Morphology formation in dynamic vulcanized PP/EPDM blends

The mechanism of morphology formation in PP/EPDM blends and its reactive compounds depends essentially on the structure of the components. By selec tive crosslinking of the rubber phase during the compounding process the former cocontinuous phase morphology of the blend can be purposely changed into a matrix-particle morphology: There, the vulcanized rubber particles become dispersed very finely (< 0,5 mu m) in spite of the higher volume amount of rubber and they are embedded into the thermoplastic matrix. This mechanism of morphology formation is connected with material and heat transport processes interacting in the processing step. Using the results from model simulations it is possible to draw conclusions about the morphology formation process. The formation of characteristic matrix-particle morphology in selectively crosslinked PP/EPDM-blends is essentially influenced by the kinetics of the vulcanization of the rubber phase and occures immediately after adding the curing agent After the fast chemical crosslinking reaction visible in the torque maximum of the laboratory mixer and the produced morphology only distribution processes of the rubber particles improve the homogeneity of the system.