Study Of Nanocomposites Based On Lignocellulose And Wood

Material industry is the basic industry of the national economy; and the new material is the forerunner of development of the material industry, and is an important strategic emerging industry. However, the raw material on the basis of the petrochemical resources is facing on the bottleneck of the sustainable development. Therefore, efficiently developing the renewable and recycling biomass resources in replacing of part of the petrochemical resources is an effective way to solve the bottleneck of sustainable development. With the purpose of making full use of the abundant biomass resources to manufacture advanced materials, and of exploring new ways of value-added utilization of the biomass resources, the study explored the preparation of biomass nanocellulose and nanocellulose-based material by organic-inorganic technology, and creatly built wood-inorganic nanocomposite and wood-organic-inorganic nanocomposite. Then, it preliminary analyzed the microstructure, mechanism and basic properties of each bio-based material from the aspects of structural characterization and properties evaluation. The conclusions are drawed as follows:(1) The study explored different ways on Amorpha fruticosa, wheat straw, poplar wood and ramulus mori to prepare nanocellulose. And it successfully prepared nanocellulose with diameter of 5-30nm and slenderness ratio>1000 by combined mechanical treatments of high-speed grinding and high-pressure homoginization, and with diamerter of 2-7nm and slenderness ratio in the range of 300-1000 by alkaline TEMPO/NaClO/NaBr mediated oxidation. From the results, we concluded that under the same craft, Amorpha fruticosa possessed the most fine and uniform structure of nanocellulose; and the alkaline TEMPO/NaClO/NaBr mediated oxidation system was superior to neutral TEMPO/NaClO/NaClO2 mediated oxidation system on preparation of nanocellulose with fine and uniform diamerter under the same mechanical treatment.(2) nanocellulose and inorganic nanomaterial weakly interacted with each other by their surface functional groups, and the composite retained each original aggregation structure. Therein, nanocellulose-graphene oxide aerogel with density of 2.257mg/cm3 and porosity of 99.86% possessed adsorption capacity of methylene blue of 265.6g/g, which could be regarded as an effective material for sewage purification; further hydrophobic treatment on the aerogel endowed it with hydrophobicity of water contact angle of 132.5° and oil absorption capacity of 125g/g, which could be considered as an effective oil-water separation material. Nanocellulose-inorganic ferriferrous oxide (Fe3O4) aerogel with density of 7.01mg/cm3 and porosity of 99.71% possessed saturated magnetic intensity of 58.6emu/g and remanence of 5.5emu/g and coercivity of 86 Oe, which demenstrating a typical ferromagnetism. It may also be an effective purification material for heavy metal ions as the unit removal rate of 52.63% for Cr (VI). Nanocellulose-inorganic SiO2 nanopaper after hydrophobicity possessed water contact angle of 158°, which demenstrating superhydrophobicity with potential applications in the area of food package and micro fluidic chip.(3) with micrometer capillary system and macrometer capillary system as containers, the study built corresponding wood-inorganic SiO2 nanocomposite with treatment within cell wall and wood-inorganic SiCO2 nanocomposite with treatment on cell wall by sol-gel method, respectively. Therein, for wood-inorganic SiO2 nanocomposite with treatment within cell wall, inorganic nano-SiO2 particles in-situ produced within cell wall as an amorphous state, and chemically bonded to fiber components; the produced content of SiO2 was significantly affected by the initial content of moisture; the higher the content of moisture, the greater the yield of SiO2; the water contact angle of the material after KH550 or KH570 treatment reached 143°, and its maximum pyrolysis temperature was improved 27° over untreated wood, and its wear resistance and decay resistance were also improved to some extent than those of untreated wood. While for wood-inorganic SiO2 nanocomposite with treatment on cell wall, inorganic SiO2 particles presented sphere state with diameter of 300nm, and evenly distributed on cell wall with chemical interaction; after further hydrophobic treatment, the static and dynamic water contact angle of the material both reached 150o, demenstrating superhydrophobicity. The study also built wood-inorganic Fe3O4 nanocomposite with treatment on cell wall bysolution coprecipitation method. The Fe3O4 presented sphere state with diameter of 200-300nm, and evenly distributed on cell wall; after hydrophobic treatment, the static water contact angle of the material reached 151°, and its saturation magnetization value reached 0.513emu· g-1, demenstrating superhydrophobicity and magnetism of the modified wood.(4) The study preliminary prepared organic-inorganic nanocomposite by sol-gel method on the basis of each MMA, PEG200DMA and GMA-PEG200DMA as monomer and TEOS as inorganic precursor, respectively; and further screeningly determined the optimal content of KH570 as 20wt% by thermal stability and distribution of inorganic phase. Then, we prepared wood-organic-inorganic nanocomposite with the optimal content of KH570 and GMA-PEG200DMA as monomer, and the resulting inorganic SiO2 presented sphere state with diameter less than 50nm, and evenly hybridized with organic polymer within wood. The organic-inorganic chemcailly bonded to wood components as an amorphous state, forming a whole material with good interface. The initial decomposition temperature and maximum pyrolysis temperature of the material was improved 55℃ and 53℃ than those of untreated wood, respectively, showing good thermal stability. The bending strength, compression strength, hardness and weight loss against decay degradation of the material was increased by 83%,156% 208% and 77% over those of untreated wood, respectively. Its anti-swelling efficiency was achieved 47% after immersion in water for 228h, indicating satisfying dimensional stability. Such excellent mechanical properties and durability could make it being potentially applied in the fields of construction, packaging and decoration.