Research Project: Yangın Acil Durumları için Bitki-Kaynaklı Biyonanokompozit Hidrojellerin Geliştirilmesi
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Contributors
Funders
ID
TB.00729
Authors
Şenses, Erkan
Faculty Member
Publications
Role of lignin on microstructure, mechanical properties and flame retardancy of nanocellulose-based composite hydrogels
(Elsevier, 2025) Turhan, Emine Ayşe; Sarıoğlu, Ebru; Şenses, Erkan; Özkan, Aybüke; Mıhlayanlar, Ezgi; Berlu, Paul; Sarıoğlu, Ebru; Özkan, Aybüke; Turhan, Emine Ayşe; Kaynak, Elif; Department of Chemical and Biological Engineering; KUBAM (Koç University Boron and Advanced Materials Application and Research Center); Yes; Berlu, Paul; College of Engineering; Research Center; Mıhlayanlar, Ezgi
Flame-retardant composite hydrogels provide significant advantages over conventional fire suppressants due to their high water retention, char-forming ability, and mechanical adaptability. However, the current formulations mostly rely on synthetic polymers or nanoparticles which restricts their large-scale application and reduces sustainability. In this work, we developed lignin-incorporated dynamically crosslinked cellulose nanocrystal (CNC) hydrogels and systematically investigated the interrelation between microstructure, rheological behavior, thermal properties, and flame-retardant performance. The incorporation of lignin at moderate concentrations enhanced hydrogen bonding, resulting in a denser and more homogeneous hydrogel network with reduced mesh size. The resulting elastic network enhanced water retention during burning, promoting flame retardancy via substrate cooling and fuel dilution effects. Additionally, lignin facilitated the formation of a compact glassy char layer, effectively serving as a heat and oxygen barrier. Thermal decomposition of dried CNC films resulted in 8.6 % residue at 700 degrees C, whereas CNC-lignin-borax composites exhibited a significant increase in char yield, reaching 70.5 %. The optimal lignin composition extended burn-through time of wood to 12 min-71 % and 33 % longer than uncoated and neat CNC samples. Our findings highlight the potential of CNC-borax-lignin hydrogels as biorenewable environmentally friendly coatings with superior flame-retardant properties, offering a sustainable approach to fire prevention in wood-based materials.
Dynamically bonded cellulose nanocrystal hydrogels: structure, rheology and fire prevention performance
(Elsevier , 2024) Koparipek, Nazlınur Arslan; Şenses, Erkan; Kaynak-Uraz, Elif; Department of Chemical and Biological Engineering; KUBAM (Koç University Boron and Advanced Materials Application and Research Center); KUYTAM (Koç University Surface Science and Technology Center); Yes; College of Engineering; Research Center
Flame retardant composite hydrogels offer many advantages over conventional flame retardants, such as high water-retention capacity, enhanced fire resistance, and mechanical tunability. Herein, we developed flame-retardant dynamic covalent hydrogels using wood-derived cellulose nanocrystals (CNCs) crosslinked with boronate ester bonds, addressing environmental and health issues associated with the presence of non-biodegradable synthetic polymer and/or inorganic nanoparticle components in the existing systems. Our rheological investigation shows a liquid-to-soft-solid transition of CNC dispersions with tunable network elasticity ranging between ≈ 0.2 kPa to 3.5 kPa and an immediate self-healing ability. Coating pine wood with these hydrogels delayed ignition by about 30 s compared to native wood, and achieved a remarkable limiting oxygen index of 64.5 %. Also, the increased borax content of the gels was found to decrease and delay the first peak of the heat release rate up to 40 s, causing an increase in the fire retardancy index by 277 %. We correlate the microstructure and rheological behavior with the fire prevention mechanisms for the rational design of sustainable fire-retardant materials, and the results showcased a circular use of plant-based dynamic gels to prevent wood fires, even after drying- a feature lacking in conventional hydrogels.
