An instrumented drop weight impact test was used to study the effect of the
rmal degradation on the impact properties of PVC compounds. The impact resi
stance of the aged compounds related well with their weight loss and hence,
with thermal degradation. Each compound showed a specific weight loss perc
entage that correlated with a 50% loss In its impact properties (failure po
int), irrespective of the aging temperature. The results were also used to
estimate a thermal index (TI) of each compound in a rapid and reliable way.