PROPERTIES OF HARDBOARDS MADE FROM ACETYLATED ASPEN AND SOUTHERN PINE

The effects of fiber acetylation, resin content, and wax content on me chanical and physical properties of dry-process hardboard made from as pen and southern pine were investigated. Test results indicate that th e modulus of rupture (MOR) and modulus of elasticity (MOE) of the hard board specimens were decreased due to the fiber acetylation. Tensile s tress parallel to face and internal bond (IB) were generally higher fo r untreated boards than for acetylated boards. Water absorption (WA) a nd thickness swelling (TH.S) were both reduced markedly by acetylation . In general, increasing resin content from 3% to 7% brought increases in MOR, MOE, tensile stress, and IB and improved WA and TH.S. Additio n of the 0.5% wax content usually caused reductions in these mechanica l properties, but improved WA and TH.S in some cases. Linear expansion (LE) in the dimensional stability test (from 30% to 90% RH) was signi ficantly reduced by acetylation and influenced by wood species. Neithe r resin nor wax contents significantly affected the LE value of hardbo ard specimens in this study.