Mechanism of acid rain etching of acrylic-melamine coatings

Citation
K. Mori et al., Mechanism of acid rain etching of acrylic-melamine coatings, PROG ORG C, 36(1-2), 1999, pp. 34-38
Citations number
3
Language
INGLESE
art.tipo
Review
Categorie Soggetti
Material Science & Engineering
Journal title
PROGRESS IN ORGANIC COATINGS
ISSN journal
0300-9440 → ACNP
Volume
36
Issue
1-2
Year of publication
1999
Pages
34 - 38
Database
ISI
SICI code
0300-9440(199906)36:1-2<34:MOAREO>2.0.ZU;2-1
Abstract
Sulfuric acid distribution in acrylic-melamine coatings immersed in 70 wt.% sulfuric acid at 60 degrees C was examined with an electron probe microana lyzer. Melamine derivatives extracted from the coatings were determined by UV spectra of the acid phase. It was found that the region containing the s ulfuric acid had a distinct boundary expanding at a constant rate and that the sulfuric acid extracted water-insoluble melamine derivatives. The extra ction rate was proportional to the permeation rate. These results indicate that the etching is caused by the extraction of the water-insoluble derivat ives by the concentrated sulfuric acid and that the diffusion of sulfuric a cid molecules at the boundary is controlled by hydrolysis of cross-links. ( C) 1999 Elsevier Science S.A. All rights reserved.