Evaluation of a bio‐coating as a solution to improve barrier, friction and optical properties of plastic films

Abstract

The present research dealt with evaluating barrier, friction and optical properties of three different plastic fi lms after deposition of a gelatin-based bio-coating. The composite fi lms showed improved barrier properties against oxygen and UV radiation. The oxygen transmission rate decreased in the order of 73% for oriented polypropylene (OPP), 56% for low-density polyethylene (LDPE) and 40% for polyethylene terephthalate (PET). The increased UV barrier characteristics ranged from 20% for OPP to 12% for both LDPE and PET. Static and kinetic coeffi cients of friction signifi cantly decreased both in the fi lm-to-fi lm and in the fi lm-to-metal tests, leading to a desirable value for many applications. However, bio-coated fi lms showed lower optical performances in terms of transparency and haze. Transparency decreased mainly for LDPE (36%), whereas the haze index increased especially for OPP (85%). Non-signifi cant differences were observed as far as the water vapour permeability was concerned, except for a slight reduction for PET (from 15.78 to 13.53 cm 3 /m 2 /day at 23°C and 90% of relative humidity), suggesting that non-meaningful effects arose from the addition of a hydrophobic component in the original formulation. Finally, the solubility of the coating in water was around 25% for all the three plastic substrates. The obtained data suggest that the lipid protein coating tested in this study, in spite of its great potential for enhancing some characteristics of plastic packaging fi lms, still exhibits negative aspects which necessitate further improvement.

State of the Art in the Development and Properties of Protein-Based Films and Coatings and Their Applicability to Cellulose Based Products: An Extensive Review

“…In addition they exhibited excellent visual and good mechanical properties on their substrates. Gelatin-based coatings on PE, PET, and PP improved barrier properties of substrate against oxygen and UV radiation [36]. Zein coated paper [37] had oxygen barrier highly over performing those of PE (barrier improvement factor up to 73) that may be usable on paper boxes as an alternative to paraffin.…”

Combination of Propylene Glycol Alginate and Lauric Acid on Water Retention and Mechanical Properties of Soy Protein Isolate-Based Films

“…For example, the SPI/PGA/La (co-dried blending) film was shown to have 512 times lower OP than LDPE. 45 Optimization using response surface analysis…”

“…For example, the SPI/PGA/La (co-dried blending) film was shown to have 512 times lower OP than LDPE. 45 Optimization using response surface analysisThe values of WVP, TS, E% and OP for SPI/PGA/La (direct blending) and SPI/PGA/La (co-dried blending) films are shown in Table 2 for each trial of the experimental design. The linear, quadratic and interaction effects of the La content (X 1 ) and RH (X 2 ), on each of the response variables are given in Table 2.…”

Active Bilayer PE/PCL Films for Food Packaging Modified with Zinc Oxide and Casein

“…[11,12] In order to obtain such polymer materials with optimal water vapour permeability for packaging of particular food it is important to adjust barrier properties of common polymer materials by incorporation of different additive types. [13,14] The possibility to improve the barrier performance of food polymer packaging by the application of nanocomposites is a very attractive approach and demands good knowledge about permeability, nanotechnology and influence of different substances. There necessarily must be taken into consideration the main factors affecting the permeability related to both polymer and nanosubstances: level of the dispersion, degree of crystallinity and mobility of polymer chains.…”