New publication: Self-foaming polyester resin systems
We are pleased to once again present a study by our working group in the journal Polymers. In their current publication, Fabian Weitenhagen and Oliver Weichold present an innovative modular system for the production of bio-based polyester foams in which the reaction water itself serves as a blowing agent – without any external additives. The work shows how a versatile foam system can be developed through the targeted selection of bio-based dicarboxylic acids and various polyols. By systematically varying these building blocks, mechanical properties such as hardness, density, thermal conductivity and thermal stability can be flexibly adapted. Particularly noteworthy are the significantly improved fire properties compared to many organic materials.
A particular highlight of the work is the scanning electron microscope (SEM) images, which provide a detailed insight into the internal structure of the foams. Compact cell walls without microporosity become visible, whereby the pore structure is specifically influenced by the varying densities.
SEM images of polyester resin foams with low (A) and higher (B) density.
Weitenhagen, F.; Weichold, O.
Preparation, Reaction Kinetics, and Properties of Polyester Foams Using Water Produced by the Reaction as a Foaming Agent.
Polymers 2025, 17, 1266. https://doi.org/10.3390/polym17091266
New publication: Self-crosslinking chitosan hydrogels with carboxylic acids
We are pleased to announce a new publication from our research group in the journal Gels. In this study, Nils Münstermann and Oliver Weichold investigated the conditions under which chitosan forms stable hydrogels without additional crosslinkers.
The formation of self-crosslinking chitosan hydrogels using simple carboxylic acids alone is severely limited. Although viscous solutions can be produced with dicarboxylic acids such as oxalic, malonic or succinic acid, stable gels cannot. Stable ionic hydrogels can only be produced by specific chemical modifications such as N-carboxyalkylation or N-succinylation. The length and flexibility of the alkyl spacer and the presence of a covalent bond are crucial for gel formation and mechanical strength. N-carboxypropylchitosan in particular forms very strong gels with low swelling, while shorter side chains produce weaker gels.
Münstermann, N.; Weichold, O.
On the Conditions Determining the Formation of Self-Crosslinking Chitosan Hydrogels with Carboxylic Acids,
Gels 2025, 11(5), 333. https://doi.org/10.3390/gels11050333
Visit “MatFo2025”
On April 2, 2025, we attended the conference “MatFo2025: Material innovations for the transformation of the economy and society” in Frankfurt am Main. Experts from politics, research and industry discussed current challenges and innovative solutions for the German innovation system. The new BMBF materials research program “Mat2Twin” was also presented.
Sketch by Till Lassmann
RWTH article on our publication: “Spectacular alternative to classic wood stain”
We are delighted that our innovative wood stain has now also been recognized by the press office of RWTH Aachen University. In a recent article, the RWTH highlights the discovery process and the special properties of our chitosan glaze. It also discusses our sustainable approach to environmentally friendly alternatives in the construction industry.
Our coating is based on chitosan, a natural substance that can be obtained from crab shells, insect shells and fungi. It is not only water and stain resistant, but also UV resistant, flame retardant and fully compostable. While wood has to be disposed of separately after treatment with conventional wood preservatives, our biodegradable coating fits perfectly into the circular economy of sustainable building materials.
The full article from the RWTH press office can be found here.
Spruce wood in a fire test: the effect of chitosan itaconate as a coating
In our publication “A fire-retardant coating for wood made from chitosan itaconate”, Nils Münstermann and Oliver Weichold test the fire behaviour of untreated spruce wood and spruce wood coated with chitosan itaconate. While the untreated spruce wood burns down completely, the flame in the coated wood goes out by itself without the test specimen burning completely.
Spruce uncoated
Spruce coated
N. Münstermann, O. Weichold
A fire-retardant coating for wood made from chitosan itaconate
Progress in Organic Coatings 2024, 197, 108793 https://doi.org/10.1016/j.porgcoat.2024.108793
Polymer Blends & Eurofillers 2025
Paul Marten and Fabian Weitenhagen attended and delivered presentations at Polymer Blends & Eurofillers 2025 in Lyon this week.
Paul Marten presented the “Development and Characterisation of a Composite Material based on Polylactic Acid, Chitin, and Lecithin”.
Fabian Weitenhagen presented “Sustainable Biopolymer Composites Using Recycling Cellulose from Wastepaper”.
Contributions to our publication: Fire-retardant wood coating
The publication “Fire-retardant Coating For Wood Made From Chitosan Itaconate” is internationally recognised by an article in the Italian trade journal Pitture e Vernici – European Coatings (Issue 1/2025, page 36) and by a web post by European Coatings entitled “A fire-retardant coating for wood made from chitosan itaconate” – News and insights for the European coatings industry. The chitosan itaconate glaze is transparent, emphasises the natural wood grain and renders the surface water-repellent. It reliably protects the wood from moisture, prevents UV-induced greying and efficiently reduces the burning rate. With just two applications on spruce and three on beech wood, the glaze is self-extinguishing. Find out more.
This bio-based approach combines resource conservation with effectiveness and demonstrates how environmental preservation and safety requirements can be successfully combined. It fills us with joy and appreciation to see that our work is attracting greater attention.
Pitture E Vernici: Fire-retardant Coating For Wood Made From Chitosan Itaconate, Fascicolo 1/Gennaio – Febbraio 2025 – Pitture e Vernici, https://www.pittureevernici.it/archivio/archivio-2025/fascicolo-1-gennaio-febbraio2025/.
European Coatings: A fire-retardant coating for wood made from chitosan itaconate – News and insights for the European coatings industry, https://www.european-coatings.com/news/application-areas/a-fire-retardant-coating-for-wood-made-from-chitosan-itaconate/.
New employee
Since the 1st of january, we are pleased to welcome Ece Meryem Durdagi to the Polymeric Materials department. She supports us in project administration and acquisition. We wish her every success in her work and welcome her to the working group.
Joint publication:Plant protection from insect larvae
The black soldier fly (Hermetia illucens) not only offers a sustainable source of protein, but also the potential to extract chitosan – a versatile biopolymer – from the larval skins. A joint study with the research group led by Dr. Sabine Gruber from the University of Innsbruck and the FH Campus Vienna shows how biological waste from BSF production can be processed into bioactive chitosan using environmentally friendly enzymatic processes. This chitosan has strong antifungal properties and improves the germination and disease resistance of plants such as sugar beet. It therefore offers an environmentally friendly alternative to chemical fungicides and chitosan, which is obtained from crescent shells. This innovation underlines the potential of the insect industry to make good use of waste and create sustainable solutions for agriculture and industry.
C. Escobar Rodríguez, V. Zaremska, T. Klammsteiner, I. Kampatsikas, N. Münstermann, O. Weichold, S. Gruber
Chitosan obtained from black soldier fly larval cuticles expands the value chain and is effective as a biocontrol agent to combat plant pathogens
Carbohydrate Polym. 2025, 349, Part B, 123023 https://doi.org/10.1016/j.carbpol.2024.123023
Anouncement: Polymer Blends & Eurofillers
We are pleased to announce that two exciting presentations from our working group have been accepted at Polymer Blends & Eurofillers 2025 in Lyon from January 27 to 30, 2025:
Paul Marten
Development and Characterization of a Composite Material based on Polylactic Acid, Chitin, and Lecithin
and
Fabian Weitenhagen
Sustainable Biopolymer Composites Using Recycling Cellulose from Wastepaper
Take the opportunity to learn about the latest results from the working group and to talk directly to the members.
