The effect of moisture content on the retention and distribution of nano-titanium dioxide in the wood

Abstract

When chemically treating wood products is used to enhance the properties, the distribution of chemicals in the wood can be more important than the amount of chemical uptake. In this research, two moisture contents (MC) (0 and 25%) were used to study the effect of MC on the nanomaterial retention and distribution in cottonwood (Populus deltoides) sapwood treated with nano-titanium dioxide. The wood samples were impregnated by a full-cell process at three levels of nano-TiO2 concentration: 0,5; 1 and 1,5%. The nanomaterial retention was calculated and SEM images were used to investigate the distribution of nanoparticles in the wood. The results showed that increasing the nano-TiO2 concentration caused more retention and the MC difference caused almost identical retention at 0,5 and 1% concentrations. Although the retention in the 0% MC samples was slightly more than those of 25% MC, this retention was significantly more in these samples (0% MC) at 1,5% concentration. SEM images indicated that the nanoparticles had more uniform distribution in the 0% MC samples than the 25% MC ones and the difference was clearly visible at 1,5% concentration. Low MC ranges (about 0%) are better than high MC’s to impregnate cottonwood samples with nano-TiO2 by using the full-cell process.