Composite materials manufactured from wood particles modified through a reactive extrusion process

Wood‐based composites such as particleboard and medium‐density fiberboard are currently made with formaldehyde‐containing adhesives. Since the government is continuously developing and implementing very stringent regulations to eliminate formaldehyde emissions into the environment, alternative approaches must be developed to replace these adhesives. This study examined the concept of using a reactive extrusion process as a means of developing a new, formaldehyde‐free binding system for wood composite products. The surfaces of wood particles were modified by grafting maleated polyolefins through a continuous reactive extrusion process. Chemical changes resulting from this treatment were followed by studying the Fourier transform infrared (FTIR), ¹³C nuclear magnetic resonance (NMR), and X‐ray photoelectron spectroscopy (XPS) spectra. The modified wood particles were compression‐molded into panels, which were tested for mechanical properties. FTIR, ¹³C NMR, and XPS data revealed that the chemical reactions have taken place between the hydroxyl groups of wood particles and maleated polyolefins. The mechanical property test results indicated that the composite panels compared favorably with current standard requirements for conventional particleboard. POLYM. COMPOS., 26:534–541, 2005. © 2005 Society of Plastics Engineers