PhD position on Closed loop recycling of flexible film-effects of small-scale contaminants

Updated: 3 months ago
Deadline: 20 Jul 2022

PhD position on Closed loop recycling of flexible film-effects of small-scale contaminants
PhD position on Closed loop recycling of flexible film-effects of small-scale contaminants
Published Deadline Location
21 Jun 20 Jul Maastricht

Job description

Closed loop (film to film) recycling of PE-based flexible film is made challenging by a significant amount of non-PE that inevitably comes into the recycling stream. Other polymer types like PET, PA are part of multilayer structures for example. The other polymer types are considered large-scale contaminants (several percent) and their effect are being understood in ongoing research. The challenge is now shifted to understanding the effects of smaller-scale contaminants, which are present it much lower amounts. Examples include labels, adhesives, inks and barrier layers.

One focus of such small-scale contaminants is adhesives, which are often PU-based. There is a trend to change multilayer structures (like PET-PE) to “full PE” structures for better recyclability. However, this still involves different layers of PE, for example a MDO (machine direction oriented) HDPE for stiffness and a LDPE for sealability. In production, these layers are laminated together with an adhesive. This adhesive is typically PU based. It is our objective to identify the recyclability of such adhesives, meaning what effects do they have on the recycling of these structures? And what is the relation between the chemical structure of the adhesive and the quality of recycling. The PhD student is not responsible for making the new chemical formulations of the adhesive (we do this with a company, global market leader), but for the assessment of recyclability and the fundamental understanding of how all these materials interact together.

As a baseline, a PU adhesive built on standard building block (one adhesive ref) and PU based on new building block (one adhesive ref) will be investigated. Objective of this step is to understand the influence of the adhesive (chemical functions, molecular weight, polymer structure) in the PE recycling stream (miscibility, number and size of gels, rheology, film mechanical properties…). The further research will keep the same focus and will allow to dig in adhesive formulation. We will characterize the polyester backbone used in the PU adhesive synthesis as well as the PU backbone itself and will check their properties in the PE stream.

What are the key parameters, in the adhesive formula, which could support a better performance vs PO recycling stream: hydroxyl index, NCO/OH ratio, molecular weight, Mw distribution, …? The expected conclusion is to get a clear mapping about raw material-adhesive structure and formula vs the PO recycling stream.

The PhD research will not be limited to just these adhesives (but will keep focus on minority components in PE film recycling), but for the sake of the required research plan, may be considered as such.

The topic is highly relevant to industry and part of several projects with industrial partners. The results will also be coupled in to the group's larger work on Recycling Quality (RQ). This PhD topic is meant to go deep into the polymer science, to then be translated to the more applied nature of the RQ work (not necessarily by you).

  • max. 38 hours per week
  • €2541—€3247 per month
  • Maastricht View on Google Maps

Maastricht University (UM)

  • You hold a MSc in one of these fields: Polymer Engineering, Polymer Science, Chemical Engineering, Materials Science – specialized polymers. Candidates without one of these degrees will not be considered.
  • Good knowledge of structure-property-processing relations in polymers and polymer characterization methods
  • While we are not looking for a chemist, you have sufficient grasp of chemistry o understand how different adhesive chemistries will affect compatibilities in recycling
  • Experience with polymer processing machinery is a bonus but not required
  • Dedicated to sustainability. Contributing to the circularity of plastics is part of your personal ambition.


Conditions of employment
  • We offer a rewarding career at a young university in the heart of Europe, with a distinct global perspective and a strong focus on innovative research and education; You’ll work in an international interdisciplinary team with cutting-edge equipment and a leading academic position in the field of plastics recycling;
  • The terms of employment of Maastricht University are set out in the Collective Labour Agreement of Dutch Universities (CAO-NU), supplemented with local UM provisions. More  information on the CAO-NU can be found on ;
  • We offer a full-time employment contract for a period of 1 year, which will be extended for another 3 years after positive evaluation. Remuneration will be according to standard salary levels for PhD candidates starting with a salary of € 2.541,- with a yearly growth to € 3.247,- gross a month (based on a full-time appointment of 38 hours per week). Each year the standard salary is supplemented with a holiday allowance of 8% and an end-of-year bonus of 8.3% of the yearly gross income.
  • We offer an attractive package of fringe benefits such as reduction on collective health insurance, substantial leave arrangements, optional model for designing a personalised benefits package and application for attractive fiscal arrangements for employees from abroad.

Maastricht University

Located in the heart of Europe, UM is the most international university in the Netherlands with half of our students and one third of academic staff coming from abroad. In total, UM has around  22.000 students and almost 5.000 employees and represents 100 different nationalities. Maastricht University is a stimulating environment where research and teaching are complementary, where innovation is our focus and where talent can flourish. Research is characterized by a multidisciplinary, thematic, and collaborative approach, and with education, forms the core of UM.

Eager to learn more? Take our virtual campus tour  to get a sense of our university culture, the city of Maastricht, and your potential working environment.

Faculty of Science and Engineering
The Faculty of Science and Engineering (FSE) is home to several outstanding departments and institutions covering education and research in Science, Technology, Engineering and Mathematics (STEM) as well as the liberal arts and sciences.

Department of Circular Chemical Engineering; Circular Plastics research group

The Circular Plastics research group is part of the newly created Department of Circular Chemical Engineering in the Faculty of Science and Engineering at Maastricht University. Our research group is uniquely situated in the heart of the Dutch chemical industry at the Brightlands Chemelot campus, 20 km north of Maastricht. Our strong links with industry give excellent opportunity to build collaborations and partnerships, giving good prospects for a future career in industry. Our group has a strong expertise in plastics recycling, polymer processing, characterization and multi-scale structure-property-processing relationships in plastics. The chair is widely recognized as a European leader in plastics recycling research.  We have excellent international connections with esteemed laboratories, and we therefore expect the applicant will have the opportunity to work abroad during their PhD.

To learn more about our department, please visit our website:

Additional information

In case you are interested you can apply by electronically submitting an application letter, a full curriculum vitae and a grade list to   

We also ask applicants to prepare a short research proposal for the intended PhD. This proposal is meant to show us your excellent grasp on the science required to conduct the PhD and as such:

  • Describes how you think all the components interact (or not) at macromolecular level and what this means for the film blowing process and the resulting film quality
  • Stays away from overly long generic introductions, explaining the plastic waste problem or the importance of recycling.
  • Does not list in excessive detail which polymer you would mix with which adhesive at different percentages and then subject to exactly which test under which parameters. That is detailed experimental planning and has no place in the first proposal.
  • Does describe which information you would get from which experiments and in this, goes well beyond the basic. E.g. do not just tell us that DSC will give you Tm and crystallinity, but how you expect these results to give you insight in what is happening in the polymer material and why it is relevant.
  • Is 2-4 pages long, excl. references

Selected candidates will be invited to make a presentation based on their research proposal.

Please use the following format for your documents:





More information on this vacancy can be obtained from Prof. Dr. Kim Ragaert ( )

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You can send your application to this e-mail:

Don't forget to mention AcademicTransfer and the job number: AT2022.275 in your letter.

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