Plastics end of life scenarios

D5.8 – Plastics end of life scenarios March 2025 Authors: Pedro López (CETEC); Alejandro Arribas (CETEC), María Mondéjar (CETEC) This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. Ref. Ares(2025)2547551 - 30/03/2025 A2C – Deliverable D5.8v1.0 Page 2 І34 Technical references Project Acronym Agro2Circular Project Title TERRITORIAL CIRCULAR SYSTEMIC SOLUTION FOR THE UPCYCLING OF RESIDUES FROM THE AGRIFOOD SECTOR Project Coordinator Fuensanta Monzó CETEC [email protected] Project Duration October 2021 – March 2025 (42 months) Deliverable No. D5.8 D41 Dissemination level* PU Work Package WP 5 - A2C technologies for the upcycling of the recycled plastics materials Task T5.4 – Compounds transformation Lead beneficiary Partner number (CETEC) Contributing beneficiary/ies Partner number (partner short name), Partner number (partner short name), Partner number (partner short name) Due date of deliverable 31 March 2025 Actual submission date 31 March 2025 PU = Public This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 3 І34 Document history V Date Comments v0.1 25/03/2025 First draft of document v0.2 28/03/2025 Revised version based on the comments of Alan Werker (WETSUS) and Ronald Zirbs (OKU) v1.0 30/03/2025 First final version, approved by the WP leader and the project coordinator, (will be) submitted to EC. v1.1 First draft based upon first final version v2.0 Second final version, approved by the WP leader and the project coordinator, (will be) submitted to EC. Document Distribution Log Version Date Distributed to v0.1 25/03/2025 Ronald Zirbs, Alan Werker V0.2 28/03/2025 Coordinator and WP leader Verification and approval Name Date Verification Final Draft by WP leader Paola Branduardi 30/03/2025 Approval Final Deliverable by coordinator Fuensanta Monzo 30/03/2025 This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 4 І34 Disclaimer and acknowledgement This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101036838 Disclaimer This document reflects only the views of the author(s) the European Research Executive Agency (REA) is not responsible for any use that may be made of the information it contains. Whilst efforts have been made to ensure the accuracy and completeness of this document, the A2C consortium shall not be liable for any errors or omissions, however caused. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 5 І34 Table of contents 1 List of abbreviations...................................................................................................8 2 Executive summary....................................................................................................9 3 Introduction................................................................................................................9 4 Plastic end life scenarios.........................................................................................10 4.1 Recyclability.......................................................................................................10 4.1.1 Extrusion....................................................................................................11 4.1.2 Injection......................................................................................................14 4.2 Characterization................................................................................................17 4.2.1 Tensile strength tests................................................................................17 4.2.2 Rheology test.............................................................................................18 4.3 Biodegradability................................................................................................20 4.3.1 Compostability...........................................................................................20 4.3.1.1 Test method........................................................................................20 4.3.1.2 Expression of results.........................................................................22 4.3.1.3 Presentation of results......................................................................23 4.3.1.4 Validity of results................................................................................25 4.3.2 Biodegradability in soil.............................................................................25 4.3.2.1 Materials.............................................................................................25 4.3.2.2 Apparatus...........................................................................................26 4.3.2.3 Principle of the method....................................................................26 4.3.2.4 Operating procedure.........................................................................26 4.3.2.5 Expression of results.........................................................................27 4.3.2.6 Validity of results................................................................................29 4.3.3 Biodegradability in seawater...................................................................30 This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 6 І34 4.3.3.1 Materials.............................................................................................30 4.3.3.2 Apparatus...........................................................................................30 4.3.3.3 Test procedure...................................................................................31 4.3.3.4 Calculation and Expression of Results............................................31 4.3.3.5 Interpretation of Results...................................................................32 4.3.3.6 Validity of Results...............................................................................33 5 Conclusions...............................................................................................................34 List of tables Table 1: extruder characteristics....................................................................................12 Table 2: extruder parameters.........................................................................................13 Table 3: Injection parameters........................................................................................16 Table 4: Mechanical properties after 5 cycles of extrusion and injection for the PHBV-PBAT1..................................................................................................................... 17 Table 5: Mechanical properties after 5 cycles of extrusion and injection for the PHBV-StarchPBAT1..........................................................................................................17 Table 6: Results of compostability test..........................................................................23 Table 7: Results of biodehgradability in soil.................................................................28 Table 8: Results of biodegradability in marine environment.....................................32 List of Figures Figure 1: recyclability squeme........................................................................................11 Figure 2: Leistrizt ZSE 18 HP extruder and feeders.....................................................12 This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 7 І34 Figure 3: Once the filament comes out of the extruder, it is cooled in a water bath and then passed to the cutter to obtain the pellets....................................................14 Figure 4: It was necessary to increase the temperatures by 5 degrees to avoid the appearance of strictions in the yarn.............................................................................14 Figure 5: Engel injection machine..................................................................................15 Figure 6: Test specimen mold........................................................................................15 Figure 7: Test specimen samples...................................................................................16 Figure 8: Rheological test after 5 cycles of extrusion and injection for the PHBVPBAT1................................................................................................................................19 Figure 9: Rheological test after 5 cycles of extrusion and injection for the PHBVStarchPBAT1.....................................................................................................................19 Figure 10: cumulative amount of carbon dioxide generated for the blends in compost............................................................................................................................24 Figure 11: percent biodegradation of the blends in compost as a function of time ...........................................................................................................................................24 Figure 12: cumulative amount of carbon dioxide generated for the blends in soil29 Figure 13: percent biodegradation of the blends in soil as a function of time........29 Figure 14: cumulative amount of carbon dioxide generated for the blends in seawater...........................................................................................................................32 Figure 15: percent biodegradation of the blends in seawater as a function of time ...........................................................................................................................................33 This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 8 І34 1 List of abbreviations Al Aluminium CETEC Centro Tecnológico del Calzado y del Plaśtico EVA Ethylen vinyl acetate EVOH Ethylen vinyl alcohol LDPE Low density polyethylene PA Polyamide PBAT Polybutylene adipate terephthalate PHBV Poly(3-hydroxybutyratehydroxyvalerate) TOC Total organic carbon RPM Revolutions per minute TM Melting temperature PM Melting pressure DOC Dissolved organic carbon BOD Biological oxygen demand This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 9 І34 2 Executive summary Recycled material formulations from aseptic bags and agricultural plastics, developed in task 5.2 have been subjected to a successive recycling process to ensure their continued use in the recycling cycle. This study has ensured, through the mechanical and rheological properties, that the formulations developed can be used without problems for at least five recycling cycles. Furthermore, the developed formulations of biodegradable polymers obtained from the fermentation process of task 5.1.2 PHBV and carotenoids production by Haloferax mediterranei cell factory and the commercial materials such as PBAT and a mixture of starch and PBAT (PHBV-PBAT1 and PHBV-StarchPBAT1), have been subjected to compostability tests using the UNE EN ISO 14855 standard, biodegradability in soil according to the UNE EN ISO 17556 standard and biodegradability in seawater according to the UNE EN ISO 19679 standard. This compostability and biodegradability study has ensured that the formulations developed with PHBV are compostable and also biodegradable in soil and seawater. 3 Introduction Recycling plastics is a fundamental pillar of the circular economy. The reuse of these materials, promoted by the different administrations and by the recycling industry itself, is providing new ways of using them and boosting the economy of the sector. One of the objectives of the Agro2Circular project is that all compounds developed from the fermentation process of task 5.1.2 PHBV and carotenoids production must be completely recyclable. To ensure that the formulations developed are recyclable, a series of experiments and tests have been designed that have allowed us to determine that at least the developed materials are capable of being recycled for 5 cycles without suffering a significant loss of properties, making them perfectly reusable as secondary raw material. On the biodegradable polymers side, Poly(3-hydroxybutyrate-hydroxyvalerate) (PHBV) copolymer is a microbial polyester presenting the advantages of biodegradability and biocompatibility over other thermoplastics with useful mechanical properties. However, their costs and performances must be adjusted by blending with suitable polymers. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 16 І34 Table 3: Injection parameters Cooling time Post-pressure time(s) Dosing stroke Mold temperature 12 s 1.25 50 mm 70º C Z1 Z2 Z3 Z4 175ºC 170ºC 170ºC 170ºC Figure 7: Test specimen samples This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 17 І34 4.2 Characterization 4.2.1 Tensile strength tests To study the effect on the mechanical properties of the five working cycles, tensile tests were carried out. These were carried out in accordance with the UNE EN ISO 527-2 standard for tensile testing of plastics in the form of specimens. All these tests were carried out using the type 2 specimen model, in accordance with the aforementioned standard. At least 5 tests were carried out per sample, after the samples were first conditioned. As a result of the tests, stress-strain curve data was collected for the mechanical response for each of the film samples studied. Table 4: Mechanical properties after 5 cycles of extrusion and injection for the PHBV-PBAT1 SAMPLE PHBV-PBAT1 Tensile strength at break (MPa) Elongation at Break (MPa) Cycle 1 17,67±0,75 256±15 Cycle 2 19,51±0,55 256±14 Cycle 3 20,51±1,25 269±25 Cycle 4 18,74±0,29 251±5 Cycle 5 18,47±0,26 256±6 Table 5: Mechanical properties after 5 cycles of extrusion and injection for the PHBV-StarchPBAT1 SAMPLE PHBVStarchPBAT1 Tensile strength at break (MPa) Elongation at Break (MPa) Cycle 1 22,62±0,44 154±4 Cycle 2 22,95±1,01 177±8 Cycle 3 22,33±1,00 187±10 Cycle 4 19,94±0,83 201±5 This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 18 І34 Cycle 5 22,66±0,74 185±14 There are no significant differences in the mechanical properties of the material after being subjected to five extrusion and injection cycles. Therefore, based on this outcome, the material can be subjected to at least five cycles without loss of key mechanical properties. 4.2.2 Rheology test The samples were developed for the project, in the form of blends based on biodegradable thermoplastics. They were to be processed by extrusion methods, and studied by means of rheology tests. In rheology tests, the melt viscosity of the initial formulation with the viscosities of each of the five cycles are compared. In the event of a drop in viscosity, one may conclude that there has been a molecular weight degradation of the material with repeated extrusion and injection processing. For this purpose, a series of rheology tests were set up, where all were performed for the melted material at 180ºC. The temperature value was determined after differential calorimetry studies, seeing that this ensured complete melting of the crystalline structures of the matrix polymers. On this basis, a method was established with floe sweep measurements of the viscosity as a function of the shear rate. As in the case of mechanical properties, there are no significant differences in the mechanical properties of the material after being subjected to five extrusion and injection cycles. Therefore, if we take into account this criterion, the material can be subjected to at least five cycles without significant loss of properties. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 19 І34 Figure 8: Rheological test after 5 cycles of extrusion and injection for the PHBV-PBAT1 Figure 9: Rheological test after 5 cycles of extrusion and injection for the PHBV-StarchPBAT1 This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 20 І34 4.3 Biodegradability Three types of test have been carried out to determine the biodegradability properties of the developed PHBV blends, specifically the mixtures of PHBV-PBAT1 and PHBV-StarchPBAT1. The first tests followed the ISO 14855-1:2012 standard for determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions — Method by analysis of evolved carbon dioxide. The second test following the ISO 17556:2019 standard for plastics — Determination of the ultimate aerobic biodegradability of plastic materials in soil by measuring the oxygen demand in a respirometer or the amount of carbon dioxide evolved. Finally, a third test was performed following the ISO 19679:2020 standard for plastics — Determination of aerobic biodegradation of non-floating plastic materials in a seawater/sediment interface by the method by analysis of evolved carbon dioxide. 4.3.1 Compostability To determine the final aerobic biodegradability of plastic materials under controlled composting conditions, the standard UNE-EN ISO 14855-1:2013 has been followed. The method is based on the analysis of the carbon dioxide generated during the biodegradation process. 4.3.1.1 Test method The test method involves exposing a representative sample of the plastic material to an inoculum derived from compost in a controlled environment. Composting is carried out in a closed container where temperature, aeration and humidity are controlled and maintained at optimal levels. During the process, microorganisms in the compost decompose the plastic material, generating carbon dioxide, water, mineral salts and new biomass. The amount of carbon dioxide generated is measured at regular time intervals. The trend allows the determination of the percentage of biodegradation of the plastic material. The percentage of biodegradation is calculated as the ratio between the carbon dioxide generated and the maximum theoretical amount of carbon dioxide that can be produced from the plastic material. We have used the following materials: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 21 І34 Reference material: TLC (thin layer chromatography) grade cellulose with a particle size less than 20 μm was used as a positive control reference material. The apparatus was as follows: 1. Composting vessels1: These are glass jars or bottles that allow a balanced gas purge in an upward direction. A minimum volume of 2 litres is required to meet the requirements of the method, although a smaller volume may be used for review purposes. 2. Air supply system1: Capable of supplying each vessel with dry or watersaturated air, free of carbon dioxide, at a predetermined flow rate. This flow rate must be high enough to ensure aerobic conditions during the test. 3. Apparatus for determining carbon dioxide1: These allow determination of carbon dioxide directly or by absorption in an alkaline solution, by determining dissolved inorganic carbon (DIC). If CO2 is measured directly in the output air, then precise control of the air flow is required. 4. Airtight tubes1: Used to connect the composting vessels to the air supply and carbon dioxide measurement system. 5. pH meter: To measure the pH of the inoculum and the test mixture. 6. Analytical equipment: Used to determine dry solids (at 105 °C), volatile solids (at 550 °C) and total organic carbon (TOC). Also used for elemental analysis of the test material and, if necessary, for the determination of DIC. 7. Balance: Optional, to measure the mass of the test vessels with compost and test material. 8. Analytical equipment (optional): To determine air oxygen, moisture, volatile fatty acids and total nitrogen. The test method includes the following steps: 1The composting vessels, the air supply system, the apparatus for determining carbon dioxide and the airtight tubers are included in the respirometer Echo from ECHO instruments, which is a device system that measures the concentration of O₂ and CO₂ in the flow through the sample under controlled conditions. Flow, temperature, pressure, humidity are also continuously measured. Software automatically calculates CO₂ production and % biodegradation. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 22 І34 1. Inoculum preparation: Mature compost is obtained and conditioned to ensure adequate microbial activity. 2. Test material preparation: The plastic material is characterized and prepared for testing. 3. Test start-up: Inoculum and test material are mixed in a composting vessel and subjected to controlled conditions. 4. Incubation period: Carbon dioxide production is monitored and test conditions are controlled for a given period of time. 5. Test termination: The test is stopped and the results are analyzed. 4.3.1.2 Expression of results Calculation of the theoretical amount of carbon dioxide: The theoretical amount of carbon dioxide (ThCO2), in grams per container, that can be produced by the test material is calculated using Equation 1: T h CO2=MTOT x CTOT x44 12 Equation 1 Where: MTOT are the total dry solids, in grams, in the test material introduced into the composting vessels at the beginning of the test. CTOT= is the proportion of total organic carbon in the total dry solids in the test material, in grams per gram. Calculation of the percentage of biodegradation: The percentage of biodegradation (Dt) of the test material is calculated for each measurement interval using Equation 2: Dt=CO 2T−CO 2B T h CO2 x100 Equation 2 Where: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 23 І34 CO2T is the cumulative amount of carbon dioxide generated in each composting vessel containing the test material, in grams per vessel. CO2B is the average cumulative amount of carbon dioxide generated in the target containers, in grams per container. The CO2 is the theoretical amount of carbon dioxide that the test material can produce, in grams per container. If the differences between the individual results are less than 20%, the average biodegradation percentage is calculated. If this is not the case, the values from each composting bin are used. The same equation is used to calculate the degree of biodegradability of the reference material. 4.3.1.3 Presentation of results Measurement data and calculations are presented in tables for the test material, reference material and blanks for each measurement day. The cumulative amount of carbon dioxide generated by each vessel is plotted as a function of time. A biodegradation curve (percent biodegradation as a function of time) is also plotted for the test material and the reference material. Mean values are used if the differences between the individual values are less than 20%. If this is not the case, biodegradation curves are plotted for each composting bin. The average degree of biodegradation is read from the stationary phase of the biodegradation curve and this value is noted as the final test result. If the test material consists of discrete pieces, the degree of disintegration of the material is described qualitatively. Additional information such as photographs or measured values of the main physical properties are added if available. Table 6: Results of compostability test This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 24 І34 Figure 10: cumulative amount of carbon dioxide generated for the blends in compost Figure 11: percent biodegradation of the blends in compost as a function of time This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 25 І34 The two materials tested, both the PHBV+PBAT mixture and the PHBV+Starch PBAT mixture, are compostable according to UNE-EN ISO 14855-1. Both materials show a degree of biodegradation of less than 20% difference with respect to the reference material. 4.3.1.4 Validity of results (a) The degree of biodegradation of the reference material must be greater than 70% after 45 days. b) The difference between the percentage of biodegradation of the reference material in the different composting vessels must be less than 20% at the end of the test. c) The inoculum in the blank must have generated more than 50 mg but less than 150 mg of carbon dioxide per gram of volatile solids (average values) after 10 days of incubation. If these criteria are not met, the assay is considered invalid and must be repeated. 4.3.2 Biodegradability in soil In order to determine the ultimate aerobic biodegradability of plastic materials in soil, the standard UNE-EN ISO 17556 has been followed. The method consists of mixing the plastic material with soil and placing the mixture in a respirometer or in a system for measuring the amount of carbon dioxide released. The level of biodegradation is calculated by comparing the oxygen demand or the amount of carbon dioxide released with the theoretical amount. The normal test period is six months, but it can be shortened or lengthened until a plateau phase is reached. However, the test must not exceed two years. 4.3.2.1 Materials The following materials were used: 1. Distilled water, containing less than 2 mg DOC per liter. 2. Carbon dioxide absorbent, preferably soda lime tablets. 3. Test material: Natural and/or synthetic polymers, copolymers or mixtures thereof; plastic materials containing additives such as plasticizers or colorants; water-soluble polymers. Must be of known mass and contain This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 32 І34 T h CO2=SxTOC ( % ) x44 12 Equation 6 Where S is the amount of test material (in mg), TOC is the total organic carbon content of the material (%), 44 is the molecular mass of CO2 and 12 is the molecular mass of carbon. 4.3.3.5 Interpretation of Results The results are plotted in graphs showing the amount of CO2 released and the percentage of biodegradation as a function of time. The maximum level of biodegradation was determined from the stationary phase of the biodegradation curve, which occurs when the CO2 release reaches a plateau value. It is important to note that the shape and wettability of the material can influence the results, so the method is best suited for comparing materials of similar chemical structure. Table 8: Results of biodegradability in marine environment Figure 14: cumulative amount of carbon dioxide generated for the blends in seawater This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 33 І34 Figure 15: percent biodegradation of the blends in seawater as a function of time Despite the necessary long duration of these tests carried out in seawater, biodegradability of the PHBV-StarchPBAT mixture in this medium was demonstrated. The PHBV-PBAT mixture also came close to achieving this standard for biodegradability. With a higher PHBV content, it is expected that the PHBV-PBAT would have also been within the standard of biodegradability. 4.3.3.6 Validity of Results For the test results to be valid, the following criteria must be met: The biodegradation rate of the reference material must be greater than 60% after 180 days. The amount of CO2 released from the blanks at the end of the test must not exceed 3.5 mg CO2/g wet sediment after 6 months. The amount of CO2 released from the three blanks should be within 20% of the mean in the stationary phase or at the end of the test. The difference between the percentage of biodegradation of the reference material in the different vessels must be less than 20% of the mean at the end of the test. The percentage of biodegradation of the negative control must be less than 10% at the end of the test. If these criteria are not met, the test should be repeated using another sediment. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. A2C – Deliverable D5.8v1.0 Page 34 І34 5 Conclusions It was found that the developed PHV based formulations, with biodegradable polymers such as PBAT and a mixture of starch and PBAT (PHBV-PBAT1 and PHBVStarchPBAT1), can undergo five recycling cycles without significant loss of important mechanical and rheological properties. This outcome was demonstrated by processing the mixtures five consecutive times by extrusion and injection molding. The, establishing the recyclability of the materials was established. The developed formulations have been furthermore tested for: 1. compostability according to UNE EN ISO 14855, 2. biodegradability in soil according to UNE EN ISO 17556, and 3. biodegradability in seawater according to UNE EN ISO 19679. The material compostability and biodegradability was confirmed. The developed formulations with PHBV are compostable and also biodegradable in soil and seawater. Only the PHBV-PBAT formulation did not quite comply with the UNE EN ISO 19679 standard by a small margin. However, based on the biodegradation trends it is expected, nevertheless, that if the test time could have been extended then the standard would have been reached for this specific PHBV-PBAT formulation. Unfortunately, the test time was limited due to the project execution time. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838.