Binderless particleboards from steam exploded woody biomass: chemical and morphological properties relate to their mechanical and physical behavior

Abstract

Wood particleboards are commonly used in the furniture and building sectors and usually contain binders with formaldehyde-based synthetic resins, which raises health and environmental concerns. Pretreatment of wood such as steam explosion allows to modify its chemical and physical structure in order to produce more environmentally friendly binderless particleboards with good bonding-strength and dimensional stability, with an easy processing. In this study, three structurally different wood species (oak, poplar and spruce) were pretreated with pilot-scale steam explosion at different severities by varying temperature and residence time. Particleboards were produced by hot pressing without additives. Mechanical and physical properties were quantified for all particleboards and correlated to structural and morphological properties of pretreated woods. Results highlighted starting material and pretreatment severity impact greatly the mechanical and hygroscopic properties. Overall, the cohesiveness and dimensional ability were improved thanks to the pretreatment compared to the commercial reference. Correlations with physicochemical properties revealed chemical composition and particle size affect internal bonding and thickness swelling of panels while flexural properties are mostly governed by the fibers aspect ratio.