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Cysteic acid is the chemical mediator of automotive clearcoat damage promoted by dragonfly eggs
Author(s) -
Stevani Cassius V.,
Liria Cleber W.,
Miranda M. Terêsa M.,
Bechara Etelvino J. H.
Publication year - 2001
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1584
Subject(s) - cysteic acid , chemistry , cystine , hydrogen peroxide , cysteine , hydrolysis , polymer chemistry , organic chemistry , enzyme
Abstract The damage caused by dragonfly eggs on automotive clearcoats exposed to sunlight occurs by a chemical mechanism similar to that caused by acid rain. Cysteine and cystine residues present in dragonfly eggs are oxidized during the egg hardening process, which releases hydrogen peroxide, to a cysteic acid derivative, a strong acid capable to catalyze the hydrolysis of acrylo/melamine clearcoat polymer. Cysteic acid was indeed identified and quantified by ion‐exchange HPLC in dragonfly egg extracts submitted to oxidation by H 2 O 2 followed by acid digestion. Moreover, H 2 O 2 concentration, temperature, and exposure time profiles of cysteic acid formation as well as an apparent activation energy for cysteine (in dragonfly eggs) oxidation to cysteic acid by H 2 O 2 (32 ± 2 kJ/mol) were determined. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1549–1554, 2001