Study of The Formation of a Porous Structure in Rubbers of Various Chemical Natures Using Supercritical Carbon Dioxide. Part 2. Influence of Technological Parameters

Abstract

Experimental results on the study of the effect of temperature and pressure in a high-pressure apparatus on the formation process and structure of porous elastomeric materials based on fluororubber obtained using supercritical carbon dioxide (SC-CO2) are presented. It is shown that an increase in temperature leads to a decrease in the degree of foaming and a certain increase in the pore size, which is explained by an increase in the diffusion coefficient of carbon dioxide in an elastomeric material with an increase in temperature. The structure of a porous material strongly depends on the rate of pressure relief. Rapid decompression can lead to the transition of carbon dioxide in a swollen polymer from a supercritical to a liquid state with the formation of a defective structure with a pore size of hundreds of microns. By adjusting the modes of technological parameters of foaming, elastomeric materials with pores ranging in size from tens to 100 microns can be obtained.