Vapor pressure by dsc: pinhole size and peak shape

摘要

In 1996, ASTM E 1782-96, Standard Test Method for Determining Vapor Pressure by Thermal Analysis received final approval and was published as a standard method. For vapor pressure measurements by DSC, the method recommends use of hermetic-type sealable pans with a single 50 #mu# to 75 #mu# pinhole in the center of the lid. Pinholes of this size produce generally acceptable results over the 5 kPa to 2 MPa operational pressure range of the method. However, as the minimum recommended pressure is approached, boiling endotherms become increasingly broad.