The incorporation of TPS particles in a PP matrix leads to important changes in blends morphology.
The fracture surface morphology of the blends was evaluated by scanning electronmicroscopy (SEM) and the resulting images are presented in Fig. 6.Fig. 6a shows a rigid surface and a weak adhesion between phases,it could explain low values in PP/TPS blends mechanical properties(Table 3).All of the tested compatibilizers provide a significant decrease of the starch particle size. For blends with PPgMA (Fig. 6b), a coarse morphology was visualized. This means that the size of the phases and the lack of adhesion (gaps between TPS and PP) were possi-ble to observed. Furthermore, it should be noted that some starch particles were “pulled-off” from PP matrix during specimen frac-ture, leaving cavities in the fracture surface. It could explain the unexpected decrease in the impact strength following the MA addi-tion. On the other hand, in the samples made with C14, C16 and C18 (Fig. 6c–e) the phases and the typical morphology of dispersed domains immersed in a continuous matrix and a dimension reduction and irregularity of starch particles could be seen.