Preparation of the methyltriethoxysilane based aerogel monolith with an ultra-low density and excellent mechanical properties by ambient pressure drying

Abstract

Methyltriethoxysilane based aerogel monoliths with excellent mechanical properties, an ultra-low density, and a highly efficient thermal insulating property were prepared by an improved simple and environmental-friendly ambient pressure drying process. The morphology, particle size, and nano-pore volume of aerogel monoliths were characterized by scanning electron microscope and nitrogen gas adsorption–desorption analyzer. The elastic modulus of particles in aerogel monoliths and the compressive stress–strain response of aerogel monoliths were estimated based upon experimental data obtained via atomic force microscope and materials testing machine. A structural model is proposed to estimate the critical compressive stress with a structural coefficient being introduced to manifest the microstructural integrity of aerogel monoliths. The mechanism for the low bulk density aerogel monoliths to exhibit a linear stress–strain response and a non-buckling failure mode under the uniaxial compression is discussed.