Purpose of Review: Conventional formaldehyde-based adhesives for wood-based composite panels are subject to significant concerns due to their formaldehyde emissions. Over the past decade, the wood adhesive industry has undergone a considerable transformation that is characterized by a major push in bio-adhesive development. Various bio-based materials have been explored to create alternatives to conventional formaldehyde-based adhesives. Moreover, growing interest in circularity has led to increasingly exploiting industrial coproducts and by-products to find innovative solutions. Recent Findings: Industrial production generates many coproducts that can serve as renewable resources to produce eco-friendly materials. These coproducts offer alternative supply sources for material production without encroaching on food production. Many bio-based compounds or coproducts, such as saccharides, proteins, tannins, and lignocellulosic biomass, can also be used to develop bio-based adhesives. As part of ongoing efforts to reduce formaldehyde emissions, new hardeners and crosslinkers are being developed to replace formaldehyde and bio-scavengers. Other alternatives, such as binderless panels, are also emerging. Summary: This review focuses on sources of bio-based material derived from by-products of various industries, which have many advantages and disadvantages when incorporated into adhesives. Modification methods to enhance their properties and performance in wood-based panels are also discussed. Additionally, alternatives for developing low-emission or formaldehyde-free adhesives are addressed, including hardeners, bio-scavengers, and binderless options. Finally, the environmental impact of bio-based adhesives compared to that of synthetic alternatives is detailed.

Purpose of review: This review explores the opportunities and challenges associated with using unconventional and underutilized wood sources, such as fast-growing species, logging residues, fire-damaged wood, and post-consumer wood, to manufacture wood-based composite panels (WBCPs), particularly particleboard, medium-density fiberboard (MDF), and oriented strand board. This paper also discusses recent advancements in lightweight and multifunctional panels, with new features such as fire resistance, electrical conductivity, electromagnetic shielding, and antibacterial laminates. Recent findings: Climate change, wildfires, and competition from the energy sector threaten current sources of fiber supply for WBCP manufacturing in some regions. Logging residues are abundant but underutilized in some areas, and the abundance of fire-damaged wood is expected to increase in the coming years due to climate change. These raw materials’ effects on panel properties and technological limitations are discussed. Recycled wood is increasingly used for non-structural panels, but challenges remain when it comes to recycling panels, particularly post-consumer MDF. Conventional and emerging materials used in lightweight and multifunctional panels are also presented. Natural substances like cellulose, nanocellulose, chitosan, lignin, protein, and phytic acid are promising alternatives to conventional fire retardants. Innovative products such as MDF that contains carbon-based conductive fibers and antimicrobial laminates that use green-synthesized metal compounds are also reported. Summary: This review shows that the WBCP industry can improve its sustainability by optimizing and diversifying wood sources, better managing and recycling post-consumer panels, and using more environmentally friendly materials. The hazardous chemicals in adhesives, fire retardants, and coatings are the main obstacles to recycling panels and creating a more circular economy within the WBCP industry.

Wood is a porous material that can be impregnated and have enhanced properties. Two species of hardwood, red oak (Quercus rubra L.) and sugar maple (Acer saccharum Marsh.), were impregnated in a reactor with a microencapsulated phase change material. The objective was to enhance the thermal mass of wood boards used as surface layers for engineered wood flooring manufacturing. Preliminary experiments were conducted on small samples in order to define suitable impregnation parameters, based on the Bethell cycle. Thin wood boards were impregnated with a microencapsulated phase change material dispersed into distilled water. Several cycles of pressure were applied. Heating storage of the impregnated wood boards was determined using a dynamic heat flow meter apparatus method. A latent heat storage of 7.6 J/g over 3 °C was measured for impregnated red oak samples. This corresponds to a heat storage enhancement of 77.0%. Sugar maple was found to be harder to impregnate and thus his thermal enhancement was lower. Impregnated samples were observed by reflective optical microscopy. Microcapsules were found mainly in the large vessels of red oak, forming aggregates. Pull-off tests were conducted on varnished samples to assess the influence of an impregnation on varnish adhesion and no significant influence was revealed. Engineered wood flooring manufactured with impregnated boards such as characterized in this study could store solar energy and thus improve buildings energy efficiency. Although wood is a material with a low-conductivity, the thermal exchange between the PCM and the building air could be good enough as the microcapsules are positioned in the surface layer. Furthermore, flooring is an area with frequent sunrays exposure. Such high thermal mass EWF could lead to energy savings and to an enhancement of occupant’s thermal comfort. This study aimed to characterize the potential of impregnation with MPCM of two wood species in order to make high thermal mass EWF.

Purpose of Review In the last decade, a transformation has occurred in the coating industry. While, in the past, the industry was primarily focused on reducing volatile organic compounds (VOC) and formaldehyde emissions, it is now circularity driving this industry. In this paper, we present several advances that have been made, as well as key trends in the wood coatings industry. Recent Findings Replacing petroleum-based chemicals in coating formulations is at the heart of current research. In recent years, various biosourced molecules from animal and plant sources have been the subject of many studies aiming to incorporate them in coatings. Despite all the progress made in the last few years, coating producers are still facing many challenges regarding the availability and quality of biobased raw materials and balancing performance versus cost. Summary While most of the sustainable coating solutions discussed in this review focus on well-known and widely accepted coating chemistries and technologies (water-based and photopolymerizable polyurethanes (PUs), acrylics, and epoxies), we also present new technologies that are expected to gain significant importance in the next few years such as layer-by-layer (LBL), polyelectrolyte complexes, and isocyanate-free PU.

The relatively low thermal mass of timber frame buildings is a limiting factor for their energy efficiency and for the thermal comfort. The aim of this study is to assess the performance of wood-based wallboards integrated with PCM (Phase Change Materials) in a cold climate (Québec, Canada), from the heating season to the summer. Two timber-frame test huts, of 2 × 2.5 × 3 m, were built following the National Building Code of Canada and placed in the LAVAL University Campus. The first hut was equipped with wood-based panels integrated with the commercial bio-based PCM Puretemp^®23 with a 23 °C melting point. The second hut was equipped with standard interior wood panels. Large double glaze windows were installed facing south. Dry indoor air temperatures were recorded for both huts and for the heating season, heating consumptions were monitored. The behaviour of the two huts was compared and PCM panels efficiency was evaluated over several seasons. A reduction of heating consumption was observed for cold months. For the heating season, panels were found to be more efficient as the months were getting milder. By gathering solar energy during the day, they allowed to reduce the test-hut heating consumption, by a maximum of 41% in May. In summer, the PCM panels had a positive impact in order to reduce the hut overheating. However their efficiency was found limited by a poor ability of discharge during the night. The solidification of the PCM was often impossible to achieve due to unsuitable night conditions. The results presented in this study will improve the knowledge concerning wood/PCM composites performance and concerning PCMs issues in cold climates. This study exposes the potential of wood-based panels integrated with PCM to achieve winter energy savings and enhance the summer thermal comfort of a timber-frame building, for a cold Canadian climate.