1 research outputs found
Self-Assembled PullulanāSilica Oxygen Barrier Hybrid Coatings for Food Packaging Applications
The scope of this study encompassed the evaluation of
pullulan
as a suitable biopolymer for the development of oxygen barrier coatings
to be applied on polyĀ(ethylene terephthalate) (PET), especially for
food packaging applications. To enhance the oxygen barrier properties
of the organic phase (pullulan) even at high relative humidity values,
an inorganic phase (silica), obtained through in situ polymerization,
was also utilized to obtain hybrid coatings via the solāgel
technique. Transmission electron microscopy (TEM) images and Fourier
transform infrared (FT-IR) spectra showed that mixing the two phases
yielded a three-dimensional hybrid network formed by self-assembly
and mediated by the occurrence of new hydrogen-bond interactions at
the intermolecular level, although the formation of new covalent bonds
could not be excluded. The deposition of the hybrid coatings decreased
the oxygen transmission rate (OTR) of the plastic substrate by up
to 2 orders of magnitude under dry conditions. The best performance
throughout the scanned humidity range (0%ā80% relative humidity)
was obtained for the formulation with the lowest amount of silica
(that is, an organic/inorganic ratio equal to 3)