Effects of water vapor on poly(vinyl butyral) ceramic binder burnout

The effects of water vapor on non-oxidative poly(vinyl butyral) functional group decomposition mechanisms are described. Species-specific evolution pr ofiles obtained by mass spectrometric analysis of gases evolved while heati ng silica, mullite, and alpha-alumina coated with poly(vinyl butyral) binde r show that volatile product yields are affected by the presence of water v apor. When water vapor is incorporated into binder burnout atmospheres, ace tic acid yields increase and C4H6O yields decrease. Acetic acid yields incr eased because water vapor interacted with oxide basic sites that otherwise reacted with acetic acid to form carboxylate species. Water vapor also inhi bits C4H6O formation, possibly by stabilizing a polar intermediate produced during side group cleavage reactions. (C) 2000 Kluwer Academic Publishers.