Functionalization of Poly(Organophosphazenes). IX. Light-Induced Grafting Reactions of Maleates onto Aryloxy-Substituted Poly(Organophosphazenes)

In this paper the light-induced grafting reaction of dimethyl maleate, diethyl maleate, dibutyl maleate and diethyl fumarate, onto aryloxysubstituted phosphazene polymers, to form polyphosphazene copolymers containing grafted succinate groups, is investigated by means of IR spectroscopy and the equilibrium swelling technique of polyphosphazene films. The importance of several different experimental factors that can influence the final succinate grafting yields is discussed, i.e. the type and concentration of the polyphosphazenes and of the unsaturated products, reaction time, the absence or presence of molecular oxygen or of the 1-vinyl-2-pyrrolidone monomer, and the concentration of the benzoin ethyl ether photoinitiator. Furthermore, it is shown that the overall efficiency of the lightinduced grafting process is lower than that previously measured for the reaction initiated thermally using peroxide species, and that the photochemical grafting reaction always occurs with no degradation of the phosphazene macromolecules. The possibility of exploiting these new phosphazene substrates in blend technology has been considered.