Penetration and distribution of paraffin wax in wood of loblolly pine and Scots pine studied by time domain NMR spectroscopy

Abstract

Abstract Impregnation of wood with paraffin wax emulsion (PWE) is a common eco-friendly approach for improving water repellency. In this study, loblolly pine (Pinus taeda) and Scots pine (Pinus sylvesteris) samples were impregnated with PWEs with different solid contents and particle sizes, and the influence of the impregnation parameters on wax penetration and distribution in treated wood was elucidated by time domain nuclear magnetic resonance (TD-NMR). A good linear correlation (R2=0.981) between wax content determined by TD-NMR and weight percent gain (WPG) of the impregnated wood was established. According to wax loading and distribution data, loblolly pine has a much better permeability than Scots pine. With decreasing solid content and particle size, the penetration of PWE increases in both species. The water contact angles (CA) on the surface at different depths of wood were also determined, and the CA results were consistent with the wax distribution found by the TD-NMR analysis.