Extension-dominated improved dispersive mixing in single-screw extrusion. Part 1: Computational and experimental validation

Extensional mixing elements (EMEs) were previously developed for twin-screw extruders (TSEs) to incorporate extensional flows through stationary single-plane or double-plane hyperbolic convergence–divergence channels. In Part 1 of this work, the EME concept is extended to single-screw extruders (SSEs), which are known for their good pumping characteristics but limited dispersive mixing capability, to enhance the latter. Flow simulations are performed to optimize the EME design for SSE. Experimental validations are performed on immiscible polymer blends (varying viscosity ratio) and nanocomposites. Morphological results show tremendous improvement in mixing capability of SSE when equipped with EME without significant throughput and pressure drop penalties. Rheological and crystallinity studies are observed to be in line with the morphological analysis. Morphological and mechanical results are benchmarked with TSE operations in Part 2 of this work.