Halato telechelic polymers. XVI. Viscoelastic properties of α,ω-transition metal carboxylato polybutadiene

A low molecular weight carboxy-telechelic polybutadiene (M̄n = 4,600) behaves as a thermorheologically simple polymer when the end-groups are neutralized with a series of transition metal cations like Cd, Cu(II), Fe(III), Ni, Co, and Mn. On the basis of the dynamic mechanical properties of the carboxylated telechelic polymers, two classes of cations can be distinguished according to their ability to efficiently stabilize a chain network. Polybutadiene containing Co, Ni, and Mn carboxylates behaves like a cured rubber, whereas Fe(III), Cu(II), and Cd carboxylate end-groups show a decreasing efficiency in contributing to the elasticity of the polymer. Such behaviour is induced by the structure of the coordinative complexes which are formed by the d orbital containing cations with carboxylate end-groups and possibly with double bonds of the polymeric backbone.