Engineered Wood Materials Utilizing Seaweed Biomass as an Adhesive

The increasing concerns associated with petroleum-derived resources call for sustainable renewably sourced alternatives. Engineered wood materials are widely used in the form of panels and particleboards in structural applications, construction and packaging. Wood-products provide multiple advantages such as sustainable feedstocks and lightweight final products that can meet load-bearing requirements for a plethora of applications. However, engineered wood products, such as medium density fiberboards (MDF), most predominately rely on formaldehyde-based adhesives to achieve wood particle/fiber bonding. Such adhesives are not only petroleum-derived but also have detrimental health effects during use (formaldehyde emissions) and at their end-of-life. To further mitigate the environmental impact of construction materials, more sustainable bonding agents need to be investigated. In this work, we hypothesize that the biopolymers within seaweed biomass can form a strong hydrogen bonding network with wood particles, that can be sufficient to create a set of fully biobased engineered wood composites. The use of seaweed as an adhesive would offer the benefits of carbon sequestering and renewable sourcing, as well as non detrimental end-of-life effects. We test our hypothesis using Ulva expansa (Ulva) as a proof-of-concept seaweed species and report the manufacturing of engineered wood composites with varying concentration of waste wood particles and Ulva, as well as a detailed study of their structure, bonding and mechanical properties. We demonstrate that upon hot-pressing, powderized Ulva flows in between the wood particles and provides a strong binding effect. We show that the flexural strength of produced engineered wood composites increases with increasing Ulva concentrations. We further report that the presence of Ulva attractively improves other properties such as water resistance and flammability. To highlight the bonding mechanisms at the biopolymeric level, we perform Fourier-transform infrared spectroscopy (FTIR) studies. We also show that the resulting wood panels can be machined using traditional drilling or laser-cutting methods. Finally, we perform an analysis of the environmental impact of ulva-bonded engineered wood composites.