Effect of Different Drying Methods on PPESK CarbonMembrane

The carbon membranesderived from the PPESK precursor in CHCl3solvent for gas separation wereprepared with freezing and refrigeration drying methods. The influences ofdrying methods on the structure and gas separation performance of PPESK carbonmembranes were investigated. FTIR, TG, XRD and gas permeation tests were used to characterize thechange of chemical and carbon structure and gas separation properties of carbonmembranes prepared with different drying methods. The result indicated that theeffects of drying methods on the structure and performance of PPESK carbonmembranes are to promote the precursor to form a polymeric membrane with thedifferent chemical structure during the drying and make the chemical structureof derived polymeric membranes change in different ways during the laterpreoxidation and carbonization. Compared with refrigeration drying, thefreezing drying weakened decomposition reaction and promoted condensationreaction during preoxidation and carbonization. As a result, the frozenmembrane exhibited a better gas separation performance with a good flexilitydue to its dense microstructure. The freezing drying was the optimum way toprepare PPESK carbon membranes using CHCl3 as solvent.