Title: Optimization of Cure Cycles Using an ESR (Encapsulated Sample Rheometer)
Authors: Richard Hanzlik, Henry Pawlowski and Louis C. Dorworth
Abstract: One of the most critical steps in the production of composite material product is the cure cycle. The recommended cure cycles are usually provided by the prepreg suppliers. These cycles are often adjusted by trial and error until optimum final product properties are achieved. Operating an autoclave or oven while simultaneously measuring material properties can prove difficult due to size and cost restraints. The introduction of the ESR (encapsulated sample rheometer), which meets the ASTM 7750, has provided a cost-effective method to cure composite materials under any cure cycle necessary. In addition, the ESR is capable of measuring gel, cure, and final physical properties from those conditions1. This paper evaluates ESR simulated cure cycles with varying temperature ramps and hold temperatures, time at temperature, and the application of pressure while measuring the inherent cure properties of several resin and fiber packages. These simulations lead to the conditions for the optimum full cure. Next, the physical properties were measured and compared at the same temperature to determine the impact of cure conditions on the final product. Comparison of physical properties and Tg leads to optimization of the process, thus balancing efficiency and ensuring reliable material properties.
References: 1. H. Pawlowski, T. Rose; “Improving the Measurement of prepreg Viscosity, Gel, and Cure Using an Encapsulated specimen rheometer” 2. DIN53529 Measurement of Vulcanization Characteristics 3. Borchardt, H.J.; Daniels, F.J., Am. Chem. Soc. 1956, 79, 41 4. ASTM Volume 15 D7750-12 5. Soltani, A Seyed, “Properties of a CFRPC Cured at Staged Cure Cycles” 21-24
Conference: SAMPE 2020 | Virtual Series
Publication Date: 2020/06/01
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