Significance and Use
5.1 This method provides a simple means of characterizing the cure behavior of a thermosetting resin specimen that is a representation of a composite part. The diameter of the specimen is approximately 38 mm and the thickness ranges from 2.6 to 3.2 mm. This corresponds to a sample volume of approximately 3 to 4 cm3. The data may be used for quality control, research and development, and verifying the cure within processing equipment including autoclaves.
5.2 Dynamic mechanical testing provides a sensitive method for determining cure characteristics by measuring the elastic and loss moduli as a function of temperature or time, or both. Plots of cure behavior and tan delta of a material provide graphical representation indicative of cure behavior under a specified time-temperature profile. The presence of fibers within the resin may change the dynamic properties measured within a material. However, it is still possible to compare different resins with the same fiber structure and obtain the relative difference due to the resin cure properties.
1.1 This method covers the use of dynamic mechanical instrumentation for determination and reporting of the thermal advancement of cure behavior of thermosetting resin on an inert filler or fiber in a laboratory. It may also be used for determining the cure properties of filled resins and resins without reinforcements. These encapsulated specimens are deformed in torsional shear using dynamic mechanical methods.
1.2 This method is intended to provide means for determining the cure behavior of thermosetting resins on fibers over a range of temperatures from room temperature to 250°C by forced-constant amplitude techniques (in accordance with Practice D4065). Plots of complex modulus, complex viscosity, and damping ratio or tan delta as a function of time or temperature, or both, quantify the thermal advancement or cure characteristics of a resin or a resin on fiber.
1.4.1 Exception—The fahrenheit temperature measurement in 10.1 is provided for information only and is not considered standard.