AbstractPoly(vinyl chloride) could be considered as an ideal basis for chemical modifications, due to its chemical structure, which contains the repeating unitCH2CHCl. Presumably, the chlorine may react as in other chlorine‐containing aliphatic compounds, but secondary degradation reactions will occur at the same time, due to irregularities in the polymer structure and consequential lowering of the intrinsic reactivity site. Nevertheless, various functional modification reactions (grafting and crosslinking), were carried out in solution and in the condensed state, in order to improve specific properties of the polymer, leading to a larger scale of applications. Furthermore, it is also important to note the potential of PVC for the manufacture of flexible products, by introduction of plasticizers, generally characterized by a good solubility in the polymer and low volatility. In order to improve the aging properties of these products, recent developments were made in the field of oligomeric and polymeric plasticizers, which may or may not be reactive. The success of this new direction depends on larger developments in reactive pro