Within the r-LightBioCom project, researchers are developing new resin systems for advanced composite materials made by replacing conventional petrochemical additives with environmentally friendly alternatives. A central focus lies on lignin, a natural component of wood, which can be transformed into functional nanoparticles. By adding these particles to resins, the project aims to improve mechanical strength, thermal stability and fire resistance while creating composites that are lighter, safer and more sustainable. A recent research exchange between three project partners in these fields demonstrated how collaboration can directly improve scientific outcomes in the r-LightBioCom project.
In November 2025, Bernardo Libonatti, a researcher from Universitat Politècnica de Catalunya (UPC), visited the laboratories of the Hochschule Kaiserslautern (University for Applied Sciences; HSKL) and Leibniz-Institut für Verbundwerkstoffe (IVW) to work on improving the formulation and processing of functionalised lignin nanoparticles for r-LightBioCom’s composite resin systems.
UPC is responsible for producing epoxidised and aminated lignin nanoparticles used in r-LightBioCom, while IVW and HSKL focus on incorporating these nano-additives into bio-based resin systems and evaluating their performance in composite applications. During previous project activities, it became clear that the nanoparticles, although promising, were difficult to disperse evenly in the resin matrix. Their particle size, surface chemistry and compatibility with resin systems directly affected mixing quality, curing behaviour and overall mechanical performance. To address this challenge, the partners agreed that hands-on collaboration was necessary to better understand the interaction between particle manufacturing and composite processing.
Enhancing Vitrimers with Bio-based Lignin Nanoparticles – Research Visit at Hochschule Kaiserslautern
Bernardo’s stay at HSKL from November 3-7, 2025 centred on working with newly developed lignin nanoparticles and examining how they behave when added to a special type of recyclable plastic known as a vitrimer. Together with HSKL researchers Laura Riehm and Sabine Lehning, the goal was to determine whether these natural, bio-based particles could enhance the material’s mechanical strength, thermal stability, and its ability to be reshaped and reused.
Over the course of the week, the team produced several different material samples, each containing varying amounts of these functionalised nanoparticles. Before mixing them into the resin, the particles were further ground to make them even finer, which helps to produce an even blend. Afterwards, they were dispersed in the resin using ultrasonic vibrations, a common method to ensure a smooth and uniform mixture.
Once the vitrimer samples were prepared, the researchers tested how well they could be reprocessed by heating and pressing them, simulating real recycling conditions. The materials then underwent a range of laboratory tests to better understand their behaviour, including assessments of the materials’ thermal behaviour, mechanical response to tension and bending, surface hardness, and impact resistance. Together, these experiments gave a comprehensive understanding of how the lignin nanoparticles behave within the vitrimer system and provided useful insights to guide future optimisations.
Results and Outlook:
The first results from the experiments showed that adding the lignin nanoparticles did not noticeably change the heat resistance or mechanical strength of the vitrimer material. Importantly, the particles also caused no negative effects. At the same time, the results suggested that achieving a more even distribution of the nanoparticles could lead to noticeable improvements in future tests.
Looking ahead, the team plans to refine the way the particles are mixed into the resin. One promising method is to introduce the particles while applying ultrasonic vibrations directly to the mixture, helping them to disperse more evenly. A more uniform distribution could enhance the material’s performance and provide new opportunities for further optimisation.
Optimising Nanoparticle Dispersion in Composite Materials – Research Visit at Leibniz-Institut für Verbundwerkstoffe
In the following week, from November 10-14, 2025, Bernardo continued his research at IVW, shifting the focus from basic material testing to the practical development and processing of composite formulations. While UPC produces the specially functionalised lignin nanoparticles, IVW is responsible for integrating them into composite materials. Because these particles can be difficult to work with, the visit provided an ideal opportunity for Bernardo to gain direct insight into how IVW manages the mixing and processing steps.
During the stay, the team tested different processing conditions to see how they affected nanoparticle behaviour and material quality. New approaches were trialled directly on IVW’s equipment to improve particle dispersion. Together, the teams prepared several formulations, exploring mixing, dissolution, and curing methods, and carried out detailed microscopic analyses using IVW’s ZEISS scanning electron microscope to examine the nanoparticles’ structure and surface features.
The joint work quickly led to improvements in how well the particles could be dispersed in the material, resulting in noticeably better mixing quality. The full scientific characterisation of the prepared samples is still in progress and will help determine how these enhancements translate into material performance.
Results and Outlook:
The work at IVW has led to better dispersion of the nanoparticles within the materials and has improved the overall quality of the formulations. The full analysis of the samples is still underway, and results from these tests will provide a clearer picture of their performance.
The next stage will begin once the equipment and materials for fire-safety testing are available. At that point, IVW will assess whether the lignin nanoparticles can enhance the materials’ flame resistance and offer a safer, non-toxic alternative to conventional flame-retardant additives.
In conclusion, the two intensive weeks of collaboration in Kaiserslautern represent a significant advancement for the r-LightBioCom project. Bernardo emphasises that this collaborative work represents an important step in validating the nanoparticles that UPC has recently scaled up using continuous single-step sonochemical processes for both amination and epoxidation.
The visits provided valuable feedback on how the nanoparticles affect mechanical performance and their potential as flame-retardant additives. This insight will support the ongoing optimisation of the nanoparticle production process in the r-LightBioCom project, and help confirm their suitability for use in real composite materials.
