| Manufacture multi-functional new composite materials of inorganic nanometer/wood by effectively loading the inorganic nanometer materials on the wood surface has great research values and practical significance to the persistent, functional and high value-added utilization of woods. However, the traditional dipping or mechanical brushing of the inorganic nanometer materials on the wood surface is easy to cause problems such as uneven dispersion and poor bonding property with the matrix interface, which makes it hard to realize the small size effect and surface effect and further restricts the full play of the properties of nanometer materials and the improved properties of woods. Therefore, the key to seek new in-situ grown nanometer material technology on the wood surface and overcome the defects of the traditional methods is to develop high value-added and multi-functional composite materials of inorganic nanometer/wood.In view of the above problems and on the basis of the wood components'characteristics of avoiding high temperature treatment, this paper presents a new thought of low-temperature-cosolvent hydrothermal method to grow inorganic nanometer materials on the wood surface. This method combines the hydrothermal crystallization method and solvothermal method, which cultivates nanocrystalline on the wood surface in advance and grows7kinds of inorganic nanometer crystal layers on the wood surface through the hydrothermal energy induction and surface active agent self-assembly. They are TiO2, ZnO, SiO2, CaCO3, MnO2, simple substance Ag and binary composite nanometer material TiO2-ZnO. This paper detailedly studies the technique of growing inorganic nanometer materials on the wood surface and systematically discusses the nanometer materials'feature, size and the crystallization properties and the controllable manufacture of crystalline, and also examines and analyzes the improved wood inherent properties and special properties derived from the nanometer materials. The major research contents and conclusion of this paper are as follows.1. Manufacture the titanate nanotubes and make profound analysis on its influence technique. The results show that TiO2of precursor anatase experiences the transition process of "particle-slice-tube-line" in the strong base hydrothermal environment. The concentration of NaOH, the temperature and time of hydrothermal all influence the formation and photecatalytic activity of titanate nanotube. The manufactured titanate nanotubes have good thermal stability and it can still keep complete tubular structure under500℃calcinations and at this time the photocatalytic activity of nanotubes is better. The research results provide a good theoretical guidance and early-stage preparation for the development of manufacturing outer-loading inorganic nanometer/wood functional materials through low-temperature-cosolvent hydrothermal method.2. Realize the controlled growth of nano TiO2on the wood surface and carry out the analysis and characterization of the characteristics and properties of the manufactured TiO2/wood functional materials. The results show that:(1) the reaction time, temperature, chemical environment and the added amount of precursors tetrabutyl titanate have significant influences on the feature, dimension, size and growing amount of anatase TiO2. Between temperatures of70℃～100℃, continuously-growing TiO2crystal layers of different particle sizes, features, dimensions and growing amounts. The particle sizes will transit from the typical nanometer scale to micron scale; features transits from nanoparticles to smooth sphere and one-dimensional scale and the growing amount increases from9.6%to32.6%.(2) After90-day cold-water dripping, the water absorption of outer loaded TiO2/wood decreases by11times of the material and there is little changes on the diametric plane, flat grain face and dimension of woods. By different humidity (20%～90%), the water absorption of outer loaded TiO2/wood is nearly3times lower than that of material and the size change is about20times lower than that of material; MOR and MOE has no significant change compared with materials.(3) Carry out secondary modification of anatase TiO2on the wood surface and cover the surface active agent SDS with lyophobic long-chain alkane under the hydrothermal effect on the surface of TiO2to manufacture hydrophobic TiO2/wood, with maximum water contact angle (WCA) of154°.(4) Successfully grow anatase TiO2and rutile phase TiO2microspheres layer on the wood surface. After1200-hour UV irradiation accelerated aging test, it is found that outer loaded rutile phase TiO2/wood owns significant uvioresistant erosion ability and protects the material color on the wood surface from photochromatism.(5) Anatase TiO2/wood has good antibacterial property and photcatalytic degradation of gas formaldehyde; the sterilization rates of escherichia coli and staphylococcus aureus are94.7%and92.6%respectively under the stimulation of4-hour ultraviolet light; and the degradation rate of gas formaldehyde can amount to98.7%in168hours at room temperature.(6) The burning tests show that, the grown TiO2inorganic crystal layer on the wood surface can prolong nearly2times burning time compared with that of material and significantly reduce the smoke release a quantity when material is burning.3. Pre-cultivate ZnO crystal seeds on the wood surface and successfully grow ZnO nano materials with different features on the surface by adopting low-temperature-cosolvent hydrothermal method and Zn source inducement and self-assembly of surface active agents. At the same time, systematically explore the influences of the different hydrothermal temperature, time, Zn source concentration and precursor proportion on ZnO crystal features, growing amount and crystallization properties as well as the growing mechanism of ZnO nanometer materials with different features on the wood surface. The results show that:(1) The influences of the different hydrothermal temperature, time, Zn source concentration and precursor proportion on ZnO crystal features, growing amount and crystallization properties are significant and the appropriate conditions for ZNA perfectly crystallized on the wood surface are:90℃C hydrothermal temperature,2.5h reaction time,0.015M precursor concentration and HMT A and zinc nitrate with molar ratio of1:1.(2) After90-day-cold water dipping, the water absorption of ZNA/wood is nearly4times lower than that of material; ASE decreases from67%to35%; water contact angle drops from118°to merely106°in20s, in which case that the water contact angle of wood material has dropped to0°. The water absorption of ZNA/wood with different relative humidity (20%～90%) in the90days is tested, with a maximum hygroscopic capacity of14%and not significantly different from18%of the material. The size change of ZNA/wood with different relative humidity is much smaller than that of material. MOR and MOE of ZNA/wood have no significant damage compared with that of material.(3)1,200-hour ultraviolet accelerated aging test shows that ZNA/wood has good uvioresistant erosion ability and the integrated color difference is not apparent, which is only about a quarter of that of wood material.(4) The water contact angle of ZNA/wood is118°and reaches156°after secondary load of DTMS. The super hydrophobicity is good.(5) Under UV irradiation at room temperature, the degradation rate of ZNA/wood on methyl orange solution with pH=6.86within5h is80%. The influences of environment temperature and solution pH values on the degradation rate on methyl orange solution are significant.(6) Under the self-assembly effect of surface active agents such as ethidene diamine, triethyl citrate, lauryl sodium sulfate and urea, on the wood surface, ZnO nano materials with different features of needle, dish, flower, sphere and others grow and the influence of different features on uvioresistant ability, surfacial wettability and photocatalytic degradation ability is significant. After1200-hour uvioresistant irradiation, ZnO/wood integrated color differences of different features in increasing tendency are nano needle, nano flower, nano dish and nano sphere. After DTMS modification, WCA of outer loaded ZnO nano needle, nano flower, nano dish and nano shpere/wood are respectively153°,151°,134°and126°; ZnO/wood of different features all have hydrophobic effect or super-hydrophobic effect; and their degradation rates on methyl orange in300minutes'uv irradiation are80%,78%,75%and62%.(7)Explore and discuss the growing mechanism of ZnO nanometer materials of different features on the wood surface and ZnO crystal nucleus formed by precursor free ions'decomposition under hydrothermal condition. Crystal nucleus grows under the controls of hydrothermal energy, precursor decomposition ability and the reaction medium. With the aid of self-assembly function of surface active agent, ZnO nano materials of different features on the wood surface forms on the wood surface. 4. By preparing precursor solution containing different inorganic free ions and adopting low-temperature-cosolvent hydrothermal method, grow5kinds of nano materials such as SiO2, CaCO3, MnO2, simple substance Ag and binary TiO2-ZnO material respectively on the wood surface and carry out analysis and characterization and property tests on the manufactured composite materials. The results show that:(1) Amorphism nano SiO2grown on the wood surface has the features of particle, sphere and line and the growing amount should increase from7.12%to14.26%. SiO2bonds with hydroxide radical on the wood surface to be connected together. The manufactured SiO2/wood has certain uvioresistant erosion ability.(2) Nano CaCO3grown on the wood surface has features of particles, spindle, square, sphere and others. The growing amount should increase from4.25%to10.72%. The grown CaCO3can improve wood surface hardness by about55%.(4) body-centered tetragonala-MnO2grown on the wood surface has the features of particles, cosh, line and others. The growing amount should increase from4.26%to11.24%. WCA of MnO2/wood is142°.(5) On the wood surface, nano Ag particles with face-centered cubic structure grow and the manufactured Ag/wood owns99.2%sterilizing rate of escherichia coli.(6) Try to grow binary TiO2-ZnO nano composite materials on the wood surface. The results show that wurtzite ZnO and anatase TiO2can successfully load on the wood surface under the effect of hydrothermal energy and the manufactured outer loaded TiO2-ZnO/wood owns90%degradation rate of methyl orange solution in300minutes.5. Put forward the mechanism of growing inorganic nanometer materials on the wood surface. The woods are set in the solution or colloid containing inorganic free ions or colloidal particles, which will grow into nanometer materials with the hydrothermal energy effect. The groups generated on the surface react with hydroxide radical on the wood surface and forms hydrogen bond, in this way to be connected on the wood surface and further generate the inorganic nanometer crystal layer on the wood surface. Finally, the wood properties are improved and new special properties are derived.
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