Studies were carried out on interfacial penetration of EPDM and amorphous portion of PP in EPDM/PP blends. Observations made with torsion pendulum

differential scanning calo-rimetry and wide-angle x-ray diffraction indicated that

though no compatibility between EPDM and PP

there existed interfacial penetration and thus partial interfacial compatibility between two amorphous phases. X-ray diffraction studies revealed that unit cell dimensions of PP did not change in the presence of EPDM. The influence of effective network chain density on mechanical properties of usual rubber vulcanizates did not apply in the case of vulcanized EPDM/PP blends.