Complex‐radical terpolymerization of phenanthrene, maleic anhydride, and trans‐stilbene

The radical terpolymerization of the donor‐acceptor‐donor monomer system, phenanthrene (P)—maleic anhydride (M)—trans‐stilbene (S), was studied. These monomers are known to be nonhomopolymerizable. The terpolymerization was carried out in p‐dioxane and/or toluene at 70°C in the presence of benzoyl peroxide used as the initiator. P and S were found to form charge transfer complexes (CTC) with M in p‐dioxane at 35°C. The results obtained are discussed in terms of the free monomer and complex propagation models. It is shown that terpolymerization is carried out at a stage close to binary copolymerization of two complexomers. The reactivity ratio of P … M and S … M complexes was estimated by the Kelen‐Tüdös method. Absorbance ratios at 1770 cm−1 (vC=0 of anhydride group), 764 cm−1 (δCH in monosubstituted benzene of S), and 820 cm−1 (δCH in disubstituted benzene of P) as a function of terpolymer composition were established. P—M—S terpolymers are shown to have high thermal stabilities.