Sustainable Micro and Nano Additives for Controlling the Migration of a Biobased Plasticizer from PLA-Based Flexible Films

Abstract

Plasticized poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) blend-based films containing chitin nanofibrils (CN) and calcium carbonate were prepared by extrusion and compression molding. On the basis of previous studies, processability was controlled by the use of a few percent of a commercial acrylic copolymer acting as melt strength enhancer and calcium carbonate. Furthermore, acetyl n-tributyl citrate (ATBC), a renewable and biodegradable plasticizer (notoriously adopted in PLA based products) was added to facilitate not only the processability but also to increase the mechanical flexibility and toughness. However, during the storage of these films, a partial loss of plasticizer was observed. The consequence of this is not only correlated to the change of the mechanical properties making the films more rigid but also to the crystallization and development of surficial oiliness. The effect of the addition of calcium carbonate (nanometric and micrometric) and natural nanofibers (chitin nanofibrils) to reduce/control the plasticizer migration was investigated. The prediction of plasticizer migration from the films’ core to the external surface was carried out and the diffusion coefficients, obtained by regression of the experimental migration data plotted as the square root of time, were evaluated for different blends compositions. The results of the diffusion coefficients, obtained thanks to migration tests, showed that the CN can slow the plasticizer migration. However, the best result was achieved with micrometric calcium carbonate while nanometric calcium carbonate results were less effective due to favoring of some bio polyesters’ chain scission. The use of both micrometric calcium carbonate and CN was counterproductive due to the agglomeration phenomena that were observed.

Plasticization Effect of Poly(Lactic Acid) in the Poly(Butylene Adipate–co–Terephthalate) Blown Film for Tear Resistance Improvement

“…Consequently, the use of PLA in blown film extrusion and foam processes is restricted [ 6 , 7 ]. To improve these properties and enable simple processability in the packaging industry, PLA has been modified by the addition of compatibilizers, such as plasticizers [ 8 , 9 , 10 ], reactive coupling agents [ 11 , 12 , 13 ], and fillers [ 14 , 15 , 16 ]. In addition, blending with other polymers [ 17 , 18 , 19 , 20 ], including copolymers and functionalized polymers, has also been reported.…”

Volume Change during Creep and Micromechanical Deformation Processes in PLA–PBSA Binary Blends

“…The present paper, starting from one of the author’s own experience [ 27 , 28 ], aimed to explore the micromechanical deformation mechanisms of blends based on polylactic acid (PLA) and polybutylene succinate adipate (PBSA). These blends were recently considered for their potential use in packaging and personal care/sanitary applications [ 29 ], hence, in sectors where products have a short life thus highly contributing to the production of enormous amounts of waste [ 30 ].…”

Biobased Materials for Skin-Contact Products Promoted by POLYBIOSKIN Project

“…Functional biomolecules with specific properties were then considered for the modification of the bio-based substrates. Both incorporation in bio-based composites [ 7 , 8 ] and surface modifications [ 9 ] are methodologies that can be applied to bio-based and biocompatible substrates to make them anti-microbial, anti-oxidant or anti-inflammatory. These methodologies, enhancing the high performance of bio-based materials, greatly enhance the competitiveness of bio-based towards fossil-based products.…”