Synthesis and characterization of a biodegradable polyaspartic acid/2-amino-2-methyl-1-propanol graft copolymer and evaluation of its scale and corrosion inhibition performance

Abstract

Herein, a novel polyaspartic acid derivative, polyaspartic acid/2-amino-2-methyl-1-propanol graft copolymer (PASP/AMP), was synthesized via a ring-opening reaction using polysuccinimide (PSI) and 2-amino-2-methyl-1-propanol (AMP). The structure of PASP/AMP was characterized via ¹H NMR and FTIR. Its scale and corrosion inhibition performances were investigated via static and weight loss tests, respectively. Additionally, its biodegradability was assessed by measuring its chemical oxygen demand. The influence of PASP/AMP on scale deposition was observed via scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The maximum scale inhibition efficiency of 100% for PASP/AMP against CaCO₃, CaSO₄, and Ca₃(PO₄)₂ was achieved at the concentrations of 1, 4, and 14 mg L⁻¹, respectively. Its corrosion inhibition efficiency for carbon steel is close to 28% at 24 mg L⁻¹. The degradation rate of PASP/AMP could reach up to 65% within 28 days. According to the SEM images and XRD spectra, the scale deposits become irregular and distorted in shape, which can easily be dispersed by flowing water. This study demonstrates that PASP/AMP as a biodegradable inhibitor exhibits better scale and corrosion inhibition performances as compared to PASP and shows promising prospect for application.