Mechanical and Thermochemical Recycling of Mixed Plastic Waste

The MATTER project aims to evaluate the recycling of mixed (post-consumer) plastic waste streams and to use the generated data to develop a decision supporting framework. Technical and market-based criteria will be developed to support an optimal plastic waste management system. More specifically, the project will focus on the P+ fraction (all plastics packaging waste) of the extended P+MD collection and recycling scheme. Partners from across the whole value chain are included in the project consortium: separation and pretreatment (Indaver and Bulk.ID), mechanical recycling (Borealis and ECO-oh!) and thermochemical recycling (Indaver and Borealis). Organizations such Fost+, Plarebel and OVAM will be closely involved in the project execution. Sustainability analyses will enable the development of a decision-supporting framework.

By generating general knowledge on the recycling of mixed plastic waste and specific knowledge on the optimization of the P+MD recycling scheme, the valorization of the project is twofold. On short-term, the collection of an extra 50.000-150.000 tons of mixed plastic waste is expected for the P+MD scheme, most of which are packaging materials for which not always alternatives to incineration are available today. The results of the MATTER project will therefore be essential for the development of sustainable recycling solutions for this significant amount of waste. In the longer run, the general recycling knowledge can result in extra activities on the processing of other plastic waste fractions.

Project Details
Project type: ICON
Approved on: 18/04/2018
Duration: 30/04/2018 – 30/10/2020
Total budget: €1.669.761
Subsidy: €1.187.783
Project Partners

A recycler’s perspective on the implications of REACH and food contact material (FCM) regulations for the mechanical recycling of FCM plastics
Ellen De Tandt, Cody Demuytere, Elke Van Asbroeck, Hiram Moerman, Nicolas Mys, Gianni Vyncke, Laurens Delva, An Vermeulen, Peter Ragaert, Steven De Meester, Kim Ragaert
Waste Management, Volume 119, 1 January 2021, Pages 315-329 – DOI: 10.1016/j.wasman.2020.10.012

This manuscript provides an overview of the legislative requirements for the use of mechanical recycled plastics in articles placed on the EU market, as seen from the perspective of a plastics recycler. The first part reviews the main principles included in the overarching legislation on Registration, Evaluation, Authorisation and Restrictions of Chemicals (REACH) and to what extent these are applicable for mechanical recyclers of plastics. The interactions between REACH and the Waste Framework Directive (WFD) is discussed, as well as the difficulties for recyclers to comply with certain REACH requirements. In a second part, the focus is moved to the use of recycled plastics as Food Contact Material (FCM). The scope of the different applicable EU FCM regulations is inventorised as well as the key legislative principles involved. A final section is dedicated to the discussion on the authorisation of recycling processes under the FCM regulation and the practical challenges involved for the effective introduction of FCMs containing recycled plastics. Altogether it could be concluded that the complexity of the different legal perspectives, a lack of communication and transparency within the plastic value chain together with technical challenges related to recycling processes have been hindering the effective uptake of recycled plastic FCM (with the exception for bottle PET). The development of targeted solutions across the entire value-chain, taking into account different perspectives in terms of legislation and health protection, economic growth and technical innovations, will be crucial in achieving a circular economy for plastics, including recycled plastics for FCM.

The full publication can be accessed for free at:

Detailed Analysis of the Composition of Selected Plastic Packaging Waste Products and Its Implications for Mechanical and Thermochemical Recycling
Martijn Roosen, Nicolas Mys, Marvin Kusenberg, Pieter Billen, Ann Dumoulin, Jo Dewulf, Kevin M. Van Geem, Kim Ragaert, and Steven De Meester
Environ. Sci. Technol. 2020 – DOI: 10.1021/acs.est.0c03371

Plastic packaging typically consists of a mixture of polymers and contains a whole range of components, such as paper, organic residue, halogens, and metals, which pose problems during recycling. Nevertheless, until today, limited detailed data are available on the full polymer composition of plastic packaging waste taking into account the separable packaging parts present in a certain waste stream, nor on their quantitative levels of (elemental) impurities. This paper therefore presents an unprecedented in-depth analysis of the polymer and elemental composition, including C, H, N, S, O, metals, and halogens, of commonly generated plastic packaging waste streams in European sorting facilities. Various analytical techniques are applied, including Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), polarized optical microscopy, ion chromatography, and inductively coupled plasma optical emission spectrometry (ICP-OES), on more than 100 different plastic packaging products, which are all separated into their different packaging subcomponents (e.g., a bottle into the bottle itself, the cap, and the label). Our results show that certain waste streams consist of mixtures of up to nine different polymers and contain various elements of the periodic table, in particular metals such as Ca, Al, Na, Zn, and Fe and halogens like Cl and F, occurring in concentrations between 1 and 3000 ppm. As discussed in the paper, both polymer and elemental impurities impede in many cases closed-loop recycling and require advanced pretreatment steps, increasing the overall recycling cost.

The full publication can be accessed for free at:

Microstructural Contributions of Different Polyolefins to the Deformation Mechanisms of Their Binary Blends
Astrid Van Belle, Ruben Demets, Nicolas Mys, Karen Van Kets, Jo Dewulf, Kevin Van Geem, Steven De Meester, and Kim Ragaert
Polymers 2020, 12(5), 1171 – DOI: 10.3390/polym12051171

The mixing of polymers, even structurally similar polyolefins, inevitably leads to blend systems with a phase-separated morphology. Fundamentally understanding the changes in mechanical properties and occurring deformation mechanisms of these immiscible polymer blends, is important with respect to potential mechanical recycling. This work focuses on the behavior of binary blends of linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP) under tensile deformation and their related changes in crystallinity and morphology. All of these polymers plastically deform by shear yielding. When unmixed, the high crystalline polyolefins HDPE and PP both exhibit a progressive necking phenomenon. LDPE initiates a local neck before material failure, while LLDPE is characterized by a uniform deformation as well as clear strain hardening. LLDPE/LDPE and LLDPE/PP combinations both exhibit a clear-cut matrix switchover. Polymer blends LLDPE/LDPE, LDPE/HDPE, and LDPE/PP show transition forms with features of composing materials. Combining PP in an HDPE matrix causes a radical switch to brittle behavior.

The full publication can be accessed for free at: