Comparison study of TEMPO and phthalimide-N-oxyl (PINO) radicals on oxidation efficiency toward cellulose

► The oxidation efficiency comparison between TEMPO and N-hydroxyphthalimide (NHPI) of viscose was studied. ► The amount of carboxylic groups formed is higher when NHPI was used as mediator. ► The best preservation of the fibers's morphology was observed when NHPI acts as mediator. ► TEMPO oxidation of viscose provides lower amount of carboxylic groups as compared with NHPI. ► TEMPO mediated oxidation of viscose leads to a higher depolymerization as compared with NHPI.