Medium-density Particleboard from Saline Jose Tall Wheatgrass

Abstract

Jose Tall Wheatgrass (JTW), Agropyron elongatum, is a salt resistant cropcurrently produced in California to help manage saline subsurface drainage water. There is aneed to find high value uses for such material. The objective of this study was tocharacterize the mechanical properties and water resistance of medium densityparticleboard made from saline JTW. A two- factor factorial experiment design was used todetermine the effects of NaOH treatment and type of adhesives, including polymericmethane diphenyl diisocyanate (PMDI) and Urea formaldehyde (UF) resin, on mechanicalproperties and water resistance of finished particleboards. To study the binding capability ofthe particles, NaOH treatment was used to wash the particles for removing the wax andinorganic silica on the surface of JTW. This study also characterized the effects of differentparticleboard densities (0.71, 0.72, 0.73, 0.74, and 0.75 g/cm3) and initial moisture contents(MC) of the particles (2%, 4%, 6%, 8%, and 10%) on mechanical properties and waterresistance of particleboards. Water resistance and mechanical properties of finishedparticleboard were measured. The water resistance properties included water absorption and thickness swell and mechanical properties included modulus of rupture (MOR), modulusof elasticity (MOE), internal bond strength (IB), and tensile strength (TS). The particleboardsmade with PMDI showed superior mechanical strength and water resistance compared withthose made with UF regardless of the use of NaOH treatment. The NaOH treatmentdeteriorated the mechanical strength and water resistance capability of the particleboards,but did not affect the contact angles between the adhesives and JTW. When the density ofthe particleboards increased, both mechanical strength and the water resistance wereimproved. Among the five MC tested, from the particles of 8% initial MC resulted in the bestmechanical properties and water resistance of the particleboard.