Effects of calcium carbonate fillers on mechanical properties of flexible polyurethane foam

Abstract

The flexible polyurethane foam was prepared with adding a small amount of calcium carbonate fillers whose average size of 1 m. The content of fillers in polyurethane foam is varied from 0, 3, 5, 7 and 10 %wt of polyol. The isocyanate index was also varied from 90, 100 and 110. The FTIR spectrum of polyurethane composite foams showed the similar peaks in the observed range. It was shown that the content of urethane linkage group decreased with an increase of calcium carbonate content. However, ether groups are increased with the increase of calcium carbonate content. Scanning Electron Microscopy (SEM) was shown the cell structure of the flexible polyurethane that the open cell structure was similar at all isocyanate index. Furthermore, the tensile strength, hardness and density of polyurethane composite foam tended to increase with increase of calcium carbonate filler but the elongation and resilience decreased with increase of the fillers. Although the soft segment was increased with of calcium carbonate filler, the hardness properties of polyurethane foam increased which could be due to the presence of the fillers. In addition, when the isocyanate index in the foam, the hardness properties also increased. In addition, increasing the isocyanate index would increase the intermolecular interaction between filler and matrix thus the tensile strength and hardness of polyurethane foam composites increased but the elongation at break decreased.