Utilization of Chinese tallow tree and bagasse for medium density fiberboard

The objective of this research was to investigate various adhesive systems and determine the best composite formulation for selected mechanical and physical properties of medium density fiberboard (MDF) made from wood and bagasse fibers. This study investigated opportunities of biomass utilization for natural fiber-based composites from agricultural (bagasse) and Chinese tallow tree (Sapium sebiferum) fibers. The mixing ratios were 100:0, 75:25, 50:50,25:75, and 0: 100 of bagasse and tallow tree fiber, and the furnish moisture content (MC) was 4 percent. The resin systems used were 8 percent urea formaldehyde (UF), 2.5 percent MDI (4,4'-diphenylmethane diisocyanate), and a mixed resin system of 1 percent MDI and 4 percent UF. Panels containing 100 percent bagasse furnish were also prepared with either 3.5 percent or 4.5 percent MDI at a furnish MC of 0 percent, 4 percent, and 8 percent. Two mixing combinations (50:50 and 25:75) of bagasse/tallow tree fibers yielded mechanical and physical proper-ties which were not statistically different from higher proportions of Sapium fibers and provided the maximum utilization of bagasse fibers into the panels. The MC of the furnish and additional moisture from the resin applications were significant factors influencing the mechanical properties of the composites. MDF made front 8 percent MC bagasse fibers obtained a 63 percent increase in modulus of rupture (MOR) and a 30 percent in modulus of elasticity (MOE) compared to composites manufactured with 0 percent MC furnish. Panels at all fiber combination ratios with the mixed resin system performed superior to all furnish mixes with 4.5 percent MDI for MOR and MOE. Internal bond (IB) test results showed that the mixed resin system yielded slightly lower IB mean values than panels produced with 4.5 percent MDI.