EFFECTS OF 2 FIBER TREATMENTS ON PROPERTIES OF HEMLOCK HARDBOARD

The effects of fiber treatments (stream and acetylation), resin conten t: and wax content on mechanical and physical properties of dry-proces s hardboard made from hemlock were investigated, Sixty 10-inch by 10-i nch by 0.125-inch boards were tested. Various board properties such as modulus of rupture, modulus of elasticity, tensile strength parallel to the surface, internal bond, water absorption, thickness swelling, a nd linear expansion were studied. Test results showed that both acetyl ation and steam pretreatment improved board dimensional stability. Thi s demonstrates that both treatments reduce the hygroscopicity of the h emlock fibers. Water absorption, thickness swelling, and linear expans ion were reduced greatly by acetylation. Increasing resin content sign ificantly improved board mechanical and physical properties. However, some mechanical properties of the boards were somewhat decreased by th e fiber treatment of acetylation.