Exploring the sustainability potential of an algae-based wood adhesive : Comparative and explorative environmental life cycle assessment of algae- vs. formaldehyde- based adhesives for particleboard production

Sammanfattning: Adhesives used for wood composites such as particleboard are conventionally of petrochemical nature with formaldehyde as a base substance and represent a pain point in the industry due their toxic emissions. Consequently, adhesives are subject to an agenda to develop more benign, low-impact alternatives. On the one hand, the issue has been addressed by means of optimisation of composition and amounts, and on the other hand, development of biobased adhesives from different renewable feedstock has been taking place over the past decades. Yet, these bio-adhesives remain a niche segment as renewability or lower toxicity alone is widely not enough despite increasingly strict regulations on formaldehyde emissions. Emphasis on a more comprehensive set of beneficial properties of ‘green’ adhesives is needed for successful adoption in the market. In this context, this study investigates the holistic sustainability potential of a yet untapped bio- adhesive feedstock: macroalgae. Current research on an algae-based adhesive from cultivated biomass in Sweden suggests suitable adhesive properties for particleboard manufacture. Complementing these promising findings on material properties, this study assesses sustainability of using an algae-based adhesive in a particleboard production system as opposed to conventional formaldehyde-based resins. A comparative cradle-to-gate life cycle assessment of different scenarios was conducted, with the specific aim to explore changes in toxicity, climate change impacts and eutrophication due to the known benefits of cultivated macroalgae in these areas. A considerably better performance for algae-based adhesives was found across impact categories (CML baseline method) compared to formaldehyde-based scenarios, as well as a similar pattern with respect to cumulative energy demand. Particularly under a low-impact preservation method for the algal biomass, relative impacts were substantially lower without exception. Furthermore, a potential for carbon sequestration and replacing of fossil with biogenic carbon flows was identified, as well as bioremediation of location eutrophication through nutrient uptake of the biomass during cultivation. Despite the early stage and the need for further research, the results point to a promising potential for macroalgae as a feedstock for biobased wood adhesives which go beyond renewability.