Application of ATR in characterizing aging conditions of polyurethane sealants

The effectiveness of using ATR to study the chemical structure of various p olyurethane formulations designed as joint sealants on building facades is discussed. Sealants were formulated, batched and exposed to various aging c onditions before mounted on ATR spectroscopy apparatus for monitoring. The study has shown that ATR is effective in characterizing the chemical struct ure in terms of physical cross-linking and conformation state. It is shown that although aging tends to occur in the surface section of a specimen it can contribute to the deterioration of the bulk mechanical properties. Sign ificant differences in the chemical structure of sealants in the surface se ction and the interior region after thorough curing was shown. (C) 2000 Els evier Science Ltd. All rights reserved.