Evaluation of Organic-Inorganic Hybrid Insulation Material Using Inorganic Filler and Polyurethane

Abstract

Recently, inorganic-organic hybrid materials have attracted much attention not only for their excellent thermal conductivity but also for their flame retardant properties. In this study, the properties of organic-inorganic hybrid insulating materials using inorganic fillers and polyurethane foam with different foaming conditions have been investigated. The addition of 1.5 wt% water to polyurethane as foaming agent shows the best foaming properties. The pore size was decreased in the foaming body with increasing of the <TEX>$CaCO_3$</TEX> addition. The apparent density and thermal conductivity were increased by increasing the <TEX>$CaCO_3$</TEX> addition. With an increasing amount of <TEX>$CaCO_3$</TEX> powder, the flame retardant property is improved, but the properties of thermal conductivity and apparent density tend to decrease. When the addition of fine particles of <TEX>$CaCO_3$</TEX>, the apparent density and thermal conductivity were increased and, also, with the addition of coarse particles over <TEX>$45{\mu}m$</TEX> in size, the apparent density and thermal conductivity were increased as well. In this study, the adding of <TEX>$CaCO_3$</TEX> with average particle size of <TEX>$27{\mu}m$</TEX> led to the lowest thermal conductivity and apparent density. After evaluation with different inorganic fillers, <TEX>$Mg(OH)_2$</TEX> showed the highest thermal conductivity; on the other hand, <TEX>$CaCO_3$</TEX> showed the lowest thermal conductivity.