The synthesis of diene and of vinyl copolymers containing predetermined quantities of polynuclear hydrocarbon or heterocyclic adducts—V. Copolymers formed from styrene or α-methylstyrene, anthracene and alkyl dihalide

Abstract

When a tetrahydrofuran solution of styrene or α-methylstyrene (M) and anthracene (A) is reacted with alkali metal, anionic species are produced which can be titrated with alkyl dibromides (RBr 2) to produce copolymers. These copolymers have been analysed structurally by NMR spectroscopy and by a model compound approach. With styrene as monomer, the copolymers have been shown to consist of two types of repeat units [AM nAR] and [AR] linked together in a random manner: at equimolar styrene to anthracene ratios, n ∼ 10 and 75 per cent of the anthracene is linked directly to the alkyl ligand as in the second repeat unit. When α-methylstyrene is used, the repeat units are predominantly [M nR] and [AR] with n ∼ 5. Production of copolymers of α-methylstyrene in particular is more efficient for decane dibromide than for butane dibromide, where formation of bridged anthracene derivatives by a cyclization and regeneration of anthracene competes with the copolymerization. The reasons for the structural differences between the copolymers of the two vinyl monomers are discussed.