Sust-Chem develops and commercializes an innovative biopolymer called poly(2,5-dihydroxy-1,4-dioxane) (PDHDO) made by the polymerization of glycolaldehyde (GA) dimer, (orange arrows) for the replacement of polyolefins. We selected GA as our bio-based monomer because it can be produced in large volumes from biomass (blue arrows) and is cheaper than petrochemical raw materials. This provides us with a competitive edge over both oil-based plastics and other bioplastics, which use expensive monomers, and the manufacture of which is difficult to scale to mass volumes. PDHDO is expected to depolymerization under certain conditions facilitating chemical recycling to recover the monomer after waste collection (dark green arrow), but also to have a benign end of life, if dispersed to the environment, where it is expected to degrade to GA, a non-persistent molecule that easily converts back to biomass (light green arrows).

In this presentation, we will highlight our synthetic efforts to improve the molecular weight of PDHDO and the development of thin film prototypes.

Introduction of plant-based new raw materials is redesigning the core of tyre industry: the rubber compound. Rice husk silica, biooils and bioresins have become rapidly new commodities and gained large volumes in the market as replacement of fossil-based additives. Other plant-based materials, instead, have a less obvious utilization in compound: Lignin is one of the main components of wood and is renewable, abundant and environmentally friendly but its chemical functionality limits application in rubber. With this in mind, we developed a mechanochemical esterification of lignin in presence of a basic activator and an enol ester acyl donor. Thanks to mechanochemistry, we succeeded to run the reaction in absence of solvent and limiting the work-up procedures maximizing atomic efficiency, according to the principles of the green chemistry. Lignin dispersion and distribution was further boosted thanks to a latex compounding technique in combination with traditional melt mixing. As a result, esterified lignin exhibited improved high deformation characteristics and dynamo-mechanical properties in rubber formulation ranging from inner compounds to tread, paving the way to a more extended use of lignin in rubber formulation, especially for high performance tyres

Polyhydroxyalkanoates (PHAs) are emerging as sustainable alternatives to conventional thermoplastics, thanks to biobased and biodegradable properties. However, widespread adoption remains hindered by challenges related to cost and scalability. Our research tackles these issues through innovative approaches for scalable PHA production and processing methods. One recent advancement involves extrusion-based methods for processing solvent-rich PHA gels. These methods integrate seamlessly with the PHA recovery process and eliminate unnecessary intermediary steps. PHA is first extracted at elevated temperatures from a dried PHA-rich biomass using simple alcohols like 2-butanol. Upon cooling, formation of solvent-rich PHA gels takes place. These gels can be directly processed via twin-screw extrusion, while solvent is concurrently recovered due to its controlled evaporation in the barrel. Solvent in a PHA gel acts to significantly lower the PHA melt temperature and can enable processing at reduced temperatures compared to dried PHA. For example, the peak melting temperature of polyhydroxybutyrate (PHB) in a gel containing 60 wt.% 2-butanol decreases from 180°C to 115°C. Gel extrusion trials, without specific optimisation of feeders and equipment, produced controlled quality dried filaments while removing over 98% solvent with 77% recovery. Streamlining of melt extrusion and solvent recovery enhances efficiency, scalability, and product quality control. Supporting analyses, including thermogravimetry, differential scanning calorimetry, rheology, and microscopy, validated the process methods and production consistency during extrusion campaigns. Furthermore, such versatile gel processing methods with solvent recovery benefits avail wider opportunities in melt processing of PHA formulation as blends and additives offering untapped pathways for advancing PHA-based materials and applications.

Proteins are largely available from waste sources and are therefore a valuable source for the preparation of circular materials. In this presentation, protein-based materials for flexible electronics are shown.
The Organic Fraction of Municipal Solid Waste (OFMSW) is a huge biomass that accounts for 1.3 billion tons/year. The Black Soldier Fly (BSF) can effectively bioconvert OFMSW [1]. In this work, the protein extracts of larvae and pupae were transformed in bionanocomposites for flexible electronics. The BSF insect proteome was characterized by means of SDS-PAGE and LC-MS/MS, and a prevalence of muscular proteins was found. Films were prepared by adding glycerol as a plasticizer and were characterized by calorimetric and infrared analysis. The organization of polypeptides was controlled by tuning the pH or protein solution and by performing annealing. Flexible and electroconductive bionanocomposite materials were formulated by combining BSF proteins with a conductive carbon black (CCB), either in its native form or functionalised with 2-(2,5-dimethyl-1H-pyrrol-1-yl)-1,3-propanediol (serinol pyrrole, SP) [2], using water as a solvent and adding glycerol and carboxymethyl cellulose [3]. Kraus plots and electrical conductivity measurements revealed a strong filler-polymer interaction after the functionalization of CCB with SP. The bionanocomposites were characterized by high electrical conductivity (up to 0.9 × 10-² S/cm at a filler content of 8% v/v (15% w/w)), strain-sensing properties, biodegradability, and high surface hydrophobicity, upon performing a low-pressure cold plasma treatment.
As a further example of biomass engineering, the preparation of flexible films from zein as a substrate for flexible electronics will be shown.

In recent years, scientific literature has increasingly focused on the study of plant raw materials, including those derived from agricultural waste. These materials have been identified as a potential source of valuable chemical substances with antioxidant activity, and some have even been found to act as dyes or exhibit antimicrobial properties [1]. These properties can be utilized to produce various types of polymer materials, by directly incorporating this raw material into composites. Plant raw materials containing polyphenols, which possess antioxidant activity, can function as both an active filler of polymers and a stabilizer [2-3]. These polyphenols influence the processes related to the degradation of polymer materials. The present study examined the antioxidant activity of various plant extracts obtained from waste fruit pomace and herbs. The extracts obtained were then subjected to a composition analysis, with the aim of determining the polyphenol content present in the raw materials utilized. The most suitable plant raw materials for the purpose of obtaining polymer composites were identified based on their antioxidant properties and thermal stability. These materials were then utilized in the production of polymer composites, and the resulting samples were examined to determine their capacity to stabilize specific polymers.

Acknowledgment:
The research was financed by the National Science Centre, grant number UMO-2023/51/D/ST11/00165.

Biopolymers can be used to replace soft plastics in packaging and drug delivery applications, however, due to their high crystallinity use of polyhydroxybutyrate (PHB or short-chain length PHA) and polylactic acid (PLA) in soft plastics remains challenging. We have developed medium-chain-length polyhydroxyalkanoate (mcl-PHA) nanoemulsions which are bioderived and biodegradable. The effect of feeding glucose and fatty acids from food waste on the microbial production of mcl-PHAs has been studied to explore the possibility of producing mcl-PHAs from food waste and to tune polymer properties for their applications. Substituting decanoic acid (F10) and dodecanoic acid (F12) with glucose maintains consistent monomer composition, and a 50% glucose substitution in the F12 feedstock boosts the PHA content to 66% in Pseudomonas putida, reducing cell dry weight to 6 g/L while keeping a similar PHA yield. This approach offers a practical way to reduce costs and maintain polymer quality, boosting its appeal for industrial-scale production [1]. Linking bioprocessing technologies with extensive material characterization enables us to develop new fundamental understanding as well as real materials for a range of applications.
This work is currently developed further as part of two ARC Research Hubs: Carbon Utilisation & Recycling (https://www.recarbhub.org/ IH220100012) & Value-Added Processing of Carbon Waste (https://vapucw.org/ IH230100011) at Monash University’s Faculty of Engineering in Melbourne, Australia.

Vanillin, a bio-based aromatic compound derived from lignin or guaiacol, is emerging as a promising sustainable building block for advanced materials. Its unique chemical structure, featuring aldehyde, hydroxyl, and methoxy functional groups, enables versatile functionalization into high-performance thermosetting resins. This work highlights recent studies that demonstrate vanillin’s potential as a platform for sustainable, high-performance material development.
In one study, vanillin was epoxidized to produce diglycidylether of vanillyl alcohol (DGEVA), which was incorporated into one or two layers of cellulose/flax fiber fabric to create fully green composites. The DGEVA monomer was then crosslinked using radical-induced cationic frontal photopolymerization (RICFP), enabling rapid curing. The resulting bio-based composites exhibited mechanical strength comparable to, or even surpassing, traditional petroleum-based materials1.
In another study, DGEVA was used to create UV-curable anticorrosion coatings reinforced with nanoclay. When applied to mild steel substrates, these coatings demonstrated excellent corrosion resistance, with nanoclay improving barrier properties by preventing the diffusion of aggressive ions. This work shows the potential of vanillin-based UV-cured coatings to reduce the environmental impact of the coating industry2.
Finally, a vanillin-based vitrimer was synthesized using dynamic covalent bonds via reversible imine reactions, introducing self-healing and reprocessing capabilities. This innovative approach results in materials with enhanced recyclability and longevity.
Together, these studies highlight vanillin’s promise as a renewable, game-changing building block for sustainable polymer development with broad industrial applications.