Technologies

CNR-ISTEC develops geopolymer composites for thermostructural applications, such as: self-supporting cavities; thermal and acoustic insulation; thermal and fire barriers; high temperature coatings and damping; molds and cores for foundry; foams and refractory linings. Geopolymers are chemically bonded materials at T <300 ° C. Being inorganic polymers without water in the structure, they tolerate high temperatures: they are incombustible, do not emit gas or fumes and do not explode.

Geopolymers are synthetic inorganic polymers obtained from an aluminosilicate powder and an aqueous solution of alkaline hydroxides or silicates. The material is mesoporous and a multidimensional and functional porosity can be generated through the addition of fillers or the use of specific techniques.

The mix-design of the mixture, pure or composite, allows to change the chemical-physical properties of the final material, also thanks to the nucleation of zeolitic phases. Geopolymers also possess ion exchange and electrostatic interaction capabilities.

Mirrors for space applications, besides featuring suitable optical properties, should be light, resistant to mechanical stresses, and unsensitive to light-shadow thermal cycling. The standard optical materials easily fulfill optical and thermal requirements, but are fragile, and the mirrors must be thick (typically 1/6 of the diameter). For this reason they are heavy, and the only available solution is to lighten them, by removing material from the back side, still preserving the necessary mechanical robustness and optical quality.

The procedure enables the fabrication of nanocomposite membranes filled with suitable amounts of exfoliated bidimensional crystals. These are obtained with an advanced wet-jet milling technique, which provides desired thickness and lateral size of nanofillers through the pulverization and colloidal homogenization of bulk nanomaterials. The bidimensional crystals are dispersed in fluids and suitably delivered inside polymeric matrixes exhibiting a singular morphology.