Current needs for minimally processed food products are spurring the development of
antibacterial packages and necessitate new antibacterial additives capable of merging with
plastic bulk material. We present a new approach that can potentially improve the physical
properties of antibacterial packaging by enhancing the compatibility between the main
polymeric ingredient of the package and an antibacterial additive. Enhance compatibility of
chitosan, a polysaccharide with known antibacterial properties, was obtained by conjugating
polyethylene glycol (PEG) onto chitosan to create PEGylated chitosan. We show that the
PEG conjugation does not hamper the antibacterial properties of the chitosan. Moreover, the
PEGylated chitosan film exhibited antibacterial activity which was absent in the native
chitosan film. Improved compatibility with polyethylene films, leading to better transparency
compared to films compounded with native chitosan, is demonstrated. The thermal
behavior of the film is governed by the bulk polyethylene due to the small concentration of
the PEGylated chitosan, yet the footprint of the additive is detectable. The addition of
PEGylated chitosan decreases the Young modulus, which was assumed to be responsible for
the compatibilizing effect of the grafted PEG side chains.