VOLUME-DEPENDENT RATE-PROCESSES IN AN EPOXY-RESIN

Results for four different volume-dependent rate processes of an epoxy resin, Epon 1001F, fully cured with a stoichiometric amount of 4,4'-diamino diphenyl sulfone are presented: (1) specific volume measurements at constant rates of cooling; (2) time-dependent volume measurements after rapid temperature changes; (3) elongational creep compliance measurements; and (4) shear creep compliance measurements. Voluminal and shear retardation spectra are compared as are the temperature time scale shift factors, a(T) obtained from the four processes. Volume-temperature cooling curves show the decreasing glass temperature with decreasing rate of cooling, but appear to reach the glass line at a constant temperature regardless of the rate of cooling. This narrowing of the "transition range" is not predicted by the Kovacs, Aklonis, Hutchinson, and Ramos (KAHR) multiparameter model, which assumes thermorheological simplicity.