Preparation,Characterization And Performance Study Of Functional Bamboo Veneer Based On Super-adhesion Gel Coating

Considering the low utilization rate issue of bamboo resources in China,this thesis selects thin and tough bamboo veneers as the substrate for the development of functional facing materials.Two functionalities including anti-freezing and anti-flaming were established and investigated in this study by coating specific hydrogel coatings on the bamboo veneer surfaces.Common physicochemical properties were characterized and corresponding functions were tested in both technical（such as polarizing microscope,cone calorimeter,etc.）and simulated（as facing materials for building）situations.The details are listed below:（1）The surface of bamboo veneer was mildly carbonized with a short-time high-temperature hot pressing method to produce carbonized bamboo（CB）veneer.The resultant CB shows an increase in carbon content and a retained flexibility after mild carbonization.The bending strength of CB is over175 MPa,slightly lower than the original bamboo veneer（200 MPa）.The photothermal trapping effect of CB caused by the porous structure and the darker color helps improve the sunlight absorbance（42%）and photothermal conversion performances.The thermal conductivity of CB is lower than 0.1 W/m K,lower than that of original bamboo（OB）and other building materials,suggesting higher thermal stability and insulation.Therefore,CB has unique mechanical and thermal advantages as a functional facing base material for buildings.（2）By coating a layer of antifreeze functional hydrogel presolution on the carbonized bamboo veneer substrate,and forming a surface gel coating after polymerization,a functional antifreeze-free bamboo veneer（BLB）is made,the BLB surface heat trap limits the heat to the surface,and the surface temperature is roughly increased by 35°C at an ambient temperature of about-20°C at a lighting intensity of 1 k W/m².The TH values of the resisting ions of BLB with Ca²⁺and Cl^-in three antifreeze modes,including ion-only suppression（IIO）,photothermal conversion only（PCO）,and IIO-PCO combinations,were measured at-18°C,-15°C,and-25°C,respectively.（3）A functional flame-retardant double-layer bamboo laminated board（BLB）has been developed by coating a flame-retardant adhesive hydrogel pre-solution onto a carbonized bamboo veneer substrate and forming a surface gel coating through polymerization.The surface gel coating of the flame-retardant BLB contains components such as ammonium polyphosphate,Si O₂,and methyl cellulose,which can exhibit synergistic flame-retardant mechanisms such as solid-phase flame retardation,gas-phase flame retardation,and heat absorption after uniform adhesion to the CB surface.The total heat release（THR）of the flame-retardant BLB is significantly reduced,to 55.4%of that of OB,and the oxygen index is increased from 21%to 31.1%relative to OB,significantly delaying the rate of heat release and reducing the production rate of gases such as CO₂,thus significantly improving the flame retardant and smoke suppression effects of the flame-retardant BLB.