Preparation Of Gamma Nano-alumina

Transition aluminas are disordered crystalline phases formed through the thermal dehydration of aluminum hydroxides and or catalyst supports in many chemical processes, including the cracking, hydrocracking, and hydrodesulfuriza-tion of petroleum feedstocks. The utility of V -A12O 3, as well as other transition aluminas, can be traced to a favorable combination of textural properties (i.e.. surface area, pore volume, and pore size) and acidbase characteristics. Synthesis of gamma nano-alumina by precipitation method using aluminum nitrate and ammonia hydrate as the staring materials was investingated. The structure, crystal type and surface state were characterized by means of physical techniques, including IR, SEM, DTA and XRD measurement. The results show that the shapes and sizes of nanoparticles could be controlled and modified by proper calcinations temperature, materials concentration and addition of proper amount of PEG.The particle size is narrow when pH is equal to 8-9, [AlJ+]is equal to 0.2-0.4 mol-"'L, [NH3-H2O] is equal to 1.0-4.5 moK'L, the reactant temper-iture is equal to 50癈, the calination temperiture is equal to 800 癈 . The particle size is equal to 20~80nm.The LDPE (Lower Density Polyethylene) has been toughened and streng-thened by using the nano-AliOs powder and an obvious brittle-tough transformation was characterized by means of physical techniques. The critical content of the nano-Al2O3 is 5% (mass fraction), the flexural-strength and impact-strength of nano-Al2O3/LDPE increases by 54.7% and 50.0%.The major work is summarized as the following:(1) The co-depositoon was used to prepare the nanometer-sized powder y -Al2O3. Efects of concentration of reactants, type of anion, pH value, stirring power, teaction temperature, and drying method on synthesis process and particle properties have been studied.(2) With IR and DTA measurements, phases formed bas been studied.(3) The LDPE has been toughened and strengthened by using the nano-A12O3 powder. The effect grain of ALO3, the quantity of ALO3.