Applicability of infrared spectroscopy for sealant degradation studies

The degradation under various accelerated weathering conditions of one and two part polyurethane, one and two part polysulphide was studied using FTIR spectroscopy. Sealants cast in rectangular aluminium moulds were exposed to various accelerated weathering conditions. FTIR spectra and elastic recovery were monitored up to 35 days. For polyurethane (one and two parts), the FTIR spectra show that the degradation of sealant as indicated by the reduction of elastic recovery could be due to hydrolysis of urethane linkage and chain degradation. On the other hand, polysulphide (one and two parts) degraded extensively with the formation of epoxy ring and broadening of CH2 deformation band indicating chain degradation.