density and thermal conductivity study of rigid polyurethane foams using rsm

The response surface method (rsm)  was applied to study the effect of different variables including r-index, polyol type, surfactant, and blowing agent content on the density and thermal conductivity of rigid polyurethane foams.  the density of the foams decreased dramatically by increasing the blowing agent content. the other important factor in density was polyol type, in a way that higher density was gained for polyol with higher viscosity. r-index and surfactant content didn’t have an obvious effect on density. thermal conductivity analysis showed that by increasing the blowing agent content, this property increases sharply, moreover a similar behavior with different values was observed for both polyols.