Abstract: The novel group of polymers is presented under the name of Powdered Metastable Polymer Material (PMPM). PMPM is in a chemically stable state at an ambient temperature of 25° C. for a relatively long time, but it is in a thermodynamically unstable state, and may change to either a stable state (in this case, re-vulcanization), or an unstable state (in this case, decomposition). According to the prior art, these PMPMs are, under various conditions, reactive, malleable, processable, compoundable, re-vulcanizable and re-polymerizable, and thus makes it possible to form new vulcanized or coagulated products, with or without moulds, with or without other polymers or elastomers, cross-linking agents, compatibilizers, various additives, etc.