Effect of PVOH/PLA + Wax Coatings on Physical and Functional Properties of Biodegradable Food Packaging Films

Polymers

Emilia Garofalo¹  Antonio Barbato¹  Paola Scarfato¹  Annalisa Apicella¹  Loredana Incarnato¹ 

[1] Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy;

关键词: biodegradable film;    polylactic acid (PLA);    polyvinyl alcohol (PVOH);    oxygen barrier;    multifunctional packaging;    wax;   

DOI  :  10.3390/polym14050935

来源: DOAJ

【 摘 要 】

Biodegradable polymers suffer from inherent performance limitations that severely limit their practical application. Their functionalization by coating technology is a promising strategy to significantly improve their physical properties for food packaging. In this study, we investigated the double coating technique to produce multifunctional, high barrier and heat-sealable biodegradable films. The systems consisted of a web layer, made of poly(lactide) (PLA) and poly(butylene-adipate-co-terephthalate) (PBAT), which was first coated with a poly(vinyl) alcohol based layer, providing high barrier, and then with a second layer of PLA + ethylene-bis-stereamide (EBS) wax (from 0 to 20%), to provide sealability and improve moisture resistance. The films were fully characterized in terms of chemical, thermal, morphological, surface and functional properties. The deposition of the PVOH coating alone, with a thickness of 5 μm, led to a decrease in the oxygen transmission rate from 2200 cm³/m² d bar, for the neat substrate (thickness of 22 μm), to 8.14 cm³/m² d bar (thickness of 27 μm). The deposition of the second PLA layer did not affect the barrier properties but provided heat sealability, with a maximum bonding strength equal to 6.53 N/25 mm. The EBS wax incorporation into the PLA slightly increased the surface hydrophobicity, since the water contact angle passed from 65.4°, for the neat polylactide layer, to 71° for the 20% wax concentration. With respect to the substrate, the double-coated films exhibited increased stiffness, with an elastic modulus ca. three times higher, and a reduced elongation at break, which, however still remained above 75%. Overall, the developed double-coated films exhibited performances comparable to those of the most common synthetic polymer films used in the packaging industry, underlining their suitability for the packaging of sensitive foods with high O₂-barrier requirements.

【 授权许可】

Unknown