Nanosilver Impregnation
A 400 ppm aqueous dispersion of silver nanoparticles was produced and applied to the specimens using electrochemical technique. The size range of silver nanoparticles was 30-80 nm. The pH of the suspension was 6-7; two kinds of surfactants (anionic and cationic) were used in the suspension as stabilizer; the concentration of the surfactants was three times the nano-silver particles. Empty-cell impregnation process (Rueping method) was carried out in pressure vessel under 3 bars of pressure. After the impregnation, all specimens were kept at room temperature for three months.
Heat-Treatment Process
All specimens for heat-treatment were randomly arranged in an oven. They were heated at 145C for 12 hours. Then, all …show more content…
5). Regression analysis showed a negative R2 between air permeability versus pull-off strength in the control unpainted specimens (Table 1). This indicated that as the permeability increased, the adhesive was more penetrated into the wood texture and failed to stick the dolly properly to the specimens, eventually the pull-off decreased. In the painted un-heated specimens, positive R2 values were observed; in this case, the paint penetrated into wood texture, providing a rather smooth and impermeable surface for the adhesive to stick to; eventually, a positive correlation was formed. All unpainted specimens showed negative R2 with the exception of those heat-treated at 185°C. This showed that penetration of adhesive into the wood texture occurred as permeability increased by heat-treatment [18]; however, at the temperature of 185°C where permeability decreased [18], a positive correlation was observed. Other treatments did not show a general trend, indicating that different factors were involved, such as the effects of heat-treatment on the rigidity and strength of the wood substrate, sticking strength of different paints on differently heat-treated substrate, the fluctuations in permeability, etc. In general, it can be concluded that air permeability can not be considered a good criteria to estimate the pull-off strength in beech wood. Although both properties (permeability and pull-off strength) are dependent on the porous structure of material, but permeability is influenced by the continuous pores while pull-off strength is more dependant on the surface pores, whether continuous or isolated. That is, an isolated vessel can be active in the penetration of adhesive, significantly affecting pull-off strength (Fig. 4-A) and the blockage of the whole vessel would not be important. However, the blockage
A 400 ppm aqueous dispersion of silver nanoparticles was produced and applied to the specimens using electrochemical technique. The size range of silver nanoparticles was 30-80 nm. The pH of the suspension was 6-7; two kinds of surfactants (anionic and cationic) were used in the suspension as stabilizer; the concentration of the surfactants was three times the nano-silver particles. Empty-cell impregnation process (Rueping method) was carried out in pressure vessel under 3 bars of pressure. After the impregnation, all specimens were kept at room temperature for three months.
Heat-Treatment Process
All specimens for heat-treatment were randomly arranged in an oven. They were heated at 145C for 12 hours. Then, all …show more content…
5). Regression analysis showed a negative R2 between air permeability versus pull-off strength in the control unpainted specimens (Table 1). This indicated that as the permeability increased, the adhesive was more penetrated into the wood texture and failed to stick the dolly properly to the specimens, eventually the pull-off decreased. In the painted un-heated specimens, positive R2 values were observed; in this case, the paint penetrated into wood texture, providing a rather smooth and impermeable surface for the adhesive to stick to; eventually, a positive correlation was formed. All unpainted specimens showed negative R2 with the exception of those heat-treated at 185°C. This showed that penetration of adhesive into the wood texture occurred as permeability increased by heat-treatment [18]; however, at the temperature of 185°C where permeability decreased [18], a positive correlation was observed. Other treatments did not show a general trend, indicating that different factors were involved, such as the effects of heat-treatment on the rigidity and strength of the wood substrate, sticking strength of different paints on differently heat-treated substrate, the fluctuations in permeability, etc. In general, it can be concluded that air permeability can not be considered a good criteria to estimate the pull-off strength in beech wood. Although both properties (permeability and pull-off strength) are dependent on the porous structure of material, but permeability is influenced by the continuous pores while pull-off strength is more dependant on the surface pores, whether continuous or isolated. That is, an isolated vessel can be active in the penetration of adhesive, significantly affecting pull-off strength (Fig. 4-A) and the blockage of the whole vessel would not be important. However, the blockage