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Despite the great potentialities of nanotechnology for food packaging applications, there are still a number of important issues to consider, mainly regarding the safety concerns and the industrial scale‐up. A feasible solution to overcome the problem of possible nanoparticles migration can be the use of a functional barrier between the nanomaterial and the food. In this work, multilayer packaging films, incorporating a layered silicate/polyamide nanocomposite (as oxygen barrier layer) and low‐density polyethylene (as moisture resistant and sealable layer) in direct contact with food, were produced by a lab‐scale blown co‐extrusion equipment using different processing conditions and film layouts, to determine the key parameters for performance improvement and to assess their potential applicability on an industrial scale. In particular, a copolyamide 6,66 was used as polymer matrix and two organomodified layered silicates (Cloisite 30B and Dellite 43B) were selected as nanofillers. The results demonstrated the potential technological interest of the proposed packaging solutions in terms of increased performances and ecofriendliness because all the multilayer hybrid films, particularly the ones filled with Cloisite 30B, display significant improvements in barrier and mechanical properties not only with respect to the corresponding unfilled systems, but also compared to similar PA/PE commercial films. The observed increments, up to 60% for oxygen barrier and 55% for stiffness, are more relevant in the case of the films with the thinner nanocomposite layer. Moreover, no detectable changes in film ductility, optical properties, and overall migration behavior were measured as consequence of nanofiller addition. POLYM. COMPOS., 39:3157–3167, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

ABSTRACT: The ability of films with an active layer of nanoporous–crystalline syndiotactic polystyrene (s‐PS) to prolong shelf‐life, not only of climacteric but also of non‐climacteric fruits, is discussed. Studies on oxygen and carbon dioxide concentrations in the environment of packaged fruits as well as in s‐PS active layers have been combined. Reported results indicate that prolonged shelf‐life can be associated with large increases and decreases of carbon dioxide and oxygen concentrations inside the package, respectively. These data are consistent with a higher barrier offered to both gases by nanoporous–crystalline s‐PS layers. This barrier phenomenon is due to reduction of gas diffusivity typical of nanoporous–crystalline polymer films, which is further enhanced by orientation, parallel to the film plane, of crystalline planes of closely packed s‐PS helices. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46256. [ABSTRACT FROM AUTHOR]

Oxygen scavenger applications in flexible food packaging are still limited due to the difficulty to ensure scavenging activity during storage and throughout the product shelf life. To avoid fast inactivation of the scavenger, multilayer active structures can be realized by inserting the active layer between two or more inert layers. In this work, an unsteady-state 1D reaction-diffusion mass transfer model was developed for predicting and optimizing the barrier-to-oxygen performance and the physical configurations of the co-extruded multilayer active films. The film configuration was a three-layers structure composed of polyethylene terephthalate (PET) as external inert layers, and PET with a polymeric oxygen scavenger as the core reactive layer. Scavenging activity of the multilayer film increased with the reactive layer thickness. Oxygen absorption reaction at short times decreased proportionally with the thickness of the external layers. The most appropriate combinations of inert-to-active film thickness were studied and analyzed. © 2017 American Institute of Chemical Engineers AIChE J, 2017 [ABSTRACT FROM AUTHOR]

ABSTRACT In recent years, consumer demand for environmental sustainability and legislative actions has pushed the plastic packaging industry toward biobased plastics. However, despite the advantages related to their ecofriendly nature, the commercial large-scale application of biobased polymers as substitutes for conventional petroleum-derived plastic as packaging materials have been limited up to this point because they show limitations in their processability and material properties performances, especially in terms of their diffusion-barrier properties to small molecules; these are critical for food-contact uses. The main strategies used to overcome these issues involve blending with other biopolymers and/or the addition of other substances, such as microfillers, nanofillers, and plasticizers. In this review, we report on the most recent advances and emerging technologies in food-packaging applications that have potential commercial interest and are based on selected biodegradable polymers from renewable sources. Our particular focus is on issues related to food-packaging interactions and the possible consequent migration of substances. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42597. [ABSTRACT FROM AUTHOR]

In this work the relationships between system composition, polymer-organoclay interaction, morphology and rheological response, under shear, and elongational flow, of different melt compounded polylactic acid (PLA)/organoclay nanocomposites are investigated, with the aim to properly select the better organoclay for a well-specified PLA grade and processing technology. Polylactide nanocomposites are prepared using two commercial polylactide grades (PLA 4032D and PLA 2003D) and two different organomodified montmorillonites (Cloisite 30B and Nanofil SE3010). FTIR analysis evidences the occurrence of stronger polymer/organoclay interactions for the system PLA4032D+C30B, resulting in a higher clay dispersion and exfoliation levels. Moreover, rheological tests at low shear rates show that, if PLA 2003D is used as polymer matrix (differing from PLA4032D by the presence of a high molecular weight tail), a better dispersed nanomorphology can be obtained with Nanofil SE3010, characterized by a double d-spacing compared to Cloisite 30B, despite the higher polar character of this latter nanofiller. On the other hand, elongational rheological measurements evidence for NSE3010-based hybrids a marked extensional thickening, whilst the stronger polar interactions between the phases in both the polylactide grades filled with C30B, determine increments in elongational viscosity, but inhibit the strain hardening behavior. POLYM. COMPOS., 36:1135-1144, 2015. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

ABSTRACT Polymeric active materials represent an innovative food packaging concept that has been introduced to improve the quality of foods and to enhance their shelf life. In this article, the effect of the inclusion of an oxygen scavenger in a polymeric matrix, realizing multilayer active polyester films by coextrusion process, is analyzed. In particular, three layer active films, at different mass ratios of the layers, were produced to form symmetrical "ABA" structures comprising polyethylene terephthalate (PET) with a polymeric oxygen scavenger (OS) as core layer and pure PET as external layers. Oxygen scavenging tests conducted on the multilayer active structures have pointed out the role of the relative layer thickness in controlling the scavenging capacity, the activity time and the oxygen absorption rate. A modeling of the scavenging phenomena, which combines a quasi steady-state distribution in the skin layers with a flat profile of O2 content in the active core layer, can explain the experimentally observed oxygen absorption rate at short times. Moreover, steady state oxygen transport measurements, performed when the scavenger reactive capacity is exhausted, have shown that the presence of the active phase slightly reduces the O2 permeability, compared with the neat PET. The effect, which progressively increases with the amount of active phase in the film formulation, was related to the different morphological state developed on processing. Finally, preliminary shelf life tests on fresh-cut untreated apples suggest that the developed three layer active films have a significant potential in the shelf-life extension of oxygen sensitive food products. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41465. [ABSTRACT FROM AUTHOR]

The aim of the work was to manufacture, using a laboratory-scale film production pilot plant, nanocomposite polylactic acid (PLA) films added with Cloisite 30B clay-derived nanofiller having one nanometric dimension, and to characterize and to assess the migration of the obtained systems, in view of food packaging applications. The study demonstrated that it is possible to obtain nanocomposite PLA films with intercalated/exfoliated morphology of the dispersed layered nanofiller using conventional film production technologies. With increasing the silicate content in the film, the developed systems show a marked improvement of the mechanical performance, with a rise in the modulus and in the elongation at break with respect to the unfilled PLA, a significant lowering in the oxygen permeability and a slight increase in the surface wettability, without given significant alteration of film transparency and chromatic perception. Compared with the unfilled PLA, no significant changes can be observed about the migration behaviour of the nanocomposite PLA systems. In fact, both the overall migration and the specific migration, measured as lactic acid, remain always well below the applicable generic specific migration limit of 60 mg/kg food (10 mg/dm2) of the Regulation EU 10/2011. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]