You are here:
EFFECTS OF ACID DEPOSITION ON PAINTED WOOD SUBSTRATES
Citation:
Balik, C., R. Fornes, R. Gilbert, AND R. Williams. EFFECTS OF ACID DEPOSITION ON PAINTED WOOD SUBSTRATES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/3-89/066 (NTIS PB89220024), 1989.
Description:
This report describes the progress that has been made within the Coatings Effect Research Program that EPA conducts for Task Group VII within the National Acid Precipitation Assessment Program (NAPAP). The major objective of this phase of the research program is to identify 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: (1) FTIR, NMR, and Sol- gel analysis indicate that SO2 attacks the base terpolymer of latex polymeric coating in the presence of UV radiation. This polymer is stable upon exposure to SO2 alone, either gaseous or aqueous as sulfurous acid, (2) sulfurous acid diffuses through both oil-alkyd and latex coatings and can degrade lignin of the wood substrate, (3) field and laboratory studies indicate that CaCO3 and O are removed from latex paints during exposures. The removal rate decreases with increasing pH, and (4) 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.