Cellulose nitrate-acetate mixed esters (CNA) were synthesized by nitration of cellulose diacetate, using HNO(3)/H(2)SO(4) as nitration agent. The CNA structures were confirmed and analyzed by IR and (1)H NMR. A decrease in molecular weight and an increase in nitrate group content were observed with increasing H(2)SO(4) ratio and reaction time. The highest degree of nitrate substitution, 9.2%, for CNA was achieved with the reaction time of 6h in concentrated HNO(3). Increasing HNO(3) ratio in nitration media resulted in more thermally stable CNA. CNA fibers were prepared by altering the polymer concentration from 15 to 30% in an 85:15 (w/w) acetone:water solvent. The electrospun CNA fibers were characterized by SEM to investigate the influence of different NO(2)% on fiber formation, diameters and architectures. (C) 2010 Elsevier Ltd. All rights reserved.