PA66 / PA6 / POE ‐ G ‐ MAH Alloys with Simultaneous High Toughness and Strength Enabled by a Multilevel Energy Dissipation Mechanism

ABSTRACT A polyamide 6/polyamide 66/maleic anhydride‐grafted polyethylene‐octene copolymer (PA6/PA66/POE‐g‐MAH) alloy with high toughness and tensile strength was successfully prepared via a simple melt blending method, where lots of phase interfaces were constructed around elastomer particles. The impact strength of the PA66/PA6/POE‐g‐MAH ternary alloy with a PA66:PA6 mass ratio of 6:4 reached 69.5 kJ/m 2 , almost three times and two times that of PA6/POE‐g‐MAH and PA66/POE‐g‐MAH binary alloys, respectively. Importantly, the ternary alloys maintained a high tensile strength while achieving enhanced toughness, which was attributed to a novel multistep energy dissipation mechanism. Specifically, the addition of POE‐g‐MAH improved the crack initiation energy through the deformation and debonding of POE‐g‐MAH particles; subsequently, the crack propagation energy was increased by the initiation and growth of crazes along the PA6/PA66 phase interfaces surrounding the POE‐g‐MAH particles. In addition, the crystallization temperature of PA66 significantly decreased with the increase of PA6 content, accompanied by a reduction in grain size, confirming the phase separation between PA66 and PA6 in the ternary alloy and the formation of abundant phase interfaces. Finally, the multistep energy dissipation mechanism was verified by the “bark‐like” impact fracture surfaces, which featured numerous cracks and holes. This work provides a facile and efficient approach for the preparation of polymer alloys with high toughness and tensile strength, with significant potential for practical applications.