Investigation of thermal stabilization of poly(vinyl chloride) by lead stearate and its combination with synthetic hydrotalcite

The effect of lead stearate on the stability of PVC during its heat treatment was examined. In the presence of lead stearate, the rate of elimination of HCl is halved as compared to non-stabilized PVC. During the degradation, lead stearate is reacted completely mainly in the neutralization of the released HCl, irrespective of the initial concentration of the former. The results indicate that the stabilization reaction is also associated with a reversible bonding of the stearate group to the polymer chain. Replacement of a fraction of the stabilizer by synthetic hydrotalcite increases the thermal and colour stability of the PVC. (C) 2004 Elsevier Ltd. All rights reserved.