Saran
From PyroGuide
Formula: Saran Resin, PVDC, Polyvinylidene chloride , Chlorinated polymer.
Description: Saran is used as a chlorine donor and fuel much in the same way as parlon and PVC are. It can also serve as a binder, in which case acetone is a suitable solvent. It is known a superior chlorine donor due to its high chlorine content and superior burning characteristics.
Hazards: Saran is not particularly dangerous or toxic.
Sources: Saran seems to be available from chemical suppliers and dedicated pyro suppliers only.