Durability evaluation of building sealants by accelerated weathering and thermal analysis

Accelerated weathering tests, exposure to heat (80 °C) and UVA ultraviolet radiation (300 W), were carried out respectively on two selected building sealants, silicone and polyurethane, in this paper. A quantificational term, deviation coefficient, was proposed to rationally evaluate the sensitivity of sealants to the different weathering conditions and sealants’ durability. The study has shown that the weathering period should be at least 5000 h in order to let distinct change on sealants’ property occur. The study has also proved that different weathering conditions have completely different influences on the properties and structures of sealants, and thermogravimetry and differential scanning calorimetry could verify their ageing mechanisms.