Research Chemist, Christopher White and his colleagues at the National Institute of Standards and Technology in Gaithersburg, Maryland have developed a new equipment to test sealants under real weather conditions.
According to existing methods, the sealants are tested statically by exposing them outdoors for substantial amount of time to gauge their resistance to the surroundings. White stated that the contraction and expansion induced by temperature on different types of materials, such as steel and glass in the building frame and window joined together by sealants, affect the sealants even under normal conditions. When sealants are used on a building to seal a gap, contraction and expansion of steel and glass occur at different rates with respect to the temperature change. These changes produce weariness in the sealant, which eventually breaks and falls, he said.
The research team used simple materials such as toilet flanges, steel supporting frames, wood and PVC pipe to develop the new equipment. They used sensors to monitor the load and dislocation of the sealants and a weather station to monitor the surrounding conditions.
White stated that the new equipment replicates the same movement like the sealant experiences on a building. The team has designed two instruments. One device places sealants in compression during cold and other places sealants in tension mode.
Source: http://www.aip.org