Aromatics such as benzene, toluene, and xylene (BTX) are widely used in bulk applications, including coatings, engineering plastics, polymers, and packaging. These fossil-derived base chemicals account for over 40% of industrial production, contributing to pollution, toxic waste, high energy consumption, and CO₂ emissions. Transitioning to sustainable chemical production is essential for a safe and circular economy. This can be achieved by developing cost-effective methods to produce these chemicals from renewable feedstocks such as biomass, algae, and agricultural waste or by designing renewable alternatives with similar or superior performance in targeted applications.

Pyridine dicarboxylic acids (PDCs) comprise six isomers that can be derived from renewable sources such as lignin, carbohydrates, and microbes. Various studies describe their potential, yet their poor thermal stability has limited their use as monomers in polymer synthesis, leaving them largely unexplored.

Recent advances in polymerization strategies have overcome these limitations, enabling the synthesis of polyesters with promising properties. The orientation of carboxylic acid groups in different PDC isomers results in polymers with distinct structural and thermal characteristics. These variations expand the scope of applications and enhance their potential as sustainable alternatives to fossil-based polymers.

By leveraging renewable PDC-based polyesters, new opportunities arise to develop safe, circular, and high-performance materials. This research contributes to the advancement of green polymer synthesis and supports the transition toward more sustainable polymer materials for diverse applications.

We are developing recyclable elastomers and thermosets based on poly(lactic acid) (PLA), the most commercially relevant bio-based polymer, and an ideal candidate as a sustainable polymeric material in a circular economy [1].
We report here new 3-coordinate pyridylamidoiron(II) catalysts [2] highly active in the polymerization of lactide and lactones, including poorly polymerizable δ-substituted δ-lactones. The latter catalysts allowed the synthesis of tailored co-polyesters, via one-pot sequential addition of different monomers, including tri-block ABA copolymers [3] consisting of PLA as semicrystalline hard A blocks and various random co-polyesters as amorphous soft B block. Physical characterization of the polymers revealed that the materials properties range from those of toughened thermoplastics to those of thermoplastic elastomers. Chemical recycling to the monomers of these materials was efficiently achieved by depolymerization in bulk in the presence of suitable catalysts.
We are also pursuing the synthesis of bio-based thermosetting resins that can be subjected to chemical recycling at the end of their life [4]. We report thermosets based on carboxyl end-capped star-shaped poly(L-lactic acid) oligomers and a non-toxic and bio-based crosslinking agent, isosorbide diglycidyl ether. The curing reaction was investigated and optimized by DSC, rheological studies, and dynamical mechanical analysis, leading to highly crosslinked materials with >90% gel contents. Preliminary chemical recycling experiments were also performed on the obtained materials.

Acknowledgment. This work was funded by the European Union Next Generation EU (PNRR): MICS Extended Partnership - PE00000004, project “ULISSE”, CUP D43C22003120001; and PRIN 2022 PNRR, Project P2022K9XN3, CUP D53D23017130001.

Monoterpenes are secondary metabolites occurring in plants, microbes, or fungi. They are available in comparably high volumes from industrial side streams, predominately from pulp & paper production. From a chemist’s perspective, they are a suitable substitute for petrochemical resources in the world of polymers. The monoterpene (+)-3-carene has been investigated for several years as a precursor for novel bio-based lactams and polyamides.
These polyamides, namely Caramid-R and Caramid-S, stand as examples for bio-based polymers that can compete with their fossil-based counterparts. The development has been driven by a Fraunhofer flagship project called “SuBi2Ma”, combining the expertise and innovation of six Fraunhofer institutes.
The polyamides are fully bio-based, have a high-performance glass transition temperature (Tg) of over 110 °C, and a decreased moisture uptake compared to PA6. Whereas Caramid-S is semi-crystalline and melts at a temperature as high as 280 °C, Caramid-R is amorphous and transparent. The synthesis of the corresponding monomers 3S-caranlactam and 3R-caranlactam aims to follow the principles of green chemistry and has been scaled to the kilogram scale. Hydrolytic polymerization and anionic ring-opening polymerization for cast polyamides are investigated, supported by adaptive design of experiment. The polyamides are suited for processing by hot pressing, extrusion, melt spinning, and foaming, and the whole value chain has been investigated in terms of an initial ecological evaluation.
For the first time, the current results of the project are presented to a broader audience, including an overview of the properties of fibers, foams and cast polyamides of Caramide polyamides.

The sustainable production of bio-derived alkoxybutenolide monomers presents a promising alternative to conventional acrylate-based coatings. Here, we report the optimization and scale-up of the synthesis of these monomers, leading to the development of a continuous-flow process with significantly improved efficiency. The first step involves the oxidation of furfural using photogenerated singlet oxygen, followed by a condensation reaction at ambient temperature to produce additional desired monomers.
This approach facilitated the scale-up of photo-oxidation to an 85% isolated yield, with a productivity of 1.3 kg day⁻¹ and a space-time yield of 0.06 mol day⁻¹ mL⁻¹. Further improvements demonstrated potential productivities of up to 4 to 10 kg day⁻¹.
Building upon these advancements, a startup has been established to further develop and commercialize this scalable synthesis platform for bio-based monomers to be used in polymers and coatings. This work demonstrates how process intensification and flow chemistry innovations can drive sustainable chemical manufacturing, offering a viable pathway for the industrial adoption of renewable monomers.

Herein, we present the development of new bio-based amphiphilic polymers designed for sustainable applications as dispersing agents, addressing the pressing need for eco-friendly alternatives in cleaning formulations. A clean environment is crucial for a healthy life, and effective cleaning, especially of everyday items like clothing, relies on efficient detergents and dispersing agents. However, many existing polymers used in these applications are neither bio-based nor biodegradable, emphasizing the need for sustainable replacements.¹
In this work, bio-based precursor polymers were synthesized via melt polycondensation using renewable diacids and diols. The reaction parameters, including temperature, catalyst concentration, and reaction time, were optimized to control molecular weights. The precursor polymers were structurally characterized by spectroscopy, finally thermal properties were analysed.
Post-modification of the precursors through thiol-ene chemistry introduced carboxylic acid groups into the polymer chains.² The degree of modification and the resulting functional group content were tuned by varying the reagent concentrations. The modified polymers displayed surface-active properties, as shown by interfacial tension measurements, and their acid-base characteristics were analysed by potentiometric titration. Enzymatic degradation tests demonstrated their biodegradability in aqueous environments.
Turbidity tests confirmed the suitability of these polymers as biodegradable dispersing agents for use in sustainable cleaning products. This approach highlights the potential of bio-based polymers to replace conventional, non-degradable materials in detergents, contributing to a cleaner and more sustainable future.