Green material solutions are instrumental in our collective pursuit of a more sustainable society. The bio-based origin is central; however, if this does not connect to circularity and benign synthesis, we will face the same plastic waste problem as today. My research team is highly interdisciplinary, covering polymer, organic, and biopolymer chemistry, with a focus on the challenges we need to solve for specific material applications. This presentation focuses on my team's recent work in polymer synthetic methodology development within the framework of biobased circular polymeric materials.
Our methodology is based on identifying the constraints and chemical challenges of a specific problem and using that as a blueprint for the desired chemistry we need to develop. We have a keen interest in addressing fundamental questions.

Recent examples of our work include:
• In-situ polymerization for transparent wood.1
• Development of modular polymerization strategies.2
• Oxime-ligation towards the reversible covalent functionalization of cellulose nanomaterials in water.3
• Chemical recycling via the ring-chain equilibria.4
• Super-charged wood fibres via radical transfer polymerization.5

Central to this work is to harness the complexity of natural resources on many different hierarchical levels, combine that with polymer chemistry and play with factors such as chemical accessibility, reactivity, and orthogonality.

Thermally expandable microspheres (TEMs) are polymeric core/shell particles consisting of a thermoplastic polymer shell encapsulating a hydrocarbon. Upon heating to a temperature close to the glass transition temperature (Tg) of the polymer shell, the increased vapor pressure from the encapsulated hydrocarbon causes the particles to expand [1]. TEMs can be used in a large variety of applications either as a blowing agent in e.g. shoe soles, or as a lightweight filler in e.g. paints and coatings. The light weight and material-savings that TEMs provide are, for example, valuable properties for energy saving and reduced raw material consumption.
The most common method to produce TEMs industrially is through in situ microencapsulation of a hydrocarbon via free-radical suspension polymerization [1]. The products that are commercially available today are typically produced from fossil-based monomers such as acrylonitrile and methyl methacrylate.
In this presentation, our work on synthesis of TEMs with bio-based, or a partially bio-based polymer shells will be described. Several examples of TEMs with copolymer shells made of the biobased monomer families α-methylene-y-butyrolactones (1) [2,3], and itaconate esters (2) [4] will be discussed.

Access to polymers from renewable resources with good biodegradability and properties that match the fuel-based polymers is of great interest. A type of polymers that have attracted a lot of attention are polyesters derived from cyclic esters such as lactide or caprolactone, since those can be bio-based monomers and their polymers may be biodegradable, biocompatible with a wide range of applications.[1]
We are focused in the preparation of main group metal complexes as catalysts for Ring Opening Polymerization (ROP) of cyclic esters. Within main group metals, aluminium stands out due to its abundance and well-known catalytic properties. As well the alkali metals Na and K, are particularly attractive not only for their abundance but also for their low toxicity. We have prepared a series of aluminium and alkali metal complexes with phenoxide ligands bearing different substituents in the aromatic rings to assess their influence on the catalytic activity and on the microstructure of the final polymer.[2-4] These compounds are very active in catalytic ROP and ROCOP processes of several cyclic esters including lactones quite reluctant to polymerized such as β -butyrolactone, which have allow us to prepare a variety of aliphatic polyesters and copolyesters. As well, we explored organocatalysts for the ROP of cyclic esters, in particular, N-heterocyclic carbene and carbodiimide betaines (NHC-CDIs),[5] which have shown to be efficient catalysts although via an alternative mechanism that leads to different microstructures. Furthermore, the polymers and copolymers obtained can find applications as matrixes or additives depending on their molecular weight and microstructure.

Addressing climate health through innovative polymer synthesis is crucial for a sustainable future. This talk will explore the transformative potential of anionic polymerisation in conjunction with sustainable diene monomers to produce atom-economic products that present viable alternatives to currently available materials.

Utilising a diverse range of quenching agents, bio-derived terpene monomer choices, and solvent systems, anionic polymerisation provides unparalleled control over resultant polymer monodispersity and the possibility for varied microstructure. This can have a huge impact the thermal characteristics of a polymer.

Herein, the synthesis of linear polymers (with a focus on polymycrene and polyisoprene) will be discussed, along with their respective modified alternatives. The polymers in this work have undergone subsequent backbone modification by epoxidation by a peracid, and catalytic hydrogenation using palladium catalysis.

Tailoring synthetic approaches also yield OH terminated polyenes, containing a variety of functional groups. Subsequent diagnostic analysis such as NMR, MALDI-TOF, and GPC has yielded useful information about the polymer structures, and thermal techniques (TGA, DSC) showcase an accurate representation of the stability of each polymer and its performance under thermal stress.

Three-dimensional porous structures were fabricated using a vapor sublimation and deposition technique, a green, solvent-free process conducted at room temperature and low pressure. This method consists of two key stages: the pyrolysis and deposition of the parylene C precursor, occurring simultaneously with the sublimation of an ice template, thereby eliminating the need for additional template removal steps. The resulting structures are precise replicas of the ice template, allowing for the fabrication of 3D architectures across a broad size range, from micrometers to centimeters. The presence of bubbles within the ice template naturally leads to the formation of porous structures in the final product, with pore size distribution and overall porosity finely tunable through experimental parameters such as sublimation temperature. Additionally, more complex structures with defined compartments can be achieved through sequenced molding and controlled cooling. This method also enables the incorporation of metals or oxides, resulting in composite particles with multifunctional properties for applications in nanomedicine, materials science, and catalysis.

Approximately 85% of acrylonitrile-butadiene-styrene (ABS) plastics, commonly used in durable products like electrical and electronic equipment, car parts, and various everyday objects, end up in landfills or being incinerated. Advanced dissolution-based recycling techniques have emerged as promising solutions for producing high-quality recyclates, with renewable solvents gaining attention due to their potential lower environmental footprint. Thus, this study aims to develop an advanced approach for the physical recycling of ABS using alternative renewable solvents, aligning with circular economy principles. First, a computational screening of renewable solvents was conducted using the COnductor-like Screening Model for Realistic Solvents (COSMO-RS) to identify candidates capable of selectively dissolving styrene-acrylonitrile (SAN), one of the components of ABS, with ester-based compounds emerging as the most promising for selective dissolution of ABS moieties. Then, wet tests were carried out, resulting in the identification of 4 biosolvents and 3 Eutectic Solvents (ESs) effective for SAN dissolution. The waste fraction and the recovered products underwent thorough characterization using various spectroscopic methods, including Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) for structural analysis. Overall, this investigation demonstrates that the strategic selection of renewable solvents enables efficient and selective dissolution of complex ABS under mild conditions of normal pressure and temperature within 40 minutes.