Date of Thesis
Polymer processing techniques make and shape many of the products we use in our daily lives. Solid-state shear pulverization (SSSP) is a novel extrusion technique that has been shown to produce materials that have been historically difficult to manufacture, and has opened a new door to unique polymer products. The process employs cold temperatures and pulverizes solid plastics into fine powders, achieving morphological changes and physical property improvements via mechanochemical reactions. These reactions, along with concurrent solid-state interactions, generate a significant amount of heat. The interplay of this heat and cooling by the instrument formulates a unique heat transfer setting. Understanding the intricate heat transfer phenomena in SSSP should rely on quantitative modeling, rather than trial-and-error methodologies. Previous modeling studies of similar extrusion systems have applied continuum mechanics as the basis, simultaneously considering the transfer of momentum, heat, and mass. Solving the balance equations leads to the development of functions that describe velocity and temperature within a given system. This thesis applies the modeling techniques of continuum mechanics to SSSP with the goal of quantifying heat transfer characteristics within the extruder system. First, profiles of velocity for the varying screw element types are developed. The resulting velocity profiles suggest flow within the extruder is a combination of drag and pressure flows. Then, temperature profiles are constructed for each element type. The profiles describe the behavior of temperature within a single screw element, and show that the system is of Graetz type flow. This study provides the necessary tools for compiling a temperature profile that describes the entire extruder, lending insight into the process parameters and material properties that are significant to the generation and removal of heat in the system.
heat transfer, momentum transfer, twin screw extrusion
Bachelor of Science in Chemical Engineering
James E. Maneval
Miu, Evan Vincent, "Modeling Transport Phenomena in Solid-State Polymer Processing" (2016). Honors Theses. 352.