To enhance the synergistic effect of phosphorus (P) and nitrogen (N) on flame retardant property, four different phytic acid-based NP flame retardants (FR-PAN) were manufactured using phytic acid and urea with various molar ratios, ranging from 1:3 to 1:12. The FR-PAN water solution was used to impregnate poplar wood under vacuum condition, and the thermal degradation performance of the FR-PAN treated wood were investigated. Compared to untreated wood, the PAN-6 (molar ratio is 1:6) group showed a reduction of 57.1% in total heat release and 80.0% in total smoke release. In the combustion, due to the introduction of P and N, FR-PAN generates O=P/C-O/C-P/C-N bonds, forming highly graphitized char residues, which effectively isolate the entry of oxygen and heat and play a good protective role in the condensed phase. Morphological and chemical analysis of the residual char layer revealed that the introduction of P and N elements formed a more stable hybrid structure, significantly improving the thermal stability of the char layer. Among them, the PAN-6 group exhibited the highest char layer stability, indicating optimal synergistic effects of nitrogen and phosphorus under these conditions.

This study aims to investigate the influence of thermal modification (TM) on the physical and mechanical properties of wood. For this purpose, the experimental part focused on selected influential parameters, namely temperature, residence time, and density, while the four-point bending strength is obtained as the output parameter. The obtained experimental data are stochastically modeled and compared with the model created by genetic programming (GP). The classical mathematical analysis obtained treatment parameters in relation to the maximum bending strength (T = 187 °C, t = 125 min $\rho$ = 0.780 g/cm³) and compared with the results obtained by genetic algorithm (GA) (T = 208 °C, t = 122 min, and $\rho$ = 0.728 g/cm³). It is possible to obtain models that describe experimental results well with stochastic modeling and evolutionary algorithms.

This paper presents differences in the drying behavior of red oak and yellow-poplar sapwood, heartwood, and bark and their relationship with selected physical characteristics. Drying experiments were performed on samples of sapwood, heartwood, and bark of respective species at 105 °C under nitrogen conditions. In addition, physical characteristics such as green moisture content, specific gravity, volumetric shrinkage, shrinkage of the cell wall, total porosity, pore volume occupied by water, and specific pore volume were calculated. The results showed that the volumetric and cellular shrinkages of sapwood were greater than those of heartwood for both species. For red oak, the specific gravity of sapwood and heartwood was not significantly different. Additionally, the total porosity of heartwood was lower than that of sapwood in red oak. The results also indicated that yellow-poplar dried faster than red oak. Among all three components, bark dried faster than sapwood and heartwood in both species. The activation energy for sapwood drying was less than for heartwood drying.