Esparto (Stipa tenacissima) grass, also called Alfa is the raw material for the manufacture of paper pulp in North Africa. To add value to one of its processing by-products, we aimed to develop lubricants from modified Soda-Lignin (SL), which could eventually compete with industrial lubricants such as zinc stearates. Linear low density polyethylene mixed formulations prepared with zinc stearate and each modified lignin was studied by rheological tests using a rotational parallel plate system to investigate the effects of such esterified SL additives. One type, made up of SL esterified with 100% stearic anhydride (W/W) was found to promote excellent external lubrication. The same result was confirmed by contact angle and thermal analysis. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 3003-3007, 2009