On-going funded research projects

The PolymeReEng group currently coordinates or participates in the following projects:

• Wood2Wood: A wood-to-wood cascade upcycling valorisation approach
• EnZyReMix: Chemoenzymatic recycling of mixed plastic waste
• PRecycling: Plastics recycling from and for home appliances, toys and textiles
• PRIORITY: COST action CA20101 - Plastics monitoring detection remediation recovery

Completed research projects

The PolymeReEng group has coordinated or participated in the following projects:

• HYSELFDROPS: Hybrid thermal spray coatings with self-lubricant properties for wear protection of Internal Combustion Engine piston rings
• FUVPP: Flame-retarded and UV-Protected Polypropylene HFLS Pipes
• SucciVitr: Comprehending and controlling the dynamics of the adaptable network in biobased vitrimers
• BioICEP: Bio innovation of a circular economy for plastics
• IKY- State Scholarships Foundation programme: Scholarships for Doctoral Thesis
• SUCCIPACK: Development of active, intelligent and sustainable food packaging using polybutylene succinate
• ANAPLASI: Production of High Quality Recycled Polypropylene and its Use for Fiber and Packaging Material Applications

Wood2Wood: A Wood-to-Wood Cascade Upcycling Valorization Approach (Horizon Europe, GA 101138789), 01/01/2023 - 31/12/2027. Visit the Project Site.

Wood-to-Wood is a Horizon Europe Funded Project composed of 25 partners from all over Europe whose aim is to transform waste management with cross-sector solutions that span from sensing to sorting and from materials to products.

Wood, a renewable resource cherished for its beauty, durability, and versatility, lies at the heart of some of the most significant industries across Europe. Yet, the linear “take-make-use-dispose” model that has dominated these sectors for centuries now poses a severe threat to our forests, ecosystems, and climate. The rate at which we consume wood, coupled with inefficient recycling and reuse practices, has led to devastating environmental impacts, including deforestation, loss of biodiversity, and increased carbon emissions.

Wood2wood, as a new circularity project for wood, seeks to revolutionise the wood industry by promoting innovation and collaboration to establish a sustainable circular economy. Through the principles of reduce, reuse, and recycle, the project aims to repurpose secondary wood materials, reduce waste, and shrink the environmental impact of construction and furniture industries.

Wood2Wood focuses on developing pollutant-free wood products, utilising wood waste for bio-composite materials, biopolymer production, and facilitating nutrient recovery. The project is a call to action for industry, policymakers, and consumers alike to rethink how we use our precious wood resources and to embrace the circular economy as the path forward for a sustainable future.

PolymeReEng will combine recovered lignocellulose-based materials from wood waste with thermoplastic matrices, to deliver composite compounds that will serve as low-cost sustainable recycled material aiming at construction applications. The group will also participate in a study on glass recycling thresholds on post-consumer flow.

EnZyReMix: Chemoenzymatic Recycling of Mixed Plastic Waste, 01/02/2024 - 31/12/2025.

The project is implemented in the framework of H.F.R.I call "Basic research Financing (Horizontal support of all Sciences)" under the National Recovery and Resilience Plan "Greece 2.0" funded by the European Union – NextGenerationEU (H.F.R.I. Project Number: 15024).

The central aim of EnZyReMix is to deliver the basic research and technology to enable a paradigm step in the frame of a circular plastics economy: where, through developing innovative methodologies for mixed plastics waste, depolymerised monomers and oligomers can be chemically and biologically re-polymerized from post-consumer materials. This proof-of-concept methodology will lead to a breakthrough in delivering regenerated biomaterials, such as polyhydroxy-alkanoates and nanocellulose, which are fully sustainable and can have equivalent properties to virgin fossil-based materials.

PolymeReEng main role in EnZyReMix will be to construct the structure-properties relationships for the target polyesters that would influence enzymes specificity and to develop the appropriate upcycling routes such as repolymerization via SSP to recycle the enzymatically degraded/separated polyesters.

PRecycling: Plastics Recycling from and for home appliances, toys and textile (Horizon Europe, GA 101058670), 01/04/2022 - 31/03/2026. Visit the Project Site.

PRecycling is a Horizon Europe Funded Project composed of 17 partners from all over Europe whose aim is to boost recycling of consumer products.

As it is addressed by the European Plastics Strategy (European Green Deal & Circular Economy Action Plan 2.0), new methods to reliably calculate, verify and report the recycled content in products needs to be developed, boosting the increase of recycled content in everyday products against the use of virgin materials. Nevertheless, measuring the recycled content in products is complex, requiring product tracing to the production source and establishing, apart from this recycled content, the composition of the recyclate, their mechanical properties, and the screening of substances of concern.

PRecycling aims to develop an easy-to use methodology for sorting, sampling, tracing and recycling plastic waste streams (PWS), including detection and separation of legacy additives, along with standard analysis procedures for both plastics waste materials and recyclates (secondary raw materials). These will allow production of consistently high quality, safe-to-use recyclates based on their degradation degree and added-value products with predicted lifetime. Smart tracing via digital systems will be developed in parallel, to ensure the quality and safety of reused materials, targeting to a sustainable, transparent and functional Circular Economy Model in the plastics and recycling market. The environmental and financial viability of PRecycling solutions will be assessed throughout life cycle and cost analysis in order to reach competitive prices of recycled products. The above will be demonstrated producing (i) home appliances components and (ii) toys/learning resources and (iii) 100 % recycled textiles, starting from the same sector recyclates and different European regions. Demonstration activities will also serve as part of a community awareness initiative, showing that ‘from waste to product’ transformation is scalable, replicable, potentially commercially viable and most importantly, safe to use, both within the same and new supply chains and products.

PolymeReEng aspiration is to develop appropriate strategies for polymer reprocessing and upcycling depending on the degradation extent of the waste materials. Three main strategies will be considered: a) restabilization, b) chain extension via reactive extrusion, and c) solid state polymerization (SSP).

PRIORITY: COST action CA20101 - Plastics monitoring detection remediation recovery, 19/10/2021- 18/10/2025. Visit the Project Site.

PRIORITY is a science and technology research network focused on developing, implementing, and consolidating strategies to tackle the global challenges of micro- and nanoplastics in the environment. This COST Action combines expertise in chemistry, physics, life science, engineering, standards, economy, and law. The network creates a robust infrastructure for scientific communication, exchange, and collaboration to foster new research activities and citizen science. PRIORITY aims to enhance the technical standards for sampling and analysis of micro- and nanoplastics in the environment, to develop a more reliable assessment of exposure and biological effects, and to advance activities in terms of environmental remediation and recovery. The Action will support the harmonization of European regulation associated with microplastics. It will assist the European Commission in critical aspects of environmental and ecosystems protection, food safety, and life science.

HYSELFDROPS: Hybrid thermal spray coatings with self-lubricant properties for wear protection of Internal Combustion Engine piston rings. Co‐financed by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH – CREATE - INNOVATE (project code:T2EDK-01883) 2020-2023. Visit the Project Site (in greek).

The self-lubricating coatings, used lately in diesel engines, deposited on complex shaped parts such as piston rings have significant contribution in the reduction of the total engine energy losses due to wear and abrasion. This reduction even in small percentages of the order of 1% is of high importance since it contributes to the reduction of fuel consumption and consequently in the operating and maintenance costs. These coatings present the additional advantage of avoiding toxic chemical substances release to the environment unlike liquid lubricants. This research proposal aims at the development of innovative techniques towards the deposition of hybrid self-lubricating coatings using thermal spray techniques. This way, the diesel engine piston rings will be significantly protected against wear and thus offer reduced energy losses during operation. The idea is the liquid lubricant microencapsulation in polymer capsules using in situ polymerization and their homogeneous distribution in an anti-wear thermally sprayed coating. This unique procedure will be performed using combined thermal spray techniques, Liquid Plasma Spray for the capsules deposition and simultaneously Atmospheric Plasma Spray for the ceramic/metallic anti-wear matrix material deposition. Furthermore, the development of powder mixtures, ceramic/metallic matrix with carbon nano-tubes (CNT's) to be used as Atmospheric Plasma Spray feedstock material will be investigated. The proposed innovation in HYSELFDROPS lies in the combined self lubricating and anti-wear thermally sprayed coatings that will be developed which will contribute to the significant energy loss reduction of diesel engines for marine applications. The expected mechanism is the release of the liquid lubricant through capsules break up during operation while the anti-wear coating degrades. This will significantly increase the piston ring service life. Furthermore, scale up activities in terms of feedstock materials production as well as thermally sprayed real parts (piston rings) for field testing will be performed. The coated piston rings will be implemented in a three cylinder Yanmar 3YM30 diesel engine producing 21.3 kW maximum power at 3200 rpm for marine applications.

FUVPP: Flame-retarded and UV-Protected Polypropylene HFLS Pipes, Co‐financed by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH – CREATE - INNOVATE (project code:T2EDK-01466) 2020-2023. (Project Coordination: PolymeReEng Group). Visit the Project Site (in greek).

The project aims to develop flame retarded polypropylene (PP) of low environmental impact and high resistance to ageing and use it for the production of novel piping systems for cables protection in superfluous installations.

The majority of fatalities in fire incidents is caused from poisoning and entrapment of victims, while most of the fire incidents are due to electricity. The use of halogen free and low smoke (HFLS) plastic pipes for cables systems contributes to the protection of human lives, the environment and equipment in the case of fire, as HFLS plastics do not produce toxic or corrosive gases nor dense smoke as halogenated materials do. For this reason, the new regulation for fire protection of buildings (Presidential Decree 41/2018) imposes the use of HFLS cables in various cases of buildings, and therefore indirectly imposes also the use of plastic pipes of the same type.

Double layer corrugated plastic pipes exhibit a two-fold advantage since the smoot inner layer allows installation of the cables with low friction, while the corrugated outer layer contributes to flexibility and materials savings compared to conventional pipes with solid layers. The production process of double layer corrugated HFLS pipes requires the use of polyolefins (PP) as raw materials, since it is most compatible with the specific processing technique. However, for polyolefins to be used in this application, it is necessary to modify them with flame retardants (FRs), as pristine polyolefins are highly flammable. Accordingly, the first objective of FUV-PP is to develop optimized FR formulations for the pertinent processing and application, so as to obtain HFLS material without adversely affecting its processability and final properties.

Particularly for outdoors applications, such as superfluous electrical installations, a further need is to develop polymeric products resistant to ageing. The use of stabilized polymers containing FRs is limited in this case, firstly because the FR additives may reduce the photooxidative stability of the polymer matrix and secondly because FRs and UV/heat stabilizers have shown to exhibit antagonistic action. As a consequence, polymeric materials containing additives of both categories often present lower stability during prolonged exposure to UV irradiation compared to their photo-stabilized counterparts with no FR. Therefore, it becomes evident that a need exists to develop environment and human-friendly as well as resistant to ageing FR formulations for polyolefins, in particular for PP, used in cables protective pipes where both flame retardancy and resistance to ageing are required. In order to respond to the above challenges, FUV-PP proposes the use of environment friendly additives for the production of flame retarded PP with resistance to ageing. First, combinations of halogen free FRs and/or halogenated FRs in appropriately low concentrations will be designed and developed, allowing the production of HFLS PP-based double layer corrugated pipes. Further, combined systems of FRs and UV/heat stabilizers will be developed to simultaneously achieve flame retardancy and resistance to ageing (no reduction of initial properties after 2000 h artificial weathering). It is highlighted that research on the simultaneous use of FRs and UV/heat stabilizers is limited. The proposed approach will cover the existent gap for applications necessitating both flame retardance and resistance to ageing. In the frame of the project, the new materials will be used in a totally new and patented production process that allows producing double layer corrugated PP pipes of very low external diameters (16-32 mm). All materials and products developed in FUV-PP will be characterized in terms of FR properties, UV resistance and physicomechanical performance using standard test methods.

SucciVitr: Comprehending and controlling the dynamics of the adaptable network in biobased vitrimers (PEVE0050). Basic Research Programme NTUA. PEVE 2020 NTUA, 2020-2023.

Polymers are classically divided into thermoplastics and thermosets, while the invention of smart, recyclable and healable thermoset polymers is in high demand. Vitrimers emerge as a viable solution bridging the gap between thermosets and thermoplastics; they possess a dynamic crosslinked structure which upon heating allows rapid chemical exchange reactions and network rearrangement, enabling deformation, healing and reprocessing. For most applications, vitrimers behave as classical thermosets, taking advantage of chemical crosslinks benefits eg insolubility, high melt strength, good barrier properties. Only under heating does the rearrangement of the dynamic network become significant, leading to controlled macroscopic flow like viscoelastic fluids, without losing network integrity.

The mechanism and kinetics of these associative exchange reactions are responsible for the dynamic nature of the crosslinked macromolecular structures and until now are considerably neglected, as scientific literature focuses mainly on fine-tuning vitrimers properties and optimization of their scaled-up production. On the other hand, compared to their fossil counterparts, biobased polymers offer significant benefits with regard to environmental performance, especially with regard to global warming potential.

SucciVitr research activities include a vigorous kinetics study of the transesterification reactions in a model biobased polymer, i.e. polybutylene succinate, which will attempt to integrate the effect of varying parameters (reaction temperature and time, reacting species concentrations) in kinetics constants, such as the apparent reaction rate constant and activation energy. The derived kinetics parameters will be correlated to the mechanisms of the associative exchange reactions that endow vitrimers their dynamic rheological behavior determining also the rate-controlling steps and variables.

BioICEP: Bio innovation of a circular economy for plastics (GA 870292), Horizon 2020, 2020-2024. Visit the Project Site.

The BioICEP consortium is a pan European-Chinese collaboration formed to reduce the burden of plastic waste in the environment. The countries have been selected to represent different mixed plastic pollution environments, with specific partners chosen which have the expertise and facilities to carry out the necessary technical innovations. A number of innovative booster technologies are at the core of this solution accentuating, expediting, and augmenting mixed plastics degradation to levels far in excess of those current achievable.

Our approach is a triple-action depolymerisation system where mixed plastic waste will be broken down in three consecutive processes: 1) mechano-biochemical disintegration processes, including a new proprietary sonic-green-chemical technology to reduce the molecular weight (MW) of the base polymer making it amenable to biodegradation; 2) biocatalytic digestion, with enzymes enhanced through a range of innovative techniques including accelerated screening utilising novel fluorescent sensors coupled with directed evolution; and 3) microbial consortia developed from best in class single microbial strains, which when combined lead to highly efficient degradation of mixed plastic waste streams. The outputs from this degradation process will be used as building blocks for new polymers or other bioproducts to enable a new plastic waste-based circular economy.

State Scholarships Foundation: Operational Programme “Human Resources Development, Education and Lifelong Learning” in the context of the Act “Enhancing Human Resources Research Potential by undertaking a Doctoral Research” Sub-action 2: IKY Scholarship Programme for PhD candidates in the Greek Universities. Visit the Foundation Site (in Greek).

• Christina Gountela. Project title: “Development of environmentally friendly polymerization processes” (05/2022-09/2023).
• Christos Zotiadis, Project tile: “Studying polymerization processes for the fabrication of polymeric microcapsules” (05/2022-09/2023).

SUCCIPACK: Development of active, intelligent and sustainable food packaging using polybutylene succinate (FP7-KBBE-2011-5), 01/2012 - 01/2015.

Food packaging plays a crucial role in preserving the quality and safety of food during distribution and storage from farm to fork, but contributes to the generation of waste. The European food packaging industry needs sustainable food packaging materials in combination with flexible packaging technologies to stay competitive on the global market. The new functional (active and intelligent), sustainable and consumer-oriented solutions have to ensure the safety and quality of food, reduce food losses, and reduce the environmental impact of food packaging. The industrial applicability of the research has to be demonstrated together with a positive impact on the environment via a Life Cycle Assessment of the whole value chain carried out according to the International Reference Life Cycle Data System (ILCD) Handbook.

ANAPLASI: Production of High Quality Recycled Polypropylene and its Use for Fiber and Packaging Material Applications (General Secretariat for Research and Technology, Program SYNERGASIA 2009), 06/2012 - 06/2015.

The concept of the project lays in the development of economical and environment-friendly polypropylene (PP) recycling methods, in order to obtain recycled plastic of high quality. This will subsequently be used as raw material for the production of new end-products either in closed or in open loop recycling systems. Industrial scrap constitutes the most appropriate type of plastic waste to be recycled. The recycling method that will be applied in the frame of the project is the so-called mechanical recycling, which involves granulating, separating of foreign matter, dehydration and, finally, remelting and remolding the plastic waste, by adding the proper stabilizers (remelting/restabilization) or reactants (reactive extrusion) to lead to high quality ending products. The aim is to use the recycled polypropylene in equal or even higher-demanding applications compared to those of the corresponding virgin material.