Synthesis and characterization of novel polyaspartic acid/urea graft copolymer with acylamino group and its scale inhibition performance

Abstract

A novel green scale inhibitor, polyaspartic acid/urea graft copolymer (PASP/Urea), was synthesized by polysuccinimide (PSI) and urea. PASP/Urea was a non-toxic, non-phosphorus, biodegradable acylamino copolymer. The structure of PASP/Urea was characterized by Fourier transform infrared spectroscopy (IR), 1H nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC) analysis. Its scale inhibition performance was estimated with static scale inhibition methods. The influence of PASP/Urea on formation of CaCO3, CaSO4 and Ca3(PO4)2 was investigated using scanning electronic microscopy (SEM). The PASP/Urea exhibited more excellent scale inhibition property against CaCO3, CaSO4 and Ca3(PO4)2 than the PASP and the comprehensive scale inhibition property of PASP/Urea is much better than the property of PASP. The scale inhibition efficiency of PASP/Urea against CaCO3 was 93% when the dosage of PASP/Urea was 10mg/L. The inhibition efficiency against CaSO4 increased to 97% in the PASP/Urea concentration of 4mg/L. The inhibition efficiency against Ca3(PO4)2 reached up to 100% in the concentration of 12mg/L. The results of SEM indicated that the scale crystals became irregular and distorted and the formation of scales was inhibited when the PASP/Urea was added.