Oxygen permeability of novel organic-inorganic coatings: II Modification of the organic component with a hydrogen-bond forming polymer

The oxygen permeability of composite materials, consisting of a LDPE substrate coated with a thin layer (0.7-1 μm) of new hybrid org./inorg. materials based on SiO2 and PE-PEG block copolymers, has been characterized at 35° and 50°. The effect of adding a second org. component capable to form hydrogen bonds, namely either poly(4-hydroxy styrene) (PHS) or malic acid, has been studied. While the addn. of PHS leads to a further significant decrease (50-70%) of the oxygen permeability both at 35° and 50°, on the contrary, the addn. of malic acid leads to poorer barrier properties. A slight decrease of the permeability was obtained after plasma treatment of the LDPE surface.