In Situ Polymerization of Furfuryl Alcohol with Ammonium Dihydrogen Phosphate in Poplar Wood for Improved Dimensional Stability and Flame Retardancy

Abstract

Fast-growing plantation wood normally possesses some undesirable intrinsic properties, such as dimensional instability, inferior mechanical strength, and flammability, limiting its usage as an engineering material. Herein, we report a green and facile approach for upgrading the low-quality poplar wood via a combined treatment with biomass-derived furfuryl alcohol (FA) and ammonium dihydrogen phosphate (ADP) acting as a flame-retardant additive. Wood/PFA/ADP composites were prepared by impregnation of the FA precursor solutions into the wood matrix, followed by in situ polymerization upon heating to form a hydrophobic FA resin/ADP network within the wood scaffold. In-depth scanning electron microscopy coupled with enregy-dispersive X-ray spectroscopy (SEM-EDX) and confocal laser scanning microscopy (CLSM) analyses reveal the wide distribution of the FA resin/ADP complexes inside the cell walls and also in the cell lumens. The incorporation of hydrophobic FA resin into wood results in reduced water uptake and remarkably enhanced dimensional stability, as well as generally improved mechanical properties. The addition of a small amount of ADP greatly enhances the flame retardancy of the modified wood and also effectively suppresses smoke generation during its combustion by reducing the heat-release rate and promoting char formation, as proven by cone calorimetry. The FA resin/ADP complexes increase phosphorus fixation in wood and reduces its leaching into water, suggesting a long-term fire protection of wood in service. Such modified poplar wood with overall enhanced properties could be potentially utilized as a reliable engineering material for structural applications.

Opening Furan for Tailoring Properties of Bio‐based Poly(Furfuryl Alcohol) Thermoset

“…[18] The addition of PFA in wood allows improvement [19,20] in its dimensional stability, mechanical properties, resistance to fire, and durability to chemicala nd environment attacks. [21] The wood/PFAc omposite is prepared by impregnating dried woodw ith al iquid resin mainly containing FA.T he complex multi-scale architecture of wood [22,23] requires protic polar solvents, [19,24] such as water or alcohol, to efficiently swell the secondary cell wall. [21] The wood/PFAc omposite is prepared by impregnating dried woodw ith al iquid resin mainly containing FA.T he complex multi-scale architecture of wood [22,23] requires protic polar solvents, [19,24] such as water or alcohol, to efficiently swell the secondary cell wall.…”

Fire‐Resistant Structural Material Enabled by an Anisotropic Thermally Conductive Hexagonal Boron Nitride Coating

“…Equation predicts a t ig of 92 s for the BN‐densified wood at an external heat flux of 50 kW m −2 . This is at least 2.3 times as long as most reported fire‐resistant wood samples at that heat flux (Figure c) . Figure d compares the ignition properties of the densified wood and BN‐densified wood.…”

“…a) Critical heat flux ( q crit ) and b) TRP are determined. c) Comparison of the calculated ignition delay time of this work with other reported fire‐resistant wood results at an external heat flux of 50 kW m −2 . (Mg–Al: Mg‐Al‐layered double‐hydroxide; PFA: Polymerization of Furfuryl Alcohol; ADP: Ammonium Dihydrogen Phosphate).…”

“…This is at least 2.3 times as long as most reported fire-resistant wood samples at that heat flux (Figure 4c). [17][18][19][20][21][22][23][24] Figure 4d compares the ignition properties of the densified wood and BN-densified wood. Ignition temperature (T ig ) is calculated by Equation (3):…”

“…Flame retardants interfere with the combustion process during ignition, pyrolysis, or flame spread either through chemical reactions or by acting as a physical barrier . The addition of flame retardants to wood can improve the material's fire resistance without sacrificing the intrinsic advantages of wood materials . Although halogen and phosphorus organic fire retardants can effectively reduce the HRR and enhance the fire resistance of wood, the environmental risks caused by toxic halogen products is problematic .…”