Low density particleboard from wheat straw and corn pith

Agricultural residuals, such as wheat straw and corn stalks, are the renewable resources that can be utilized as raw materials for making particleboard. The objective of this research was to characterize the tensile strength (TS) and compressive strength (CS) of low-density particleboard made from wheat straw and corn stalk pith as affected by soy protein-based adhesive, press time, straw particle size, and particleboard density. A particleboard derived from 70% of wheat straw blended with 4% of methylene diphenyl diisocyanate (MDI) and 30% of corn stalk pith blended with 10% of sodium hydroxide (NaOH)-modified soy protein isolate (SPI) had the highest TS and CS. The results showed that NaOH-modified SPI increased the TS and CS of the particleboard. The TS and CS values of the particleboard with larger straw particles were greater than those of the particleboard with small and large straw particles together. The TS and CS of the particleboard increased as density increased. TS and CS increased from 2.11 MPa and 3.01 MPa to 3.24 MPa and 4.29 MPa, respectively, and the density increased from 0.30-0.34 g/cm(3). The changes in the equilibrium moisture content and dimension of particleboard were less than 9.0% and 0.25%, respectively, at conditions of the temperature from 27 to 50 degreesC and relative humidity from 35-90%. (C) 2002 Elsevier Science B.V. All rights reserved.