Nine lignin fractions from bamboo (Dendrocalamus brandisii) were sequentially isolated with hot water at 80, 100, and 120 degrees C for 3 h and 60% aqueous ethanol containing 0.25, 0.5, 1.0, 2.0, 3.0, and 5.0% NaOH at 80 degrees C for 3 h. Molecular weight and purity analysis revealed that the lignin fractions isolated by hot water (L1, L2, and L3) had lower weight-average molecular weights (between 1350 and 1490 g mol-1) and contained much higher amounts of associated hemicelluloses (between 9.26 and 22.29%), while the lignin fractions isolated by alkaline aqueous ethanol (L4, L5, L6, L7, L8, and L9) had higher weight-average molecular weights (between 2830 and 3170 g mol-1) and contained lower amounts of associated hemicelluloses (between 0.63 and 1.66%). Spectroscopy (UV, FTIR, 13C-NMR, and HSQC) analysis showed that the bamboo (Dendrocalamus brandisii) lignin was typical grass lignin, consisting of p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) units. The major interunit linkages presented in the alkaline aqueous ethanol extractable bamboo lignin were beta-O-4' aryl ether linkages (about 74.3%), followed by beta-beta' resinol-type linkages and beta-1' spirodienone-type linkages (both for 7.8%), together with small amounts of beta-5' phenylcoumaran (6.8%) and p-hydroxycinnamyl alcohols end groups (3.1%). In addition, a small percentage (1.0%) of the lignin side-chain was found to be acetylated at the ?-carbon, predominantly over syringyl units. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012