Effect of surface-modified clay on the thermal stability and insulation of polyorganosiloxane foam

Abstract

Polyorganosiloxane foam(SIF) nanocomposites reinforced with vinyl-modified montmorillonite(Mt-V) and hydroxyl-modified montmorillonite(Mt-OH) were prepared through cross-linking and foaming. The effects of modified Mt on the density, pore morphology, and thermal and compressive properties of the prepared polyorganosiloxane foams were investigated. The structure of the polyorganosiloxane foam was studied by solid-state nuclear magnetic resonance analysis. Clay dispersion in polyorganosiloxane nanocomposites and pore morphology were investigated by X-ray diffraction and scanning electron microscopy analyses. The thermal and mechanical properties of the prepared materials were also evaluated by differential scanning calorimeter, thermogravimetric analysis, thermal diffusivity and compressive strength. The results show that Mt-V exhibits improved cell structure, thermal insulation, and crush compressive than Mt-OH. The addition of modified Mt reduces the density, cell size, and thermal conductivity but increases the high-temperature resistance and compressive strength of the nanocomposite. The amount of the residues of SIF/Mt-OH nanocomposites increases by 9% compared with that of the pure SIF. Furthermore, SIF/Mt-V decreases the thermal conductivity to 0.014 W/mK and the cell size to 98 μm. Those properties give the material potential application value in the aerospace and construction industry.