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.
5.3 This method can be used to assess the following:
5.3.1 Cure behavior, as well as changes as a function of temperature or time, or both,
5.3.2 Processing behavior, as well as changes as a function of temperature or time, or both,
5.3.3 The effects of processing treatments,
5.3.4 Relative resin behavioral properties, including cure behavior, damping and impact resistance,
5.3.5 The effects of reinforcement on cure.
5.3.6 The effects of materials used to bond the resin and reinforcement,
5.3.7 The effect of formulation additives that might affect processability or performance.
5.4 This provides a method to assess the cure properties of a thermosetting resin containing woven fiber or other reinforcing materials.
5.5 This method is valid for a wide range of oscillation frequencies typically from 0.002 to 50 Hz.
Note 1: It is recommended that low-frequency test conditions, generally 1 to 2 Hz, be used to generate more definitive cure-behavior information. Slower frequencies will miss important cure properties. Faster frequencies will reduce sensitivity to cure.
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 ). 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.
1.3 Test data obtained by this method is relevant and appropriate for optimizing cure cycles.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4.1 Exception—The fahrenheit temperature measurement in is provided for information only and is not considered standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.