Sodium polyaspartate

Sodium polyaspartate is a sodium salt of polyaspartic acid. It is biodegradable condensation polymer based on the amino acid aspartic acid.

Sodium polyaspartate
Names
IUPAC name
polyaspartic acid sodium salt
Identifiers
Properties
(C4H4NNaO3)n
Molar mass variable
Hazards
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
0
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

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). In the subsequent step, this polymer is reacted with sodium hydroxide in water, which hydrolyzes one of the two amide bonds of the succinimide ring to form a sodium carboxylate. The remaining amide bond is thus the linkage between successive aspartate units. Each aspartate unit is identified as α or β according to which carbonyl of it is part of the polymer chain. The α form has one carbon in the backbone in addition to the carbonyl itself (and a two-carbon sidechain) whereas the β form has two carbons in the backbone in addition to the carbonyl itself (and a one-carbon sidechain). This reaction gives a sodium poly(aspartate) copolymer composed of approximately 30% α-linkages and 70% β-linkages.

Synthesis of sodium poly(aspartate)

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]

See also

Polyaspartic acid


References
  1. Bennett GD (2005). "A Green Polymerization of Aspartic Acid for the Undergraduate Organic Laboratory". J. Chem. Educ. 82 (9): 1380–1381. Bibcode:2005JChEd..82.1380B. doi:10.1021/ed082p1380.
  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.
  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.
  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" (PDF). Journal of Macromolecular Science, Part A. 42 (9): 1299–1315. doi:10.1080/10601320500189604. S2CID 94818855.
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