Producing Microlayer Pipes and Tubes through Multiplication Coextrusion and Unique Annular Die: Simulation and Experiment

Abstract

Traditional tubular structures with multilayer annular structures (MAS) are limited in the number of layers; as a result of fewer layers, the layers are typically thick, rigid, and unsuitable for many tubular applications. An advanced technique to produce MAS with layer numbers up to 2048 and individual layer thickness remaining low to a few micrometers is successfully designed here. Planar multilayers with high layer numbers were first produced via a flat-die layer multiplication coextrusion, followed by being shaped into an annular structure by using a custom-made annular die that is designed with the aid of numerical simulation. Experimental verifications show that the microlayer pipes with layer numbers up to 2048 and uniform thickness on the circumference can be readily produced by using this advanced technique. Therefore, this work may provide a valuable solution to develop the processes and equipment for tubes with microlayer structures.