Modeling and optimization of formaldehyde‐free wood composites using a Box‐Behnken design

Abstract A response surface model using a Box‐Behnken design was constructed to statistically model and optimize the material compositions‐processing conditions‐mechanical property relationships of formaldehyde‐free wood composite panels. Three levels of binding agent content, pressing time, and press temperature were studied and regression models were developed to describe and optimize the statistical effects of the formulation and processing conditions on the mechanical properties of the panels. Linear models best fit both the flexural strength (modulus of rupture [MOR]) and internal bond (IB) strength of the panels. Increasing any of the manufacturing variables resulted in greater MOR and IB strength. Flexural stiffness (modulus of elasticity [MOE]) was best described by a quadratic regression model. Increased MOE could be obtained through higher pressing times, binding agent concentrations, and/or pressing temperatures. However, binding agent concentration had less effect on increasing the MOE at higher pressing temperatures. Numerical optimization showed that formaldehyde‐free panels with desired mechanical properties could be manufactured at pressing temperatures ranging from 187.18 to199.97°C, pressing time from 3.31 to 8.83 minutes, and binding agent concentration from 7.66 to 11.86%. POLYM. COMPOS., 27:497–503, 2006. © 2006 Society of Plastics Engineers