Preparation and Characterization of Sandwich Structured Materials with Interesting Insulation and Fire Resistance

Abstract

A cellular material in the form of 3-layered sandwich structure material was prepared via sole use of mechanical stirring without any use of a foaming agent, while Tween-80 was employed as a foam stabilizer via a developed in-situ mold casting. The resulting structure displayed a good appearance with no visual defects. The 3-layered composition of the sandwish structure, “nonporous resin layer-porous foam layer-nonporous resin layer”, was examined in terms of the microstructure, density & density distribution, pulverization ratio, mechanical strength, insulation and flame retardant performance. It was indicated from the results that the bonding between the resin layer and foam layer was tight, while the tensile rupture always occurred in the porous layer. Also, the density of the sandwich structure material was symmetrical with “saddle” distribution, and a uniform density for any given layer. The increase in the density at the interface layer provided a good interpretation for the tensile rupture never occurred at the interface. The brittleness resistance of the developed material was significantly improved, and the pulverization ratio was sharply decreased from 9.93% to 0.31%. The material acquired a thermal conductivity and limiting oxygen index (LOI) of 0.0241 W/m ⋅ K and 29.92%, respectively, indicating potential use of such materials broadly in fields of insulation and flame retardancy.