Comparing the Continuous Chaotic and Shear Mixing-Induced Morphology Development of Polyblend and its Nanocomposites

Continuous chaotic and shear mixing-induced morphology development of 60/40 w/w polypropylene/polyamide 6 (PP/PA6) blend and its nanocomposite with 5 wt% clay was investigated. PP and PP nanocomposite were mixed with PA6 in a single-screw extruder, respectively. Two screw geometries were used to induce chaotic and shear mixing, respectively. It was demonstrated that for PP/PA6 blend, the PA6 domains were transformed from large particles to short striations and to small droplets finally in shear mixing, whereas morphology of PA6 phase developed from lamellar layers to a partial continuous structure finally in chaotic mixing. For (PP/clay)/PA6 blend nanocomposite, the PA6 domains were deformed gradually from droplets to irregular fibrils in shear mixing and from short layers to thin fibrils in chaotic mixing. The PA6 fibrils formed finally in the latter were much thinner and uniform than those in the former. The dynamic storage moduli of samples prepared in both shear and chaotic mixing with these PA6 fibrils presented a solid-like response at lower frequencies. Moreover, the clay platelets dispersed initially in the PP phase migrated into PA6 phase finally in both shear and chaotic mixing and the exfoliation of clay platelets in PA6 phase was obviously improved in the latter.