The use of monomers based on natural materials as a future supply of raw materials has gained more interest in the last decade. Sources ranging from wood to plant oils and algae are exploited as alternatives to traditional fossil‐based resources for the synthesis of polymeric materials. The use of these raw materials is not only of interest because of its abundance, but also in terms of price, durability, and/or biodegradability. In the present study, a series of resins utilizing a monomer derived from birch bark is prepared. The thermoset resins are formed by reacting an epoxy‐functional ω‐hydroxy fatty acid with methacrylate monomers using enzyme catalysis to form multifunctional resins via a one‐pot synthesis. The derived oligomers are crosslinked through different polymerization routes to produce thermosets with different properties and/or functionalities. This approach allows natural‐based resins with tuned functionalities and mechanical and thermal properties to be obtained.

The work herein presented describes the synthesis and polymerization of series of bio-based epoxy resins prepared through lipase catalyzed transesterification. The epoxy-functional polyester resins with various architectures (linear, tri-branched, and tetra-branched) were synthesized through condensation of fatty acids derived from epoxidized soybean oil and linseed oil with three different hydroxyl cores under bulk conditions. The selectivity of the lipases toward esterification/transesterification reactions allowed the formation of macromers with up to 12 epoxides in the backbone. The high degree of functionality of the resins resulted in polymer thermosets with T values ranging from -25 to over 100 °C prepared through cationic polymerization. The determining parameters of the synthesis and the mechanism for the formation of the species were determined through kinetic studies by H NMR, SEC, and molecular modeling studies. The correlation between macromer structure and thermoset properties was studied through real-time FTIR measurements, DSC, and DMA.

The present work describes the synthesis and characterization of fully biobased soft polymer networks for pressure sensitive adhesives applications. The incorporation of different sugars into fatty-acid-based monomers, made it possible to tailor the viscoelastic properties of the materials. Lipase catalysis allowed to afford monomers with varying hydroxyl content and epoxy-functionalities. Step-growth polymerization catalyzed by DBU resulted in soft-polyester networks through combination of the monomers with a biobased diacid. Rheological and adhesion studies were performed to elucidate the different viscoelastic and adhesive properties of the materials as a function of their composition.

Candida antarctica lipase B (CalB) was used as a chemoselective catalyst for the synthesis of multifunctional oligoester resins based on an epoxy-functional ω-hydroxy-fatty acid (EFA) extracted from birch bark.

SummaryWe present a novel near ambient temperature approach to telechelic renewable polyesters by exploiting the unique properties of supercritical CO2 (scCO2). Bio-based commercially available monomers have been polymerised and functional telechelic materials with targeted molecular weight were prepared by end-capping the chains with molecules containing reactive moieties in a one-pot reaction. The use of scCO2 as a reaction medium facilitates the effective use of Candida Antarctica Lipase B (CaLB) as a catalyst at a temperature as low as 35°C, hence avoiding side reactions, maintaining the end-capper functionality and preserving the enzyme activity. The functionalised polymer products have been characterised by 1 H-NMR, MALDI-TOF, GPC and DSC in order to carefully assess their structural and thermal properties. We demonstrate that telechelic materials can be produced enzymatically at mild temperatures, in a solvent-free system and using renewably sourced monomers without pre-modification, by exploiting the unique properties of scCO2. The macromolecules we prepare are ideal green precursors that can be further reacted to prepare useful bio-derived films and coatings.