Properties of foamed glass upon addition of polysiloxane

Changes in the pore size, porosity, compressive strength, and thermal conductivity of closed-pore foam glass with a pore size of 450 µm upon the addition of 0–24 wt% of polysiloxane at a low sintering temperature of 750 °C were investigated. Micro-Raman analysis demonstrated the uniform dispersion of polysiloxane after sintering, and it was confirmed that the entire foam glass processed to have closed pores. With increasing polysiloxane, the pore size decreased from 452 μm to 131 μm, and the porosity decreased from 62% to 41%. The compressive strength increased from 2.0 to 5.7 MPa, and the thermal conductivity also increased from 0.146 to 0.233 W/m·K. However, when more than 15 wt% of polysiloxane was added, the thermal conductivity exceeded 0.160 W/m·K, rendering unsuitable as an insulating material. Therefore, we fabricated closed-pore foam glass with proper pore size and porosity, a strength of 4.1 MPa, and a low thermal conductivity below 0.160 W/m·K by adding 15 wt% of polysiloxane at a low sintering temperature.