The result can be suggested that at high amount of uncoated CaCO3 the agglomerate of CaCO3 was easily occurred. So, the reduction of the dissipated CaCO3 particles is affecting the impact strength.
Relatively, the eggshell filler (figure 4b.) present similarly behavior. Figure 5 shows impact strength as a function of filler loading for all of CaCO3 and egg shell filler.