||Effects of acid deposition on painted wood substrates /
Balik, C. M. ;
Fornes, R. E. ;
Gilbert, R. D. ;
Williams, R. S.
||North Carolina State Univ. at Raleigh. ;Forest Products Lab., Madison, WI.;Environmental Protection Agency, Research Triangle Park, NC. Atmospheric Research and Exposure Assessment Lab.
|| U.S. Environmental Protection Agency, Office of Research and Development, Atmospheric Research and Exposure Assessment Laboratory,
||EPA/600/3-89/066; EPA-R-814166; EPA-R-814121
Acid deposition--Environmental aspects ;
Ultraviolet radiation ;
Sulfur dioxide ;
Alkyd resins ;
Calcium carbonates ;
Zinc oxides ;
Sulfurous acid ;
Air pollution effects(Materials) ;
||Some EPA libraries have a fiche copy filed under the call number shown.
||48 pages ; 28 cm
The research program identifies early failure processes associated with acidic deposition on painted wood substrate systems. Effects that have been observed during short term accelerated exposure studies are as follows: FTIR, NMR, and Sol-gel analysis indicate that SO2 attacks the base terpolymer of latex polymeric coating in the presence of UV radiation. The polymer is stable upon exposure to SO2 alone, either gaseous or aqueous as sulfurous acid. Sulfurous acid diffuses through both oil-alkyd and latex coatings and can degrade lignin of the wood substrate. Field and laboratory studies indicate that CaCO3 and ZnO are removed from latex paints during exposures. The removal rate decreases with increasing pH. Discoloration or yellowing of CaCO3 containing paints on wood substrates has been observed after three months field exposure. Based on the findings, it is recommended that research be continued to develop dose response relationships for the effects of acid deposition on coated wood substrate systems.
"J.W. Spence, project officer." "July 1989." "EPA/600/3-89/066." Microfiche.