Poster

P2.28 – Lignin-based organogels: a tough and flexible renewable solution

Vu Thanh Truong

Department of Chemistry, Stockholm University

Co-author(s):
Alexandros Alexakis, Stockholm University

Organogels are soft materials fused with an organic liquid phase. Developing organogel with good mechanical durability, non-toxicity, and environmental stability offers potential for diverse applications. However, conventional organogels often rely on synthetic materials and toxic solvents, exhibit insufficient mechanical strength, and involve energy-intensive fabrication methods. Biobased organogels offer certain advantages. In this regard, lignin, a wood-derived macromolecule, presents a sustainable alternative due to its natural abundance, rigidity, multifunctionality, and antioxidant properties. However, its hydrophobicity and molecular irregularity pose challenges in gel fabrication. In this study, a tough and elastic acetoacetylated lignin (AL)/poly(vinyl alcohol) (PVA) double-network organogel (50 wt% of lignin) is developed in which lignin is a reinforcing component. Using cyrene, a green and biocompatible solvent, along with a cyrene/water binary mixture as the liquid phase, enhanced temperature stability of the organogel. Dynamic mechanical analysis (DMA) confirmed the organogel maintains stable mechanical strength over a broad temperature range (-30 to 80 °C). Fourier-transform infrared (FT-IR) spectroscopy validated the chemical cross-linking of lignin within the PVA matrix. This synthesis design efficiently intercalates lignin within the PVA matrix and creates beneficial interactions between lignin and PVA, resulting in excellent material properties; compared to pure PVA organogels, the AL/PVA organogels exhibit a 1.6-fold increase in tensile strength and a 4.2-fold increase in toughness. These properties make the organogel a promising candidate for applications in harsh environments.

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