Diffusion of Cu2+ catalysts from Cu-metal polymer or Cu-oxide/polymer interfaces into isotactic polypropylene

Diffusion coefficients of Cu²⁺ in the form of its carboxylate have been measured in isotactic polypropylene as a function of temperature (90–128°C) and extent of preoxidation. Diffusion take place from the metal catalyst/polymer interface into the bulk polymer. The diffusion is dependent on the extent of preoxidation and temperature but not on the type of catalyst (Cu, CuO, CuO_0.67). Analysis of polymer sections for Cu²⁺ ions was carried out with a selective Cu²⁺ electrode. Diffusion in isotactic polypropylene is about 1000 times faster than in lowdensity polyethylene. The carboxylate anion appears to have about 7 C-atoms for diffusion in isotactic polypropylene compared with 29 C-atoms for low-density polyethylene.