Redox polymerization of poly(acrylonitrile-co-acrylic acid) (poly(AN-co-AA)) is performed at 40 °C under N2 gas by varying the ratio of acrylonitrile (AN) and acrylic acid (AA) in the feed. The yield production of poly(acrylonitrile) (PAN) is 73% and poly(AN-co-AA) with a feed ratio of 93:7 is the highest yield (72%). The PAN and poly(AN-co-AA) are further chemically modify with hydroxylamine hydrochloride. The FTIR spectroscopy is used to confirm the copolymerization of poly(AN-co-AA) and chemical modification of poly(AN-co-AA). Elemental microanalysis shows that the overall trend percentage of carbon, hydrogen, and nitrogen for all feed ratios are slightly decreasing as the feed ratio of AA is increasing except for poly(AN-co-AA) 93:7. The SEM images shows that spherical diameter of poly(AN-co-AA) is smaller compared to the PAN and amidoxime (AO) OPEN ACCESSPolymers 2015, 7 1206 modified poly(AN-co-AA). The TGA (thermogravimetric analysis) analysis reveals that the poly(AN-co-AA) degrades at lower temperatures compared to the PAN but higher than AO modified poly(AN-co-AA). The case study adsorption test showed that the AO modified poly(AN-co-AA) 93:7 had the highest percentage removal of Cd 2+ and Pb 2+.