FINAL DEVELOPMENTS
IN THE POLYNSPIRE PROJECT

In this 4th, and final, edition of polynSPIRE newsletter, our consortium is happy to present work and some developments done in the last year of the project. The main objective of our project was to demonstrate at technology readiness level (TRL) 7 a set of innovative, cost-effective and sustainable solutions with an aim to improve the energy and resource efficiency of plastic recycling processes for materials containing at least 80% polymers.

The innovative solutions are:

1.       Innovation A – Chemical recycling:

•  assisted by microwaves

• assisted by smart magnetic materials

2.       Innovation B – Mechanical recycling

•  Vitrimers

• Compatibilising additives

• High energy radiation

3.       Innovation C – Valorisation of plastic residues

Our goal was to compare these different approaches and reveal best technical, environmental and economic fit for the different materials depending on waste source (post-industrial or post-consumer), composition, contaminants or other relevant parameters.

Chemical recycling using microwaves (MW)

The main goal was to develop and test an innovative route for chemical recycling of PA6, PA6.6 and PU based on the integration of microwaves to improve the efficiency of the system.

The active tasks during this last period were carried out in order to achieve the following results:

• Analysis of recycled monomers recovered from PA

• Recycling of PA66/ PA1010

• Optimization of aminolysis recycling process for PUFs

• Detailed engineering of the MW assisted reactor

• Report on semi-industrial scale results using microwaves

Due to the revocation of the demo site manufacturing, lab-scale and semi-industrial scale trials aimed to optimize MW assisted depolymerisation of PA6, PA6.6 and PU have been extended during the third period in order to provide larger samples of monomers to the validating partners.

Lab-scale and semi-industrial scale study and optimization of MW assisted depolymerisation of polyamide and polyurethane based materials:

Subtask: Lab-scale and optimization of MW assisted depolymerisation of polyamide and polyurethane based materials.

Although this task was mostly finalized during previous reporting periods, works continued during this last period to send larger amounts of monomers for validation, and to optimize larger scale isolation and purification of the monomers.

The activities led by The Slovenian National Institute of Chemistry (NIC) were focused on the following activities:

1. Recycling of PA1010 to recover sebacic acid and 1,10-decanediamine for Arkema;

2. Recycling of PA66 to recover adipic acid and 1,6-hexamethylene diamine for Kordsa;

3. Analysis of recycled monomers recovered from PA samples recycled polyols (RPs) recovered from polyurethane foams (PUFs) at CIRCE;

4. Optimization of aminolysis recycling process for PUFs;

5. Development of an HPLC method for determination of end-group functionality of polyether polyols recovered from polyurethane foams by chemical recycling.

    

Subtask: Semi-industrial scale study and optimization of MW assisted depolymerization of PA and PU based materials.

The main objectives of this subtask during the last period were:

• the supply of recycled polyol (RP) from microwave-assisted polyurethane foam (PUF) depolymerization to Repsol and Novamont

• the supply of recovered adipic acid (AA) and hexamethylene diamine (HMDA) monomers from microwave-assisted PA 6,6 depolymerization to Kordsa and Novamont

Improvement of recycled materials by means of advanced techniques

Development and optimization of vitrimer formulations for enhancing recycled materials:

Although the task was mostly finalized in a previous periods, focusing on synthesis and preparation of all the different tests within the last period, activities continued on optimization of the reaction conditions and catalyst concentration used.

Demonstration of optimized recycled materials in a pilot line (simulated operational environment):

The activities carried out were completely focused on the testing and understanding of the different materials behaviour at preindustrial scale and in the injection moulding of 2D parts.

Valorisation of plastic waste in the Steel Sector

Long term industrial trials:

This task was focused on the industrial trials of utilization of polymers grains in the steel sector as partial substitute of fossil coal. These trials started in month 30 and has been extended up to the end of the project. About 2.000 of tests were performed without recording variations in the main process parameters.

Please have a look at polynSPIRE newsletter #3 or our video to get more insights on this work package.

Validation of recycled products

Polyamide monomers validation at industrial level:

 During this period, three types of polyamides were studied in this task:

• Long chain polyamides - ARKEMA

  Arkema received only small-scale samples throughout the project, of depolymerized polyamides that it provided (PA11, PA12, PA10.10). The monomers produced by NIC were analyzed in Arkema, and whenever possible they were repolymerized.

   

• PØ  A66 - KORDSA

  Kordsa received small amount of recycled adipic acid and hexamethylene diamine for the project. Depolymerization and purification processes of PA66 were done by NIC and Circe. Recycled monomers (adipic acid and hexamethylene diamine) were analysed before polymerization process in order to check the quality of the monomers.

Validation of monomers as raw materials for biobased polymers:

During this last period, the main objectives were:

• To define the optimal ratio of recycled adipic acid vs virgin adipic acid allowing to obtain bio-polyesters with properties similar to reference;

• To evaluate the use of the PU recycled polyol from NIC in starch-based bioplastic composition;

• To evaluate the use of the PU recycled polyol from Circe in bio-polyester preparation to increase its solubility.

LCA/LCC/TE analysis of Demo Cases

New technologies characterisation and evaluation through LCA/LCC/TE:

The main objective of this task was to perform LCA, LCC and TE Analysis of the different value chains involved in polynSPIRE project and compare the results with the baseline in order to measure the impacts achieved by the project innovations from an environmental and economic point of view. The different innovation addressed in the project have been analysed:

• Chemical recycling of Polyamides and Polyurethane by using microwave assisted technology as well as smart magnetic catalysts;

• Mechanical recycling of Polyamides and Polyurethane by using vitrimers and high energy irradiation technologies;

• Biopolymer and bioplastic production using the recycled adipic acid as raw material;

• Valorisation of low-grade plastic waste in the steel sector.

Validation of monomers as raw materials for biobased polymers:

During this last period, the main objectives were:

• To define the optimal ratio of recycled adipic acid vs virgin adipic acid allowing to obtain bio-polyesters with properties similar to reference;

• To evaluate the use of the PU recycled polyol from NIC in starch-based bioplastic composition;

• To evaluate the use of the PU recycled polyol from Circe in bio-polyester preparation to increase its solubility.

polynSPIRE Exploitation and Workshop Event

Relevant activity that was carried out for this third period was the exploitation workshop held in Mestre, Italy on November 8, 2022. Other projects and companies involved in the plastic and recycling sectors joined the event. An excellent feedback was obtained from the attendees who were able to take advantage of the event to learn more about the project, enhance their possibilities of exploiting their results and network. Read more about the event here.

Last results in open access publications

In the last stage of the project the most interesting and advanced results were achieved and some of them were published in prominent journals. The followings are highlighted:

Chemical Recycling of Flexible Polyurethane Foams by Aminolysis to Recover High-Quality Polyols

Repository Link: https://doi.org/10.1021/acssuschemeng.3c02311

A Novel Combined Design of Vessel and Resonant Cavity for Microwave Multi-Frequency Heating Chemical Reactor Using Antennas as Applicators

Repository Link: https://doi.org/10.1109/ACCESS.2023.3268538

Effect of Gamma Radiation on the Processability of New and Recycled PA-6 Polymers

Repository Link: https://doi.org/10.3390/polym15030613

Find all open access publications, technical articles and peer-reviewed publications generated via polynSPIRE project here.