Determination of the cure behavior by Dynamic Mechanical Analysis according ASTM D4473 for thermosetting resins.
Cure Behavior by Dynamic Mechanical Analysis determines the cure properties of thermosetting resins by isothermal heating or thermal ramping in an oscillatory mode. Properties such as elastic modulus (or storage modulus, G'), viscous modulus (or loss modulus, G''), complex modulus (G*), complex viscosity (n*) and damping coefficient (Tan D) as a function of temperature or time can be determined.
The test sample is dispensed between the movable and stationary parallel plate fixtures and then enclosed in the thermal chamber. Frequency, amplitude, and a temperature range which is appropriate for the material are input in the equipment. The analyzer applies torsional oscillation to the test sample while slowly moving through the specified program.
Typically several grams of thermosetting material is required. Typical specimen sizes include 8mm, 25mm and 50mm depending on the viscosity of the material.
Results are typically provided as a graphical plot of G', G'', G*, n* and Tan D versus temperature or time.
The intersection of the G’ and G” curves is defined as the Gel Point of the thermosetting resin system.
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