Abstract: In order to improve the thermal stability of PVC, a novel organic calcium/zinc stabilizer was prepared from calcium adipate and zinc adipate and use lanthanum stearate as a costabilizer. Influences of Ca/Zn ratios and lanthanum stearate on the thermal stability of PVC were studied. Congo red testing method, thermogravimetric analysis, dynamic rheology, dynamic mechanical analysis, and mechanical property were determined. When Ca/Zn mass ratio was 1/4, the Congo red time reached the maximum time of 86 min. When lanthanum stearate was added and the mass ratio of Ca/Zn was 2/3, the Congo red time reached the maximum of 135 min, and the impact strength of the sample was increased by 30 %. However, the introduction of lanthanum stearate decreased the storage modulus, loss modulus, and tanδ of PVC.

Key words: Polyvinyl chloride, co-stabilizer, Calcium adipate, Zinc adipate, Lanthanum stearate, congo red method