Properties and set-recovery of surface densified Norway spruce and European beech

The chemistry and wetting behaviour of surface densified wood were investigated using FT-IR spectroscopy and contact angle analyses. Furthermore, set-recovery of the surface under conditions of fluctuating humidity was measured and quantitative microscopy analyses were undertaken. FT-IR indicated that no significant chemical changes took place during the densification process. However, the wettability of the densified surfaces was significantly lower than unmodified surfaces. Following several high humidity-oven dry cycles, it was found that this densification process was almost completely reversible, i.e., there was full set-recovery.