Time dependent solid-state 13C NMR study on alkaline hydrolysis of polyacrylonitrile hollow fiber ultrafiltration membranes

► Hydrolysis of PAN UF membrane in an alkaline solution. ► The hollow fiber membrane is treated at a pH 13 alkaline condition. ► Time-dependent solid-state 13C NMR spectra are analyzed. ► Two distinct rates in the conversion of the cyano groups. ► A rapid conversion on or near the membrane surface and a slow conversion of the bulk.