Mechanical properties of PP-LDPE blends with novel morphologies produced with a continuous chaotic advection blender

When immiscible polymer melts are combined by chaotic advection, melt domains are recursively stretched and folded. A multi-layer blend morphology results that has a hierarchical structure and intrinsic mechanical interlocking. Novel derivative morphologies can be obtained via the formation and interactive growth of holes among melt layers. In this study, a unique continuous chaotic advection blender (CCAB) was used to investigate influences of these morphologies on tensile and impact toughness properties of polypropylene (PP)-low density polyethylene (LDPE) blends. Although prior related work has focused on batch processing, this study also demonstrated the viability of chaotic advection in continuous flow modes suited for extruding blends with target morphologies. Extrusions were producible with morphologies giving an overall combination of improved properties relative to properties associated with droplet morphologies typically obtained with conventional compounding equipment. Applicability to injection molding is also discussed. Novel processing control features of the CCAB-type devices are briefly described.