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Enzymatic polymerization of sustainable polymers using biobased solvents

Driven by the need for sustainable alternatives to fossil-based polymers, this research explores enzymatic polymerization using biobased solvents. By employing enzymes and eco-friendly solvents, the study advances green polymer science, paving the way for a sustainable future.

This study addresses the pressing demand for sustainable polymers by focusing on furan-based polyesters and copolyesters synthesized through enzymatic catalysis in biobased solvents. Utilizing enzymes such as Candida antarctica lipase B (CALB) and renewable solvents like p-cymene, pinacolone, and D-limonene, this research highlights a potential shift towards greener polymerization methods, replacing traditional fossil-derived chemicals. The findings not only optimize polymer properties but also contribute to sustainable industrial practices.

The depletion of petroleum-based resources has fueled a growing demand for biobased polymers. Furan-based materials have garnered significant attention due to their renewability and potential to replace conventional plastics like polyethylene terephthalate (PET). Among these, 2,5-furandicarboxylic acid (2,5-FDCA) has become a focal point for the development of high-performance polyesters. Traditional polymer synthesis methods, however, often rely on toxic and non-renewable solvents. To address this issue, this study examines the enzymatic polymerization of furanic polymers using biobased solvents as a sustainable alternative.

Enzymatic Polymerization in Biobased Solvents

The research explores the use of Candida antarctica lipase B (CALB) for polymerizing 2,5-FDCA and 2,5-bis(hydroxymethyl)furan (2,5-BHMF) into polyesters and copolyesters. CALB is a widely studied biocatalyst known for its ability to operate under mild conditions, making it ideal for sustainable synthesis. However, many studies to date have utilized non-renewable organic solvents, which limits the environmental benefits of enzymatic catalysis. This research thus pivots to biobased solvents, including p-cymene, pinacolone, and D-limonene, derived from renewable resources like citrus and pine oil. These solvents were selected based on their environmental compatibility and ability to enhance enzymatic activity.

Key Findings

  1. High Molecular Weight Polymers The study achieved high-molecular-weight polyesters and copolyesters using p-cymene, demonstrating its suitability as a biobased solvent. When compared to traditional solvents like toluene, p-cymene showed comparable performance, yielding polymers with molecular weights up to 12,800 g mol⁻¹. In contrast, pinacolone and D-limonene resulted in lower molecular weights but still showed promise as green alternatives.
  2. Structure-Property Relationships The enzymatic polymerization of dimethyl 2,5-furandicarboxylate (2,5-DMFDCA) with various diols revealed significant variations in the thermal properties and crystallinity of the resulting polymers. For instance, the study found that copolymerizing 2,5-BHMF as a rigid diol produced materials with enhanced rigidity and thermal stability, making them suitable for high-performance applications.
  3. Impact of Solvent Properties The solvent’s physicochemical properties, such as log P values, hydrogen bond accepting ability (β), and molar volume (Vm), were shown to significantly affect enzymatic activity and product quality. p-Cymene, with its high Vm and low β, provided a more conducive environment for the enzymatic polymerization process compared to pinacolone and D-limonene.

Sustainability and Future Directions

This research aligns with the United Nations Sustainable Development Goals (SDGs), particularly SDG 12 (Responsible Consumption and Production) and SDG 13 (Climate Action), by promoting environmentally friendly industrial practices. The use of biobased solvents in enzymatic polymerization reduces dependence on fossil resources and minimizes the environmental impact of polymer synthesis.

Conclusion

The study successfully demonstrated the feasibility of using biobased solvents for the enzymatic polymerization of furan-based polymers. p-Cymene emerged as the most promising solvent, producing high-quality polyesters comparable to those obtained using conventional organic solvents. The findings suggest a significant step forward in the development of sustainable polymerization techniques, making enzymatic synthesis in biobased solvents a viable pathway for greener polymer production.

  • Note: This article is based on Enzymatic Polymerization of Furan-Based Polymers in Biobased Solvents

Silvianti, F.; Maniar, D.; de Leeuw, T.; van Dijken, J.; Loos, K. RSC Sustainability 2024. DOI: 10.1039/D4SU00358F

Author: Katja Loos

Keywords

Biobased polymers; enzymatic polymerization; furan-based polyesters; sustainable solvents; Candida antarctica lipase B; green chemistry; 2,5-furandicarboxylic acid; polymer synthesis