Synthesis of the complex of lanthanum (III) with N-(2-amino ethyl) maleamic acid radical and its application to PVC as thermal stabilizer

The complex (LaL3) of lanthanum (III) with N-(2-amino ethyl) maleamic acid radical (L−) was synthesized and characterized by Fourier infrared spectrum (FT-IR), elemental analysis and melting point measurements. The complex LaL3 was a chelate, in which lanthanum (III) ion was coordinated with the carboxylate oxygen and amide nitrogen atoms of N-(2-amino ethyl) maleamic acid radical (L−). The stabilization effect of LaL3 as a thermal stabilizer on polyvinyl chloride (PVC) was evaluated by static thermal stability test, ultraviolet–visible spectrum (UV–vis), FT-IR and thermogravimetric analysis (TGA). The results showed that the addition of LaL3 as thermal stabilizer could significantly enhance static stability time of PVC. Compared with the TG of pure PVC and LaL3/PVC, within the range of 200–300 °C, the degradation rate of pure PVC was significantly accelerated, whereas the degradation rate of the PVC added LaL3 stabilizer decreased obviously. The stabilizing efficiency of PVC improved by the addition of LaL3 is partially attributed by the formation of coordinate bonds between lanthanum (III) and chloride atoms in PVC main chain.