Sugarcane bagasse was esterified with acetic anhydride using N-bromosuccinimide as a catalyst under mild conditions in a solvent free system. The extent of acetylation was measured by weight percent gain, which varied from 2.1% to 24.7% by changing the reaction temperature (25-130 degreesC) and duration (0.5-6.0 h). N-Bromosuccinimide was found to be a novel and highly effective catalyst for acetylation of hydroxyl groups in bagasse. At a concentration of 1% of the catalyst in acetic anhydride, a weight percent gain of 24.7% was achieved at 120 degreesC for 1 h, compared with 5.1% for the un-catalyst reaction under the same reaction condition. FT-IR and CP-MAS C-13-NMR studies produced evidence for acetylation. The thermal stability of the products decreased slightly upon chemical modification, but no significant decrease in thermal stability was observed for WPG greater than or equal to 24.7%. More importantly, the acetylation significantly increased hydrophobic properties of the bagasse. The oil sorption capacity of the acetylated bagasse obtained at 80 degreesC for 6 h, was 1.9 times higher than the commercial synthetic oil sorbents such as polypropylene fibres. Therefore, these oil sorption-active materials can be used to substitute non-biodegradable materials in oil spill cleanup. (C) 2004 Elsevier Ltd. All rights reserved.