Antioxidant migration resistance of SiO layer in SiO/PLA coated film.

As novel materials for food contact packaging, inorganic silicon oxide (SiO) films are high barrier property materials that have been developed rapidly and have attracted the attention of many manufacturers. For the safe use of SiO films for food packaging it is vital to study the interaction between SiO layers and food contaminants, as well as the function of a SiO barrier layer in antioxidant migration resistance. In this study, we deposited a SiO layer on polylactic acid (PLA)-based films to prepare SiO/PLA coated films by plasma-enhanced chemical vapour deposition. Additionally, we compared PLA-based films and SiO/PLA coated films in terms of the migration of different antioxidants (e.g. t-butylhydroquinone [TBHQ], butylated hydroxyanisole [BHA], and butylated hydroxytoluene [BHT]) via specific migration experiments and then investigated the effects of a SiO layer on antioxidant migration under different conditions. The results indicate that antioxidant migration from SiO/PLA coated films is similar to that for PLA-based films: with increase of temperature, decrease of food simulant polarity, and increase of single-sided contact time, the antioxidant migration rate and amount in SiO/PLA coated films increase. The SiO barrier layer significantly reduced the amount of migration of antioxidants with small and similar molecular weights and similar physical and chemical properties, while the degree of migration blocking was not significantly different among the studied antioxidants. However, the migration was affected by temperature and food simulant. Depending on the food simulants considered, the migration amount in SiO/PLA coated films was reduced compared with that in PLA-based films by 42-46%, 44-47%, and 44-46% for TBHQ, BHA, and BHT, respectively.