Performance magnesia porous insulation materials preparation process research

Magnesia porous insulation materials were prepared via foam-gelcasting using industrial grade mid-range magnesia powder as the main raw materials, a copolymer of isobutylene and maleic anhydride (Isobam-104) as the dispersing and gelling agent, sodium carboxymethyl cellulose (CMC) as the foam stabilizing agent, and cetyltrimethylammonium bromide (CTAB) as the foaming agent. The effects of processing parameters such as amount of Isobam-104 (0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, and 0.3 wt%) and firing temperature (1300 ℃, 1350 ℃, and 1400 ℃) on magnesia porous insulation materials were investigated. In addition, the universal testing machine (WDW-100E) and the scanning electron microscope (SEM) were employed to characterize the firing samples. The results indicated that the compressive strength of the prepared samples increased with the increase in firing temperature, and the porosity decreased gradually. When the firing temperature was 1350 °C, the internal pores of the samples were uniformly distributed, the average pore size was in the range of 26.2 μm to 35.6 μm, and the compressive strength was in the range of 7.8 MPa to 11.5 MPa when porosity varied from 65.2% to 60.4%. The thermal conductivity of the prepared magnesia porous insulation materials was in the range of 0.481 W/(m·K) to 0.842 W/(m·K).