Periodic Reporting for period 2 - NATURE (Innovative designs to enable plastic packaging circular economy)
Reporting period: 2023-01-01 to 2024-12-31
Over the past century, plastics have become the material of choice for packaging because of their low cost, high performance, and easy processability, occupying an ever-expanding range of applications. Far from decreasing, their production is constantly increasing, and estimations indicate that by 2050, the production of plastic packaging could exceed 250 million metric tons. Although it was envisioned since a couple of decades that polyesters such as poly(lactide) (PLA) or poly(3-hydroxybutyrate) (P3HB) could be part of the solution thanks to their renewable origins (e.g. starch, cellulose, and bacteria) and biodegradability, the inferior properties of these materials compared to most of synthetic plastics currently used in the packaging industry (mainly polypropylene (PP), polyethylene (PE) and poly(ethylene terephthalate) (PET)) have considerably limited their insertion in the plastic market. NATURE-EID is an innovative research training program at the forefront of the circular economy of biobased polyesters for packaging applications. The project offers to develop new synthetic routes for novel biobased polyesters where a material is not only designed based on its performance and low cost but also considering the overall sustainability of the product, considering its sourcing, the use of green chemistry synthesis, the potential scalability of the production process, and the management of its end-of-life. To achieve this goal, 4 ESRs have been trained on organic chemistry, synthesis and analysis of polymers, recycling processes, and sustainable chemical processing: Flore Kilens (ESR 1), Claire Morand (ESR 2), Gabriella Garbonova (ESR 3) and Bige Bati (ESR 4).
NATURE-EID has proudly achieved important objectives. Regarding the scientific tasks involved in the project:
- Bio-sourced monomeric synthons have been identified as key materials focusing on biobased diols and dicarboxylic acids like 1,3-propanediol (All ESRs), 1,4-butanediol (ESR 3 and 4), maleic acid (ESR 2) or lactic acid (ESR 1). Some bio-sourced molecules, such as taurine or nicotinic acid have been also explored as organocatalysts (ESR 1, 2 and 3).
- Bio-sourced compounds, including terpenes and thiol-based structures, have been investigated for additive manufacturing applications (ESR 2). Organocatalysts have been priorly used for the synthesis including organics bases (ESR 1, 2 and 4) as well as acid:base catalysts (ESRs 1, 3 and 4) and bio-sourced molecules (ESR 2) yielding moderate to excellent yields. Special care was taken by all ESRs in developing the most benign synthesis possible, in the limit of the required reactivity and yield. ESR 1 was focused on obtaining block copolymers based on PLLA and bio-based polyethers using organic catalysts while ESR 2 obtained fully bio-sourced polyester resins under solvent-free conditions. Finally, ESR 3 and ESR 4 used bio-sourced molecules for the synthesis of the macrolactones and organic catalysts for their subsequent ring opening although it was demonstrated that metallic catalysts were more efficient in these specific cases.
- All the materials synthesised in this project have undergone physico-chemical characterisation and analysed for packaging applications. Notably, the thermal properties (DSC and TGA) (all ESRs), the processing properties, such as curing or 3D printing (ESRs 2 and 4) but also the mechanical properties such as tensile strength, elongation at break and viscosity (ESRs 2, 3 and 4), and the barrier properties towards CO2 and O2 (ESR1, 3 and 4). Although the materials prepared are not all reaching the ideal packaging properties, most of the polymers have demonstrated interesting properties: good processability in printing for the polyesters (Claire Morand, ESR 2), high molecular weights and good mechanical and barrier properties for PES (Bige Bati, ESR 4), interesting crystalline behaviour for the triblock based on PLLA and polyether (Flore Kilens, ESR 1), unique thermal properties for the PHAs with etheric bonds (Gabriella Garbonova, ESR 3).
- Finally, in this project, the end-of-life of the different materials was studied. It was demonstrated the feasibility of depolymerising different polymers such as the poly(ethylene succinate) (PES) into cyclic oligomers (ESR 4), and the poly(hydroxy acid) (PHA) into small molecules (ESR 1) which represent for both families of material a crucial step towards chemical recycling. Through hydrolysis biodegradation tests, we demonstrated that polymers synthesised in this project were biodegradable with up to 80% of mass loss after 70 days, notably PES of high molecular weight (ESR 4) and PLLA-based block copolymers (ESR 1).
Considering the management of the project and the different workshops and dissemination activities included in the formation:
- Four talented ESRs have been recruited and they have been enrolled in their respective doctoral programs at the university of the Basque Country (UPV-EHU) (Spain) and the University of Birmingham (UK).
- Three workshops as well as one summer school and one final conference were oragnised on various topics, i.e. Workshop 1: Sustainable packaging materials, Workshop 2: Life cycle assessment, Workshop 3: Oral Communication skills, Summer school: Recycling of plastics + training on IP for R&D, Final conference: "Is a circular economy for plastics possible".
- Virtual meetings with all ESRs and ERs are also regularly organised, every two months, to ensure a tight follow-up of the project.
- ESRs have been encouraged to participate in different outreach activities, and some have participated in different events including science open days, days of the women in science, the realisation of a project video targeted at students focused on the importance of recycling.
- Bio-sourced monomeric synthons have been identified as key materials focusing on biobased diols and dicarboxylic acids like 1,3-propanediol (All ESRs), 1,4-butanediol (ESR 3 and 4), maleic acid (ESR 2) or lactic acid (ESR 1). Some bio-sourced molecules, such as taurine or nicotinic acid have been also explored as organocatalysts (ESR 1, 2 and 3).
- Bio-sourced compounds, including terpenes and thiol-based structures, have been investigated for additive manufacturing applications (ESR 2). Organocatalysts have been priorly used for the synthesis including organics bases (ESR 1, 2 and 4) as well as acid:base catalysts (ESRs 1, 3 and 4) and bio-sourced molecules (ESR 2) yielding moderate to excellent yields. Special care was taken by all ESRs in developing the most benign synthesis possible, in the limit of the required reactivity and yield. ESR 1 was focused on obtaining block copolymers based on PLLA and bio-based polyethers using organic catalysts while ESR 2 obtained fully bio-sourced polyester resins under solvent-free conditions. Finally, ESR 3 and ESR 4 used bio-sourced molecules for the synthesis of the macrolactones and organic catalysts for their subsequent ring opening although it was demonstrated that metallic catalysts were more efficient in these specific cases.
- All the materials synthesised in this project have undergone physico-chemical characterisation and analysed for packaging applications. Notably, the thermal properties (DSC and TGA) (all ESRs), the processing properties, such as curing or 3D printing (ESRs 2 and 4) but also the mechanical properties such as tensile strength, elongation at break and viscosity (ESRs 2, 3 and 4), and the barrier properties towards CO2 and O2 (ESR1, 3 and 4). Although the materials prepared are not all reaching the ideal packaging properties, most of the polymers have demonstrated interesting properties: good processability in printing for the polyesters (Claire Morand, ESR 2), high molecular weights and good mechanical and barrier properties for PES (Bige Bati, ESR 4), interesting crystalline behaviour for the triblock based on PLLA and polyether (Flore Kilens, ESR 1), unique thermal properties for the PHAs with etheric bonds (Gabriella Garbonova, ESR 3).
- Finally, in this project, the end-of-life of the different materials was studied. It was demonstrated the feasibility of depolymerising different polymers such as the poly(ethylene succinate) (PES) into cyclic oligomers (ESR 4), and the poly(hydroxy acid) (PHA) into small molecules (ESR 1) which represent for both families of material a crucial step towards chemical recycling. Through hydrolysis biodegradation tests, we demonstrated that polymers synthesised in this project were biodegradable with up to 80% of mass loss after 70 days, notably PES of high molecular weight (ESR 4) and PLLA-based block copolymers (ESR 1).
Considering the management of the project and the different workshops and dissemination activities included in the formation:
- Four talented ESRs have been recruited and they have been enrolled in their respective doctoral programs at the university of the Basque Country (UPV-EHU) (Spain) and the University of Birmingham (UK).
- Three workshops as well as one summer school and one final conference were oragnised on various topics, i.e. Workshop 1: Sustainable packaging materials, Workshop 2: Life cycle assessment, Workshop 3: Oral Communication skills, Summer school: Recycling of plastics + training on IP for R&D, Final conference: "Is a circular economy for plastics possible".
- Virtual meetings with all ESRs and ERs are also regularly organised, every two months, to ensure a tight follow-up of the project.
- ESRs have been encouraged to participate in different outreach activities, and some have participated in different events including science open days, days of the women in science, the realisation of a project video targeted at students focused on the importance of recycling.
NATURE-EID offers a unique balance between the excellency of academic institutions (the University of Birmingham and the University of the Basque Country) and the industrial expertise of an SME (POLYKEY). This training is a chance for researchers in the first stage of their scientific careers to develop strong knowledge and a solid experience in the crucial field of circular economy, eco-design, and biopolymers. Apart from the undeniable scientific acquisitions, this project is a special opportunity to train young scientists about important topics too often undervalued such as sustainability, renewability, or recyclability, to participate in the formation of a new generation of scientists, conscious of the importance of preserving the environment and the challenges that this is supposing for our societies. The ultimate goal of such an initiative is to improve the career prospects of the ESRs as researchers through a Ph.D. experience half in academia and half in a company.