Vitrocrystalline foams produced with EPS as pore former: Processingand characterization

tIn this work, discarded soda-lime-silica glasses (from glass bottles) and expandable Styrofoam, EPS(d50< 1 mm) were successfully converted into vitrocrystalline foams for thermal insulation applications.Physical, chemical and thermal properties of the selected and prepared raw materials (wastes) were char-acterized. Batches containing well mixed glass powder (d50< 5 m), EPS powder beads (10–40 vol.%) andBonder Plus®(Na2SiO3solution) were prepared so that powder compacts uniaxially pressed at 20 MPawere obtained. The powder compacts were dried at room temperature for 24 h and then fired at 850◦C,10◦C/min for 30 min. Vitrocrystalline foams with interconnected cells sizes between 150 and 850 m,homogeneously distributed in a crack free matrix were produced and characterized from the point ofview of their typical physical, chemical, morphological, thermal conductivity and mechanical properties.The results showed that it is possible to obtain vitrocrystalline foams (cristobalite and devitrite as crys-talline phases), with porosity up to 90%, compressive strength of 2.75 MPa and thermal conductibilityof 0.06 W/m K, for foams containing 40 vol% of pore former. The magnitude of the measured propertiesof the produced vitrocrystalline foams are adequate for a number of applications requiring low thermalconductivity.