Synthesis and characterization of biopolymer-based aerogel particles
Aerogels being known as the lightest solid materials have a tremendous potential in a wide range of applications, where high pore volume and high surface area play major roles. The low densities (< 0.2
g/cm3), high porosities (> 90% v/v), high specific internal surfaces (up to 1200 m2/g) are extraordinary properties of aerogels, which make them usable materials in many different areas. The preparation
of aerogels heavily relies on supercritical fluid technology and thus cannot be thought as purely chemical synthesis: it necessarily requires the technological knowledge. The overall scheme of aerogel production involves three steps: (I.) formation of a gel through different mechanisms; (II.) solvent exchange; (III.) supercritical drying with carbon dioxide at high pressure (~ 120 bar). During gel formation (I.) in situ shaping is possible: the first step of gel formation significantly determines the physicochemical and mechanical properties of the resulting aerogel. The production in form of beads requires a gelation mechanism which induces a quick formation of a stable gelled layer on the biopolymer droplet surface, stabilizing its shape.
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