Sodium polyaspartate

Sodium polyaspartate is a condensation polymer based on the amino acid aspartic acid.

Polymerization

The polymerization reaction is an example of a step-growth polymerization to a polyamide and in one practical procedure[1] aspartic acid is simply heated to 180 °C resulting in water release and the formation of a poly(succinimide) with succinimide repeating units. In the subsequent step this polymer is reacted with sodium hydroxide in water which results in partial cleavage of the amide bonds. Two different bonds (α and β) are hydrolyzed resulting in a sodium poly(aspartate) copolymer with 30% α-linkages and 70% β-linkages.

Uses

This material can be synthesized in an environmentally friendly way and is biodegradeable, thus it is a green alternative to several materials such as sodium polyacrylate used in disposable diapers and agriculture.[2][3]

In addition and due to its water-solubility and ability to chelate metal ions, polyaspartate is used as a biodegradeable anti-scaling agent and a corrosion inhibitor.[4][5]

References

  1. ^ Bennett GD (2005). "A Green Polymerization of Aspartic Acid for the Undergraduate Organic Laboratory" (Abstract). J. Chem. Educ. 82 (9): 1380–1381. doi:10.1021/ed082p1380. http://jchemed.chem.wisc.edu/Journal/Issues/2005/Sep/abs1380.html. 
  2. ^ Gross, R. A.; Kalra, B. (2002). "Biodegradable Polymers for the Environment". Science 297 (5582): 803–807. Bibcode 2002Sci...297..803G. doi:10.1126/science.297.5582.803. PMID 12161646. http://www.sciencemag.org/cgi/content/abstract/297/5582/803. 
  3. ^ "Presidential Green Chemistry Challenge Awards: 1996 Small Business Award: Donlar Corporation (now NanoChem Solutions, Inc.): Production and Use of Thermal Polyaspartic Acid". US Environmental Protection Agency. http://www.epa.gov/greenchemistry/pubs/pgcc/winners/sba96.html. 
  4. ^ Low, K. C.; Wheeler, A. P.; Koskan, L. P. (1996). Commercial poly(aspartic acid) and Its Uses. Advances in Chemistry Series. 248. Washington, D.C.: American Chemical Society. 
  5. ^ Thombre, S.M.; Sarwade, B.D. (2005). "Synthesis and Biodegradability of Polyaspartic Acid: A Critical Review". Journal of Macromolecular Science, Part A 42 (9): 1299–1315. doi:10.1080/10601320500189604. http://www.informaworld.com/index/718581646.pdf.