Chitosan was used as environmentally friendly and bio-based scavenger for reducing the formaldehyde emission from medium density fiberboard. Using of chitosan powder showed better capacity of formaldehyde adsorption rather than the chitosan solution. Liquid ¹³C-NMR showed that the free formaldehyde in urea formaldehyde adhesive having chitosan powder was drastically reduced. Additionally, the observed peak at 155 ppm showed that that the chitosan powder was copolymerized with urea formaldehyde adhesive. Increasing the amount of chitosan powder was significantly reduced the emitted formaldehyde. It was shown that the formaldehyde adsorption of chitosan was strongly influenced by the pH value of adhesive composition. The pH value and the adhesive gel time tended to increase with addition of chitosan powder, due to the proton affinity of chitosan. The mechanical and physical properties of panels did not significantly change when the chitosan content as scavenger was raised up to 3%, while a formaldehyde emission class of wood level was achieved. It is supposed that the emission of formaldehyde might well increase again while the reactive sites of the chitosan added were already saturated with formaldehyde. Hence, performing of long-term formaldehyde emission is recommended for further analysis based on the obtained results in this study.

Geopolymer binders are an emerging class of mineral polymer that can be manufactured from natural raw materials and industrial byproducts containing high amounts of silica (Si) and alumina (Al) in mineral compositions. Various ratios of materials used for manufacturing geopolymer binder have been tested to evaluate the bonding performance of geopolymers with wood by means of tests performed on an automated bonding evaluation system (ABES). Tests with a binder based on sodium silicate water glass (Na 50T) are partly promising, which resulted only 10% lower shear strength than that based on urea formaldehyde. The binder characteristics were significantly influenced by changing the ratio of SiO₂:M₂O (M=Na or K) and the ratio solid content to chemical base in the water glass. Expectedly, increasing press temperatures and pressing times showed a positive correlation with the curing performance of geopolymer binder. It was also demonstrated that the binder properties can be changed in wide ranges to obtain binders which fulfill the minimum requirements set by industrial users.

This study was aimed to evaluate the position of lightweight panels and their application in furniture production in Iran by investigating consumers’ behavior and preferences. Here, consumers’ preferences toward effective criteria to choose furniture made of wood-based panels (WBPs) were evaluated on the basis of analytical network process method. Furthermore, respondents were asked about their attitudes and preferences regarding lightweight furniture. The results revealed that the main sub-criteria for buying furniture were product quality, design, price, environmentally-friendly, and guarantee features. Furthermore, the technological feature was the most important criterion affecting consumers buying decisions more than the visual/appearance and economical features of the furniture. Consumers believed that conventional WBPs were heavy for some applications in the furniture. Respondents emphasized that they would buy lightweight furniture, even with a bit more price (5–9%) in comparison to conventional furniture (furniture made of WBPs) if there would be a product guarantee, more varieties of the products available in the market, and environmentally-friendly certification. In general, the consumers showed a willingness to buy furniture made by panels with mid-range density (480 kg/m3 density), but they should have to be sure of the panels’ quality and the furniture made thereof before buying this product.

In this research, a sandwich panel with particleboard as surface layers and rigid polyurethane (PU) foam as core layers (foam-core particleboard) was produced with a one-step in situ foaming process. The effects of hydrofluorocarbon concentration as the blowing agent (BA) on the foam features and physical and mechanical properties of the produced panels were investigated. Typical micrograph of the rigid PU foam showed well-defined closed cells of spherical and polyhedral shapes. It was shown that the number of fractured cells in the foam structure was increased with the addition of BA in the amount of more than 4.5%. The results showed that the bending strength and internal bond values significantly raised with increasing BA concentration up to 6%. Screw withdrawal resistance from the face and thickness swelling were not significantly changed while the BA concentration varied. Edge screw withdrawal resistance and water absorption were drastically decreased when the blowing agent concentration was raised in the whole studied range. ABBREVIATIONS: PU: polyurethane; OH: hydroxyl; PO: polyol; ISO: isocyanate; BA: blowing agent; PMDI: polymeric methylene diphenyl diisocyanate; BS: bending strength; IB: internal bond; SWR: screw withdrawal resistance; TS: thickness swelling; WA: water absorption