PhD Candidate in Rheology of Diluted Polymer Melts

Welcome to Maastricht University! 
The Circular Plastics research group at Maastricht University is looking for a highly motivated PhD candidate to join our team in developing predictive rheological insights into the processing behavior of polymer melts under dilution.

PhD Candidate in Rheology of Diluted Polymer Melts 

• Our goal: you will investigate how dilution affects polymer melt viscosity and develop physically grounded models that connect thermodynamics, rheology, and processing. Your work will generate fundamental insights that improve the predictability and efficiency of extrusion and recycling technologies.
• Your colleagues: you will work in the Circular Plastics team in the Faculty of Science and Engineering located at Brightlands Chemelot Campus in Geleen. You will become part of a young international research group, specialized in the mechanical recycling of plastics with a strong polymer science background. You will be guided by assistant professor Dr. Ali Gooneie and supported by other experts in the Circular Plastics group on this exciting topic. This project will be done in collaboration with Prof. Steven De Meester (Ghent University, Belgium) and Prof. Nino Grizzuti (University of Naples, Italy). You will have the opportunity to embed your work in an international collaboration.

We are seeking a motivated PhD candidate to advance the fundamental understanding of viscosity reduction in polymer–diluent systems. While the addition of low-molecular-weight diluents is widely used to improve processability in extrusion and recycling, current modeling approaches remain inadequate for complex, real-world materials. In particular, classical thermodynamic and free-volume-based models fail to quantitatively predict viscosity reduction, especially under processing conditions far above the glass transition temperature. At the same time, their application to thermoplastics is limited by unknown material characteristics such as molecular weight distribution, branching, and compositional heterogeneity. This project aims to develop a physically grounded framework that links thermodynamics, rheology, and polymer processing, with a focus on understanding and modeling viscosity reduction in polyolefin-based systems with conventional liquid diluents. You will work in close collaboration with partners to generate fundamental insights with direct relevance for extrusion and recycling technologies. 

What you will do

In this project, your responsibilities will entail: 

• Design and perform experiments using extrusion equipment, as well as off-line and in-line rheometry to characterize viscosity reduction in polymer–diluent systems.
• Investigate the physical mechanisms governing viscosity reduction, with particular emphasis on the limitations of classical free-volume theory.
• Develop and refine physically based rheological models (e.g., time–concentration superposition, thermodynamic approaches) for polymer–diluent mixtures.
• Study the influence of molecular architecture (e.g., molecular weight distribution, branching) on rheological behavior.
• Develop strategies to approximate or infer relevant material parameters of recycled polymers from experimental data.
• Extend modeling approaches to complex and multicomponent recycling streams.
• Present your work at international conferences and project meetings, and publish results in peer-reviewed scientific journals.
• Contribute to teaching activities and supervise MSc/BSc students.

Are you ready to set the course for the years ahead? Then we’d love to meet you. 

What you bring 
We’re not looking for checkboxes; we’re interested in who you are and what you bring. Do you recognize yourself in this?

You are a self-motivated, open-minded and hands-on individual with strong communication and interpersonal skills, capable of working both independently and within an interdisciplinary team, and interested in an international research environment.

Furthermore, the requisites for this position are:  

• MSc degree in Chemical Engineering, Polymer Science, Materials Science, or a related field. 
• Strong background in polymer rheology and physics, demonstrated for example through relevant university coursework, publications, conference presentations, and/or a thesis conducted within a recognized research group.
• Experience with experimental techniques (e.g., rheometry, extrusion) is highly desirable.
• Solid understanding of transport phenomena or continuum mechanics is an advantage,  demonstrated for example through relevant university coursework, publications, conference presentations, and/or a thesis conducted within a recognized research group.
• Excellent communication skills in English.  

What we offer 
At Maastricht University, you’ll work in an international, open, and engaged environment. We offer:

• A 12-month contract of 1FTE with the prospect of a three-year extension, based on mutual satisfaction.
• A gross monthly salary between € 3.059 to € 3.881 (based on full-time employment of 38 hours per week). 8% holiday allowance and an 8.3% year-end bonus.
• 29 vacation days (based on full-time), four additional days off (Carnival Monday and Tuesday, Good Friday, and Liberation Day), and the possibility to accrue up to 12 extra days through compensation hours.
• Flexible working hours, a home office allowance, and the option to work from home.
• Freedom and space to shape your work independently and develop your ideas.
• A close-knit community of colleagues to collaborate and grow with.
• A solid pension plan via ABP, company fitness schemes, and access to various university sports facilities.
• An inspiring work environment in the heart of Europe. 

About the Faculty of Science and Engineering (FSE)
At the Faculty of Science and Engineering (FSE), we focus on themes such as circularity and sustainability, future farming, digitisation and (scientific) instrument development.  FSE's leading projects, like the Einstein Telescope Pathfinder, are sure to grab anyone's attention.  The faculty is a vibrant hub of education and research in Science, Technology, Engineering, and Mathematics (STEM) and Liberal Arts and Sciences (LAS).  At FSE, over 450 staff members and 3700 students gather to explore exciting interdisciplinary research and educational programmes. Feel welcome, be part of our team and put your brilliant mind to work!  

FSE at the Brightlands Campuses 
Maastricht, Sittard-Geleen, Heerlen, and Venlo, the home of four creative Brightlands campuses, are bustling with 30,000 entrepreneurs, researchers, and students working diligently to solve global challenges. The Faculty of Science and Engineering is active on all four Brightlands campuses, and this is where our impact reaches its peak. To give you an idea of what is happening at each campus: Sittard-Geleen is home to the largest chemical site in the Euregion, while Venlo is a large hub for agri-food innovation. Maastricht is the site of the Health Campus, and Heerlen is the place to be for Smart Services. 

Interested? 
Want to know more about this position or what it’s like to do a PhD in Rheology of Diluted Polymer Melts? Reach out to Ali Gooneie at Ali.Gooneie@maastrichtuniversity.nl. The position will remain open until a suitable candidate has been found.

Please upload your CV, motivation letter, grade list, and if applicable an publication list. Note that incomplete applications will not be considered.

Apply now via the button below. We look forward to getting to know you!

About Maastricht University
At Maastricht University, we collaboratively seek solutions to help move the world forward. We do this with 23,300 students and 5,400 employees across 5 regional locations, 6 faculties, and more than 70 research institutes. We encourage you to push boundaries and discover new opportunities for yourself and the world around you. Together, we can find the answers for tomorrow. 

At Maastricht University, we prefer to contact potential candidates directly. We therefore kindly ask that no agencies or intermediaries submit offers or approaches.

Maastricht University is committed to promoting and nurturing a diverse and inclusive community. We believe that diversity in our staff and student population contributes to the quality of research and education at UM, and strive to enable this through inclusive policies and innovative projects led by teams of staff and students. We encourage you to apply for this position.