The present work provides better knowledge for composition analyses of the sludge and evaluates the best effective and economical treatment of petroleum sludge. In this respect, nonionic polymeric surfactants based on rosin were prepared by esterification of rosin with different molecular weights of polyethylene glycol (PEG 400, 600, 1000, 2000) to produce rosin ester surfactants. The esterified rosin was reacted with maleic anhydride followed by reaction with diaminobutane or triethylene tetramine to produce rosin-imide. The products were etherified with PEG 600 and PEG 2000 to produce rosin-imide ERID-1, ERID-2, ERIT-1 and ERIT-2, which were characterized by FT-IR and (1)H-NMR analyses. The surfactants were tested as sludge dispersants from viscosity measurements of sludge crude oil mixtures at different times. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 183-192, 2011