Controllable preparation and performance of bio-based poly(lactic acid-iminodiacetic acid) as sustained-release Pb2+ chelating agent

Abstract

The bio-based lactic acid (LA) and the common metal ion chelating agent iminodiacetic acid (IDA) are used to design and prepare a polymeric sustained-release Pb²⁺ chelating agent by a brief one-step reaction. After the analysis on theoretical calculation for this reaction, poly(lactic acid-iminodiacetic acid) [P(LA-<i>co</i>-IDA)] with different monomer molar feed ratios is synthesized via direct melt polycondensation. P(LA-<i>co</i>-IDA) mainly has star-shaped structure, and some of them have two-core or three-core structure. Thus, a possible mechanism of the polymerization is proposed. The degradation rate of P(LA-<i>co</i>-IDA)s can reach 70% in 4 weeks. The change of IDA release rate is consistent with the trend of the degradation rate, and the good Pb²⁺ chelating performance is confirmed. P(LA-<i>co</i>-IDA) is expected to be developed as a lead poisoning treatment drug or Pb²⁺ adsorbent in the environment with long-lasting effect, and this research provides a new strategy for the development of such drugs.