A pyrogallol-coated modified LDPE film as an oxygen scavenging film for active packaging materials

Oxygen scavenging films were prepared with 1, 3, 5, 10, and 20% pyrogallol coated onto a modified LDPE film. The color, mechanical, barrier, and surface properties of the LDPE/PG oxygen scavenging films were compared to those of a pure LDPE film. The results demonstrate that pyrogallol was well coated onto the surface of the modified LDPE film. The LDPE/PG films had a slightly rough film surface, which results in higher water and oxygen permeabilities as well as lower TS due to the addition and agglomerations of sodium carbonate and pyrogallol. The pyrogallol coating also caused color alterations of the LDPE/PG film. In addition, the oxygen scavenging properties of the LDPE/PG films were evaluated at different relative humidities (RH) and temperatures. The oxygen content (%) in the headspace of the absorption cell containing the LDPE/PG 20% film, which was initially 20.9%, decreased to 9.42% after 8 days at 23 °C. The LDPE/PG 20% film showed an effective oxygen scavenging capacity of 0.443 mL/cm2 at 23 °C. Water was used as an activator to initiate the oxygen scavenging reaction.