The preparation, production and properties of light weight, porous cellulose aerogels in the form of
thin extruded fibers is compared to monolithic pieces. The cellulose aerogels were synthesized from
microcrystalline cellulose in a hydrated calciumthiocyanate salt melt, which upon cooling forms a gel at
around 80 ◦C. Twin screw extrusion experiments were performed systematically yielding thin and wet
cellulose filaments. Washing and coagulation of the wet gels in ethanol was followed by supercritical
drying with CO2 yielding cellulose aerogel filaments. These were characterized with regard to envelope
density, nitrogen adsorption-desorption (BET) analysis, thermal conductivity measurements, tensile and
compression tests and scanning electron microscopy (SEM). The microstructure can be described as an
open porous network of nano-fibrils with pore sizes ranging from 10 to 100 nm and fibril diameters of
around 10 to 25 nm. The densities of supercritically dried (SCD) cellulose aerogels were in the range
of 0.009–0.137 g/cm3 and the BET specific surface areas (SSABET) were between 120 and 230 m2/g. The
cellulose aerogel possessed thermal conductivities from 0.04 to 0.075W/m.K and compressive moduli
up to 16.2 MPa. The tensile strength of aerogel filaments increases with the increasing cellulose amount
in the spin dope. Extruded cellulose aerogel filaments show a dependency of their specific surface area
on the extrusion temperature: the higher the spinning temperature the higher the surface area