| In wet conditions, the wood is easy to absorb moisture, mildew and burn when it encountersthe fire, this’s not only reduces the utilization rate of wood, but also hinders the application ofwood in the production and living. In order to solve the problems of wood moist mildew andburn easily, expand the wood application areas, improve the wood utilization rate, this thesisused hydrothermal method to prepare TiO2/wood composite and ZnO-doped TiO2/woodcomposite, explored the influence of reaction temperature T, reaction time t and volume ofTBOT to wood mechanical properties, moisture resistance, flame retardancy and mildewprevention. TiO2had four aspects to protect wood. First, part of the small size of TiO2enteredinto the wood cell, blocked the H2O and O2transport channels, also formed a protective film inthe wood; Second, when the wood burns, TiO2could promote and protect the residual carbon;Third, TiO2was modified by Sodium Dodecyl Sulfate (SDS) has hydrophobic; Fourth, TiO2is akind of photocatalytic antibacterial agent.By X-ray Diffraction(XRD), Energy Dispersive X-ray Spectroscopy(EDX), ScanningElectron Microscope(SEM), Equilibrium Moisture Content(EMC), Anti Swelling Efficient(ASE),Water Contact Angle(WCA), inhibition zone, Limit Oxygen Index(LOI), Thermo GravimetricAnalyzer(TG), Heat Release Rate(HRR) testing and data analysis, the optimal condition toprepare TiO2/wood composite was T=80℃,t=1h,VTBOT=10ml（8.9%v/v）, the minimum size ofTiO2in the wood was10nm~20nm,when the compression was90%, the maximum compressionstrength perpendicular to grain of wood was17632.46MPa. Using SDS to modify TiO2hydrophobicity, improved TiO2/wood moisture resistance, its dimensional stability gain(ΔD)increased24%, EMC was12.3%，ASE was22.5%，WCA was137°, the moisture resistance hadimproved. Put TiO2/wood into the RH=90%environment, its surface didn’t appear a lot ofmould and hyphae, under light, the bacteriostatic circle average diameter of E.coli and S.aureuswere23.8mm,34.8mm, This suggested that the sample could prevent mildew. The LOI of TiO2/wood was30.4vol%, hemicellulose and cellulose pyrolysis temperature increased to270℃and392℃, compared to the blank wood, the samples had flame retardancy.To improve the mildew prevention of TiO2/wood under the dark condition, doped ZnO intoTiO2, prepared the ZnO-doped TiO2/wood composite. The results showed that, ZnO-dopedTiO2/wood had mildew prevention to E.coli and S.aureus in light and dark condition, in lightcondition the bacteriostatic circle average diameter of E.coli and S.aureus could improve16%and25%than under the dark condition. The EMC of wood improved1.17%than blank wood,which showed that the sample had moisture resistance.Through the cone calorimeter testing, thebiggest exothermic peak of ZnO-doped sample delaied380s, HRR maximum value reduced266kW/m2,compared to the blank wood, the ZnO-doped sample had good flame retardancy.This thesis used hydrothermal method to prepare TiO2/wood composite and ZnO-dopedTiO2/wood composite under different reaction temperature T, reaction time t and volume ofTBOT, the samples compression strength perpendicular to grain were increased or decreased, butthe moisture resistance, flame retardancy and mildew prevention had increased when T from120℃to80℃, t from9h to1h, VTBOTfrom2ml to10ml, Especially after doped ZnO, samples under thedark condition also had good mildew prevention, and its flame retardancy had been furtherimproved. |
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