Suppression of phase coarsening in immiscible, co-continuous polymer blends under high temperature quiescent annealing

Abstract

The properties of polymer blends greatly depend on the morphologies formed during processing, and the thermodynamic non-equilibrium nature of most polymer blends makes it important to maintain the morphology stability to ensure the performance stability of structural materials. Herein, the phase coarsening of co-continuous, immiscible polyamide 6 (PA6)-acrylonitrile-butadiene-styrene (ABS) blends in the melt state was studied and the effect of introduction of nano-silica particles on the stability of the phase morphology was examined. It was found that the PA6-ABS (50/50 w) blend maintained the co-continuous morphology but coarsened severely upon annealing at 230 °C. The coarsening process could be divided into two stages: a fast coarsening process at the initial stage of annealing and a second coarsening process with a relatively slow coarsening rate later. The reduction of the coarsening rate can be explained from the reduction of the global curvature of the interface. With the introduction of nano-silica, the composites also showed two stages of coarsening. However, the coarsening rate was significantly decreased and the phase morphology was stabilized. Rheological measurements indicated that a particle network structure was formed when the concentration of nano-silica particles was beyond 2 wt%. The particle network inhibited the movement of molecular chains and thus suppressed the coarsening process.

Structure development in co-continuous polymer blends filled with carbon black during annealing

“…3). This is in agreement with the recent findings of Liu [3] on co-continuous PA/ABS blends filled with nanosilica. These experiments also confirms the work of Elmendorp [10] who has found that the appearance of yield stress prevents grow of capillary instabilities which can be directly related to the coarsening rate.…”

“…Pronounced suppression of structure coarsening during annealing was observed in filled co-continuous blends with selective localization of the filler particles in one phase or at the interface [2,3]. Simultaneously, the value of percolation threshold is reduced as the filler is not distributed homogeneously in the material [4][5][6][7].…”

Phase structure, rheology and electrical conductivity of co-continuous polystyrene/polymethylmethacrylate blends filled with carbon black

“…Pronounced suppression of structure coarsening during annealing was observed in filled co-continuous blends with selective M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 localization of the filler particles in one component or at the interface [12][13][14].…”

“…The incorporation of fillers into a co-continuous polymer blend leads often to a refinement of blends structure and to a suppression of coarsening during quiescent annealing. These changes in the morphology development are explained by an increase in the viscosity of the component containing the filler [12] or by the formation of particle structures preventing the motion of polymer chains [13,26]. If the filler is localized at the interface, immobilization of the interface by filler particles and reduction of interfacial tension are other plausible explanations (see [22] for more details).…”

Conductivity and phase morphology of carbon black-filled immiscible polymer blends under creep: an experimental and theoretical study

“…After annealing at 200 1C for 600 s (Point b), the composite sample underwent phase morphology coarsening due to the minimization of interfacial free energy. [41][42][43][44] After the shear for 60 s (Point c), the domains were significantly deformed and appeared as elongated lamellar structures, indicating that the phase morphology deformed significantly after the application of the large shear. During the View Article Online recovery period the phase morphology changed from a highly elongated lamellar structure to a fine-range co-continuous structure (Point d).…”