The Effect of Aspen Bark from Butt and Upper Logs on the Physical Properties of Wafer-Type and Flake-Type Particleboards

The effect of adding aspen bark from butt, middle, and top logs of two 11 inch DBH aspen trees on the physical properties of 42 lb/ft3 phenolic-bonded flake-type and wafer-type aspen particleboards was evaluated. Flakes 1/2 inch by .015 inch thick and wafers 1-1/2 inches by .025 inch thick with non-tapered ends were cut on a laboratory flaker from tree sections with the bark intact for those boards containing bark. The properties of the wafer-type boards generally were affected by bark when compared to the all-xylem board. Bark from the butt log reduced MOR and MOE 30 percent, increased linear swelling 75 percent, but decreased thickness swelling and increased IB 28 percent each. Adding bark from the upper logs reduced MOR and MOE an average of 15 percent and had little or no effect on lB and linear and thickness stability. The finishes for the 1/2 inch flake-type boards were hammermilled to reduce flake width which in turn reduced the three bark types to the same fineness. MOR and MOE of the flake-type boards were decreased an average of 15 percent regardless of bark position in the tree, but IB was not affected. Butt log bark increased linear swelling 75 percent but decreased thickness swelling 11 percent. bark from the upper logs increased linear and thickness swelling an average of 18 percent and 9 percent respective

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member