Morphology and Mechanical Properties of the Polyketone/Polycarbonate Blends Compatibilized with Polyamides

To enhance impact strength of polyketone (PK) without loss of stiffness, PK was blended with polycarbonate (PC) via melt mixing. Three types of polyamides (PAs) with varying structures, — polyamide 6 (PA6), polyamide 612 (PA612), polyamide 12 (PA12) — were employed as polymeric compatibilizers. To elucidate the effect of the structure of PAs on the compatibilization, morphology, mechanical properties, and fracture behavior of the blends were investigated. The addition of PA6 and PA612 reduced the size of dispersed particles by encapsulating the PC phase, while PA12 was found not to affect the morphology of the PK/PC blend. The change in particle size, glass transition temperature ( T g ), and elongation at break exhibited that PA6 was the most effective compatibilizer for the PK/PC blends of this study. These results were interpreted with the change in interfacial tension between PK and PA due to the difference in polarity of the PAs. It was found that the impact strength was not highest in the blend with the smallest particle size. The observation of sub-surface damage zone also indicated that effective toughening by intensive crazing in polymer blends requires dispersed particles of optimum size.