polyurethane rigid foam synthesis using response surface methodology(rsm); morphological study

In this study, polyurethane rigid foams were synthesized using the rsm method. the effect of polyol type, r-index, surfactant content, and foam agent content on the morphology of the foam was studied. sem results revealed that by increasing surfactant content the cell size decreases and the cell size distribution becomes more narrow. moreover, the cell size showed a decreasing trend by increasing foam agent content. also, a similar morphology and cell size were observed for samples with different surfactant and foam agent content, but with a similar ratio of the mentioned factors.  furthermore, by increasing the viscosity of the polyol, the size of the cell decreased.