Like parlon and saran, PVC is a polymeric chlorine donor and fuel. It can be used in the form of a fine powder or as a solution in tetrahydrofuran (THF). It is sometimes used as a binder, but it is very brittle. Small amounts of plasticiser (dioctyl phtalate is common) may be added to improve the mechanical properties.
As an alternative to the PVC powder available from chemical suppliers and dedicated pyro suppliers, PVC glue may also be used. It is usually sold in hardware stores and comes in two varieties: gelling or gap-filling and normal. Both are essentially a concentrated solution of PVC. I have no experience with the gelling variety, but the normal variety can succesfully be used in compositions. The gelling variety may be better suited for pyro purposes since it seems it contains more PVC. Another possibility is to use 'Sculpy' or 'Fimo' clay. These modelling clays consist of PVC with a large amount of plasticiser. The plasticiser may affect the color of a composition negatively, but reasonable results can still be obtained with it. It can simply be kneaded into a composition with some effort. This type of clay is usually hardened by heating it in an oven, but do not be tempted to do this with pyrotechnic mixtures as they may ignite.
PVC itself is not particularly dangerous or toxic. Dioctyl phtalate is a suspected carcinogen however and THF is a very flamable and volatile liquid.