Effect of Mixing Ratio and the Addition Ration of Magnesium Oxide on the Properties of The Rigid Polyurethane Foam in Open Medium

Abstract

The quality of polyurethane foam products is affected by several factors, such as the mixing ratio of the polyurethane mixture and the proportion of additives. This study investigated the effect of varying the mixing ratio of polyol and isocyanate on the density of the final product, and monitored the changes in the overall shape of the cells with varying mixing ratios. The effect of the added percentage of magnesium oxide on the internal structure of the product (at each mixing ratio) was also studied, as was its density and compressive strength.

The results showed that high percentages of isocyanate (80%) are detrimental to the final product and make the structure rigid and lumpy. Increasing the percentage of polyol increases the cell dimensions, while balanced percentages of both allow for a structure with somewhat uniform cells. Experiments have shown that adding magnesium oxide increases the product height during foam formation and reduces the cell dimensions within the structure. However, it is associated with the formation of internal defects in the form of gaps that reduce the product density compared to pure polyurethane. The addition of magnesium oxide at a rate of (5%) at a mixing ratio of (60/40) achieved the highest compressive strength value.