Characterization of oxygen scavenging films based on 1,4-polybutadiene

To better characterize the fundamentals of oxygen scavenging as a means to prepare high oxygen barrier polymer films, the oxidation of 1,4-polybutadiene, in the presence of a transition metal salt catalyst, cobalt neodecanoate, was studied at 30 °C. Oxygen uptake of 1,4-polybutadiene films was measured as a function of cobalt neodecanoate concentration. In these samples, oxygen mass uptake values as high as 15 wt % were observed, and the kinetics of oxidation were of the order of 10 days. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis suggest that the oxidation was heterogeneous, with the film surface being highly oxidized and the film center being less oxidized. Interestingly, the oxygen uptake exhibited a maximum with catalyst loading, which is believed to be related to the heterogeneous nature of the oxidation process. Since antioxidants are typically added during the industrial scale preparation and the amount of antioxidants would affect the oxygen mass uptake value and oxidation kinetics, the importance of an antioxidant removal method and a normalized purification strategy were determined prior to oxygen uptake experiments.