Blends containing core-shell impact modifiers - Part 2. Melt rheology of rubber-toughened plastics (IUPAC technical report)

The influence of impact modifiers composed of an elastomer-based core and a poly(methyl methacrylate) (PMMA) shell on the melt flow properties of diff erent thermoplastics has been studied, using both steady-state and dynamic viscosity measurements. The melt viscosities of the rubber-toughened blends were similar to those of the matrix polymers, over the range of shear rate s commonly applied during melt processing. In the case of the matrix polyme rs, viscosity curves obtained under dynamic conditions coincided with those obtained under steady-state conditions. However, for blends the two curves show a slight divergence at low strain rates, where yielding is observed.