Strategies to enhance the circularity of non-bottle PET packaging waste based on a detailed material characterisation.

The compositions of Dutch lightweight packaging waste (LWP) and sorted products named "PET (Polyethylene terephthalate) trays" have been determined on object level. Additionally, the PET trays from both waste types were sorted in 16 categories representing their packaging use and material build-up. The material composition of at least 10 representative trays from each category was determined with chemical and thermal analysis, based on which the average material composition per category was established. Based on this data the average material composition of sorted PET tray products was approximated. The recyclability of the various categories of PET trays was assessed based on their material build-up. The most ubiquitous PET trays in Dutch LWP and sorted products were only found to be suitable to produce opaque recycled PET with mechanical recycling processes. Whereas only some more uncommon PET trays can be used to produce transparent recycled PET with mechanical recycling processes. Depolymerisation is deemed to be a more appropriate recycling process that will allow the production of transparent food-grade recycled PET.

Prospects for Recyclable Multilayer Packaging: A Case Study.

Food preservation is an essential application for polymers, particularly in packaging. Complex multilayer films, such as those used for modified atmosphere packaging (MAP), extend the shelf life of sensitive foods. These mostly contain various polymers to achieve the necessary combination of mechanic, optic, and barrier properties that limit their recyclability. As the European Union's Circular Economy Action Plan calls for sustainable products and business models, including waste prevention policies and recycling quotas, with plastic packaging being a high priority, solutions towards more sustainable multilayer packaging are urgently needed. This study evaluated and compared the recycling potential of functionally equivalent PET (polyethylene terephthalate) and PP (polypropylene) post-consumer MAP through structure analysis and recycling simulation. The structure analysis revealed that both types of MAP contained functional (stability) and barrier layers (oxygen and moisture). The recycling simulation showed that the PP-based packaging was recyclable 10 times, maintaining its mechanical properties and functionality. At the same time, the PET-based MAP resulted in a highly brittle material that was unsuitable for reprocessing into similar economic value products. The secondary material from the PP-based MAP was successfully manufactured into films, demonstrating the functional possibility of closed-loop recycling. The transition from a linear to a circular economy for MAP is currently still limited by safety concerns due to a lack of sufficient and efficient purification methods, but the proper design of multilayers for recyclability is a first step towards circularity.

Nanoemulsion-Based Multilayer Films for Ground Beef Preservation: Antimicrobial Activity and Physicochemical Properties.

This study aimed to improve the physical, mechanical, and biological properties of a monolayer pectin (P) film containing nanoemulsified trans-Cinnamaldehyde (TC) by incorporating it between inner and outer layers of ethylcellulose (EC). The nanoemulsion had an average size of 103.93 nm and a zeta potential of -46 mV. The addition of the nanoemulsion increased the opacity of the film, reduced its moisture absorption capacity, and improved its antimicrobial activity. However, the tensile strength and elongation at break of the pectin films decreased after the incorporation of nanoemulsions. Multilayer films (EC/P/EC) showed a higher resistance to breaking and better extensibility compared to monolayer films. The antimicrobial activity of both mono and multilayer films was effective in inhibiting the growth of foodborne bacteria during storage of ground beef patties at 8 °C for 10 days. This study suggests that biodegradable antimicrobial multilayer packaging films can be effectively designed and applied in the food packaging industry.

Trends in Bioactive Multilayer Films: Perspectives in the Use of Polysaccharides, Proteins, and Carbohydrates with Natural Additives for Application in Food Packaging.

The harmful effects on the environment caused by the indiscriminate use of synthetic plastics and the inadequate management of post-consumer waste have given rise to efforts to redirect this consumption to bio-based economic models. In this sense, using biopolymers to produce materials is a reality for food packaging companies searching for technologies that allow these materials to compete with those from synthetic sources. This review paper focused on the recent trends in multilayer films with the perspective of using biopolymers and natural additives for application in food packaging. Firstly, the recent developments in the area were presented concisely. Then, the main biopolymers used (gelatin, chitosan, zein, polylactic acid) and main methods for multilayer film preparation were discussed, including the layer-by-layer, casting, compression, extrusion, and electrospinning methods. Furthermore, we highlighted the bioactive compounds and how they are inserted in the multilayer systems to form active biopolymeric food packaging. Furthermore, the advantages and drawbacks of multilayer packaging development are also discussed. Finally, the main trends and challenges in using multilayer systems are presented. Therefore, this review aims to bring updated information in an innovative approach to current research on food packaging materials, focusing on sustainable resources such as biopolymers and natural additives. In addition, it proposes viable production routes for improving the market competitiveness of biopolymer materials against synthetic materials.

Pyrolysis behavior, kinetics, and thermodynamics of waste pharmaceutical blisters under CO2 atmosphere.

The disastrous impact of COVID-19 pandemic has caused a significantly increased production and use of pharmaceutical drugs, which is accompanied by the rapid generation of waste pharmaceutical blisters (WPBs). Nonetheless, its treatment has not gained appropriate attentions and a perceptible process development was not achieved. In this study, the WPBs pyrolysis in CO2 atmosphere was conducted as well as the thermodynamics and kinetics were investigated. The thermogravimetric analysis revealed that the WPBs decomposition could be divided into two stages of 25 - 365 °C and 365 - 900 °C with mass loss of 56.5 - 60.5 wt% and 22.5 - 25.9 wt%, respectively. Fourier-transform infrared spectroscopy analysis indicated the dechlorination process initiating at ∼300 °C. The simultaneous asymmetric stretching of HCl and stretching vibration of C-Cl bond was detected in the range of 2600 - 3250 cm-1 and 660 - 750 cm-1, respectively. The dechlorination reactions were almost complete at ∼520 °C and minor peaks (2900 -3100 cm-1) due to C-H vibrations were observed. Gas chromatography-mass spectrometry analysis indicated that the evolved products included alkanes, benzene, olefin, as well as HCl. The cycloalkenes content significantly increased during the second conversion stage, implying the addition reactions between alkanes and olefins. The apparent activation energy was calculated using three model-free methods and the values from Flynn-Wall-Ozawa model increased from 142.0 to 255.8 kJ·mol-1 with an average value of 147.4 kJ·mol-1. The methods of Coats-Redfern as well as Malek were applied to determine the reaction mechanism. The one-dimensional diffusion model was more reliable to describe the WPBs pyrolysis. This study will represent a significant reference case for the thermochemical conversion of multilayer packing waste and facing the increasing demand for the medical waste recycling.

Lifting the Sustainability of Modified Pet-Based Multilayer Packaging Material with Enhanced Mechanical Recycling Potential and Processing.

Sustainability and recyclability are among the main driving forces in the plastics industry, since the pressure on crude oil resources and the environment is increasing. The aim of this research is to develop a sustainable thermoformable multilayer food packaging, based on co-polyesters, which is suitable for hot-fill applications and allows for recycling in a conventional waste stream. As a polymer material for the outer layer, we selected a modified polyethylene terephthalate (PETM), which is an amorphous co-polyester with a high glass transition temperature (±105 °C) and thus high thermal stability and transparency. The inner layer consists of 1,4-cyclohexylene dimethanol-modified polyethylene terephthalate (PETg), which is allowed to be recycled in a PET stream. Multilayers with a total thickness of 1 mm and a layer thickness distribution of 10/80/10 have been produced. To test the recyclability, sheets which contained 20% and 50% regrind of the initial multilayer in their middle PETg layer have been produced as well. The sheet produced from virgin pellets and the one containing 20% regrind in the middle layer showed no visible haze. This was not the case for the one containing 50% regrind in the middle layer, which was confirmed by haze measurements. The hot-fill test results showed no shrinkage or warpage for the multilayer trays for all temperatures applied, namely 95, 85, 75 and 65 °C. This is a remarkable improvement compared to pure PETg trays, which show a visible deformation after exposure to hot-fill conditions of 95 °C and 85 °C.

Recyclability and Redesign Challenges in Multilayer Flexible Food Packaging-A Review.

Multilayer flexible food packaging is under pressure to redesign for recyclability. Most multilayer films are not sorted and recycled with the currently available infrastructure, which is based on mechanical recycling in most countries. Up to now, multilayer flexible food packaging was highly customizable. Diverse polymers and non-polymeric layers allowed a long product shelf-life and an optimized material efficiency. The need for more recyclable solutions asks for a reduction in the choice of material. Prospectively, there is a strong tendency that multilayer flexible barrier packaging should be based on polyolefins and a few recyclable barrier layers, such as aluminium oxide (AlOx) and silicon oxide (SiOx). The use of ethylene vinyl alcohol (EVOH) and metallization could be more restricted in the future, as popular Design for Recycling Guidelines have recently reduced the maximum tolerable content of barrier materials in polyolefin packaging. The substitution of non-recyclable flexible barrier packaging is challenging because only a limited number of barriers are available. In the worst case, the restriction on material choice could result in a higher environmental burden through a shortened food shelf-life and increased packaging weights.

Multilayer packaging: Advances in preparation techniques and emerging food applications.

In recent years, with advantages of versatility, functionality, and convenience, multilayer food packaging has gained significant interest. As a single entity, multilayer packaging combines the benefits of each monolayer in terms of enhanced barrier properties, mechanical integrity, and functional properties. Of late, apart from conventional approaches such as coextrusion and lamination, concepts of nanotechnology have been used in the preparation of composite multilayer films with improved physical, chemical, and functional characteristics. Further, emerging techniques such as ultraviolet and cold plasma treatments have been used in manufacturing films with enhanced performance through surface modifications. This work provides an up-to-date review on advancements in the preparation of multilayer films for food packaging applications. This includes critical considerations in design, risk of interaction between the package and the food, mathematical modeling and simulation, potential for scale-up, and costs involved. The impact of in-package processing is also explained considering cases of nonthermal processing and advanced thermal processing. Importantly, challenges associated with degradability and recycling multilayer packages and associated implications on sustainability have been discussed.

Recyclable Multilayer Packaging by Means of Thermoreversibly Crosslinking Adhesive in the Context of Food Law.

Lacking recyclability of multilayer packaging can be overcome by using a thermoreversible crosslinking adhesive consisting of maleimide- and furan-functionalized polyurethane-(PU-)prepolymers, reacting in a Diels-Alder-reaction. Here, the furan-functionalized PU-prepolymer carries furan-side-chains to avoid the usage of an additional crosslinking agent. Thus, N­(2­hydroxyethyl)maleimide and furfurylamine are the only two chemicals contained in the adhesive that are not listed in the appendix of EU Regulation 10/2011. Using migration modelling, it could be shown that, at 23 °C, both chemicals have lag-times of only a few minutes if 45 µm PE is used as a barrier. However, if the residual content is below 30 mg/kg, the legally specified maximum amount of 0.01 mg/kg food is not reached. After determining the diffusion coefficients and the activation energy of diffusion through ethylene-vinyl alcohol copolymer (EVOH), it could be determined that the lag-time of the migrants can be extended to at least 9 years by the use of 3 µm EVOH. From a food law point of view, the use of the described adhesive is possible if the above­mentioned measures are complied.

Identification of unexpected chemical contaminants in baby food coming from plastic packaging migration by high resolution accurate mass spectrometry.

Plastic multilayers are widely used for baby food packaging. However, it is important to consider that migration of food contact materials (FCM) into the baby food can occur. The comprehensive identification of potential migrants, including intentionally added substances (IAS) and non-intentionally added substances (NIAS), is required to assess the safety of these packaging materials. In this study, high resolution accurate mass spectrometry (HRAMS) with a data-independent acquisition method of sequential mass windows enables the detection of substances with corresponding deconvoluted fragment mass spectra. The identification of unexpected migrants present in the food simulants and in real baby food was facilitated by filtering strategies and by an in-house library. This approach has allowed the identification of 42 migrants, including eight NIAS detected for the first time. Two oligomers were quantified by means of reference standard materials at concentration levels above 0.010 mg/kg, exceeding the maximum residue levels for baby food.