Aspartic acid is prepared chemically or by the fermentation of carbohydrates. Currently, low molecular weight polyaspartic acids are prepared commercially by heating aspartic acid at high temperatures (>220 degrees C) for several hours in the solid state. In an effort to develop a more rapid, Continuous, melt polymerization scheme, aspartic acid was copolymerized with adipic, azelaic, sebacic, and dodecanedioic acids using a vented twin-screw extruder. Copolymers having ratios of aspartic/diacid <= 16 and M,, LIP to 9100 were prepared at temperatures of 240-260 degrees C and residence times of only about 5 min. M-w generally increased with aspartic/diacid ratio but melt viscosities became very high and processing became difficult at ratios >16. Most of the copolymers exhibited inhibition of calcium carbonate precipitation at concentrations similar to that Of pure polyaspartic acid and thus may find application as antiscalants. (C) 2008 Wiley, Periodicals, Inc. J Appl Polym Sci 110: 3348-3354, 2008