Self-assembled multifunctional bulk hollow microspheres: Thermal insulation, sound absorption and fire resistance

Abstract

How to produce materials with thermal insulation, sound absorption and high fire resistance at low cost has always been a challenge for researchers. In this paper, large-size (diameters up to 100 mm) nanoporous materials composed of hollow microspheres with thermal insulation, sound absorption and high fire resistance are prepared by a facile sol–gel method and self-assembly process. Enhanced by adding silicon with a mass fraction of 5–15%, the performance of hollow microspheres is significantly improved. The bulk density, specific surface area, and thermal conductivity of the samples are determined to be 0.069–0.078 g cm−3, 515.6–550.3 m2 g−1 and 0.039 W m−1 K−1, respectively. Significantly, the sound absorption coefficient of the hollow microspheres was detected by the standing wave tube method. The noise reduction coefficient was determined to be 0.283. In addition, the samples remained crack-free and showed high specific surface area and low linear shrinkage even after calcination for 2 h at 1200 °C. This multifunctional material with thermal insulation, sound absorption and fire resistance has potential to be used in building materials in situations where fire requirements are higher.