Post-consumer PET Research Articles

Exploring the potential of Meldrum’s acid-bearing chain extenders for mechanical recycling of PET

Abstract Poly(ethylene terephthalate) (PET) is a widely used thermoplastic polymer with exceptional properties, making it a cornerstone in various industries. However, the extensive global demand for PET, particularly in the packaging sector, has led to significant ecological concerns due to inadequate recycling rates. This paper explores the potential of Meldrum’s acid-based chain extenders as a solution to enhance PET recycling. Initially, 2,2,5-trimethyl-5-(4-vinylbenzyl)-1,3-dioxane-4,6-dione (St-MA) was synthesized, and its homopolymers were produced through free radical polymerization and characterized through 1H NMR, FTIR and TGA analyses. Dynamic interactions between recycled PET (rPET) and the synthesized chain extender (HP) in an extrusion environment was further explored, resulting in higher T g and T c for rPET when 0.5 wt% of HP was added as a reactive chain extender. The chemical tunability of this functional ketene-based chain extender holds promise to enhance PET recycling practices. The continuous evolution of regulatory frameworks and environmental concerns may prompt the exploration of novel approaches, such as tailored Meldrum’s acid-bearing chain extenders, which might have the potential to reduce the ecological consequences associated with post-consumer PET waste.

Superior glycidol-free chain extenders for post-consumer PET bottles and PET thermoform blends

The development of non-toxic, glycidol-free chain extenders is essential for enabling the recycling and reuse of both bottle-grade PET (PET-B) and thermoform PET (PET-T) in the packaging industry without the need for separation, thereby addressing the health concerns associated with commercial glycidol-based extenders. Herein, two novel series of novel glycidol-free chain extenders for bottle-grade recycled polyethylene terephthalate (PET-B) and thermoform-grade PET (PET-T) blends are reported. Blends of PET-B with up to 20 wt% of PET-T were incorporated into novel epoxy acrylate chain extenders with terminal (PEAT-BA) and internal (PEAI-BA) epoxy groups. These chain extenders are glycidol-free and improve the mechanical, rheological, and thermal properties of the PET-B/PET-T blends, offering better performance enhancements than are provided by commercial chain extender Joncryl ADR (J). The results showed significant improvements in intrinsic viscosity and mechanical properties by around 10 and 15 %, respectively, without affecting thermal properties. These findings can play a role in enabling the recycling and re-use of PET-B and PET-T blends without requiring separation while offering glycidol-free solutions.

Bio-based unsaturated polyester resin from post-consumer PET.

This study explores the utilization of post-consumer poly(ethylene terephthalate) (PET) as a material in the synthesis of styrene-free unsaturated polyester (UP) resin. The process involves glycolysis of PET waste with diethylene glycol and condensation polymerization with bio-based itaconic acid. The resulting unsaturated polyester possesses reactive methylidene functions that, in contrast to commonly employed fumarates/maleates, facilitate copolymerization with non-styrene reactive diluents. To formulate the resins, methacrylates and itaconates were used for dilution, and the curing process is achieved through a redox initiation system at room temperature, followed by post-curing at elevated temperatures. The cured formulations were characterized by their glass transition temperature, determined by DMA analysis. Mechanical properties were evaluated using standardized tests in tension, flexure, and compression. Particularly promising characteristics are observed in formulations incorporating bio-based dimethyl itaconate (DMI), allowing the formulation of materials with a high ultimate flexural strength (σf,max = 161.4 MPa) and compressive yield point (σc,yield = 131.3 MPa). Furthermore, the low volatility of DMI addresses the health, safety, and ecological concerns associated with the commonly used styrene. This technology not only presents a promising avenue for sustainable UP resin for glass fiber reinforced composites but also allows upcycling PET waste.

Safety assessment of the process Reciclar, based on the EREMA Basic technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Reciclar (EU register number RECYC314), which uses the EREMA Basic technology. The input material is ■■■■■ washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post-consumer PET containers, including no more than 5% PET from non-food consumer applications. The flakes are heated in a continuous reactor under vacuum before being extruded. Having examined the challenge test provided, the Panel concluded that the continuous decontamination (step 2), for which a challenge test was provided, is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migration of 0.1 μg/kg food, derived from the exposure scenario for infants, when such recycled PET is used at up to 95% in mixtures with virgin PET, and of 0.15 μg/kg food, derived from the exposure scenario for toddlers, when used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 95% in mixtures with virgin PET for manufacturing of materials and articles for contact with all types of foodstuffs, including drinking water bottles, and at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, except drinking water, for long-term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave or conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process Novatex, based on the EREMA Basic technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Novatex (EU register number RECYC313), which uses the EREMA Basic technology. The input material is ■■■■■ washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post-consumer PET containers, including no more than 5% PET from non-food consumer applications. The flakes are heated in a continuous reactor under vacuum before being extruded. Having examined the challenge test provided, the Panel concluded that the continuous decontamination (step 2), for which a challenge test was provided, is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migration of 0.1 μg/kg food derived from the exposure scenario for infants when such recycled PET is used at up to 95% in mixtures with virgin PET, and of 0.15 μg/kg food, derived from the exposure scenario for toddlers when used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 95% in mixtures with virgin PET for manufacturing of materials and articles for contact with all types of foodstuffs, including drinking water bottles, and at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs except drinking water, for long-term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave or conventional ovens and such uses are not covered by this evaluation.

Using waste to treat waste: efficient alcoholysis of PET waste with a shrimp shell derived catalyst using the response surface method

The recycling of post-consumer PET waste is a significant area of scientific research, with great importance for resource recycling and environmental protection.

Acid catalyst screening for hydrolysis of post-consumer PET waste and exploration of acidolysis

We screen various acid catalysts (mineral, carboxylic, carbonic acids, zeolites, ionic liquids, and metal salts) for PET hydrolysis.

Complete decomposition of poly(ethylene terephthalate) by crude PET hydrolytic enzyme produced in Pichia pastoris

Using enzymes to decompose poly(ethylene terephthalate) (PET) is an attractive strategy to the sustainable utilization of PET, and an effective production platform of PET degrading enzyme is a prerequisite to achieve this goal. Here, we exploited the industrial yeast strain Pichia pastoris to produce a potent PET hydrolase termed FAST-PETase, whose performance was further elevated by removing two N-linked glycosylations through molecular engineering. The expression of the yielded variant, FAST-PETase-212/277, was elevated by antibiotics selection and chaperon co-expression to exceed 3 g/L in a 30-L fermenter. Notably, the crude fermentation product can be directly applied to decompose PET without purification. More than 95 % postconsumer PET can be achieved by 0.5 mgenzyme gPET-1 in 24 h in a 10-L reaction system in a reactor. These results demonstrate the economic viability of producing PET hydrolytic enzyme with modern fermentation facilities for large scale PET decomposition.

Post-consumer Recycled PET Active Films Containing β-Cyclodextrins-Based Inclusion Complexes with Essential Oils: A Comparative Study between Processing Methodologies

Post-consumer Recycled PET Active Films Containing β-Cyclodextrins-Based Inclusion Complexes with Essential Oils: A Comparative Study between Processing Methodologies

Exploring Microorganisms from Plastic-Polluted Sites: Unveiling Plastic Degradation and PHA Production Potential.

The exposure of microorganisms to conventional plastics is a relatively recent occurrence, affording limited time for evolutionary adaptation. As part of the EU-funded project BioICEP, this study delves into the plastic degradation potential of microorganisms isolated from sites with prolonged plastic pollution, such as plastic-polluted forests, biopolymer-contaminated soil, oil-contaminated soil, municipal landfill, but also a distinctive soil sample with plastic pieces buried three decades ago. Additionally, samples from Arthropoda species were investigated. In total, 150 strains were isolated and screened for the ability to use plastic-related substrates (Impranil dispersions, polyethylene terephthalate, terephthalic acid, and bis(2-hydroxyethyl) terephthalate). Twenty isolates selected based on their ability to grow on various substrates were identified as Streptomyces, Bacillus, Enterococcus, and Pseudomonas spp. Morphological features were recorded, and the 16S rRNA sequence was employed to construct a phylogenetic tree. Subsequent assessments unveiled that 5 out of the 20 strains displayed the capability to produce polyhydroxyalkanoates, utilizing pre-treated post-consumer PET samples. With Priestia sp. DG69 and Neobacillus sp. DG40 emerging as the most successful producers (4.14% and 3.34% of PHA, respectively), these strains are poised for further utilization in upcycling purposes, laying the foundation for the development of sustainable strategies for plastic waste management.

Safety assessment of the process Intco Malaysia, based on the VACUNITE (EREMA basic and Polymetrix SSP V-leaN) technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Intco Malaysia (EU register number RECYC309), which uses the VACUNITE (EREMA basic and Polymetrix SSP V-leaN) technology. The input consists of hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are pre-decontaminated in the ■■■■■ at ■■■■■ under ■■■■■ (step 2), then extruded and pelletised. The ■■■■■ pellets are then ■■■■■ and submitted to solid-state polycondensation (SSP) at ■■■■■ under ■■■■■ and ■■■■■. Having examined the challenge tests provided, the Panel concluded that the step 2 (flake reactor) and steps 4 and 5 (preheating and SSP) are critical for determining the decontamination efficiency of the process. The operating parameters to control the performance are temperature, pressure and residence time for steps 2, 4 and 5 as well as the ■■■■■ for steps 4 and 5. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern, when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long-term storage at room temperature or below, with or without hotfill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process Guangxi Wuzhou Guolong Recyclable, based on the Vacunite (EREMA basic and Polymetrix SSP V-LeaN) technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Guangxi Wuzhou Guolong Recyclable (EU register number RECYC310), which uses the VACUNITE (EREMA basic and Polymetrix SSP V-leaN) technology. The input consists of hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes, mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are pre-decontaminated in the ■■■■■ at ■■■■■ under ■■■■■ (step 2) before being extruded, pelletised and crystallised (step 3). The ■■■■■ pellets are then ■■■■■ (step 4) and submitted to solid-state polycondensation (SSP) (step 5) at high temperature under ■■■■■ and ■■■■■. Having examined the challenge tests provided, the Panel concluded that step 2 as well as steps 4 and 5 are critical for determining the decontamination efficiency of the process. The operating parameters to control the performance are temperature, pressure and residence time for steps 2, 4 and 5 as well as the ■■■■■ for steps 4 and 5. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern, when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long-term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process Rekis, based on the VACUNITE (EREMA basic and Polymetrix SSP V-leaN) technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Rekis (EU register number RECYC311), which uses the VACUNITE (EREMA basic and Polymetrix SSP V-leaN) technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are pre-decontaminated in the ■■■■■ at ■■■■■ under ■■■■■ (step 2) before being extruded, pelletised and ■■■■■ (step 3). The crystallised pellets are then ■■■■■ (step 4) and submitted to solid-state polycondensation (SSP) (step 5) at ■■■■■, under ■■■■■ and ■■■■■. Having examined the challenge tests provided, the Panel concluded that step 2 as well as steps 4 and 5 are critical for determining the decontamination efficiency of the process. The operating parameters to control the performance are temperature, pressure and residence time for steps 2, 4 and 5 as well as the gas velocity for steps 4 and 5. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern, when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long-term storage at room temperature or below, with or without hotfill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process INCOM RESOURCES RECOVERY (TIANJIN), based on the Buhler technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process INCOM RESOURCES RECOVERY (TIANJIN) (EU register number RECYC312), which uses the Buhler technology. The input material consists of hot washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post-consumer PET containers, e.g. bottles, including no more than 5% PET from non-food consumer applications. Washed and dried flakes are extruded into pellets, which are dried and crystallised in a reactor and then preheated and further treated in a solid-state polymerisation (SSP) reactor. The recycled pellets are intended to be used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long-term storage at room temperature or below, with or without hotfill. The Panel concluded that the information submitted to EFSA is inadequate to demonstrate that this recycling process is able to reduce potential unknown contamination of the input PET flakes to a concentration that does not pose a risk to human health.

Upcycling spent coffee grounds and waste PET bottles into electrospun composite nanofiber mats for oil structuring applications

Spent coffee grounds (SCG) and post-consumer PET bottles (PETbot) are major waste materials from the food industry. In this work, their use to obtain electrospun composite nanofibers is explored aiming to develop a new route for their upcycling into high added-value oil-based products. Raising the proportion of PETbot increased the average fiber diameter (from 0.36 to 0.89 μm) and enhanced the tensile properties of the mats. Young's modulus and strain-at-break increased from 5.1 to 32.8 MPa and from 13.8 to 39.4 %, respectively, as the SGC:PETbot weight ratio decreased. Dispersions of the mats in castor oil exhibited shear-thinning and gel-like viscoelastic properties which can be tuned through the SCG:PETbot ratio. Friction coefficient values of resulting oleogels tested in a tribological contact ranged from 0.165 to 0.092. SCG and PETbot can be used to obtain electrospun nanofibers with oil structuring capabilities while resulting oleogels are proposed as environmentally-friendly alternatives to semisolid lubricants.

Safety assessment of the process Acepolymer, based on the Vacurema Prime technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Acepolymer (EU register number RECYC305), which uses the Vacurema Prime technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are heated in a batch reactor (Step 2) under vacuum and then treated at higher temperature in a continuous reactor (Step 3) under vacuum before being extruded into pellets. Having examined the challenge test provided, the Panel concluded that Steps 2 and 3 are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these steps are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, soft drinks, juices, tea, milk, oil, alcoholic beverages and other food products, for long-term storage at room temperature or below, with or without hot fill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process Umincorp, based on the NGR technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Umincorp (EU register number RECYC302), which uses the NGR technology. The input consists of washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are dried (step 2), melted in an extruder (step 3) and decontaminated during a melt-state polycondensation step ■■■■■ (step 4). In step 5, the melt is cooled down and granulated. Having examined the challenge test provided, the Panel concluded that the melt-state polycondensation (step 4) is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance are the pressure, the temperature, the residence time (depending on the mass and throughput of the melt) and the characteristics of the reactor. It was demonstrated by the challenge test that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long-term storage at room temperature, with or without hotfill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process Ambiental de Plasticos Recyclapet, based on the Vacurema Prime technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panelon Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Ambiental de Plasticos Recyclapet (EU register number RECYC304), which uses the Vacurema Prime technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are heated in a batch reactor (Step 2) under vacuum and then treated at higher temperature in a continuous reactor (Step 3) under vacuum before being extruded into pellets. Having examined the challenge test provided, the Panelconcluded that Steps 2 and 3 are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these steps are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panelconcluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, soft drinks, juices, tea, milk, oil, alcoholic beverages and other food products, for long-term storage at room temperature or below, with or without hot fill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process Poly Recycling, based on the Vacurema Prime technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panelon Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Poly Recycling (EU register number RECYC307), which uses the Vacurema Prime technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are heated in a batch reactor (Step 2) under vacuum and then treated at higher temperature in a continuous reactor (Step 3) under vacuum before being extruded into pellets. Having examined the challenge test provided, the Panelconcluded that Steps 2 and 3 are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these steps are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panelconcluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, soft drinks, juices, tea, milk, oil, alcoholic beverages and other food products, for long-term storage at room temperature or below, with or without hotfill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process Battenfeld-Cincinnati Germany, based on the Battenfeld technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Battenfeld-Cincinnati Germany (EU register number RECYC303), which uses the Battenfeld technology. The input consists of washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are heated and pre-decontaminated in an ■■■■■, then further decontaminated by extrusion to sheets ■■■■■. Having examined the challenge test provided, the Panel concluded that the ■■■■■ drying (step 2) and extrusion (step 3) are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these critical steps are temperature and residence time for step 2, temperature, throughput and pressure for step 3. The Panel concluded that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.15 μg/kg food, exposure scenario for toddlers, under the following conditions of use of the recycled PET: (a) 45% in mixtures with virgin PET to produce trays for storage of fruits and vegetables up to 30 days at room temperature or below, (b) 100% to produce cups for storage of soft drinks and beers up to 1 day at room temperature or below, (c) 100% to produce trays for meat storage up to 30 days at 6°C. Hotfill is not included. Therefore, the Panel concluded that the recycled PET produced by this process is not of safety concern when used under the evaluated conditions. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.