Fabrication And Mildew Resistant Mechanism Of Nano-Ag/TiO₂ Wood-based Composite Materials

Wood anti-mildew modification and its mechanism of is one of the key scientific concerns for wood efficient use and functional improvement.The goal of this paper is to prepare high-efficiency wood-based anti-mildew materials.We fabricated innovation Nano-Ag/TiO2 wood-based composites and carried out research on the anti-mildew mechanism,preparation and modification of Nano-Ag/TiO2 mildew preventive by advanced detection and analysis devices.The technique and anti-mildew performance of Nano-Ag/TiO2 wood-based composites improved by ultrasonic-assisted and vacuum impregnation were investigated.Further,the anti-mildew mechanism of Nano-Ag/TiO2 wood-based composites were also deeply studied.The main conclusions are as follows:(1)Nano-Ag/TiO2 prepared by the sol-gel method turned out to be the anatase phase crystal type,and it’s the average particle diameter was 32.20 nm.The anti-mildew effect of Nano-Ag/TiO2 was better than that of Nano-TiO2.When the silver-loaded amount was 1%,the anti-mildew effect of Nano-Ag/TiO2 was the best,the antibacterial rates increased along with the addition of irradiation time and reagent concentration.When the concentration of Nano Ag/TiO2 was 0.125%,the antibacterial rates under the ultraviolet and natural light both reached 99.99%.(2)The surfactants and silane coupling agents were introduced to Nano-Ag/TiO2 for dispersibility and stability improvement.The optimum surfactant,sodium hexametaphosphate and the silane coupling agent,KH560 were identified,and the compound modified agent was prepared.The particle size distribution of Nano-Ag/TiO2 added composite modifier became more uniform,the average size reduced 25.74%,and the dispersion effect was remarkable.The absolute potential value of Zeta was increased by 3 times and the compound modified agent system was stable.(3)Ultrasonic-assisted and vacuum impregnation significantly increase the drug loading amount and the anti-wastage rate of Nano-Ag/TiO2 wood-based composites.The ultrasonic power and vacuum degree significant affected on the wastage rate of wood composites and the impact of Nano-Ag/TiO2 concentration on drug loading was outstanding.Based on fuzzy mathematics comprehensive evaluation,the optimal technological parameters for ultrasonic-assisted impregnation method were ultrasonic power of 150W,Nano-Ag/TiO2 concentration of 2%and ultrasonic time of 40min;the optimal technological parameters for vacuum impregnation method were vacuum degree of-0.08Mpa,Nano-Ag/TiO2 concentration of 2%and ultrasonic time of 20min.Nano-Ag/TiO2 entered into the wood tracheid and attached to the wood fiber with great dispersibility.Nano-Ag/TiO2 bonded with wood cellulose by hydrogen-bond association.The maximum degradation temperature of Nano-Ag/TiO2 wood-based composites was increased and the composites thermal stability was improved.(4)The anti-mildew efficiency of Nano-Ag/TiO2 wood-based composites prepared by ultrasonic-assisted and vacuum impregnation were 93.33%and 96.67%respectively,and the anti-mildew performances were 14 times and 14.5 times better than that of the untreated composites.The Nano-Ag/TiO2 mainly existed in the micropores and mesopores of wood,the porosity rates were decreased by 13.24%and 19.70%respectively.The surface hydrophobicity of wood was increased,the static contact angles were increased by 37.51%and 33.90%respectively,and the anti-shrinkage rates were increased by 17.03%and 17.79%respectively.(5)The photocatalytic activity of nano-TiO2was enhanced by Nano-Ag loaded.The anti-mildew efficiency of Nano-Ag/TiO2 was improved by the antimicrobial effect between synergistic Nano-Ag and Nano-TiO2.the dispersion stability of Nano Ag/TiO2 was improved by the effect of static stability and space barrier of composite modifier.Nano-Ag/TiO2 effectively blocked the channels for mold and spores to wood inside,which significantly decreased the wood porosity rate.Hydrophobic groups were introduced by the silane coupling agent KH560,which enhanced wood hydrophobicity,blocked the mold infection of wood and improved the anti-mildew properties of Nano-Ag/TiO2 wood-based composites.