Formaldehyde-derived wood adhesives have dominated in woody composites production up to now, while facing a significant challenge in non-renewable raw materials and the formaldehyde emission. To solve these problems, an eco-friendly soybean protein-based wood adhesive was explored via the addition of renewable cardanol based epoxy (CBE) as cross-linking agent. The curing mechanism and viscosity of the adhesives were investigated and the bonding performance was evaluated with three-ply plywood. Fourier transformed infrared spectroscopy (FTIR) analysis confirmed the formation of new ether linkages and the consumption of epoxy groups in the cured adhesives, thereby improving the thermal stabilities and cohesion. Plywood bonded with the CBE-modified soybean protein-based adhesive reached the maximum wet shear strength of 1.11 MPa (4 wt.% CBE addition), a 48% increase compared to the control, whereas the viscosity of adhesive decreased by 68.2%. The wet shear strength of the plywood met the requirements of the Chinese National Standard GB/T 9846-2015 for interior plywood application. The formaldehyde-free adhesive with excellent water resistance adhesiveness performance shows great potential in woody composites as an alternative to formaldehyde derived wood adhesives.
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http://dx.doi.org/10.3390/polym14142831 | DOI Listing |
Materials (Basel)
December 2024
Division of Structural Mechanics and Material Mechanics, Faculty of Civil Engineering, Cracow University of Technology, 31-155 Kraków, Poland.
In this study, we investigated the vibration of adhesively bonded composite cantilevers consisting of two beech wood lamella and a bondline of flexible polyurethane. The beams had a constant total height, while the thickness of the adhesive layer varied. We analyzed both the driven and free vibration of a single cantilever beam and a cantilever with an additional mass attached to its end.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
International Joint Research Center on High-Value Utilization of Agricultural Waste Biomass Between Jiangsu University, China, and Mie University, Japan, Zhenjiang 212013, China.
Currently, wood-based panels are mainly made from wood and adhesives containing formaldehyde. With the growing demand for raw materials and increasing concern for human health, the use of residues from annual crops to manufacture binder-free biodegradable biomass boards has attracted increasing interest. The aim of this study was to develop a biodegradable bio-board without any adhesives using eggplant straw fibers.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Department of Sustainable Bioproducts, Mississippi State University, P.O. Box 9820, Starkville, MS 39762, USA.
This study explores the potential of using underutilized materials from agricultural and forestry systems, such as rice husk, wheat straw, and wood strands, in developing corrugated core sandwich panels as a structural building material. By leveraging the unique properties of these biobased materials within a corrugated geometry, the research presents a novel approach to enhancing the structural performance of such underutilized biobased materials. These biobased materials were used in different lengths to consider the manufacturing feasibility of corrugated panels and the effect of fiber length on their structural performance.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Faculty of Forestry, University of Belgrade, 11030 Belgrade, Serbia.
The surfaces of beech wood samples were treated with polyethylenimine (PEI) solutions at three different concentrations-0.5%, 1% and 2%-and two molecular weights-low molecular weight (LMW) and high molecular weight (HMW). The effects of PEI surface treatment of wood were characterized by FT-IR spectroscopy, the penetration depth of PEI (EPI fluorescence spectroscopy), the bonding position of PEI (by SEM), the wetting and surface energy, and the water uptake.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Sree Chitra Tirunal Institute for Medical Sciences and Technology, Bioceramics Division, Biomedical Technology Wing, 695011, Thiruvananthapuram, INDIA.
A collagen-inspired helical protein-mimic has been synthesized via topochemical polymerization of a designed tripeptide monomer. In the monomer crystal, molecules arrange in a head-to-tail manner, forming supramolecular helices. The azide and alkyne of adjacent molecules in the supramolecular helix are proximally preorganized in a ready-to-react arrangement.
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