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 ofbiomass utilization for natural fiber-based composites from agricultural (bagasse) and Chinese tallow tree (Sapiurn sebijerum) fibers. The mixing ratios were 100:0,75:25,50:50,25:75, and 0: 100 ofbagasse and tallow tree fiber, and the firnish 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 amixed resin system of 1 percent MDI and4 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 properties which were not statistically different from higher proportions ofSapium 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 ofthe composites. MDF made from 8 percent MC bagasse fibers obtained a 63 percent increase in modulus ofrupture (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.