The morphology of hyperbranched polymer compatibilized polypropylene/polyamide 6 blends

The influence of hyperbranched polymer grafted polypropylene (PP‐HBP) on the morphology of polypropylene (PP)/polyamide 6 (PA6) blends has been investigated. The final morphology was strongly influenced by the PP‐HBP compatibilizer concentration. At low concentrations, PP‐HBP acts as an emulsifying agent, reducing the size of the dispersed phase and preventing coalescence. This is due to the high reactivity and diffusitivity of PP‐HBP rapidly forming a high density of copolymers at the interface. Compared to the use of maleic anhydride grafted PP (PP‐MAH) at identical concentrations, PP‐HBP yielded a smaller dispersed phase particle size. Therefore, PP‐HBP allows the use of less compatibilizer to obtain identical morphologies. At higher compatibilizer concentrations, it has been shown that the PP‐HBP efficiently stabilizes the interface and inhibits both coalescence and breakup of the PA6 droplets. The high concentration of reactive sites and the ability of PP‐HBP to react with both chain‐ends of PA6 suggest that interfacial stabilization occurs because of the formation of a partly crosslinked interface. The interfacial stabilization effects generated by PP‐HBP should allow one to control the morphology of polymer blends in order to create specific functional morphologies.