Sustainable particleboards: renewable building materials from agricultural and forestry by-products

Abstract

The aim and significance of this research is to develop more sustainable options to standard particleboards by applying a life cycle approach. This research brings together and applies principles and frameworks from industrial ecology. The focus of the research is on the development of sustainable composites based on Australian agricultural and forestry by-products, particularly macadamia shells, pine cones and Eucalyptus capsules, bonded with non-toxic, renewable or recycled environmentally friendly resins. These resins were castor oil-based polyurethane and recycled polypropylene. The first part of the research consisted of a study of appropriate fillers and resins for alternative sustainable particleboards and an assessment of the life cycle environmental impacts of standard particleboards. The second stage explored the feasibility of using the proposed fillers combined with the selected resins. These composites were compared with reference panels based on radiata pine wood. The studied composites were assessed by testing their physical and mechanical properties. Microstructural analysis was also performed. The particleboards with castor oil-based polyurethane were further analysed for their level of formaldehyde emissions. All proposed composites demonstrated exceptionally good physical properties, with results up to 92% lower thickness swelling for the new proposed composites compared with standard particleboards. Composite materials based in castor oil polyurethane recorded up to 360% greater internal bond strength than traditional particleboards, and formaldehyde emissions were 99% lower than those of standard particleboards. The flexural properties of the new proposed composites were, however, 36% - 68% lower than the current practice but still acceptable for use in non-structural applications. The results of the analysis of the samples filled with macadamia shells, pine cones and Eucalyptus capsules bonded with recycled polypropylene and castor oil polyurethane showed that the alternative fibres and resins considered in this study have acceptable properties for use in composites. These new materials were able to ameliorate the identified environmental impacts of standard particleboards and resulted in valuable new panel applications in the built environment, particularly in high moisture environments.