Effects of bark, density profile, and resin content on medium-density fiberboards from southern hardwoods

Abstract

Pressure-regined barky fibers of hickory, sweetgum, and southern red oak had a greater percentage of fines than did refined bark-free fibers of these species. Inclusion of bark decreased tensile and bending strengths of fiberboards by 16 to 18 percent, MOE by 10 to 14 percent, and IB by 8 percent. Density profile of boards strongly influenced their bending properties. Specimens with greatest density variation from face to core were 37 to 59 percent higher in MOR and 32 to 50 percent higher in MOE than specimens with uniform density. Increasing resin level from 8 to 10 percent improved bending and tensile properties by only 4 to 10 percent, but IB was increased by 38 percent linear expansion (50 to 90 percent RH) was greatest in high density boareds and was not affected significantly by inclusion of bark. Thickness swell was significantly less in southern red oak boards than in sweetgum or hickory boards. Inclusion of bark decreased thickness swell of southern red oak and hickory boards but increased it in sweetgum boards.

Citation

Woodson, G.E. 1976. Effects of bark, density profile, and resin content on medium-density fiberboards from southern hardwoods. Forest Products Journal 26(2):39-42