Process Development of CO2-Assisted Polymer Compression for High Productivity: Improving Equipment and the Challenge of Numbering-Up

The CO2-assisted polymer compression method is used herein to prepare porous polymer materials by bonding laminated polymer fiber sheets using a piston in the presence of CO2. In this work, the CO2 flow line connections were moved from the pressure vessel to the piston to increase productivity, which makes the pressure vessel free-moving and the processing time of sample introduction and removal seemingly zero. In addition, a numbering-up method suitable for CO2-assisted polymer compression is proposed and verified based on the variability of the products. The variability of the product was evaluated using porosity, which is one of the most important properties of a porous material. It is found that the CO2 exhaust process, specific to this method, that uses high-pressure CO2, causes product variation, which can be successfully suppressed by optimizing the CO2 exhaust process.