, XPS, and scanning electron microscope, SEM respectively probed the evidence of corrosion protection. The computational results obtained revealed that there existsa correlation between the electron molecular structures of modified inhibitors and their inhibition efficiency, and the theoretical results obtained are in agreement with experimental data. Therefore, the modification of chitosan has aided in solving the global problem of corrosion in engineering.
Description
This thesis is for the award of Master of Engineering (M.ENG) in Polymer Science and Engineering
Keywords
Chitosan, nicotinic acid anhydride, steel, corrosion, inhibition, Department of Polymer and Textile Engineering, polyaspartic acid
Citation
Obasi, A. C. (2023). Anticorrosion potentials of derived chitosan and polyaspartic acid modified with organic compounds on steel in acidizing environment (Unpublished Master's Thesis). Federal University of Technology, Owerri, Nigeria