Manufacture and properties of particleboard using herbaceous plants from a dry river-bed

The variety and quantities of various herbaceous plants available in the dry bed of the Yodogawa River were investigated. Chigaya (Imperata cylindrica Linn.) and seitakaawadachiso (Solidago altissima Linn.) were chosen as the raw materials for the manufacturing of particleboards. The influences of adhesive types, grass species, and particle configurations on board properties are discussed. The effectivenesses of mixtures of urea formaldehyde (UF) resin and emulsion-type isocyanate (E-MDI) resin for upgrading board properties were examined. The internal bond (IB) strengths of boards bonded with only UF or urea melamine formaldehyde (UMF) resin were very small, due to the retardation of resin hardening. Mixtures of UF and E-MDI resins were used to improve the IB and bending strengths of the boards. The resin contents used in these UF and E-MDI mixtures were 10%. The UF and UMF mixing ratios were 10/0, 9/1, 8/2, and 6/4. The mechanical properties and dimensional stabilities of the boards were improved greatly by replacing 20 similar to 40% of the UF using E-MDI. In addition, the influences of particle sizes and configurations on the dimensional stabilities were observed. The water resistance of chigaya particleboards bonded with only polymeric-type isocyanate (P-MDI) resin was small, but the bending strengths of the boards were comparable to those of commercial wood-based particleboards.