The Study Of Modification Of Wood Fibers By Sol-gel Technology And Performance Of Fiberboard

The fast-growing poplar has some shortcomings, such as flammability, low hardness, poor dimensional stableility, etc., which limits the application range. In this project, we put forward to a new idea of designing and controlling structures and composites of wood fiber materials on the level of nanometer or cell by sol-gel technology through imitating or improving natural composites under low temperature, which will endow the materials higher performance. The key step in our method which distinguishes from other traditional ways lies in the introduction of sol into nano lumen and cell of fiber. The congregation and subsequent reaction with the polar groups locating in specific positions within wood cell will lead to a great deletion or reduction of the amount of the polar functional groups within fiber materials, which is a puzzling difficult problem that the scientists in wood industry have encountered for long time.Some conclusions were obtained as follows:1) With cheap FeCl3 as raw material, iron hydroxide sol modified poplar woodfibers were prepared. IR and TG suggested that hydrophilic property had been greatly reduced and the thermal stableility had been enhanced for iron oxide-wood fiber nanocomposites, which proved it is feasible to modify wood fibers by sol-gel technology.2) With TEOS as precursor and boric acid as additive, Si-B sol was produced, and was applied to modify poplar wood fibers. The results showed that the diameter of the sol is 1.794 nm, which can enter the wood fiber cell (the amount of Si in cell wall is 3.79%) resulting the largest WPG of fibers, when the ratio of H2O and TEOS was 10. FTIR suggested that Si-B sol had reacted with hydroxyl of fibers. TG showed that thermo-stableility of modified wood fibers had been greatly enhanced.3) The performances of fiberboard from modified wood fibers through Si-B sol reached national standards, and the CONE and white-rot and brown-rot fungi test exhibited that the fire resistance and white-rot decay-resistance and brown-rot fungi-resistance performance of this fiberboard were good.4) With TEOS as precursor and boric acid as additive, Si-P sol was produced, and was applied to modify poplar wood fibers. The results showed that the diameter of the sol is 1.720 nm, which can enter the wood fiber cell (the amount of Si in cell wall is 1.33% and P is 1.07%) resulting the largest WPG of fibers, when the ratio of H2O and TEOS was 30. FTIR suggested that Si-P sol had reacted with hydroxyl of fibers. TG showed that thermo-stableility of modified wood fibers had been greatly enhanced.