Study Nano α-Al₂O₃Prepared,Dispersed And Composite Polymer Materials Prepared

In this paper, nano a-Al2O3powders were prepared via sol-gel, co-precipitation and homogeneous precipitation method, respectively.(1) Sol-gel method was employed to prepare the nano α-Al2O3with AlCl3·6H2O and C6O7H8· H2O as raw materials, PEG as surfactant, the effect of the degree of polymerization of PEG, calcining heat and soaking time to the performance of nano a-Al2O3was also studied. The result showed that:with the PEG600as surfactant, the nano a-Al2O3with average particle diameter25nm was obtained via calcined at1075℃for2hr.(2) Co-precipitation method was employed to prepared nano α-Al2O3with aluminium nitrate and ammonium bicarbonate as raw materials. The effect of adding order and velocity, the type of surfactant, the proportion of water and alcoholic in solution, calcining heat, holding time, and seed crystal to the formation of nano a-Al2O3was also studied. The result showed that:With PEG600as surfactant, the aluminium nitrate was added into the ammonium bicarbonate solution, the proportion of water and alcoholic is1:1, and the nano a-Al2O3with average particle diameter32nm was obtained via calcined at1135℃for2hr; therefore, adding seed crystal could make the temperature of phase transformation fall60℃.(3) homogeneous precipitation method was employed to prepared the nano a-Al2O3with aluminium nitrate and ammonium bicarbonate as raw materials; the ammonium citrate was used in the first time to control the formation of precipitation. The influence of surfactant, filtering method, calcining heat, and other technological conditions to formation of nano a-Al2O3was studied. The result showed that:using ordinary pressure filter, the pure nano a-Al2O3with average particle diameter20nm was obtained via calcined at1050℃for2hr. Above there methods were contrasted, the results indicated that:the operating steps of sol-gel method were hardly controlled; the calcining temperature of co-precipitation was high; the homogeneous precipitation had many advantages, such as operating steps were simple, calcining temperature was low, and the size of nano a-Al2O3was small.The nano α-Al2O3was modified using monodisperse method with polymeric surfactant as template. The effect of the content, the component and proportion of surfactant, and pH of dispersion medium to the dispersion of nano α-Al2O3was discussed. The results indicated that:most of aggregates of α-Al2O3were removed via monodisperse method, surface modification and depolymerization. The nano α-Al2O3powders which were easily dissolved in aqueous phase and organic solvent were obtained, and the shape of particle were virgate or longstring.The nano α-Al2O3after dispersed were added into the polymer materials PVC, which could prepare composite polymer materials. The thermal conductivity of the composites materials were researched. the transmission of light and thermal conductivity were researched.The result proved that the thermal conductivity of composite materials had increased with powders added, the powders and PVC had been had chemical bond, and the powders homogeneously dispersed in the PVC and connected with each other formed thermal chain.