This phenomenon is discussed together with the
reaction mechanism of H2. Formation of CaCO3 is believed to be
the key factor. Different fromthe dechlorination reaction, which can
be triggered by milling operation, the formation reaction of CaCO3
with PVC has not been observed just by milling operation. Heating
the milled sample with Ni(OH)2 results in the formation of CaCO3,
indicating that both heating operation and Ni(OH)2 existence are
necessary.