Synthesis of lanthanum ricinoleate and its effect on thermal stability and mechanical properties in PVC

The lanthanum ricinoleate (abbreviated as Lari(3)) of rare earth heat stabilizer was synthesized by the reaction of ricinoleic acid, lanthanum nitrate and sodium hydroxide. The IR and fluorescence spectra methods confirmed the structure of the product. The thermal stability of PVC in the presence of Lari(3) was studied by the Congo method and using TG analysis. The results showed that Lari(3) could be used as a thermal stabilizer for PVC. When the ratio of Lari(3)/pentaerythritol was 3: 1, the complex exhibited better synergistic effect. Incorporation of Lari(3) to PVC resulted in a marked increase of maximum and onset degradation temperature as well as elongation and impact strength of PVC. Lari(3) might replace the labile chlorine atoms to interrupt the formation of conjugated double bonds in PVC chains and act as HCl scavenger to restrain the self-catalyticdehydrochlorination.