Studies On Operating Parameters Of The Preparation Of Polymer Using Supercritical CO₂

In order to ulteriorly solve problem that the porous material has too low open porosity and the utilization ratio of materials is low by the conventional supercritical CO2 decompressed method at constant temperature and constant pressure. In this researeh, one new method is firstly put forward to fabrieate porous PMMA by supercritical CO2 which is a unconventional continuous heating combining pressure discharge time after time after CO2 injection once decompressed method. The main researeh is focused on the influence of the different component pressure on the inner conditions, size of the pore, apparent density, porosity, cell density, mechanical capacity of the porous material. We compared conventional decompressed method and improved decompressed proeess by investigating the effects of the inner conditions, mechanical capacity, foaming time and detailed specifications of materials.The results show:when pressure is 25 MPa, pressure discharge time is 14 min, temperatures is 100℃, porous PMMA has been formed by improved decompressed proeess in 6 h with cell mean diameter 22.2～45.2μm, apparent density 0.12～0.24 g·cm-3, porosity 80～90 %, cell density 2×104～5.4×105 mm-3, and compared to cell mean diameter 41.2μm, apparent density 0.29 g·cm-3, porosity 75%, cell density 1.9×104 mm-3 of porous PMMA foamed by conventional decompressed method in 8 h, not only the cell mean diameter of porous PMMA foamed by improved decompressed proeess included the latter, but also the foaming magnification of porous PMMA foamed by improved decompressed proeess and material utilization are more higher, experimental time and energy consumption are less than conventional decompressed method. Homogeneous porous PMMA has been formed by improved decompressed proeess, and its connectivity of pores, preparation efficiency, material utilization and energy consumption are better than conventional decompressed method.