Preparation of a Stearic Acid N‐Methyl Glucoside Lanthanum Heat Stabilizer and Its Thermal Stabilization Performance in <scp>PVC</scp>

ABSTRACT In this study, a novel lanthanum‐based alcoholate heat stabilizer, stearic acid N‐methyl glucoside lanthanum alcoholate (SG‐La), was successfully synthesized via esterification and alcoholate formation using N‐methyl‐D‐glucamine and lanthanum acetate. The structure of SG‐La was characterized by FTIR, XPS, elemental analysis, and DFT calculations. The results confirmed the formation of La‐O coordination bonds within the SG‐La molecular structure. The thermal stability performance of SG‐La in PVC was systematically investigated through oven aging tests, conductivity measurements, torque rheometry, and mechanical property evaluations. The results demonstrated that SG‐La exhibited excellent long‐term thermal stability, with an ability to absorb 98.14 mg HCl per gram of stabilizer, comparable to CaSt 2 . Furthermore, when combined with ZnSt 2 at a mass ratio of 2:2, SG‐La significantly improved the initial whiteness and prolonged the thermal stability time to 72 min. DFT calculations revealed that SG‐La interacts with HCl mainly via hydrogen bonding and coordinates strongly with ZnCl 2 , forming stable complexes with adsorption energies as high as −2.18 eV. These coordination interactions effectively inhibit ZnCl 2 ‐catalyzed degradation of PVC, explaining the superior synergistic effect observed when SG‐La is combined with ZnSt 2 .