A Step Towards Sustainable Recycling

As composites continue to revolutionize industries—from aerospace to automotive—the critical question remains: What happens to these advanced materials at the end of their life?

With increasing environmental concerns and stricter regulations, sustainable solutions for composite recycling are no longer an option — they are a necessity.

At NPSP, we are addressing this challenge through the Nabasco 80-series, developing bio-based and waste-based Bulk Moulding Compound (BMC) composites. These materials incorporate bio-based thermosetting resins, natural fibres, and recycled fillers, offering a more circular approach to composite production. Thermosets are polymers that undergo an irreversible chemical reaction (curing) when heated or mixed with a hardener, offering superior mechanical properties, UV and fire resistance and a very long-life e time expectance. Thermoplastic polymers offer lower properties, but can be melted and reshaped a number of times without undergoing a permanent chemical change.

The Challenge: Composite Waste Management

Today, most thermoset composite waste ends up in landfills or is incinerated—neither of which is a sustainable long-term solution. However, there are four key approaches to composite recycling:

1) Combustion – Energy recovery but results in CO₂ emissions
2) Mechanical recycling (shredding, milling) – Low energy use and allows reintegration into new products as a filler

3) Chemical recycling (solvolysis, pyrolysis) – Potential for material recovery but often energy and chemicals-intensive
4) Biological recycling – A developing field with promising potential for biodegradation using dedicated micro-organisms

Our first Approach: Mechanical Recycling for BMC

At NPSP, we currently focus on mechanical recycling, also a good first step for chemical and biological recycling, where we grind and mill BMC products to reuse them as fillers in new BMC formulations. In our latest research under the C-Recycle project, we tested both aged (real-time and accelerated weathered) and non-aged BMCs. These materials were shredded, ground, and milled to the correct size, replacing conventional fillers in new BMC doughs at 50% and 100% replacement levels.

What Did We Find?

The preliminary results were interesting and promising:

1) Flexural strength increased by 25-30%
2) Flexural strain increased by 75-90%
3) Flexural modulus decreased by 35-50% (indicating increased toughness)
4) Density decreased by 13-20% (which could be beneficial for lightweight applications)

These findings suggest that incorporating mechanically recycled BMC into new composites not only diverts waste from landfills but can also improve material properties, making this a viable and scalable solution for composite recycling.

What’s Next?

♻ How can we further optimize mechanical recycling to enhance performance and processability?
♻ Can a hybrid approach (combining mechanical and chemical recycling) improve the circularity of composites?
♻ What applications could benefit most from recycled BMC with modified properties?

The journey towards sustainable composite solutions is just beginning, and collaboration is key. If you’re working on composite recycling or have insights on sustainable material strategies, let’s connect!

The research we are doing falls within the C-Recycle project. The Centre for Chemical Recycling Education and Research, is a groundbreaking project focused on the transition from a linear to a circular chemical industry in West-Noord-Brabant. This initiative, funded by the Just Transition Fund (JTF), combines innovative chemical recycling techniques with extensive education and training programs to contribute to a sustainable future.

What are your thoughts on the future of composite recycling? Drop your comments below!