Fluid Flow of Polar and Less Polar Liquids through Modified Poplar Wood

Hamid R Taghiyari,Hanieh Abbasi,Holger Militz,Antonios N Papadopoulos

doi:10.3390/f12040482

Abstract

Fast-growing species often have a low natural durability and can easily be attacked by fungi and insects, and therefore it is often better to preserve them before use. Permeability is a physical property in porous media that significantly affects the penetration of water- and oil-based preservatives into the texture of wood. In the present study, the specific gas permeability and liquid permeability to water and kerosene in poplar wood (Populus nigra var. betulifolia) were measured. The poplar trees were grown in plots with two spacings of 3 × 4 m and 3 × 8 m. Separate sets of specimens were also thermally modified in order to examinethe effects of this modification on gas and liquid permeability values. The results showed higher gas permeability in specimens grown in the plot with wider spacing (3 × 8 m), which was attributed to their larger vessel diameter. Kerosene demonstrated significantly higher permeability in comparison to water. This was attributed to the polar nature of water molecules, which tend to make stronger bonds with wood cell-wall polymers, ultimately delaying the movement of water through vessel elements. Thermal modification had an increasing effect on specific gas permeability. The increase was attributed to cracks that occur in the pits and wood cell wall during thermal modification, making way for the easier flow of fluids. Decreased wettability caused by thermal modification resulted in a significant increase in both water and kerosene permeability values.

Highlights

Wood is a renewable construction material with many applications
The results showed that specific gas permeability values in poplar wood were 11.13 ± 8.9 (×10−13 m3 m−1 ) and 14.25 ± 8.2 (×10−13 m3 m−1 ) in plots with 3 × 4 m and 3 × 8 m spacings, respectively
High variability in the specific gas permeability of some solid wood specimens is quite natural, and it is considered an inherent property [14,15]. This high variability in permeability is further translated into high variability in liquid uptake, which has repeatedly been reported in different poplar wood species [16,17]

Summary

Introduction

Wood is a renewable construction material with many applications. Though it has several advantages over other construction materials, it suffers from some inherent drawbacks, like dimensional instability and susceptibility to some bio-organisms [1,2,3,4,5].Some of these drawbacks can be mitigated through preservation techniques that involve the penetration of preservatives and fire retardants into the porous structure of solid wood.The preservation of wood is considered a practical way to extend the service life of fastgrowing wood species, which are generally categorized as perishable. Wood is a renewable construction material with many applications Though it has several advantages over other construction materials, it suffers from some inherent drawbacks, like dimensional instability and susceptibility to some bio-organisms [1,2,3,4,5]. Some of these drawbacks can be mitigated through preservation techniques that involve the penetration of preservatives and fire retardants into the porous structure of solid wood. The preservation of wood is considered a practical way to extend the service life of fastgrowing wood species, which are generally categorized as perishable. Thermal modification can specially be used to improve dimensional stability in wood and to improve biological resistance to wood-deteriorating fungi [5,6,7,8]

Methods

Results

Conclusion