Improvement of dimensional stability of wood by in situ synthesis of organo-montmorillonite: preparation and properties of modified Southern pine wood

Southern pine (Pinus spp.) wood was impregnated sequentially with sodium montmorillonite (Na-MMT; in concentrations of 1%, 2%, and 4%) and didecyldimethylammonium chloride (in a concentration of 2%) in a two-step method to form organo-montmorillonite (OMMT) inside the wood. The impregnated samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy/energy-dispersive X-ray spectroscopy analyses. Moreover, the water absorption, anti-swelling efficiency, compression strength, and surface hardness of the modified samples were investigated. In the first step, wood is impregnated with Na-MMT, and in the second step, Na-MMT is transformed to OMMT by in situ synthesis and the silicate layers of the clay are intercalated into the cell wall. As a result, the dimensional stability of the modified wood was improved as a function of increased clay concentration. The compression strength and surface hardness of OMMT-modified wood were also improved greatly compared with the untreated control.