Received: 11 November 2024 Revised: 13 February 2025 Accepted: 14 February 2025 DOI: 10.1002/pc.29690
RESEARCH ARTICLE
Fiber level catalyst-free oxidative carboxylation enhances physical properties of wood polymer composites
Emine A. Turhan 1
| TugayYar ı c ı 2 | Bekir Dizman 3,4 | Nurullah Binay 2 |
Basak Bengu 2 | CanErkey 5 | Erkan Senses 1,5
1 Department of Material Science and Engineering, Koç University, Istanbul, Turkey 2 Department of Research and Development, Kastamonu Integrated Wood Industry, Istanbul, Turkey 3 Faculty of Engineering and Natural Sciences, Materials Science and Nano Engineering, Sabanci University, Istanbul, Turkey 4 Integrated Manufacturing Technologies Research and Application Center & Composite Technologies Center of Excellence, Sabanci University, Istanbul, Turkey 5 Department of Chemical and Biological Engineering, Koç University, Istanbul, Turkey Correspondence Erkan Senses, Department of Material Science and Engineering, Koç University, Rumelifeneri Yolu, Sariyer, Istanbul 34450, Turkey. Email: esenses@ku.edu.tr Funding information TÜB _ ITAK under the 2244 Program, Grant/Award Number: 119C160
Abstract The widespread use of environmentally friendly medium-density fiberboard (MDF) panels as a wood composites is driven by their versatility, affordability, and durability. However, reliance on traditional wood preservatives and modi- fications raises significant environmental, health, and cost concerns due to harmful chemicals. To address this, we present a one-step nitric acid steam oxidative modification on wood fibers to directly introduce carboxylic acid groups on the surface and eliminate the need for catalysts, organic solvents, or complex multistep procedures often used in traditional methods, such as TEMPO-mediated oxidation. Our multiscale characterization techniques revealed significant changes in the morphology, crystallinity, and surface fea- tures of the treated wood fibers, which directly translated to enhanced bulk mechanical properties of the wood composites. Remarkably, the internal bond strength (IBS) of the wood panels increased from 0.27 MPa in untreated panels to 0.89 MPa in panels treated with 5% carboxylated (CA) fibers, suggesting a 3.3-fold enhancement. Additionally, the water uptake of the modified panels was dramatically reduced, with 5% CA-treated panels absorbing only 3.46% compared with 30.38% in unmodified panels, signifying dimensional stability. Furthermore, the curing temperature of the adhesive with CA-treated fibers was lowered by 50 C without reducing composite strength, highlighting signif- icant energy savings. Also, formaldehyde emissions from the 10% CA-modified panels were reduced by 14.82% compared with unmodified panels, aligning with regulatory standards. These findings demonstrate that catalyst-free oxida- tion enhances adhesive bonding and mechanical performance in wood com- posites while providing an eco-friendly method for lignocellulosic fiber modification. Highlights • Catalyst-free, one-step oxidation of wood fibers with nitric acid steam. • Carboxylation greatly enhanced fiber bonding with adhesives. • Modified fibers improved panel strength and reduced water absorption.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. © 2025 The Author(s). Polymer Composites published by Wiley Periodicals LLC on behalf of Society of Plastics Engineers.
Polymer Composites. 2025;1 – 15.
wileyonlinelibrary.com/journal/pc
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