The goal of this research is to develop a prototype of a continuous manufacturing process for microcellular plastics. A microcellular plastic is characterized by cell densities greater than 109 cells/cm3 and fully grown cells smaller than 10 μm. Microcellular structures have been produced in batch processes by using a thermodynamic instability to promote a large bubble density in polymer/gas systems. In order to utilize such a thermodynamic instability in a continuous process, two major process steps must be performed:​ a) continuous formation of a polymer/gas solution, and b) microcell nucleation by a thermodynamic instability in the polymer/gas solution. The basic strategy for the process design is to integrate these two steps into a process such that the functions of the overall process are independently satisfied.

The aims of the research are threefold. The first is to develop a means for continuous formation of the polymer/gas solution at an industrial processing rate by creating the super gas concentration in the polymer. The second is to promote a high bubble nucleation rate in the gas-saturated polymer by making use of the thermodynamic behavior of polymer/gas systems. The third is to develop a process model for controlling the cell morphology by identifying the central parameters of polymer/gas solution formation and cell nucleation. An extrusion process for manufacturing filamentary microcellular plastics is presented as a case study. This research includes not only the basic science of the polymer/gas systems, but also the development of an industrially viable technology that exploits the full potential of the unique properties of microcellular plastics.