Glass transition temperature of a fluoroelastomer-diluent system

The glass transition temperature has been measured carefully for the fluoroelastomer, Tecnoflon, a copolymer of vinylidene fluoride and hexafluoropropene, diluted with variable amounts of 2‐butanone. Of the several different theoretical treatments found in literature, that presented by Gordon and coworkers appears to give the equation that describes well the experimental results, without making use of adjustable parameters. Some features found at very high diluent content can be interpreted with a treatment based on free volume.