Toughening of polyamide 6 with p-nucleated thermoplastic vulcanizates based on polypropylene/ethylene-propylene-diene rubber grafted with maleic anhydride blends

摘要

The toughening of polyamide 6 (PA 6) with p-nucleated thermoplastic vulcanizates (TPVs) based on poly propylene (PP)/ethylene-propylene-diene rubber grafted with maleic anhydride (EPDM-g-MAH) blends was studied. A series of TPVs without and with different dosage of p-nucleating agent (p-NA) were pre pared and used to toughen PA 6 at the same proportion. Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) measurements showed that p crystals of PP were effectively induced in the TPVs. The PA 6 blends toughened with p-nucleated TPVs (p-TPVs) exhibit significantly enhanced toughness, balanced mechanical properties and thermal properties compared with PA 6 tough ened by TPV without p-NA or only by EPDM-g-MAH. Phase morphologies of the blends characterized by scanning electron microscopy (SEM) showed that better interfacial adhesion caused by the migration of p-NA from PP to PA 6/PP interface and PP/EPDM-g-MAH interface gives rise to more uniform dispersion and smaller size of the dispersed phase; moreover, the core-shell structure comprised of rubber particles enveloped by PP on the surface, brings about easier and stronger interference of the stress field of EPDM phase.