Physical properties of furniture panels from macadamia shells

Abstract

Most food industry activities result in large amounts of by-product that are often treated as waste and sent to landfill. In Australia, the macadamia nut industries generate as much as 28,000 tonnes of empty shells on an annual basis. These by products are under-utilized, often used for garden mulching or ground and used for animal filler, or else incinerated, as their disposal in landfill is cost-prohibitive, through sheer volume. However, these by-products are perfectly suited to the manufacture of panels, as they come clean and dry after processing, and present excellent physical properties when exposed to high humidity environments, particularly when compared to softwood. This makes them suited to applications such as panel furniture in high moisture environments, including kitchen and bathroom sink countertops or drawers where dimensional, swelling and adhesive problems are often an issue. This paper presents results of research into panels made from macadamia industry by-products in Australia, identified as being particularly abundant and underused. The matrices of these composite materials have been chosen from non-toxic and organic bonding agents, such as castor oil based adhesives. The present study considers and explores the suitability of these materials for high-moisture environment panel applications. Results are presented for the main physical properties and are compared with mixes already available in the market. The results show that these new materials compare well with commercially available materials, exceeding their performance in several cases, particularly with respect to water absorption and thickness swelling. These new panels have the potential to become a sustainable replacement option for high-humidity environment furniture particleboards, made with waste resources