Influence of lanthanum stearate (LaSt3) as a co-stabilizer on stabilization efficiency of calcium stearate
(Ca)/zinc glutarate (Zn) stabilizers to polyvinyl chloride (PVC) at 180 C in air was investigated. The
results showed that combination of LaSt3 with Ca/Zn stabilizers presented an obvious improvement of
stabilization efficiency to PVC compared with the Ca/Zn stabilizers. Moreover, addition of LaSt3 to the Ca/
Zn stabilizers could significantly enhance static stability time of PVC. Incorporation of 2 phr LaSt3
co-stabilizer to PVC containing 3 phr Ca/Zn stabilizers resulted in marked increase of onset degradation
temperature and reductions in average degradation rate as well as the dynamic storage modulus (G0) and
loss modulus (G00) at 180 C. Influence of Ca/Zn ratio on tensile strength of PVC in the absence or in the
presence of LaSt3 was discussed in detail. At low Ca/Zn ratios LaSt3 had an obvious improvement in the
tensile strength, while at high Ca/Zn ratios this effect became inconspicuous.