Preparation And Performance Study Of Sodium Alginate Induced Calcium Carbonate Biomimetic Mineralized Poplar Wood

Wood has many benefits as a common substance,including being eco-friendly,renewable,biodegradable,and biocompatible.However,because of its flammability,fire resistance must be replaced.Although materials like concrete,steel,brick,and plastic can take the place of wood,steel burns more quickly or causes more structural harm than wood.It is crucial to prepare wood that has excellent fire retardant and smoke-suppression properties.Poplar wood has a distinctive honeycomb structure that makes it capable of functionalization,such as increased mechanical strength and fire retardant qualities,and can therefore be a substance with high added value.The cyclic pressure impregnation process is used to create an imitation mineralized wood microenvironment in the cell walls and pores of fast-growing poplar wood,inducing CaCO3 nucleation and growth in situ inside the wood,forming an organic-inorganic hybrid structure,which enhances the physical and mechanical properties of the wood.The method also has excellent application prospects and broadens the range of uses for mineralized wood because it is straightforward,ecologically friendly,and does not result in any byproducts.The conclusion of this study can be summarized as followed:(1)CaCO3 was produced inside the wood using CaCl2 and(NH4)2CO3 solutions by pressure impregnation and precipitation reaction,and it was then analyzed using SEM electron micrographs,FTIR spectra,and XRD spectra;when compared to the control group,the treated wood’s physical and mechanical characteristics demonstrated an 18.75%weight gain(WPG),a significant increase in compressive strength(CS)and flexural modulus of elasticity(MOE)of 31.82%and 47.61%,respectively,but no significant change in flexural strength(MOR);the pyrolytic behavior of the treated wood was significantly suppressed under nitrogen and air atmospheres,where the peak heat release rate(pHRR)and total heat release(THR)were decreased by 41.51%and 45.06%,respectively.This was demonstrated by thermogravimetric(TG)analysis and cone calorimetric data(CONE)analysis.Better flame retardant qualities were demonstrated by the decreased heat release rate,decreased volatile gas content,and dramatically decreased hazard factor.(2)Utilizing the hydroxyl and carboxylate ions found in the molecular chain of sodium alginate,a wood biomimetic mineralization microenvironment based on the biomimetic mineralization principle was effectively created.SEM electron micrographs showed that some of the pores were filled with calcium carbonate and CaCO3 particles were deposited in the cell walls,indicating that sodium alginate can promote the rapid formation of calcium carbonate in wood cell walls and voids;FTIR and XRD analyses confirmed that sodium alginate successfully entered the micro-pores of wood cell walls and induced the in situ production of CaCO3.In the cell wall and voids of wood,sodium alginate can cause the fast deposition and directional crystallization of calcium carbonate;the density,flexural strength,compressive strength,and flexural modulus of the mineralized wood induced by sodium alginate were found to be increased after physical and mechanical property tests;in thermal analysis,the poplar wood with bionic mineralization had higher thermal stability and flame retardant properties.The quantity of calcium carbonate present in the mineralized wood under nitrogen atmosphere was increased by 86.54%in comparison to that impregnated with calcium carbonate alone,according to thermogravimetric analysis.The mineralized wood demonstrated better flame retardancy and smoke suppression properties in the microform and cone calorimetry data,with a 59.51%reduction in Peak heat release rate,30.78%reduction in C/W,and 51.67%reduction in TSP compared to the control group,as well as suppression of CO and CO2 emissions.(3)To determine the pyrolysis kinetic parameters of the control,CaCO3mineralized poplar,and sodium alginate induced CaCO3 biomimetic mineralized poplar,TG studies were carried out using the model-free method and the Coats-Redfern method.According to the Starink and FWO methods,the activation energies’ average values were determined to be 139.74-142.33 kJ/mol,154.79-156.81 kJ/mol,and 148.85150.04 kJ/mol.CaCO3 mineralized poplar and sodium alginate induced CaCO3 biomimetic mineralized poplar higher mean activation energy than the control,indicating that more energy or higher reaction temperature is required for the pyrolysis reaction;according to the Coats-Redfern method,it is known that in the conversion range of 20-80%,the control wood follows more closely the two-dimensional diffusion(D2)in the thermal diffusion model throughout the pyrolysis process;while CaCO3 mineralized poplar and sodium alginate induced CaCO3 biomimetic mineralized poplar are closer to the three-dimensional diffusion(D3)and the third-order stochastic nucleation reaction(F3).