Application of drag-reducing polymers in forest firefighting: Effects on wood properties and mechanism study

Abstract

Based on the successful utilization of polymer additives in drag reduction for long-distance transportation and the intricacies of their application in firefighting contexts, this study investigated the impact of additives on wood properties in forest fire suppression through a combination of experiments and molecular dynamics simulations, focusing on wettability, fluidity, and combustibility. Optimal concentrations of polymer solutions were determined through contact angle measurements and surface flow experiments. The effects of polymers on wood water retention, thermal stability, and microstructure were analyzed using thermogravimetric analysis, infrared spectroscopy, and wood impregnation experiments. Wetting and flow models of polymers on cellulose surfaces were simulated to elucidate the wetting mechanism and dynamic behavior of polymers during flow. The results revealed that polyacrylamide (PAM) and polyethylene oxide (PEO) promoted wood surface wetting, improved flowability, enhanced water retention, and delayed decomposition at optimal concentrations. PAM exhibited superior effects in flow stability, thermal stability, and liquid absorption enhancement, attributed to strong hydrogen bonding between PAM and surfaces, primarily through amide groups. During flow, PAM molecules gradually aggregated and moved as aggregates along the X-axis. In contrast, the PEO system relied on electrostatic forces between water and surfaces, with dynamic processes involving repeated stretching and shrinking of PEO molecular chains to facilitate water flow and enhance wetting. This research contributes to delineating the application conditions and benefits of polymer on wood surfaces, enhancing the efficacy and potential of drag-reducing agents in firefighting applications.