Mechanical and thermal properties of modified red mud‐reinforced phenolic foams

Abstract

A new type of composite based on phenolic foams reinforced with red mud microparticles was prepared using a thermal foaming method. Red mud was ground into ultrafine particles with grain diameters ranging from 1 to 1.5 μm. Silane coupling agent γ‐ureidopropyltriethoxysilane was used to modify the red mud microparticles to improve particle dispersion and adhesion between the particles and the phenolic matrix. The effects of the modified red mud microparticles on the mechanical and thermal properties of the composite were investigated at weight ratios ranging from 0 to 21%. The phenolic foams incorporating 15 wt% of the filler exhibited the best integrated performance. In comparison with native phenolic foams, tensile strength and impact strength were increased by 81.8 and 82.3%, respectively. Furthermore, the addition of modified red mud microparticles to the phenolic foam significantly decreased its thermal conductivity while increasing its limiting oxygen index. A morphological analysis using scanning electron microscopy indicated that incorporation of the modified red mud microparticles into the foam produced relatively small and uniformly sized cells within the material, which indicated that the observed improvements in mechanical and thermal properties were primarily due to the chemical adhesion between the particles and the matrix and good dispersion of particles in the matrix. The reinforced foams described in this study can be used in a variety of applications in the field of heat insulation. © 2018 Society of Chemical Industry

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