Plasma Deposition to Improve Barrier Performance of Biodegradable and Recyclable Substrates Intended for Food Packaging

Abstract

The extensive application of biodegradable polymers in the food packaging industries was partially limited due to poor barrier performances. In the present work, we investigated the improvement of oxygen barrier performances by means of the deposition of a few nanometres of SiOx coatings on Poly(butylene succinate) (PBS) films. The coated samples produced by the plasma-enhanced chemical vapor deposition technique were tested in terms of morphology and composition of the surface and barrier properties. Barrier performances studied as a function of SiOx thickness were greatly improved and a reduction of at least 99% was achieved for oxygen transmission rate. In order to reduce the formation of residual stress between PBS substrate and SiOx coatings, a proper buffer layer (silicon organic SiOxCyHz) was used.

Stretchable Clay Nanocomposite Barrier Film for Flexible Packaging

“…Moreover, the two sandwiching PVOH layers represent a kind of “buffering layers” that alternatively or additionally might explain the tolerance of the barrier system to stretching. Such buffering layers have been shown to improve the flexibility of otherwise nonstretchable thin films or brittle inorganic coatings. − For instance, it was found for nanometer-thick vapor-deposited SiO x coatings that an organic silicon sublayer minimized internal stress and improved the barrier properties . Furthermore, the water vapor barrier properties could be maintained upon 10% elongation for a HfO 2 thin film made by atomic layer deposition with the support of a polyamide buffering layer providing high tolerance against mechanical stretching .…”

“…44−46 For instance, it was found for nanometer-thick vapor-deposited SiO x coatings that an organic silicon sublayer minimized internal stress and improved the barrier properties. 7 Furthermore, the water vapor barrier properties could be maintained upon 10% elongation for a HfO 2 thin film made by atomic layer deposition with the support of a polyamide buffering layer providing high tolerance against mechanical stretching. 47 Another approach that can be compared to the ″buffer layer″ effect is the layer-by-layer assembly of alternating layers of a cationic polymer and negatively charged clay nanosheets that have also been shown to provide stretchability and maintain gas barrier properties upon stretching.…”

“…This drawback of vapor-deposited barrier coatings has been mitigated to some extent by covering or (nano)­laminating the SiO x /Al 2 O 3 -coated substrate. The laminate buffers mechanical stress and counteracts embrittlement of the complete barrier system by the inorganic coating. ,, …”

“…The laminate buffers mechanical stress and counteracts embrittlement of the complete barrier system by the inorganic coating. 2,6,7 Blister packaging as applied for pharmaceuticals, 8 shrink wraps for vegetables, 9 or vacuum packaging for instant coffee powder as one example, all require thermoformable polymers.…”

Cold Plasma Technology Based Eco-Friendly Food Packaging Biomaterials

“…A surface coating thickness range that combines a very low oxygen permeation and insignificant residual stress effects was determined using gas barrier measurement data from Vasallo et al on the plasma-induced deposition of SiO x surface coating deposited from the HMDSO/O 2 mixture on the PBS. Due to the extremely quick deposition time, the thin coating might enable industrialization from the perspective of process scalability [ 33 ]. The application of various gases enhanced the polar functional groups (such as peroxide, carboxylic acid, C–N, C=N, etc.)…”