Effect of Different Drying Methods on PPESK Carbon Membrane

The carbon membranes derived from the PPESK precursor in CHCl3 solvent for gas separation were pre-pared with freezing and refrigeration drying methods.The influences of drying methods on the structure and gas sepa-ration performance of PPESK carbon membranes were investigated.FTIR,TG,XRD and gas permeation tests were used to characterize the change of chemical and carbon structure and gas separation properties of carbon mem-branes prepared with different drying methods.The result indicated that the effects of drying methods on the struc-ture and performance of PPESK carbon membranes are to promote the precursor to form a polymeric membrane with the different chemical structure during the drying and make the chemical structure of derived polymeric mem-branes change in different ways during the later preoxidation and carbonization.Compared with refrigeration drying,the freezing drying weakened decomposition reaction and promoted condensation reaction during preoxidation and carbonization.As a result,the frozen membrane exhibited a better gas separation performance with a good flexility due to its dense microstructure.The freezing drying was the optimum way to prepare PPESK carbon membranes using CHCl3 as solvent.