*2.1. Materials*

Low molecular weight Chitosan was purchased from Sigma Aldrich. The chitosan samples were dipped in deionized (DI) water for at least 30 min before subjected to ACC treatment. Softwood bleached kraft pulp was received from Chungnam National University, Daejeon, South Korea. 2,2,6,6-tetramethylpiperidine-1-oxylradical (TEMPO 98%), sodium bromide (NaBr 99%) and hydrochloric acid (HCl 37%) were purchase from Sigma-Aldrich, St. Louis, MO, USA. Sodium hypochlorite solution (NaClO 12%) was purchase from Yakuri Pure Chemicals Co. Ltd. Uji, Japan. Sodium hydroxide anhydrous (NaOH 98%) was purchase from Daejung, South Korea.
