## 3 Results and Discussion  
### Drying Curve and Drying Rate  
The trend of change in MC is depicted in Figure 3. The two MC sample boards from each experimental group exhibited basically similar change trends. MC decreased abruptly at first and then decreased gradually when MC reached 30%. The reason could be that during drying, when the MC was higher than the fiber saturation point (FSP), the internal moisture flowed under capillary tension and water vapor pressure. This occurrence was caused by an increase in temperature and moisture along the large capillary system to the moving evaporation interface, prompting evaporation diffusion into the drying medium. At the early stage, the wood had a positive temperature gradient with high internal and low external surface areas, which increased the driving force of evaporation. This process accelerated the drying rate at this stage and reversed the temperature gradient, significantly decreasing the drying rate. Figure 3d shows that the highest MC was obtained by T1, followed by T3 and T2. This result could be attributed to the solidification of the DM/MA resin in the wood conduit and cell cavity, which hindered the outward diffusion of moisture and led to a gradual decrease in the MC of T2. T3 was faster than T2 because of its high initial MC, impeding the complete penetration of modifiers into the interior of the wood conduit during immersion. Thus, a large amount of moisture was still diffused from the large capillary.  
Figure 3: Curve depicting changes in the moisture content of T1, T2, and T3 during drying. 1# and 2# MC curves of T1 (**a**); 1# and 2# MC curves of T2 (**b**); 1# and 2# MC curves of T3 (**c**); Average MC curves of T1, T2, and T3 (**d**).  
The drying rates are presented in Figure 4, and the regression equations obtained using the least squares method and \(R^{2}\) are also presented. The curve trends of the two sample boards in each group were similar. The average drying rates of T1, T2, and T3 were about 0.52%, 0.28%, and 0.33% per hour, respectively. These results are listed in Table 2. As shown in the table, the standard deviation (STDEVA) of the initial MC of the three groups varies between 0.59% and 11.73%, and that of the final MC fluctuates between 0.42% and 1.74%, confirming that the error between different sample boards fell within a reasonable range. In addition, the MCs of T2 and T3 were reduced by about 46% and 37%, respectively, relative to that of T1. Simultaneously, the drying rates of T1 and T2 were close to the fitted regression line. The drying rate of T1 and T2 at each stage was significantly correlated with the regression equation (\(R^{2}\) > 0.8), whereas the drying rate of T3 was more dispersed. The degree of fitting was also significantly correlated with the regression equation; regardless, the degree of fitting of T3 was slightly lower than those of T1 and T2 (Figure 4). The reason might be that after immersion, the drying rate was adversely affected by the curing of modifiers, which hindered moisture migration along the large capillary tube. After immersion of wood at different initial MC stages, the drying rate of the wood was reduced to a similar extent, but the stability of the drying rate was not as good as that at a stage with a lower MC than those of T1 and T2; thus, the uniformity of the effect of impregnation could be determined by the initial MC.  
Figure 4: Curves depicting changes in the drying rates of T1, T2, and T3 during wood drying. 1# and 2# drying rate curves of T1 (**a**), (**b**); 1# and 2# drying rate curves of T2 (**c**), (**d**); 1# and 2# drying rate curves of T3 (**e**), (**f**).