Research Project: Ağaç Bazlı Liflerde Yüzey Modifikasyonları ve Fiziksel Özelliklere Etkilerinin İncelenmesi
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Contributors
Funders
ID
TB.00509
Authors
Şenses, Erkan
Faculty Member
Publications
Unraveling the effects of cellulose nanoparticle types on dispersion, rheological behavior, and shear strength in adhesive formulations
(Elsevier, 2025) Sarıoğlu, Ebru; Tarhanlı, İlayda; Erkey, Can; Şenses, Erkan; Sarıoğlu, Ebru; Tarhanlı, İlayda; Yarici, Tugay; Bengu, Basak; Graduate School of Sciences and Engineering; Department of Chemical and Biological Engineering; KUBAM (Koç University Boron and Advanced Materials Application and Research Center); Yes; Research Center; College of Engineering; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING
Cellulose chains self-assemble at the nanoscale, forming cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and cellulose microfibrils (MFCs), which have been widely incorporated into petroleum-derived adhesive formulations to mitigate environmental and health impacts. However, the microstructure-rheology-performance relations of different morphologies need to be elucidated. This study investigated the dispersion, stability, phase behavior, rheology, and curing behavior of urea-formaldehyde (UF) adhesives modified with wood-derived cellulose nanoparticles, including CNCs, CNFs, and MFCs. Our results show that CNC and CNF were homogeneously distributed in the UF solution, whereas MFCs agglomerated due to a higher degree of entanglement. The addition of CNCs to UF resin allowed precise tuning of the flow properties of the composites with filler content, affecting the properties over several orders of magnitude at concentrations as low as a few percent. Composites with low CNC concentrations (1–3 wt%) were homogeneously dispersed in the UF solution, forming a network between negatively charged CNCs and the UF matrix. However, adhesives with higher CNC concentrations (4 and 5 wt%) disrupted the long-range particle network, causing clustering in the UF-CNC mixture and promoting gel formation- an undesirable form for practical applications. These physicochemical characteristics are well reflected in the adhesion behavior characterized by lap-shear tests.
A facile method for cross-linking of methacrylated wood fibers for engineered wood composites
(Elsevier, 2023) Sarıoğlu, Ebru; Erkey, Can; Karaz, Selcan; Turhan, Emine Ayşe; Şenses, Erkan; Bengu, Basak; Bicer, Aziz; Yarici, Tuga; KUYTAM (Koç University Surface Science and Technology Center); KUBAM (Koç University Boron and Advanced Materials Application and Research Center); Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; Yes; College of Engineering; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING; Research Center
Chemical modifications are widely used to enhance the properties of wood composites and create a strong bonding mechanism for enhancing the dimensional stability, water resistance as well as decreasing carcinogenic formaldehyde emission. Esterification is the most-known modification way to enhance the durability of wood composites, but it does not improve mechanical performance. In this work, we demonstrated a two-step, easy and quick wood surface modification strategy based on microwave heating and UV crosslinking. Firstly, the fiber surface was reacted with methacrylic anhydride, then using methacrylated groups on wood, the fibers are covalently linked. As a proof-of-concept the fibers cross-linked within five minutes under UV radiation using benzophenone solution. Then, the effect of crosslinked wood fiber on the properties of mechanical and swelling of fiberboard were studied. Using SEM, FTIR-ATR, and swelling tests, we investigated the wood-based products' reaction mechanism, morphology, and internal bonding strength. The chemical cross-linking gives stronger bonding, compared to hydrogen bonding, between fibers even in wet conditions, resulting in a cross-linked foamlike structure. Also, wood panels were fabricated, compared to unmodified fibers, the internal bond strength and dimensional stability of fiberboards increased slightly. Overall, these results show that chemical cross-linking of wood fibers can be a fast and promising way to produce multi-functional wood composites.
