Preparation, Properties, and Bonding Utilization of Pyrolysis Bio-oil

The rapid increase in energy consumption, limited fossil fuel resources, and environmental concerns have stimulated research need for biomass- derived fuels and chemicals. Pyrolysis is a thermal degradation process of biomass in the absence of oxygen. The liquid product from pyrolysis is known as bio-oil. Currently, it can be used as an energy source as well as feedstock for chemical production. In this chapter, we first discuss the pyrolysis process used in the preparation of bio-oil and its chemical components and properties. The bio-oil obtained from pyrolysis process is a multi-component mixture of molecules with different molecular weights derived from depolymerization of cellulose, hemicellulose, and lignin. Then, we review the current research progress of bio-oil in wood bonding utilization. Bio-oil can be blended or synthesized with commercial chemicals to prepare phenol formaldehyde (PF), polymeric diphenylmethane diisocyanate (pMDI), epoxy, and starch resin/adhesive. These bio-oil modified/blended adhesives have been applied in plywood, oriented strand board (OSB), particleboard, and flakeboard manufacturing. 261Finally, we conclude with discussions and future research directions. Efforts still have to be made to meet the challenges of making quality comparable products at a reasonable cost. Future research should focus on improving resin properties, developing new phenol separation/oil processing technology, and optimizing panel press parameters. Moreover, the bio-oil production process should also correspond with its target application to make better use of its potential as renewable resources.