Effects of mat composition and pressing time on citric acid-bonded ultra-low-density hemp hurd particleboard

Abstract

This study investigated the feasibility of using citric acid (CA) as a biobased and formaldehyde-free binder for producing ultra-low-density (320 to 338 kg/m3) hemp hurd particleboard (ULHPB). Mechanically decorticated hemp hurd chips were milled and then separated into fine (F), medium (M), and coarse (C) particle sizes. Three particle size mixes (PSM) were used to fabricate the panels: 100% C, 100% M, and a 50/50% mixture of CM. Each PSM was combined with low and high CA contents (20 and 30 wt%) and subjected to short and long pressing times (8 and 12 min) at 200 °C. Physico-mechanical characteristics were evaluated following Australian standard AS/NZS 1859.1 (2017) for reconstituted wood-..