Utilizing brewer's-spent-grain in wood-based particleboard manufacturing

Abstract

Brewer's spent grain (BSG) is a major by-product of the beer industry, representing around 85% of their entire by-products. In this research, chemical, physico-mechanical and structural properties of particleboard made with brewer's spent grain (BSG) are presented first time. BSG had even-balanced contents of cellulose, lignin and hemicelluloses, which was at about 20% each. Wood particles were replaced by BSG at percentages of 10, 20, 30 and 50. These BSG-based particleboard types were produced with a common density of 620 kg/m3, bonded with UF resin, and they were tested for modulus of rupture, modulus of elasticity, internal bonding, thickness swelling and water absorption. Scanning electron microscopy was employed to study the inner structure of the boards. Overall, the mechanical properties of BSG-based particleboards were lower compared to wood-based control. Likewise, thickness swelling and water absorption of BSG-based particleboards were found to be higher. SEM images suggested that smaller fraction of BSG tend to cover wooden particles, which may have potentially restricted the internal bonding status. Further, smaller BSG have shown to fill voids in the boards, with the consequence of retaining more water and cause higher swelling and water absorption. Although BSG-based particleboards show altogether a reduced performance, it can also be stated that particleboards having 10% of BSG do meet the requirements for general purpose particleboards, used in dry conditions.